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This is to certify that the

dissertation entitled

EFFECTIVENESS OF A PROGRESSIVE RESISTANCE TRAINING
PROGRAM ON WORK PRODUCTIVITY AND MUSCULAR STRENGTH
AMONG ADULT MALES WITH MENTAL RETARDATION

presented by
Lorenzo Parker

has been accepted towards fulfillment
of the requirements for

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6/01 cJCIRC/DateDue.p65cp.15

 

EFFECTIVENESS OF A PROGRESSIVE RESISTANCE TRAINING PROGRAM ON
WORK PRODUCTIVITY AND MUSCULAR STRENGTH AMONG ADULT MALES
WITH MENTAL RETARDATION.

By

Lorenzo Parker

A DISSERTATION
Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of
DOCTOR OF PHILOSOPHY
Department of Kinesiology

2001

ABSTRACT
EFFECTIVENESS OF A PROGRESSIVE RESISTANCE TRAINING PROGRAM ON
WORK PRODUCTIVITY AND MUSCULAR STRENGTH AMONG ADULT MALES
WITH MENTAL RETARDATION
By
Lorenzo Parker

This study was designed to investigate the effects of a 9-week progressive
resistance-training program on work productivity and muscular strength among adult
males with mental retardation (MR). Data were collected on: (a) work productivity
using the simulated work tasks of hand-truck push and box stacking; (b) work
productivity using “on-site” work tasks (assembly work, dishwashing, mail sorting, and
custodian) in jobs that were held by the participants; and (c) muscular strength as
determined by one repetition maximum lifis using Nautilus, Universal, and Icarian
weight machines.

The research design used for this study was a single-subject ABA applied
behavior analysis that was replicated for each of four adult males with MR age 25 to 29
years. The participants' performance levels were assessed once every week during the 5-
week baseline, the 9-week treatment, and the 6-week retention periods. During the
treatment period, participants were involved in a twice-a-week progressive resistance-
training program using leg extension, leg curl, chest press, biceps curl, triceps extension,
and abdominal curl weight-fitting exercises. Front-lying chest lifis using the
participants’ body resistance were used for strengthening back muscles. The 9-week

intervention period was divided into 3 phases. The first phase lasted for a period of 2

weeks (4 Sessions) and included 2 sets of 12 repetitions of each of the 6 strength-training
exercises with low resistance of 30% to 40% of participants’ l-RM lifts. The second
phase of the intervention lasted for a total of 3 weeks (6 sessions) and involved lifting 3
sets of 8 repetitions of each exercise with a moderate increase in the amount of
resistance set at 50% to 60% of participants’ l-RM lift. The third and final phase of the
lifting program was 4 weeks (8 sessions) and included 4 sets of 6 repetitions of lifting
with an increased resistance of 70% to 80% of each participant's l-RM lifts.

Data were collected and visually analyzed using the split middle technique.
Visual analyses involved comparison of the participants’ celeration and trend lines of the
strength and work productivity data. Results indicated that participants showed
improvements in both muscular strength and the Simulated work tasks of box stacking
and hand truck push. It was concluded that participation in a 9-week resistance-training
program improved participants’ muscular strength on the simulated work tasks. The
results did not reveal significant improvements in productivity for the on-Site work tasks
as a result of increased strength. This may have been due to inadequate instrumentation
for assessing productivity at participants’ actual jobs. Recommendations for future

studies are also provided.

ACKNOWLEDGEMENTS

It has been a long journey. Much has been learned over the years. There are many
people to thank for the inspirations and the support I have gotten during my educational
endeavors. I want to start by thanking my mother, Katie McNealy, and grandmother,
F lorine Jackson who have backed me fi‘om day one during my studies at MSU. A heart-
felt thank you to my wife Beth, whom I adore dearly, she has given much of her time and
effort to make sure I had all the support I needed during my educational endeavors. I also
want to give my love to Samantha, my daughter; you have been an impetus for my final
push to completion. Daddy thanks you for playing so patiently and seeming to be so
understanding whenI needed the time to write. I would be remiss if I did not thank Gil
and Monica for being so willing to look after Samantha, so many early mornings. I am
also very appreciative to my advisor, Dr. Gail M. Dummer, who has been patient and has
given me a great deal of support and assistance, by putting up with all those edits. I
immensely respect your professionalism over the past years. My completion would not
have been possible without your assistance. I must also extend thanks to other faculty
members, Dr. Martha Ewing, Dr. Lynette Overby, Dr. Eugene Pemell, and Dr. Yevonne
Smith, for their support and guidance. Thanks also to Dr. Jim Rimmer for his advice and
guidance. I would like to extend a Special thank you to my participants, their parents, and
those who allowed me to use their facilities during my study. Lastly, a special thanks
goes out to my friends Drew, Geff, Ivy, and James for their encouragement and support.

I will always be indebted to all of you.

iv

TABLE OF CONTENTS

Page
LIST OF TABLES ....................................................................................................... viii
LIST OF FIGURES ......................................................................................................... x
CHAPTER 1
INTRODUCTION ........................................................................................................... 1
Purpose of the Study ................................................................................................... 4
Need for the Study ...................................................................................................... 4
Hypotheses ................................................................................................................. 7
Assumptions .............................................................................................................. 8
Limitations ................................................................................................................. 8
Definition of Terms .................................................................................................... 9
CHAPTER 2
LITERATURE REVIEW .............................................................................................. 11
Importance of Employment for Persons with Mental Retardation. ............................. 11
Muscular Strength and Job Maintenance ................................................................... 16
Strength Characteristics among Persons with Mental Retardation ............................. 19
Strength Gains for Persons with Mental Retardation ................................................ 20
Muscular Strength and Work Productivity ................................................................ 23
Implications of the Literature for this Study .............................................................. 25
CHAPTER 3
METHODS .......................................................................................................... 27
Research Design ....................................................................................................... 27
Justification for the Design ....................................................................................... 28
Participants ............................................................................................................... 34
Recruitment of Participants .................................................................................. 34
Informed Consent ................................................................................................ 35
Participant Sample ............................................................................................... 35
Orientation Sessions ................................................................................................. 38
Test Administration ............................................................................................. 39
Baseline Measures of the Dependent Variables ......................................................... 41
Simulated Work Tasks ......................................................................................... 43
On-site Work Tasks ............................................................................................. 44
Muscular Strength Exercises ................................................................................ 45
Intervention .............................................................................................................. 51
Resistance Training Protocol ................................................................................ 51
Typical Intervention Setting ................................................................................. 52
Safety Precautions ............................................................................................... 54

Page

Data Collection Procedures ....................................................................................... 55
Testing Schedule .................................................................................................. 56
Testing Personnel ................................................................................................. 57

Data Analyses ........................................................................................................... 57
Visual Inspection of the Data ............................................................................... 57
Statistical Analyses .............................................................................................. 58
Decision Rule for Effective Intervention .............................................................. 61

(HIAJVTEII4
IKESIHUTS ..................................................................................................................... 63

Hypothesis 1 ............................................................................................................ 63
Level and Trend Changes for Composite Strength ............................................... 66
Celeration Line for Composite Strength ............................................................... 72
Percent Performance Changes for Strength .......................................................... 79

Hypothesis 2 ............................................................................................................ 83
Comparison of Participants’ Hand-Truck Push Scores ......................................... 84
Level and Trend Changes for the Hand Truck Push Task ..................................... 85
Celeration Line for the Hand Truck Push Task .................................................... 92
Comparison of Participants’ Box Stacking Scores ................................................ 98
Level and Trend Changes for Box Stacking Task ............................................... 101
Celeration Line for Box Stacking Task .............................................................. 107
Percent Performance Changes for Simulated Work Tasks .................................. 115

Hypothesis 3 .......................................................................................................... 115
Shane ............................................................................................................. 117
Jacob ................................................................................................................ 119
Jun .................................................................................................................... 119
IBob .................................................................................................................... 127

CTLAPTTHtS
DISCUSSION ............................................................................................................. 130

EhnnufihtBahu; ........................................................................................................ 130
Non Disabled Persons ........................................................................................ 130
Persons with Mental Retardation ........................................................................ 131
Score Variability ................................................................................................ 132
Detraining Effects .............................................................................................. 134
Training Protocol and Equipment ...................................................................... 135

Performance on Simulated Work Tasks .................................................................. 138
Improvements on Simulated Work Tasks ........................................................... 139
Score Variability of Simulated Work Tasks ....................................................... 141
iLhnhafions ........................................................................................................ 142
bkuuneofthetiunuhued‘WknkaaSks .................................................................. 144

Improvements at On-site Work Tasks ..................................................................... 145
Instrumentation Concerns .................................................................................. 145
Performance Ratings .......................................................................................... 147

vi

Page

Conclusions and Recommendations ........................................................................ 148
Recommendations .............................................................................................. 150
APPENDIX A - Informed Consent ............................................................................. 153
Consent to Participate in a Weight Training and Work Task Study ......................... 154
Assent Form ........................................................................................................... 157
UCRIHS approval .................................................................................................. 158
APPENDIX B — Data Collection Forms ...................................................................... 159
Employment Observation Form .............................................................................. 160
Health History/Background Information Form ........................................................ 161
Work Task Data Performance Sheet ....................................................................... 162
Work Out Schedule ................................................................................................ 163
Work Performance Forms for On-site Job Tasks ..................................................... 165
APPENDIX C — The ABILITIES Index ...................................................................... 166
The Abilities Index ............................................................................................... 167
APPENDIX D — Data Files ......................................................................................... 173
Strength Data Files for Shane’s 1-RM Lifts for Baseline, Intervention,
and Retention ......................................................................................................... 174
Strength Data Files for Jacob’s l-RM Lifts for Baseline, Intervention,
and Retention ......................................................................................................... 175
Strength Data Files for Jim’s l-RM Lifts for Baseline, Intervention,
and Retention ......................................................................................................... 176
Strength Data Files for Bob’s l-RM Lifts for Baseline, Intervention,
and Retention ......................................................................................................... 177
Data Files for Shane’s Average Time for Completion of Simulated Work Tasks ..... 178
Data Files for Jacob’s Average Time for Completion of Simulated Work Tasks ..... 179
Data Files for Jim’s Average Time for Completion of Simulated Work Tasks ........ 180
Data Files for Bob's Average Time for Completion of Simulated Work Tasks ........ 181
REFERENCES ............................................................................................................ 182

vii

LIST OF TABLES

Table Page
1 Summary of Research Design ................................................................................. 3O
2 Overview of the Exercise and Testing Routine ........................................................ 31
3 Summary of the ABILITIES Index Scores for all Participants ................................. 37
4 Summary of Instrumentation ................................................................................... 42
5 Description and Frequency of Data Recorded for On-site Job Tasks ........................ 46
6 Effects of the Intervention on Performance of the Dependent Variables .................. 64
7 Mean Composite Strength Scores for Baseline, Intervention, and Retention ............ 65
8 Number of Points On or Above the Celeration Line for Composite Strength ........... 74
9 Percentage Change in Mean l-RM Scores for Strength Data for Each Exercise ....... 81
10 Mean Scores for Time to Completion of the Hand Truck Push ................................ 84
11 Number of Points On or Below the Celeration Line for the Hand-Truck

Push Task ............................................................................................................... 93
12 Mean Time to Completion of Box Stacking Task .................................................. 100
13 Number of Points On or Below the Celeration Line for the Box Stacking Task ..... 109
14 Percent Change in Mean Scores for Simulated Work Tasks ................................... 116
15 Productivity Data for Shane’s Workshop Job ........................................................ 118
16 Shane’s Weekly Job Performance Ratings/Comments for High School Job ........... 120
17 Productivity Data for Jacob’s Workshop Job ......................................................... 122
18 Jacob’s Weekly Job Performance Rating/Comments for Restaurant Job ................ 123
19 Jim’s Weekly Job Performance Rating/Comments for Mail Room Job .................. 125
20 Bob’s Weekly Job Performance/Rating Comments for Health Club Job ................ 128

viii

Table Page

21 Strength Data Files for Shane’s l-RM Lifts for Baseline, Intervention,
and Retention ........................................................................................................ 174

22 Strength Data Files for Jacob’s l-RM Lifts for Baseline, Intervention,
and Retention ........................................................................................................ 175

23 Strength Data Files for Jim’s l-RM Lifts for Baseline, Intervention,
and Retention ........................................................................................................ 176

24 Strength Data Files for Bob’s l-RM Lifis for Baseline, Intervention,
and Retention ........................................................................................................ 177

25 Data Files for Shane's Average Time for Completion of Simulated
Work Tasks ........................................................................................................... 178

26 Data Files for Jacob’s Average Time for Completion of Simulated
Work Tasks ........................................................................................................... 179

27 Data Files for Jim's Average Time for Completion of Simulated
Work Tasks ........................................................................................................... 180

28 Data Files for Bob's Average Time for Completion of Simulated
Work Tasks ........................................................................................................... 181

ix

LIST OF FIGURES

Figure Page

1 Comparison of Composite Strength Score for all Participants .................................. 67

2 Slmne’s Level and Trend Changes for Composite Strength ..................................... 68
3 Jacob’s Level and Trend Changes for Composite Strength ...................................... 70
4 Jim’s Level and Trend Changes for Composite Strength ......................................... 71
5 Bob’s Level and Trend Changes for Composite Strength ........................................ 73
6 Celeration Line for Shane’s Composite Strength ..................................................... 76
7 Celeration Line for Jacob’s Composite Strength"... .................................................. 77
8 Celeration Line for Jim’s Composite Strength ......................................................... 78
9 Celeration Line for Bob’s Composite Strength ........................................................ 80
1 0 Comparison of Hand Truck Push Scores for all Participants .................................... 86
1 1 Shane’s Level and Trend Changes for Hand-Truck Push Scores .............................. 87
1 2 Jacob’s Level and Trend Changes for Hand-Truck Push .......................................... 89
13 Jim’s Level and Trend Changes for Hand-Truck Push Scores .................................. 90
1‘4 Bob’s Level and Trend Changes for Hand-Truck Push Scores ................................. 91
15 Celeration Line for Shane’s Hand Truck Push Scores .............................................. 94
16 Celeration Line for Jacob’s Hand Truck Push Scores .............................................. 96
17 Celeration Line for Jim’s Hand Truck Push Scores ................................................. 97
18 Celeration Line for Bob’s Hand Truck Push Scores ................................................. 99
19 Comparison of Box Stacking Scores for all Participants ........................................ 102
20 Shane’s Level and Trend Changes for Box Stacking Scores .................................. 103

Figure Page

2 l Jacob’s Level and Trend Changes for Box Stacking Scores ................................... 105

2 2 Jim’s Level and Trend Changes for Box Stacking Scores ...................................... 106
2 3 Bob’s Level and Trend Changes for Box Stacking Scores ..................................... 108
24 Celeration Line for Shane’s Box Stacking Scores .................................................. 110
2 5 Celeration Line for Jacob’s Box Stacking Scores .................................................. 112
26 Celeration Line for Jim’s Box Stacking Scores ...................................................... 113
27 Celeration Line for Bob’s Box Stacking Scores ..................................................... 114

xi

CHAPTER ONE
INTRODUCTION

Employment is important to the quality of life of adults with mental retardation (MR).

There are numerous benefits to being employed for persons with MR. For example,

Wehman (1993) indicates that being satisfied with employment, having monetary
compensation, and obtaining opportunities for being productive at work can directly
influence one’s self-perceptions and financial and social freedom. Having a job and
earning compensation allows individuals a chance to increase their quality of life by
becoming more financially independent. Additionally, Serr, Lavay, Young, and Greene,
( 1 994) mention that work provides intrinsic rewards, allows interaction with others, and
provides opportunities to contribute to society as a whole. That is, if persons with MR are

working citizens, they are able to provide financial support for themselves. This

independence subsequently can lead to benefits for society.

Persons with disabilities, particularly those with MR, often are employed in jobs that
1‘equire some type of physical or manual labor which involves the lifting or carrying of
heavy Objects (Barrett, 1978; Wehman, Kregel, & Seyfarth, 1985b). In conjunction,
William (1977) stated that persons with MR are more likely to require physical rather
than cognitive skills in their employment. These jobs may include task assemblers,

warehouse workers, carpenters, janitors, maintenance workers, dock loaders, laborers,
fin-n) laborers, painters, restaurant workers, factory workers, bag persons in grocery
StoreS, grounds maintenance worker, and dishwashers (Barrett, 1978; Wehman, Kregel, &
Seyt‘El'th, 1985a). In order for persons with MR to perform these tasks, they must have

he necessary muscular strength and endurance. If this is the case, it is probable that some

individuals with MR fail to get jobs or lose their jobs because they do not possess the
necessary physical skills.
It is imperative that persons with MR be able to perform their job duties and still have
energy to carry out activities of daily living. Zetts, Horvat, and Langone (1995) indicated
“individuals with MR are disadvantaged when competing with the general population for
jobs that require increased physical fitness and exercise performance” (p. 166). This
statement may lead us to believe that having the necessary physical skills may enable

persons with MR to do their jobs comparable to, if not better than their non-disabled

coworkers.

Muscular strength and endurance are especially important for job maintenance for
persons with MR especially those who jobs that require physical labor. Eichstaedt and
Lavay (1992) noted that “lack of acceptance and of equal opportunity for persons with
IVIR will always be an obstacle unless these individuals have the physical skill and motor
ability to fit into the job market ” (p.361). In addition, Bellamy, Rhodes, Bourdeau, and
Mank (1986); Coleman, Ayoub, and Friedrich (1976); and Tomporowski and Hayden
( 1 990) have indicated that persons with MR not only lack the cognitive and social skills,
13‘“ also lack the motor Skills, fitness, and consequently physical strength needed to

perform the jobs in which they are employed. Therefore, enabling persons with MR to
deVelOp the necessary physical skills needed to obtain and keep jobs, and perhaps more
importantly, to achieve a higher quality of life seems very important.
Researchers (Croce & Horvat, 1992; Pitetti, Climstein, Mays & Barrett, 1992; Pitetti

& Tan, 1991; Reid, Montgomery, & Seidl, 1985; Schurrer, Weltman, & Brammell, 1985)

baVre indicated that persons with MR also demonstrate low exercise and strength

performance, and limited work capacity levels. In addition, Fernhall and Tymeson,

( l 987); Fernhall, Tymeson, and Webster, (1988); Montgomery, Reid, and Seidl, (1988);
and Reid et a1. (1985) have stated that persons with MR are characterized as having low
fitness and strength levels as compared to the non-disabled population.

It can be assumed that participation in a resistance-training program may lead to an
increase in muscular strength and fitness. This strength increase may assist persons with
MR in maintaining jobs that are physically demanding. As with non-retarded individuals,
inlproved strength and fitness allows for persons with MR to function throughout daily
activities and become more productive at work (Combes & Jansma, 1990; Croce &
Horvat, 1992; Rimmer & Kelly, 1991).

Current job training programs for people with MR do not address problems of
strength and fitness. They often focus on teaching specific job training skills and
acceptable work behaviors (Belfiore, Lirn, & Browder, 1994; Rusch, Connis, & Sowers,

1 979; Schutz & Rusch, 1982; Sowers, Rusch, Connis, & Cummings, 1980). More
SPGCifically, job training programs prepare individuals for completing job applications,
interviewing, adjusting to work, and learning of specific tasks and skills (Coker, 1994;
Montague & Lund, 1988; Szymanski & Danek, 1985). It also may be important for job
training programs to place more of an emphasis on increasing strength, endurance, and the
OVeI‘all motor ability of individuals with MR in order that they may have the necessary
Stamina to complete various job Skills. Tanner (1993) indicated that incorporating
physical fitness and resistance exercise programs into the school curriculum of children
811d adolescents has the potential to make graduates more desirable in the work force.

I ogressive resistance training may be an effective way of increasing muscular strength

and endurance among persons with MR. Participation in a weight training program is not
only beneficial for improving muscular strength, health, and wellness, but it can also be fun
and motivating.
If increased fitness and strength has beneficial effects for workers with MR, curricular
and vocational programs that focus on preparing individuals for the work force could
Wmmate fitness and more specifically resistance training. Participation in a progressive
resistance-training program is possible with minimal equipment and expertise. The
rationale for research in this area is significant to determine if participation in a resistance-
training program has the potential to enhance muscular strength and work productivity
and consequently lead to improved health, quality of life, and job maintenance for
individuals with MR. Therefore, there should be a sense of urgency among job training

personnel and vocational-staff to properly prepare these individuals for employment in all
work settings.
Purpose of th_e Study
This study was designed to investigate the effects of a nine-week progressive
1‘ eSiStance-training program on work productivity and muscular strength among adult
Inales with MR. Data were collected on: (a) work productivity using the simulated work
tasks of hand-truck push and box stacking; (b) work productivity using “on—site” or actual
Work tasks in jobs that were held by the participants; and (c) muscular strength as
determined by one repetition rmximum lifts using weight machines.
Need for th_e Study
The need for this study is obvious given the rate of unemployment and

underemployment of persons with MR, the concern for lowered work capacity among

persons with MR, the impact to society of persons with MR being employed, and the
limited research done regarding the relationship of weight training and work productivity.
Each of these factors will be explored in this section.

Unemplomnt and underemploment. Underemployment and unemployment are
major problems among persons with MR. Throughout the years, unemployment rates for
persons with disabilities have been reported as high as 50% to 90% (Wehman, 1993).
Some of the reasons offered for this high rate include the prevalence of cognitive deficits

and a tendency to engage in unacceptable work behaviors such as being off task and or
(provide and example of behaviors ) In addition to the cognitive and behavioral aspects
that limit employment, persons with MR may not possess the necessary motor ability,
fitness, and consequently the physical strength, needed to keep jobs.

Concern for lowered work productivity. A related concern among persons with MR
is low work productivity. It seems apparent that decreased work productivity would
adversely influence employers’ hiring and retention choices (Wehman, 1993). Minimized
Work productivity and lowered levels of strength and fitness also have the potential to
negatively affect quality of life perceptions and self-esteem among persons with MR.
Therefore, it may be important that persons with MR are prepared to take on the daily
demands of employment. Participation in a resistance-training program may help workers
with MR to increase their work productivity levels.

Societal benefits of employment for persons with mental retardation. Employment of

 

perSOns with MR has a large impact on society. That is, being employed and earning an
income may allow for financial independence rather than dependence upon various forms

of Public assistance. These persons will be tax paying citizens and contributing members

of their community. This employment will also help reduce unemployment rates among
persons with MR. Consequently employment for persons with MR will benefit local,
state, and federal budgets and the overall economy (Wehman, 1993).

Limited research on work productivig and strength The relationship between
muscuhr strength and work productivity is not known for the population of people with
IVIR. Hence, there was a need to determine if a positive relationship existed between
muscular strength and work productivity for persons with MR. Results of this study will
contribute to the body of knowledge on this topic. Past research on employment of

persons with MR has focused on social, cognitive, and quality of life factors in addition to
movement skills. For example, some of the variables studied included staff intervention

(Wetzel & Taylor, 1991), analysis of body movements (Belfiore et al., 1994), visual

feedback and ratio scheduling of pay (Martin & Morris, 1980), verbal reinforcement
(Crouch, Rusch, & Karlan, 1984), quality of life (Sinnot-Oswald, Gliner & Spencer,
199 l ), jogging (Beasley, 1982), and dexterity test scores (Serr et aL, 1994). However,
recent research (Croce & Horvat, 1992; Zetts et al., 1995) is limited in examining weight
training and its relationship to work productivity among adult persons with MR. To date
110 Studies have researched the relationship that muscular strength has on both simulated
and actual or "on-site" job tasks.

Furthermore, the results of this study can be used to help employers and potential
etllI>loyment or training sites to better prepare workers with MR for the job market.
Service personnel and staff can emphasize the benefits of engaging in a progressive
liesistance-training program in order for persons with MR to endure the physical demands

of a particular job and to become more productive workers. This study is significant

because the results are beneficial for persons with MR who are employed in a variety of
sheltered, supported, and competitive work settings.
There is a clear need for interventions tlmt help people with MR to get and keep jobs.
A strength intervention, such as the progressive resistance training used in this study,
could help those persons with MR who need physical strength to perform their jobs.
Designing a weight-training program is not too difficult, the equipment used can be
minimal, and the cost is minimal. Lastly, the generalizability of the results from this study
may provide additional empirical data on the effects of weight training for improving work
performance among individuals with MR. The implications fiom this study will be
important for persons with MR, as well as job training personnel and businesses that hire
people with MR. It is important that persons with MR are prepared to handle the rigors
of employment, especially job responsibilities which involve a higher level muscular
Strength, if they are to experience success in the workforce.
Hypgtheses
The specific research hypotheses to be tested in this investigation include:

1. Participation in a progressive resistance-training program (leg extension, leg
CllI‘ls, chest press, biceps curl, triceps extension, and abdominal curl) will improve
In“Scalar strength and endurance among adult males with mild to moderate MR

2. Participation in a progressive resistance-training program will improve work
Productivity of simulated job tasks (box stacking and box cart push) among adult males
with mild to moderate MR

3 . Participation in a progressive resistance-training program will improve work

pro(imlctivity of on-site job tasks among adult males with mild to moderate MR.

Assumptions

The researcher was unable to obtain direct records of participants’ intelligence scores.
Therefore, it was assumed that parents, supervisors, and directors provided accurate
information regarding participants' mental capacity. It was assumed that the participants
had the mental capacity to follow verbal instructions, observe a model perforrmnce, and
imitate demonstrations on the various lifting and work tasks. It was also assumed that
participants tried their best when performing exercises and work tasks. The final
assumption was that progressive resistance training helps persons with MR to increase

muscular strength and endurance as it does for individuals without MR.

Limitations
1. The researcher could not control for participants practicing the simulated job
tasks (box stacking and hand truck push) outside of the observation/testing periods.

Practicing these tasks may create a learning effect causing variable productivity scores.

2. Participants in this study were selected fi‘om similar group homes, community

housing, or family living environments in a rural or urban mid-westem city.

3. Participants in the study were selected fiom different employment settings;

therefore, different criteria were needed to measure on-site work productivity for each

Participant.
4. On-site work productivity records were obtained fi'om participants' places of

en‘Dloyrnent. The researcher accepted records of work productivity provided by the

ernI>loyer.
5. There were a small number (r_1=4) of participants in the study, which limited the

nature ofthe statistical analysis.

 

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Definition of Terms
Compgtitive emloyment. Employment programs that have persons with
developmental disabilities working alongside non-disabled coworkers in the regular job

setting. There is usually minimal support fiom supervisors or job coaches needed in this

environment.

Mthal retardation ( MR). "MR refers to substantial limitations in present functioning.
It is characterized by significantly sub-average intellectual fimctioning, existing
concurrently with related limitations in two or more of the following applicable adaptive
skill areas: communication, self-care, home living, social skills, community use, self-
direction, health and safety, fimctional academics, leisure, and work. MR manifests before

age 18 " (Luckasson et al., 1992).
On-sjite job tasks. On-site job tasks refer to the actual jobs held by the participants

 

used in this study. These tasks were performed in the employment setting and were not

under the control of the researcher. On-site jobs for the purpose of this study consisted of

a Variety of tasks, all of which required some type of physical labor.

Progmssive resistance tr_a1__nmg' ' . "Progressive resistance exercise refers to the

continual increase in the stress placed on the muscle as it becomes capable of producing
greater force" (Fleck & Kraemer, 1987, p. 6). Exercises are designed to strengthen
specific muscles by causing them to overcome a fixed resistance, usually in the form of a
barIJeII, dumbbell, or weight machine (McArdle, Katch, & Katch, 1991, p. 461). In this
Study, progressive resistance training refers to a 9-week weight-training pro gram. The
Program consisted of three phases with workloads at varying percentages (30% to 80%)

of tile participants’ one-repetition(1-RM) lifts. Phase one (2 weeks) included lifts

performed at 30% to 40% of l—RM for 2 sets of twelve repetitions. Phase two (3 weeks)
was done at 50% to 60% of participants l-RM lifts for 3 sets of eight repetitions. Lastly,
phase three (4 weeks) was 70% to 80% of l-RM lifts for 4 sets of six repetitions.

Sheltered workshop emplomrgnt. Sheltered work refers to employment programs
that provide work for persons with various developmental disabilities in a setting that
provides ongoing supervision. Participants receive compensation for the work they
perform. Sheltered workshop employment often involves tasks such as assembly, mailing,
collating, and packaging tasks.

Simulated work tasks. The simulated jobs used in this study were chosen by the
researcher and closely resemble tasks found in typical job settings of individuals with MR
(Barrrett, 1978; Shafer, Rice, & Metzler, 1989; Wehman et al., 1985a). The tasks

included box stacking (e.g., weighted cardboard boxes were lifted to a table fiom the
floor) and push cart with boxes (e.g., a two-wheel hand dolly was loaded with weighted
boxes and pushed for a set distance). These tasks were modifications of those used by
Zetts et a1. (1995).

Sumrted employmnt. The Federal Register (1987; 1992) defines supported
enIltzbloyment as “paid work in a variety of settings, particularly regular work sites,
especially designed for handicapped individuals: (i) for whom competitive employment has

not traditionally occurred; and (ii) who, because of their disability, need intensive ongoing

Support to perform in a work setting.”

10

CHAPTER TWO
LITERATURE REVIEW
The literature related to muscular strength and endurance among persons with mental
retardation (MR) indicates that these persons generally have lower fitness and strength
levels than non-retarded persons (Croce & Horvat, 1992; Rimmer & Kelly, 1991; Reid, et.
al., 1985). Low fitness levels may be a result of persons with MR not being afforded the
opportunity to participate in consistent exercise programs. In addition, knowledge about
the efiects that muscular strength has on the employability of these persons is limited as
welL Large amounts of money are spent on training programs to develop job skills for
persons with MR. As mentioned previously, these programs tend to focus on work-
related skills, but not on muscular strength and physical endurance. This literature review
focuses on the importance of employment for persons with MR, the types of jobs

comnnonly required by those persons, and lastly, several factors that relate to the strength

and work productivity of persons with MR.

Itmnmrtance of Employmt for Persons with Ment_al Retardation

Employment for persons with MR is very important and can have a huge impact on

 

their lives. As a matter of fact, Billions of dollars are spent each year on employment
pro grams, vocational education, and special education for persons with disabilities
(Wehman et al., 1985a). These programs train and place individuals who have various
disabilities into jobs in order that they may become more economically and personally
independent. However results of past research by The US Commission on Civil Rights
(1 98 3) has indicated that 50% to 75% ofall persons in the United States with disabilities

were tmemployed in the mid 19803. Others (Brickey, Browning, & Campbell, 1982;

ll

Hasazi, Gordon, & Roe, 1985; Mithaug, Horiuchi, & Farming, 1985; Patton, Bernie-
Smith, & Payne (1990); Schalock & Lilley, 1986; Wehman et al. 1985a; and Wehman et
al., 1985b) have conducted studies tlmt also support claims of high unemployment,
underemployment, or the failure to keep jobs. Furthermore, Jones, Ulicny, Czyzewski,
and Plante (1987) proposed that there are limited opportunities in traditional employment
for persons with disabilities, and that they are in constant competition with nondisabled
workers. Smith (1981) surveyed 74 potential employers of persons with MR on their
hiring concerns. The results indicated that 79% of the employers surveyed did not
presently have any persons with MR working for them. These employers were concerned
about factors such as hiring persons with MR because of lack of responsibility on the job,
inappropriate social behavior, and inability to get along with other workers.

Much emphasis throughout society is placed on individuals being able to become
independent and support themselves (Patton, Bernie-Smith, and Payne, 1990). Many
people who are mentally retarded are able to have jobs if given the proper training,
assistance, and opportunities. In conjunction, The Association for Retarded Citizens
(ARC; 1994) stated the effects of MR varies among this population. About 87% of
POOple with MR show mild to moderate deficits in learning new information and skills. As
these persons get older and complete training, they are capable of performing a variety of

jobs. The remaining 13% of people with MR have more pronounced deficits in learning;
however, some can still become employed and demonstrate effective performance in
certain jobs. Job assistance for persons with MR is common in many settings (workshop,
Sheltered, and competitive). The ARC (1994) recommends that a job coach “accompanies

the individual with MR to the job to assist in the initial training period” (p. 1), especially

12

during the initial stages of employment. The job coach offers recommendations on ways
to accommodate the worker with MR. The goal is to have the job coach eventually be
removed from the work setting and act as a consultant when needed. This strategy is
important for persons with MR; however, it may not be suflicient. Persons with MR must
continue to possess the necessary strength to perform their jobs. Consequently,

progressive resistance training may be a way to increase their strength and provide the

necessary endurance to further assist in their job independence.

gluing of life and job satisfaction. Goode (1990) states that quality of life variables

are the same for non-disabled and the disabled. The quality of life variables involve a
social construct that included interacting with others and could be attained by meeting the
needs and responsibilities of individuals in the environment in which they live. Parent

( l 993) indicated the importance of choice, control, empowerment, and job satisfaction to
the quath of life of persons with disabilities. Sinnott-Oswald, Gliner, and Spencer (1991)
conducted a study to examine differences in perceived quality of life of two groups of
adults with MR (r_1=30) from three different groups: (a) supported employment; (b)
Sheltered workshop; and (c) control group. The factors they used to define quality of life
included environmental control, community involvement, and perception of personal
Change. An l8-item questionnaire was used and analyzed on a per-question basis. Results
of this study indicated that participation in leisure activities, use of leisure time, self-
esteem, activity involvement, mobility, perceptions of job skills, and increase in income

Were better for persons in supported employment settings as opposed to the sheltered

W0 rkshop.

l3

Sands and Kozleski (1994) examined the quantitative differences in quality of life
factors between adults with (r_1=86) and without (l_1=131) disabilities. Subjects ranged in
age from 18 to 70 years. The majority (61%) of the participants with disabilities identified
their primary disability as MR, 13% as cerebral palsy, and 4% as head injury. Participants
with disabilities were interviewed and administered the Consumer Satisfaction Survey

(Temple University Developmental Disabilities Center, 1990). Non-disabled subjects
completed a slightly modified version of the survey. This instrument was designed to
evaluate consumer satisfaction and quality of life of individuals with developmental
disabilities. The constructs of the survey were grouped into 6 categories, including: (a)
services received; (b) satisfaction with those services; (c) independence / interdependence;
((1) community activities; (e) productivity; and (f) needs for supports, services, and
assistance. Results indicated tlmt there was a significant relationship between presence of
a disability and levels of participation in choice for life activities. That is, persons with
disabilities had fewer choices than nondisabled individuals. Although all subjects were
generally satisfied with their life, independence was low for individuals with disabilities
(Sands & Kozleski, 1994).

Mehnert, Krauss, Nadler, and Boyd (1990) suggested that persons who are employed
are more satisfied than those who are not employed. Thus, it is reasonable to assume that
l'laVing and maintaining a job can lead to enhanced quality of life and ofi’er personal
satisfaction by fostering interpersonal relationships, psychological well-being, security, and
independence (Parent, 1993).

Benefits of emplomnt. There are numerous benefits of employment for persons
with MR. Earning money and having a chance for advancement can improve self-esteem,

l4

social opportunities, and financial fieedom, as well as the way that society views an
individual (Wehman, 1993). Earning money and being satisfied with employment also
may have a significant effect on a person’s self-perception and quality of life. The jobs
that are held by many persons with MR might seem less desirable than those held by
persons without disabilities; however, they are a vital part of employment for this
population. Although the jobs may be physically demanding, they allow individuals a
chance to become socially accepted by family and community, make money, and become
financially independent (Wehman, 1993). These factors can eventually lead to positive
self-perceptions and improve quality of life.
Employers also experience apparent benefits when they hire people who are mentally
retarded. The ARC (1994) stated that employers may be able to receive on the job

training reimbursement from the ARC, the state’s rehabilitation agency, or a local Job

Training Partnership Act (JT PA) program. For some employers, tax credits from the
Internal Revenue Service may also be available. Additionally, persons with MR usually

are classified as loyal workers. They work hard and do what they can to please their
elnployers. Hence many employers are usually satisfied with the performances of these
individuals. Blanck (1993) conducted a survey to determine how satisfied employers were
with their MR workers. Results indicated that the majority (96%) of the employers
reported they were happy with work attendance. Others (78%) were pleased with the
employees’ dedication to work, and 95% indicated their employees with MR have lower
tnI‘llover rates than nondisabled workers with the same type of jobs. Lastly, many of the

e11llsloyers were very satisfied with the employees’ work productivity (59%) and initiative

(58%).

15

Employment for persons with MR carries economic benefits for these persons as well
as society as a whole. Wehman (1993) mentions that money earned by persons who are
disabled goes back into the local and state economy. He filrther states “when combined
with the taxes, it is apparent that significant reductions in the employment rate for persons
with disabilities would quickly become a considerable benefit for state and federal budgets
and the general economy” (p. 56). In addition, there are supplemental security income

savings to be had as well. That is, persons with disabilities who can work and gain wages
would not require as much of the supplementary income. Sylvestre and Gottlieb (1992)
indicated, “persons with MR will become less dependent on government largesse and

charitable organizations, and achieve a significant measure of economic independence” (p.

4).

Muscular Strengt_h and Job Maintenance

Muscular strength and endurance has an effect on the ability of persons with MR to
obtain and maintain jobs. It seems apparent that fitness, more specifically muscular
Strength, has the ability to effect productivity, job attendance, and the health of persons
With MR who have physical tasks as their employment. Research by Barrett (1978),
Wehman et al. (1985a, 1985b) has shown that persons with disabilities, particularly those
With MR, are usually employed in jobs that require some type of physical or manual labor
which involves the lifting or carrying of heavy objects. Some of the jobs may include task
assembler, warehouse worker, carpenter, janitor, maintenance worker, loader on a dock,
laborer, farm laborer, painter, busboy, factory worker, baggers in a grocery store, grounds

IIlaintenance, and dishwasher. The ARC (1994) listed several additional jobs that persons

with MR have been successful in performing, such as animal caretakers, textile machine

16

tenders, store clerks, nursery worker, messengers, cooks, hospital attendants,
housekeepers, furniture refinishers, building maintenance workers, and grocery clerks.
Smith (1981) added to this list mentioning, maintenance, kitchen worker, laundry worker,
shoe repair, bus boy, production worker, farm worker, grounds keeper, mailroom clerk,
mail delivery, and carpenter’s helper jobs. Although the aforementioned jobs are physical
tasks, there was no mention of persons with MR having the necessary strength to perform
the jobs. The importance of strength for the jobs as suggested by these experts cannot go
ignored.

It is well documented in the research literature that adults who are mentally retarded
possess lower fitness and strength levels than persons who are not retarded (Beasley,
I982; Fernhall & Tymeson, 1987; Fernhall & Tymeson, 1988; Fernhall et al. 1988; Janicki

& Jacobson, 1985; Pitetti & Tan, 1990; Pitetti, Jackson, Stubbs, Campbell, & Battar,

l 989; Schurrer et al., 1985; Seidl, Reid, & Montgomery, 1987). Low fitness and strength
performmes, along with the current push toward more integrated working environments
(supported employment), means that adults with MR may have a difficult time competing
With nonretarded persons for jobs. Substandard strength and fitness levels of individuals
who are MR may also lead to increased absenteeism in the work place as well (Cox,
Shephard, & Corey, 1981; Cox, Shephard, & Corey, 1987).

Several researchers (American College of Sports Medicine [ACSM], 1990, 1991;
Blair, Kohl, & Barlow, 1993; Blair, Kohl, & Gordon, 1992; Blair, Kohl, Gordon, &
Paflenbarger, 1992; Debusk, Stenestrand, Sheehan, & Haskell, 1990; Fletcher et al., 1992;
Gordon, Kohl, & Blair, 1993) have indicated that participation in physical activity is

important in preventative health as well as disease prevention. Additionally, a report from

17

the US Department of Health and Human Services (1996) details several benefits of

participation in physical activity for persons with disabilities. The benefits include: (a)
reduced risk of dying from coronary heart disease and having high blood pressure; (b)
improved physical stamina for persons with chronic conditions; and (c) reduced likelihood
of anxiety and depression and enhanced feelings of well-being. Persons who are healthy
and flee from disease may have better work attendance and increased productivity levels.
Therefore, the importance of fitness and strength programs in the work force and the
increase of work productivity is an important concern for employers.

Furthermore, job maintenance is important to the success of persons with MR in
competitive employment as they are competing against people who are non-disabled.
Therefore, having the necessary strength and stamina to complete the job tasks at hand is
an important quality. It is important to determine more viable ways to prepare persons for
the physical rigors of the work force. Improved stamina, less work absenteeism, and
lower health insurance costs are benefits to being physically fit and healthy. Cox et al.

( l 987) mentioned that persons with MR often have a high rate of absenteeism due to
illness and sometimes lack of job satisfaction. It is important to lmve stamina and energy
to make it through a typical workday, making it apparent that some level of fitness and
Strength is needed to be successful and productive in the work force. The challenge will
be for special education, vocational training, and job training personnel to focus on
essential benefits of resistance training and the accompanying benefits to quality of life, of

Work productivity, and health and fitness for individuals with MR.

18

Strength Chgagteristics among Person with Mental Ram

Persons with MR have the capacity to gain muscular strength and endurance by
participating in consistent resistant programs. Zetts et al. (1995) investigated the effects
of a progressive resistance exercise program (bench press, military press, leg press, leg
curls, leg extensions, and biceps curl) on simulated work productivity (box stacking, hand
truck push, and pail carry) for 4 men and 2 women with moderate to severe MR who
ranged in age fiom 15 to 20 years. The equipment used included a Universal Gym, Icarian
Fitness Leg Curl and Leg Extension machines, and fiee weight dumbbells. Strength was
recorded using a Nicholas Manual Muscle Tester and a hand-held dynamometer. Data
were analyzed by visual inspection for changes between baseline and intervention for each
participant. Results indicated that strength increased from baseline to post intervention in
all muscle groups for all participants. Simulated work productivity also increased for all
participants during intervention, with the pail carry showing the lowest increase.
However, the strength gains showed more of a significant increase than did work
productivity.

A study by Rimmer and Kelly (1991) involved a progressive resistance training
program for 24 adults (13 women and 11 men) with MR (IQ 40 to 70) ranging in age
from 23 to 49 years. Participants completed a 9-week program using Nautilus equipment
and a pull-up machine at a community-based exercise facility. Strength was measured
uSing one repetition maximum lift (1-RM) on the following machines: leg extension, leg
curl, pectoral deck, shoulder abduction, pull over, biceps curl, triceps extension, and pull

up. The results suggested that participation in the 9-week resistance-training program

improved the strength levels of persons with MR. The improvements were quite

l9

significant on all measures except the leg extension. It was also reported that participants
seemed motivated to participate in the resistance-training program, suggesting that this
type of program could be beneficial to persons with MR. These results further provide
evidence of the importance that resistance training plays in the life of persons with mental
retardation.

The findings of the previous studies are significant in that they used a variety of
resistance equipment and settings, and/or each person had resistance training programs
individualized specific to his or her strength. These results clearly indicate that persons
with MR have the ability to participate in a fitness program and possess the ability to
increase their muscular strength, endurance, and work productivity if given the
0990an-

Lastly, in a critical review of the literature, Moon and Renzaglia (1982) reported that
persons with MR need systematic intervention strategies for leisure-time skills and
physical fitness because they are not self-directed enough to know their options.
Therefore, exercise programs should be monitored and simple enough so that persons with
MR are motivated to participate. One such exercise program that could enhance
participation of persons with MR is resistance training.

Strggth Gains for Persons with Mental Retardation
Weight training can vastly improve the efficiency of muscles. The body's
physiological responses to weight training and exercising are many. Hypertrophy and
increase in strength are some of the responses tlmt are sought by persons participating in
weight training. The intensity, duration, and frequency of exercise determine the degree of

improvement in muscular strength and endurance. Brzycki (1995) indicates that “each

20

for 1h

111W

that

time the maximum number of repetitions are attained the resistance should be increased
for the workout” (p. 39). Utilizing the principle of progressive overload is imperative in
increasing strength. Overload involves placing additional stress on the muscles more than
what they are accustomed to doing.

The key to progressive resistance training is to gradually increase the amount of
weight lifted and the number of sets performed as the person’s strength increases.
Muscles respond better if the progression is challenging. Therefore, the increases in
weight of progressive resistance training should be specific for the individual.
Comparisons to others should not be of major concern, but the person should try to
improve his or her previous performance (Brzycki, 1995). Therefore, weight is adjusted
based on a person’s maximal lifi in one repetition or l-RM. Lastly, participation in a
progressive resistance-training program is a way of increasing strength and muscular
endurance, and may result in reduction of risk for cardiovascular diseases (Fleck &
Kraemer, 1988).

Past researchers have reported problems related to the inability of persons with MR to
understand, maintain, and follow certain testing cadences or protocols. Fernhall and
Tymeson (1987), Lavay, Reid, and Cressler-Chaviz (1990), and Rimmer and Kelly (1991)
Stress the importance of making sure that subjects are familiar with test settings. Although
these concerns about following test or exercise protocols do exist, once these problems
are overcome, persons with MR respond to exercise physiologically the same as
nonretarded persons (Croce, 1990; Tomporowski & Ellis, 1984; Tomporowski &

Jameson, 1985).

21

Fernhall (1997) indicated that exercise training for persons with MR is beneficial.
Standard protocols are acceptable if low fitness capacities for this population are taken
into consideration. Additionally, Fernhall (1997) recommends being aware of safety
concerns, motivation, concentration, and understanding difiiculties related to the task.
Therefore the use of weight machines over free-weights are recommended because they
are easier to use and control, and may present less of a safety hazard. Additional benefits
were outlined by Rirmner (1996) who stated the following facts regarding muscle strength
among persons who are MR: (a) body strength is valuable for recreation activities and
activities of daily living; (b) good upper body muscles increase vocational opportunities;
and (0) there is a relationship between good muscle strength and good performance of
people with MR in industrial work settings (p. 2).

An increase in strength can lead to persons with lvm having more vitality and
endurance to make it through a typical workday. In addition, increased strength may
improve the person’s energy level so he or she may engage in other activities outside of
the work place. There have been several studies that report on the benefits of weight
training programs for persons who are nonretarded (Fleck & Kraemer, 1988; Kraemer &
Fleck, 1988; McDonagh & Davies, 1984; Sailors & Berg, 1987). These studies have
shown that resistance training can increase muscular strength and endurance and the ability
to perform work. Only a few studies have looked at the effects of resistance training
programs for persons with disabilities (Nordgren, 1971; Pitetti et al. 1992; Rimmer &

Kelly, 1991; Zetts et al., 1995).

22

Muscular Strergthzmd Work Productivm
There have been a few studies (Nordgren & Backstrom, 1971; Zetts et al., 1995) that
looked at the effects that muscular strength and endurance have on work productivity.
Serr et al. (1994) mentioned that the majority of jobs performed by persons with MR in
workshop or competitive work settings involve the use of the hands. They perform
assembly, lifiing, cleaning, packaging, and various other tasks. A certain amount of
strength is also required in these tasks. A study by Beasley (1982) looked at the effects of
a jogging program, 5 days a week for 8 weeks, on cardiovascular fitness and work
perforrmnce of 30 adults with mild to moderate MR who were employed in a workshop
setting. Cardiovascular fitness was measured using posttest measures from Cooper's 12-
minute Run-Walk Test (Cooper, 1968). Work productivity was measured by the amount
of heat clip assembly tasks completed. Data analysis revealed a significant difference
between the experimental and control group on Cooper's Test (Beasley, 1982). The
experimental group had better fitness values and assembled more heat clips than the
control group. An analysis of absenteeism indicated no significant difference between the
two groups. However, the experimental group had a mean absentee rate of approximately
one-day below tlmt of the control group. Although this study provides encouraging
results, it does not provide data on the importance of muscular strength in jobs requiring
physical labor.
Croce and Horvat (1992) conducted research to determine the effects of a
rCinforcement-based aerobic and resistance exercise program on fitness and work
productivity of three obese men with MR and low fitness levels. The behavior

reinforcement involved a token system and was used to help with participant motivation.

23

Treatment effectiveness was evaluated on body weight, percent body fat (body
composition), oxygen consumption (predicted max V0; in ml/kg/min), composite
isometric strength (kg of force), and work productivity (pieces of work completed).
Results from the analyses of a multiple-baseline-across—subjects-design indicated that
participants improved from their baseline scores on cardiovascular fitness, strength, and
work productivity measurements (p<.05). There were no significant differences for the
body weight and body composition for the treatment and retention phases (p>.05). This
study further indicated the importance of strength on work productivity.

Successful work experiences for both persons with and without MR depend a great
deal on work productivity. Jobs such as assembly tasks and packaging involve persons
being compensated for the amount of work they produce. Zetts et al. (1995) conducted a
study to determine how a community-based progressive resistance-training program
affected the work productivity of six adolescents with moderate to severe intellectual
disabilities. The jobs used in the study were simulated and included box stacking, hand
truck push, and a pail carry. The results indicated that there were increases in strength
from the pretesting to the posttesting on all strength measures. In addition, the mean
values of all work productivity tasks increased during the intervention stage. This study
further indicated the positive effect that strength can have on work productivity, indicating
its importance to persons with MR who have jobs that require physical labor.

Strength and endurance are especially important to perform job skills. More business
and corporations are using resistance training and physical fitness as a possible
enhancement of work productivity (Bernacki & Baun, 1984; Driver, 1992; Karma, 1987;

Shephard, 1986; Zetts et al., 1995). In addition, Bemacki and Baun (1984), Driver

24

*— -.. M‘ """

(1992), and Kaman (1987) indicated that corporations are becoming more interested in
including and stressing the importance of physical activity in the work place as a way of
increasing employee work productivity. Therefore, being physically stronger may also
enhance the individual’s chances of obtaining and maintaining long term employment.
Persons with MR should be prepared to take on this challenge and become physically
stronger and subsequently more physically fit to perform on job tasks and improve their
quality of life.

Lastly, Shephard (1994) states it best by indicating that, “perhaps the most important
benefit that can be anticipated fi'om a regular exercise program is enhanced quality of life”
(p. 96). The effects of exercise are immediate and a person’s life can be enlmnced by as
much as 10%. This provides more evidence for the importance of a consistent and
sustained exercise program Resistance training has the potential to produce the
aforementioned effects.

Implications of thflfiegrture for this Study

A review of the literature revealed that progressive resistance training has the
potential to increase strength and possmly work productivity among persons with MR. It
has been documented that a certain level of muscular strength is needed for persons with
MR who work in jobs that require physical labor. Nine weeks has been shown to be a
sufficient amount of time for persons with MR to experience noticeable strength gains
using upper and lower body exercises. Participation in strength programs has improved
work productivity for simulated work tasks; however; the data regarding its affect on

actual job tasks is inconclusive.

25

Participation in a consistent resistance-training program has many ramifications for
job maintenance and performance. Getting and keeping jobs and being productive at work
is important for persons with MR. The significance of having a job to help enhance one’s
quality of life is paramount. The importance of improving the muscular strength and
endurance of persons with MR has implications for job success and job maintenance. In
addition, information from this study may offer guidelines to those who supervise work-

training programs for persons with MR.

26

CHAPTER THREE
METHODS

The purpose of this study was to determine the effects of a weight training program
on work productivity and muscular strength among adult males with MR. It was
hypothesized that participation in a weight-training program would positively affect work
productivity by increasing the amount of work completed on simulated and actual job
tasks and improve the participants' muscular strength on one repetition max lifts.

Research Des_igr_1

The design used for this study was a single-subject ABA applied behavior analysis
design (Barlow & Hersen, 1984; Huck, Cormier, & Bounds, 1974) with four replications.
The independent variable was a 9-week progressive resistance-training program. The
participants' performance levels were assessed on the dependent variables once every
week during the 5-week baseline (A), the 9-week treatment (B), and the 6-week retention
(A) periods. During the treatment (B) period, participants were involved in a twice-a-
week progressive resistance-training program.

The dependent variables were performances on a box-stacking task, a hand-truck
push task, on-site work tasks, and selected muscular strength measures. Measurements
across all A and B phases of the research design included: (a) work productivity using
simulated work tasks of box stacking and hand truck push; (b) work productivity using
on-site or actual jobs; and (c) muscular strength using leg extension, leg curl, chest press,
biceps curl, triceps extension, and abdominal curl. In addition, participants performed
front-lying chest lifis to strengthen the low back muscles. The chest lifts were a substitute

for back extensions, because the back extension machine at one of the three workout sites

27

was not in operation. Therefore, to maintain consistency within the treatment, chest lifts
were performed because the exercise required the use of no equipment. No strength data
were recorded on the back exercise. Table 1 provides a summary of the research design
used for the study.

Participants were not engaged in strength training during the baseline period (A);
however, their strength was measured once a week for the 5-week period. The
participants indicated that they had not engaged in a strength-training program within the
past three years. During the treatment period, participants lifted weights two days a week
on non-consecutive days. The duration of each lifting session was approximately 2.0 to
2.5 hours. Table 2 shows an overview of the schedule used for the participants during the
study. The independent variable was believed to be effective if the participants improved
in composite strength and on the simulated and actual work tasks during the treatment
period and then decreased during the retention period.

JfliLcation for the Design

Reversal strategy designs are common in single-subject or small group studies. This
design allowed for the researcher to conclude with a high degree of certainty that the
treatment variable (resistance training program) caused changes in the dependent variables
(work productivity and muscular strength) (Barlow & Hersen, 1984). The behavior of
each participant was monitored weekly during the baseline and intervention phases of the
study. These periodic observations allowed participants to serve as their own controls.
The repeated measures conducted within this investigation also helped to establish

experimental reliability in the scoring of work and strength outcomes.

28

Another justification for the use of this design is that it helped to control for several
threats to internal validity (Huck, et al., 1974; Thomas & Nelson, 1996). Shavelson
(1981) defines internal validity as "the extent to which the outcomes of a study result from
the variables which were manipulated, measured, or selected in the study rather than from
other variables not systematically treated" (p. 22). It should be noted that the nature of
behavioral research designs being conducted in the "real world" setting could lead to some
threats to internal and external validity.

Threats to internal and external validity were minimized whenever possible.
Nevertheless, the following possible threats to internal validity were apparent for this
study.

H_istfl Threats due to history may have been a factor if participants performed
lilting exercises outside of this study. To help control for this threat, participants were
asked not to engage in lifting weights until completion of the study. The investigator
asked parents/guardians, and group home supervisors to monitor participants so they did
not participate in weight training during baseline or intervention periods. In addition,
participants were asked to indicate on the health history form if they had previous weight
training experience.

Maturation. Maturation was not a major threat to validity given that the total
duration of this study was only 20 weeks. However, fatigue during testing sessions did
represent a possible maturation threat. To help control for this variable, participants were
given rest periods after each lift, as well as after each trial of the simulated work tasks

during testing sessions. Hunger and thirst may have also been a problem.

29

Table 1

Summary of Research Design

 

 

Duration Treatment Data Collection

Orientation 2 one-hour sessions None None

Baseline (A) 5 weeks None Box —stacking

Hand-truck push
On-site work tasks
Muscular strength
all measured once a
week.

Treatment (B) 9 weeks Progressive Box —stacking
resistance training Hand-truck push
program with warm- On-site work tasks
up, multiple Muscular strength
repetitions of 7 all measured once a
strength exercises, week.
and cool-down

Baseline (A) 6 weeks None Box —stacking

Retention Hand-truck push

Orr-site work tasks
Muscular strength

all measured once a
week.

 

3O

Table 2

Overview of the Exercise and Testhgjouthle

 

 

Activities/Exercise Duration (min) Equipment

Meet in dance studio (Shane 5 None

& Jacob)

Meet in aerobic room (Jim)

Meet in gymnasium (Bob)

Retrieve data and get sports 5 Record sheet, pencil, sports
drink or bottled water fi'om drink or bottled water,
cooler cooler

Perform stretching exercises & 15-20 Padded exercise mat
warm-up (all sessions)

Perform box stacking, hand truck 40-50 Weighted boxes, hand truck,
push, & l-RM lifts.(once a week table 30” high, stop watch,
on testing days) cones (6), weight machines
Rest period (on testing days)’1 5-10 None

Weight training (all sessions) 60-80 Weight machines

Cool down (all sessions) 5-10 None

 

'Additional rest periods were allowed as needed.

31

The investigator encouraged the participants to eat at least one to two hours prior to
arriving at the testing site and provided water/sports drink during all sessions. Fatigue and
hlmger may have affected each participant differently; therefore, the investigator
monitored this by periodically asking the participants how they felt.

Testing effects. Testing effects may have been a threat in this study. Participants may
have been more motivated because the investigator and the assistants were present or
because they were getting rewarded with verbal praise. To help control for this,
participants had a chance to engage in practice sessions prior to participation in the study.
This allowed the participants to become familiar with the testing site, and investigator to
minimize the likelihood of testing effects. Furthermore, weekly baseline measures were
taken on all participants prior to starting the intervention. Testing conditions were the
same for all participants. In addition, the participants were required to have worked at
their present job for a period of two months before they were allowed to take part in this
study. This two-month period of time allowed participants to become familiar with their
job tasks, thus decreasing the likelihood of threats due to testing effects of work
outcomes.

Instnmrentation. This seemed to be an unlikely source of invalidity because
observations and those making the observations were consistent during the study. The
instrumentation was not complex. For the box stacking and hand-truck push, testers used
a stopwatch to assess the amount of time it took participants to lift eight boxes and push a
land truck for a distance of 160 feet. For the strength measures, the investigator had to
add up the weight (in pounds) lifted by the participants on the various machines. The

weight machines were not calibrated for this study. Proper positioning on the weight

32

machines is simple, and each participant had assistance from the investigator. The
investigator was the only person observing all participants throughout the study.

Selection bias. There was no selection bias because each participant served as his
own control.

Mortflty’ . This would have become a threat had participants dropped out of the
study, or if any participant had a high absentee rate. The researcher attempted to control
for mortality by keeping the participants motivated and giving them verbal praise each
time they were present. Participants were also made aware of their attendance record.
The researcher also carefully explained the study to the participants and their
parents/guardians and mentioned the importance of completing the study. The
parents/guardians made sure that the participants were at all exercise and testing sessions.

Statistical regr_ession. The threat of statistical regression was not a concern because
baseline measures were established and several measurements were taken prior to
intervention.

External validity is defined as the extent to which the conclusions of a study can be
generalized across populations other than the sample used in the study (Huck et al. 1974;
Shavelson, 1981). External validity is typically controlled by selecting the participants,
treatments, experimental situation, and tests to be representative of some larger population
or "real life" (Thomas & Nelson, 1996). To minimize the risk of external invalidity, the
researcher attempted to recruit participants who were representative of working class
males with MR (see the section on participant selection and recruitment for more detail).
The testing environments or tasks were similar to the "real world" setting in that the

simulated tasks were similar to tasks participants may perform at their actual jobs. Lastly,

33

the weight machines used are typical of those used at many community health club or
fitness centers.
Participants

The eliglhility criteria for participation in this study included: (a) males with mild to
moderate MR; (b) chronological age of 25 to 40 years; (c) independently ambulatory, free
from gross motor difficulties and medications that prohibit performance of physical work
tasks, and relative good health; (d) signed medical release form; (e) no involvement in a
weight training program during the past 12 months; (f) physical labor tasks as
employment; (h) able to follow verbal directions (g) employed at current job for a
minimum of two months; and (i) informed consent. The strict selection criteria were used
to minimize the risk of injuries to the participants. For example, participants who were
not in good health or who had gross motor difficulties were excluded because they might
injure themselves while lifting weights or performing the simulated work tasks.
Recruitment of Participants

Participants were recruited fiom group homes and sheltered work sites in a
Midwestern city in the United States. Potential sites for participants were identified by
one of the researcher's dissertation committee members and the investigator. After
potential group homes and job sites were identified, the researcher telephoned and visited
those agencies approximately one month prior to the start of the study to recruit
participants. The study was explained to the group home supervisor and job-site
coordinators, as well as potential participants and their parents and guardians.

The description of the research study that was provided to potential participants and

their parents and guardians included a complete description of the intervention and data

34

collection procedures as well as the benefits and risks associated with participation.
Individuals who were interested in participating in the study were asked to have their
parents or guardians notify the investigator by telephone or email. The actual sample of
four participants was randomly selected fiom the pool of given individuals (p= 5) who
satisfied the selection criteria.
Informed Con_s_e_n_t

The intervention and data collection procedures were explained verbally and were
demonstrated in a videotaped presentation that showed an adult male performing the
intervention and data-collection tasks. The actual consent procedures were also outlined
in the video by the investigator. After viewing the videotape, the participants and their
parent(s) or guardian(s) were given an opportunity to ask questions and were asked to
sign the consent and assent forms (Appendix A). Verbal consent was obtained fi'om the
participants’ job supervisors who recorded the on-site work productivity data. A copy of
the consent forms approved by the Institutional Review Board at the investigator’s
university and signed by the participants is located in Appendix A.
Particlp' ant Smle

Participants included 4 males, aged 20 to 40 years, with mild to moderate MR, who
resided either in group homes or with their parents or guardians. All participants were
employed in jobs that involved some type of physical labor. Parents or guardians
completed a demographic and health history questionnaire that requested information on
the participant’s living environment, gender, date of birth, history of injuries, and exercise
habits (Appendix B). Information fiom this form was also used to help the researcher

screen for eligibility criteria. The investigator relied on the information provided by

35

parents, guardians, and participants to gain personal information about the participants’
level of cognitive impairment and job history.

In addition participants were observed and assessed using the ABILITIES index
(Simeonsson & Bailey, 1991). A copy of the index can be found in Appendix C. This
instrument allowed the investigator to develop a profile of the participant’s abilities in nine
major areas including audition, behavior and social skills, intellectual fimctioning, limbs,
intentional communication, tonicity, integrity of physical health, eyes, and structural status
(Simeonsson & Bailey, 1991). The scale is commonly used for children however; the
investigator used it with the participants in this study as reference to their fimctional
ability. The investigator made all observations; however, parents were contacted if further
clarification was needed. Participants’ abilities ranged fi'om normal to moderate in the
nine categories. Adhering to the established criteria, no participant had any physical
disabilities that would prevent them from performing the exercises used in the study. An
overview of participants’ scores on all components of the index is listed in Table 3.

The personal characteristic information that was provided in this study was voluntary.
The investigator did not view any personal records of the participants. The names used in
this study are not the actual names of the participants. Descriptions of the participants are
provided in the subsequent paragraphs.

M Shane is a 5’9”, 124 pound, 25-year-old, Caucasian male who resides with his
mother. His mother and job supervisors described him as having mild MR. He recently
graduated fiom high school and now has a job at a sheltered workshop where he is

responsible for assembly work. He also works at a local high school cafeteria where

36

Table 3

 

 

 

 

8mm of the ABILITIES Index Scores for all Participants
Shane Jacob Jim Bob
Audition
Left 2.0 1.0 1.0 1.0
Right 2.0 1.0 1.0 1.0
Behavior 3.0 3.0 3.0 2.0
Social Skills 3.0 3.0 3.0 2.0
Lntellectugl Funlctioning 3.0 3.5 3.0 3.0
Limbs
Hands
Left 1.0 1.0 1.0 1.0
Right 1.0 1.0 1.0 1.0
Lms
Left 1.0 1.0 1.0 1.0
Right 1.0 1.0 1.0 1.0
Legs
Left 1.0 1.0 1.0 1.0
Right 1.0 1.0 1.0 1.0
Intentional Communication
Understanding 2.0 3.0 2.0 2.0
Communicating 2.0 3.0 2.0 2.0
Tonic' 1.0 1.0 1.0 1.0
Integmy' of Physical Health 1.0 2.0 1.0 1.0
Eyes (Vision)
Left 1.0 3.0 2.0 1.0
Right 1.0 3.0 2.0 1.0
Structural status 1.0 1.0 1.0 1.0

 

Note. 1.0 = Norm; 2.0 = Suspected disability; 3.0 = Mild disability; 4.0 = Moderate

disability; 5.0 = Severe disability; and 6.0 = Profound disability.

37

he washes dishes and performs general cleaning duties. At the time of the study he had
been employed at his jobs for 5.5 years and 2.0 years respectively.

@011. Jacob is a 5'11", 190 pound, 26-year-old, Caucasian male who resides with his
mother. His mother described him as having mild to moderate MR. Jacob is presently
employed as a task assembler at a sheltered workshop and has held his job for
approximately 4.5 years. In addition, Jacob works at local restaurant where he washes
dishes and does general cleaning. He has been at this job for a period of 2 years.

Lin Jim is a 5’10”, 185 pound, 29 year old, Afiican American who resides with his
father. Jim’s dad described him has having mild MR. Jim works as a mail sorter at a
university in an urban area. He also stated that he lifts mailbags, boxes and packages, and
prepares them for distrlhution to various buildings on the university campus.

Bo_b. Bob is a 5’8”, 137 pound, 25 year old, Caucasian male who resides with his
mother and father. Bob’s parents described him as having mild MR. He works at a local
health club where he is responsible for cleaning the men’s locker room and the weight
machines in the aerobic fitness room. Bob has been employed at this job for 1.5 years.

Orientation Sessions

 

Prior to the baseline period, participants underwent two one-hour orientation sessions
on the use of the weight nmchines and simulated work tasks (box stacking and hand truck
push). The participants viewed a videotaped performance on the proper use of the
Nautilus weight equipment, hand truck push, and box stacking, and practiced each task.
The investigator assisted participants with performing the work tasks and positioning
themselves onto the weight machines for lifting. To minimize the risk of injury while

performing lifts, participants practiced with only one or two weight plates (an average

38

weight of 10 to 20 lb per plate) on each of the six exercise machines. Upon the
completion of practice in the weight room, participants were escorted to the gymnasium
or aerobic studio to practice the simulated work tasks (box stacking and hand truck push).

Participants also viewed a videotaped performance of the hand truck push and box
stacking simulated work tasks including: (a) proper lifting techniques for box stacking; (b)
placement of boxes on the table; and (c) proper grip and push of the hand truck. For
example, they were informed to lift with their knees, keep their back straight, and maintain
afirmgripontheboxbeing liftedandthehandtruckhandle.

A typical practice session for the work tasks involved participants performing two
trials of lifting 8 boxes (10 pounds each) from the floor onto a table. Lastly, participants
practiced pushing the hand truck twice around the perimeter of the gymnasium. The hand
truck was weighted with two 25-pound boxes. The modest amount of weight of each box
was done to provide for resistance and minimize the risk of injury. The practice sessions
enabled the researcher to screen for potential problems and participant capability to
perform the desired tasks measured in this study. The researcher was confident that
participants understood the lifting tasks when they could perform each task independently
on two consecutive trials with only verbal directions.

Test Administration

Participants were instructed to wear comfortable clothing (warm-up pants or shorts,
and T-shirt or sweatshirt) that allowed them to move and bend freely during all testing
sessions. Tennis shoes and socks were also required for safety. Participants were not able
to wear any dangling jewelry or objects that interfered with the performance of the

simulated work tasks or weight lifting exercises. All testing was done individually,

39

however, there may have been other persons present in the facilities with the participants.
Participants performed the lifting exercises before the simulated work tasks. Fluids and
additional rest periods were provided as needed.

A typical testing session included: (a) arriving at the gymnasium; (b) stretching;

(c) performing weight exercises; (d) resting for 15 minutes; and (e) performing the hand
truck push and box stacking. Supervisors at the participant’s job site assessed on-site
work productivity. A more detailed description of testing can be found in the
instrumentation section of this study.

Participants were verbally instructed and assisted if needed, to properly position
themselves onto the weight machine to prepare for lifting. An appropriate weight was
chosen close to, but below, the participant's maximum lifting capabilities to allow for
warm-up. Participants were asked to lift the designated weight once and then lower it
back to the weight stack. Weight was then progressively added to each machine in 2.5 to
10.0 lb. increments, depending upon the exercise being performed. The weight was added
to the machine until maximum lift capability was achieved. Once the participant reached a
weight tlmt he could not successfully lift for one repetition, the weight amount preceding
the unsuccessful attempt was considered his l-RM lift. The data for all strength and
exercise measures were recorded on the weight training work out form (Appendix B).
Each participant received verbal praise and encouragement for motivation during all lifts.
For example, the investigator said, "come on, you can lift it, try to do your best." When
participants completed a successful lift, one of the comments from the investigator was
"Great job buddy, way to go." The l-RM lifts were done on an individual basis and each

participant lmd the investigator present while he performed the lifts. It should be noted

40

that at times there were more people than the participant and the investigator present in
the weight room. The three sites used were open to the general public during many of the
exercise sessions. The presence of others during testing did not seem to present a problem
during weight training and testing.

Participants were allowed a maximum of four initial trials to reach l-RM on each
exercise. To minimize the risk of muscle fatigue, if l-RM was not determined after the
fourth trial, the participant moved to another machine that involved a different muscle
group (Rimmer & Kelly, 1991). For example, if Jacob attempted the chest press and his
l-RM was not achieved within four lifts, he was not allowed a fifth trial, but had to move
to the next exercise of leg curl. The participant could return to the chest press machine,
where he had the unsuccessful attempt, after performing an exercise that worked a
different muscle group. Participants were given a 3-min rest period between each exercise
station. For the purpose of testing, participants performed the lifting exercises using the
lower body muscle groups (leg extension, leg curl), then the upper body muscles (chest
press, arm curl, triceps extension), and lastly the trunk muscles (abdominal curl and fiont
lying chest lifts).

_B_aselineL Measures of the Dependent Variables

A summary of the instruments used in this study, the variables they assessed, and the
persons who administered the instruments are listed in Table 4. The job simulations used
in this investigation were similar to those suggested by Zetts et al. (1995). These

investigators measured social validity of the work tasks by having two local merchants,

41

Table 4

 

 

 

 

 

 

Summary of Instrumentation

Dependent Variable Measurement Task Person Responsible

Productivity

Box Stacking Timed stacking of eight 25 lb Investigator
boxes

Hand Truck Push Timed pushing of hand truck Investigator
loaded with two 85 1b boxes
for a 160 ft distance

On-site Task Amount of work or Work Supervisor
assemblies completed - Job Coach
depends upon participant’s
job and ratings

Strer_1gth

Leg Extension 1 RM lift Investigator

Leg Curl 1 RM lift Investigator

Chest Press 1 RM lift Investigator

Biceps Curl 1 RM lift Investigator

Triceps 1 RM lift Investigator

Extension

Abdominal Curl 1 RM lift Investigator

Front Lying No data Collected (3 sets of Investigator

Chest Lift 15 s)

 

Note. All weights were added in 2.5 to 10 lb increments.

42

two vocational rehabilitation specialists, and a high school supported work trainer identify
the job tasks as ones that are common for workers with MR. In addition, other
researchers (Hughes & Wehman, 1992) have reported that the jobs identified (hand truck
push and box stacking) for this study closely match those that are common for persons
with MR.

Simulated Work Tasks

The simulated work tasks were performed in a gymnasium or fitness area near the
participant's home. These tasks included timed stacking of eight 25-pound boxes and
timed pushing of a hand truck loaded with three boxes totaling 85 pounds over a 160-feet
distance. Data were recorded on the simulated work task performance sheet (Appendix
B). To minimize the risk of injury fi'om the lifting and pushing, all participants were
required to wear a back support belt.

Box stachg' . A total of eight cardboard boxes with dimensions of 17.5 x 11.5 x 10
inches were filled with papers and magazines to the weight of 25 pounds per box. The
boxes used were constructed to hold 10 reams of paper. The contents of the boxes were
secured and sealed with packaging tape to prevent spilling. Participants were timed using
a stopwatch as they lifted the eight boxes one at a time from the floor to a table 30 inches
off the ground. The boxes were positioned next to the table or a platform in four equal
stacks (2 high). Participants had to walk no more than two feet to retrieve boxes fiom the
floor. Participants were instructed not to stack the boxes any more than two high on the
table. Each participant performed the box-lifting tasks three times, with a rest period of 5
minutes between trials. The first trial served as a practice trial. To prevent fatigue, the

boxes used during the practice trial weighed only 15 pounds each. The results of the last

43

two trials were recorded and averaged to determine the participant's score. If a participant
dropped a box, he was instructed to pick it up and continue until the task was completed.
This did contribute to the participants' score.

Hand truck push. Materials used were a two-wheeled hand truck and two cardboard
boxes with a combined weight of 85 pounds (40 lb. and 45 1b.). Box dimensions were
17.5 x 11.5 x 10 inches. The boxes were filled with papers and magazines and stacked
onto the hand truck. The contents of the boxes were secured and sealed with packaging
tape to prevent spilling. The boxes were secured to the hand truck using packaging tape.
Participants were timed as they pushed the loaded hand truck around a rectangular course
160 feet in perimeter. The course for the hand truck push was formed by placing cones in
a rectangular formation measuring 20 feet by 60 feet. Participants performed the task
three times, with the first trial serving as a practice trial. To prevent fatigue, the boxes on
the hand truck during the practice trial weighed only 50 pounds. The averaged time of the
last two trials served as the participant's score. If a participant dropped or tipped the hand
truck, he was instructed to pick it up and continue until the task was completed. This trial
did contribute to the participant's score. A rest period of 5 minutes was given between
trials.

On-s_ite WoriLTLlslgs

The "on-site" job tasks were performed at the participant's place of employment.

Two of the participants had more than one job. Work productivity measures varied
among participants. A description of participant’s on-site jobs and the measurements
taken can be found in Table 5. On-site job tasks were measured on the same schedule as

the simulated job tasks and muscular strength. However, productivity information was

44

obtained fiom job supervisors rather than the investigator. The investigator only visited
the participants’ job sites at the beginning and end of the study. Additionally, the
investigator called some of the job supervisors to clarify requested work productivity data.
It should be noted that the amount of work completed was kept on record and was made
available to the investigator during his visits to the job sites. Participants’ employers
compensated them for the amount of work they completed. The investigator had no
control over the working conditions, hours worked, or amount of work completed for the
participant.
Mum Strengh Exmsg

In this study, weight machines were used rather than fi'ee weights. The weight
rmchines were chosen because of their availability, ease of use, and safety, as well as
better control over exercise movements than free weights. Shane and Jacob used Nautilus
machines (Nautilus Sports/Medical Industries, Deland, FL). Jim used both Nautilus and
Universal machines (leg extension and leg curl). Lastly, Bob used Icarian machines for his
weight training. The major muscles that were targeted included leg curls (harnstrings), leg
extensions (quadriceps), chest press (pectoralis muscles of the chest), biceps machine
(biceps of upper arm), triceps machine (triceps of upper arm), and abdominal machine
(rectus abdominis). The lower back (erector spinae group) was strengthened using front
lying chest lifts. More detailed descriptions of the specific exercises performed on the

various types of equipment are listed below.

45

Table 5

Descriptions and Frgquency of Danae Recorded for On-Site Job Tas_ks_

 

 

Job Descriptions Frequency of Data Recorded
Shane Sheltered Work Shop Data on hours worked and pay
Packaging per hour were collected every
Assembly two weeks.’
Material handling
High School Weekly comments and rating
Dish washer scale of poor, average, good,

General cleaning (sweep, mop and great.
floor, take out garbage, wipe
tables, cleaning, and painting

lockers)
Jacob Sheltered Work Shop Data on hours worked and pay
Packaging per hour were collected every
Assembly two weeks.b
Material Handling
Restaurant Weekly comments and rating
Dish washer scale of poor, average, good,

General cleaning (wipe tables, and great.
sweep floor, take out garbage,

clean restrooms)
Assemble delivery boxes

Jim Mailroom at University Weekly comments and rating
Mail sorter scale of poor, average, good,
Package mover (bags and and great.
boxes)

Bob Health Club Weekly comments and rating
Clean men’s locker room scale of poor, average, good,
Clean aerobic machines and great.

 

a‘bJob descriptions varied and were dependent on the work contracts held from various
companies. Examples included packaging nuts and bolts, toys, and tools, and assembling

boxes.

46

Nautilus Equipment (Brzycki. 1995. pp. 86-98)

1. Leg extension (guadraceps). Sit down, place your feet behind the roller pad,
with the backs of the knees against the end of the seat pad. There should be little, if any
space between the buttocks and the back pad. Fasten the seat belt and hold onto the
handles located on the side of the seat pad. Extend both legs smoothly as high as possrhle
by pushing against the roller pads. Pause briefly at the end of the extension phase, then
lower to start position in a controlled manner.

2. Leg curl (hamstmg' ). Lie face down on the bench pad and place feet under roller
pads with knees just over the edge of the bench. Lightly hold onto the handles on sides of
the bench pad to prevent your body from moving. Curl legs and try to pull the heels as
close to your buttocks as possible. Pause briefly at completion of the curl then lower the
weight in a controlled fashion until the legs are fully extended back to the starting position.

3. Abdominal curl (fidomfiinalfi. Sit in the machine. Locate the axis of rotation on
the right side. Adjust the seat so that the axis of rotation is at the same level as the lower
part of your sternum, or breastbone. Place ankles behind the roller pads. Rotate the
shoulder pads to the most comfortable position. Rest your hands on your legs. Rotate the
shoulders forward and down in an are around the sternum as far as your range of
movement allows. Pause during the crunch phase. Return to the starting position.

4. Double chest or arms cross (pectorali__s)_. Adjust the seat height so that the front
part of the shoulder is directly below the axis rotation. Sit on the seat and fasten the seat
belt. Place the forearms against the arm pads and grasp the upper handles. The elbows
should be slightly higher than the shoulders. Without moving the upper torso or the head

away from the back pad, bring the elbows as close together as possible by pushing against

47

the arm pads. Pause briefly in the mid-range position and lower the weight under control
to the starting position (arms apart) to get a good stretch.

5. Bigps curl (biceps). Sit down and place the feet flat on the floor (or on the
bottom portion of the flame). Reach across the elbow pad and grasp the handles with the
palms facing upward. Adjust the seat so the shoulders are slightly lower than the elbows.
The elbows should be placed on the elbow pad in alignment with the axis of rotation. Curl
both arms to the contracted or flexed position without moving the elbows or bending
backward at the waist. Pause briefly during flexed position and then return the weight
under control to the starting position.

6. Tri9_ep§ extension (triceps). Adjust the seat so that the shoulders are slightly
lower than the elbows. Place sides of hands on movement arms and elbows on the pad
andinlinewiththeaxisofthe cams. Positionthehandsonthewristpadssothat thepalms
are facing each other and the hands are open (i.e., fingers extended). Place the feet flat on
the floor (or the bottom portion of the frame). Keep the elbows against the elbow pad and
push the movement arms forward by straightening the lower arms. Pause briefly in the
mid-range position and then lower the weight in a controlled fashion to the starting
position (arms flexed).

Exercises with they Universal Welg' l_lt fiuipment (Bmcki. 1995. pp. 108-109)
1. Leg extension (quadriceps). Sit down, place the backs of the knees against the
end of the bench pad and position the feet behind the roller pads. Lightly grasp the sides
of the bench pad and lean back slightly. Extend the lower legs as high as possible by
pushing against the roller pad. Pause briefly in the mid-range position and then return the

weight under control to the starting position to obtain a proper stretch.

48

2. Leg curl (mm gs). Lay face down on the pad and place the lower legs
underneath the roller pads. Position the top of the knees just over the edge of the bench
pad, not on the pad. Lightly grasp the support bars located on the sides of the bench pad.
Pull the heels up as close to the buttocks as possible. Pause briefly in the mid-range
position and then lower the weight under control to the starting position (legs firlly
extended) to allow for a good stretch

3. Abdomi_n_al curl with lat pulldown machine (abdominals). Remove the straight
bar and replace with rope grip handle. Sit down on the bench facing away fi'om the
machine. Grasp the rope part of the grip, just above the end stops. Place hands on side of
head by the ears. While keeping hands by cars, slowly bend forward at the waist then sit
back up while still holding rope by the ears. Repeat movements. Do not sit totally erect
when performing exercises. This exercise was a modification by the investigator for

abdominal curl.

Exercises with the ICARIAN Weight Equipment (Fitness Product Intematiofl,

Sun Valley. CA)

 

l. Leg extension 605 (quadriceps). Select appropriate weight. Adjust back pad so

that the knees align with pivot point. Adjust the leg pad to rest comfortably above the
foot over the ankle. Lightly grasp the handgrips on the side of the machine. Extend the
legs upward with a slow controlled movement. Slowly return to start position.

2. Prone leg curl 606 (hamstpmg' s). Select appropriate weight. Adjust leg pad to
rest comfortably above foot. Align the knee with the pivot point and lay down in the

prone position on the machine. Grip handles lightly. Curl legs upward, with slow

49

controlled movements keeping hips on the bench. Slowly return the weight to the start
position.

3. mar magma (1er 405 (pectoraljg). Select the appropriate weight. Adjust
seat so arms are shoulder level. Press arms together with forearms, pause, and slowly

return to start.

4. _Cgpber curl 204 (highs). Select the appropriate weight. Adjust seat so arms
rest comfortably on pad and elbows align with pivot point. Grip handles with both hands
and pull upward with a slow controlled movement. Slowly return to the start position.

5. Seated tricep 208 f triceps). Select the appropriate weight. Align elbows with
pivot point. Grip the handles firmly and push forward.

6. Abdomi_nal isoLator 712 iafbdominalfi. Select appropriate weight. Adjust start
position to desired extension. Adjusts seat height so chest pad rests comfortably on upper
chest. Place the feet on the footrest (select desired foot position by flipping foot bar).
Push upper body toward knees with a slow, controlled movement. Slowly return to the
start position.

To determine muscular strength, the participant performed one repetition maximum
lift (l-RM) for each exercise. One repetition maximum lift referred to "the maximum
amount of weight lifted one time with correct form during the performance of a
predetermined weight-lifting exercise" (McArdle et al. 1991, p. 454). The l-RM lifts
comprised the composite strength scores for each participant. Composite strength was

defined as the sum of the l-RM lifts for each of the exercises performed per week.

50

Intervention

The intervention consisted of a 9-week weight-training program, two days a week.
Participants performed the weightlifting exercises with a partner to simulate a typical
setting for a fitness or health club. A typical intervention session included a warm-up,
lifting, and cool-down period. Descriptions of the resistance training protocol, typical
setting, and safety precautions used for this study are provided below.
Resistance Tm ' Protocol

The 9-week intervention period was divided into three phases based on changes with
weight percentages and the number of sets and repetitions lifted. The first phase lasted for
a period of 2 weeks (4 sessions) and included 2 sets of 12 repetitions of each of the 7 .
strength-training exercises with low resistance (30% to 40% of their l-RM lift). The
second phase of the intervention lasted for a total of 3 weeks (6 sessions) and involved
lifting 3 sets of 8 repetitions of each exercise with a moderate increase in the amount of
resistance. Resistance was set at 50% to 60% of l-RM lift. The third and final phase of
the lifting program was 4 weeks (8 sessions) and included 4 sets of 6 repetitions of lifting
with an increased resistance of 70% to 80% of each participant's l-RM lift. (Appendix D).

The weight progressions were developed to place a progressive overload on the
muscles to produce maximal strength gains. Atha (1981) has indicated that multiple sets
are more effective for developing strength and muscle endurance than single sets.
McArdle et al. (1991) mentioned that a load that is equal to 60% to 80% of a muscle’s
force-generating capacity (l-RM) is suflicient to increase strength Although these
percentages were established for persons without MR, the percentages have been shown

to be effective for persons with MR (Rimmer & Kelly, 1991). The investigator looked at

51

factors of fatigue, facial expressions, sets, and repetitions completed. Participants initially
performed exercises at lower percentages of l-RM (30%) because of low fitness levels
and to minimize the risk of injury. Furthermore, the researcher attempted to start the
participants out with a resistance that would be motivating and produce the most success.
Typical Intervenfion Setting

Each weight lifting period was approximately 1 to 1.5 hours long and consisted of 15-
20 minutes of warm-up and stretching exercises, 40-60 minutes of lifting, and 5-10
minutes of cool down stretching exercises. Participants may have performed their lifting
periods with others present in the workout facility. This was done because the facilities
used were open to the public.

Warm-up. Each lifting period started with a warm-up session. Participants entered
the building and reported to the gynmasium to collect their folders (which contained their
exercise data) and prepared for warm-up. Participants jogged or walked once around the
perimeter of the gymnasium (276 feet), stretched certain muscle groups (shoulder, back,
groin, knees, and legs), and reviewed directions for performing the lifting exercises.
Participants performed eight stretching exercises during warm-up. The exercises included:
(a) anterior shoulder and posterior shoulder stretch; (b) double knee to chest and figure
four for the lower back; (c) lunge and butterfly for the hip and groin area; and (d) the knee
and legs, quadriceps stretch (standing), and hamstring stretch using the straight leg raise
(Sudy, 1991). Each stretching exercise was performed for three repetitions and held for
the duration of 5-7 s. Descriptions of the stretching exercises used are listed below (Sudy,

1991, pp. 287-289).

52

l. Anterior shoulder stretch. Grasp hands behind the back. Gently push arms
upward.

2. Posterior shoulder stretch. Place left hand on right shoulder. With the elbow up
and parallel to the floor, use the right hand to apply pressure above the elbow and toward
the body. Repeat for right side.

3. Double knee to chest. On back, with kmes bent, gently pull both knees toward
chest, lifting feet off the floor, hold and relax. This exercise may also be done using one
leg.

4. Eigpre four stretch. On back, with head down, flex right knee across the body
and pull toward left shoulder. Repeat for left side.

5. @flexor stretch (lungg). Assume a lunge position, rmking sure fi'ont knee is
directly over the foot and ankle. With weight supported by both hands, press hip toward
the floor.

6. Groin stretch (butterfly). Sitting erect with soles of feed together, gently pull
heels toward groin and press inside of knees toward floor.

7. M'cgps stretch (standmg' ). Using a wall or chair as support, reach back with
the right hand and grasp right ankle. Be certain hips are forward and knees are adjacent to
each other. Repeat on left.

8. Hamstmg’ stretch (straigl_1t leg raises). On back, with knees bent and feet flat on
floor, raise the right leg without lifting hips fiom the floor. Repeat on the left. Grasp the
leg below the knee to increase the stretch.

Rotation throagh weight stations. The proper number of weight plates for each

participant was placed on the weight machines by the investigator. Participants performed

53

one set of the designated amount of repetitions on a particular exercise, then moved to the
next exercise machine. Participants completed one set of all the exercises before
beginning the second set. Exercises were performed in this order: leg extension, leg curl,
chest press, biceps curl, triceps curl, abdominal curl, and back extension. Participants
performed exercises for the lower body muscle before the upper body; therefore, the
larger muscle groups were worked before the smaller muscles to prevent fatigue.
Participants were allowed a 3 to 5 minute rest period before they proceeded to the next
exercise machine.

Participants were not allowed to exceed the number of sets or repetitions (2 x 12, 3 x
8, and 4 x 6) designated for each phase of the intervention. Conversely, if participants
could not perform all of the repetitions using the designated percentages of their l-RM,
they were verbally encouraged by the investigator to lift what they could. Verbal
encouragement included such phrases as "good work, way to go," and "nice try, you will
get it next time.” Weight adjustments were made accordingly and noted on the
performance data forms by the investigator or assistants.

Cool down. Each lifting period ended with a cool down session. Participants
performd the same stretching exercises (shoulder, back, groin, knees, and legs) as in the
warm-up. They turned in their folders and departed.

Safeg Precautions

There were several safety precautions taken to minimize the risk of injury to
participants while performing lifting exercises. The investigator is a certified instructor of
first aid and cardiopulmonary resuscitation (CPR). Each participant had the opportunity

to practice the lifting exercise prior to intervention. Participants were required to perform

54

warm-up flexrhility exercises before lifting. The investigator supervised or did all seat and
weight adjustments. Participants had at least one day of rest between lifting sessions, and
all lifting was done under supervision by the investigator. Each participant had an
individualized program, and lifted a weight amount that was appropriate for his strength
level. Muscles were trained from the largest to the smallest to minimize the risk of fatigue
(Brzycki, 1995). Other safety precautions used with the participants included lifting the
weight with slow, smooth, controlled movements; breathing naturally during lifts and not
holding the breath; and taking a rest period between exercises (Brzycki, 1995; Sudy,
1991)

Data Collection Procedures

Data collection during the intervention phase was conducted to verify participation in
the intervention. Therefore, each participant had the amount of weight lifted, the number
of repetitions and sets required, and the machine used, recorded on his data sheet by the
investigator. Data files of the lifts and muscles worked can be found in Appendix D. The
investigator was also responsible for assisting and supervising participants with stretching
and spotting on the lifting exercises.

Each participant was: (a) assigned a time to come to the weight room, become
familiar with the weight equipment, and ask questions; 0)) familiarized with the procedures
for strength and work tasks measurements/observations by viewing a videotaped
performnce; and (c) assigned a time to be tested on muscular strength and work
productivity tests. Observations for strength and on-site work tasks took place at local

university gymnasiurns and weight room or health club. The on-site work task was

55

performed at each participant's place of employment. All transportation to and from data
collection sites was the responsibility of the participant or parent/ guardian.
Testing Schedule

Participants were tested once a week for a total of 20 weeks on strength and work
productivity measures, with 5 testing occasions during the baseline period, 9 for the
intervention period, and 6 during the second baseline or retention period. Due to time
constraints, testing during the intervention was done on the days subjects were scheduled
to weight train. To minimize the possibility of muscle fatigue due to overuse of muscles,
especially with the lifting exercises, participants were given additional rest time.
Participants needed approximtely 85 to 100 min to complete the lifting exercises, 35 to
50 min for the simulated work tasks, and 15 to 30 min for rest periods, resulting in a total
duration of 135 to 180 nrin per session.

The researcher encouraged participants to attend each testing and intervention
session. If a participant missed a day, he was able to rmke it up on one of the days that
regular testing was not scheduled. However, if a participant missed more than three
testing sessions and could not make them up, he was excluded from the study. No
participants were excluded fi'om the study for excessive absences. After data collection,
participants were provided with thank you letters, a record of their performances, and a
certificate of participation. Letters of appreciation were sent to people who were
instrumental in facilitating this study. Letters of recommendation were written for

participants if requested by the participant or parent/ guardian.

56

Testing Personnel

The investigator collected all data. The investigator helped to monitor participants
during testing and intervention by setting the proper weight amounts, seat heights, and
timing of the simulated work tasks. The investigator has had extensive experiences in
working with persons who have MR. He has a master’s degree in adapted physical
education, and has taught adapted physical education for 12 years. Lastly, the investigator
has lifted weights for several years and has taught several weight training courses at both
the secondary and university levels.

Data ses

Data were analyzed by graphic presentation and visual inspection at the conclusion of
each baseline and the intervention period. Calculation of the split-middle line to determine
the celeration line of trend estimation and changes in level, variability, trend, or slope of
trend line of the data points were of importance for strength and work productivity
outcomes for each participant (Ottenbacher, 1986).

Visual Imtion of the Data

Visual inspection involves plotting the data on graphs and looking at the increases
and/or decreases in scores for the various variables. More specifically, visual inspection
involves analyzing changes in level, variability, trend, and slope of the graphed data points.
Changes in level refer to the magnitude of the data (Bloom & Fischer, 1982). A change in
level refers to the shift of a participant’s performance fiom the end of one phase to the
start of the next phase (e.g., fi'om baseline to intervention) (Ottenbacher, 1986).
Variability is the amount of change or fluctuation in the spread of scores in a series.

Performance in the baseline phase should be stable to determine the effectiveness of the

57

intervention. Changes in trends refer to direction in which the data pattern is moving.
Changes in trend are usually associated with the presentation of the intervention. The final
step of visual inspection involves the slope of the trend line across time.

Statistical Analyses

Statistical significance for the strength and work productivity was determined by
analysis of the celeration line as suggested by Ottenbacher (1986). "The term celeration
derives from the notions of acceleration and deceleration if the trend is ascending or
descending, respectively" (Barlow & Hersen, 1984, p. 313). To determine the rate of
changes in strength and work productivity scores due to treatment, each participant's
performance was measured on several occasions over each testing/observation phase.

As suggested by Ottenbacher (1986) a trend or celeration line was computed for the
baseline plmse and extended into the other phases of the study. The extension of the
celeration line was done to predict the data trend of the participant’s behaviors. This
celeration line is similar to the regression line or line ofbest fit in which a line is drawn
through a set of data points on a graph in the direction of the trend or cluster of data
points. If the proportion of data points were above or below the celeration line during
treatment or observation phases floor the baseline, this indicates change in the response to
the treatment. A visual description of the celeration line using the participant’s data is
discussed in the result section of this study.

Rationale for Statistical A_nal_ysis. It should be noted that statistical tests are not
usually used in applied behavior analysis research (Barlow & Hersen, 1984; Huck et a1.
1974). Interpretation of the results is frequently done by graphic presentation and visual

inspection. Barlow and Hersen (1984) and Wolery and Harris (1982) suggest that both

58

visual inspection and statistical analysis should be considered to better investigate the

changes that occur within and between experimental conditions.

For the purpose of this study, statistical analyses consisted of determining the slope,

level of change, and the linear trend of strength and work productivity outcome data by

incorporating the split middle technique. An explanation of calculating the split middle

technique, as described by White and Haring (1980), involves seven steps and can be

found below.

Calculation of the split middle line of trend estimation is based on the medians of two

halves of the data series for which the trend line is being determined (White and Haring

(1980).
l.

2.

Plot the data on semi logarithmic graph paper.

Count the datum points in the phase for which a trend line is being drawn, divide
by 2, and add 0.5 to the quotient.

The final answer from Step 2 is used in Step 3. Count over fiom the left,
beginning with the datum point nearest the ordinate, the number of datum points
in the final answer of Step 2 and draw a hash line through the data series. If the
answer fiom Step 2 were a whole number, such as 4, the experimenter would
count over, from the left, that number of datum points and draw a hash line
through the datum point equal to the whole number. This datum point is ignored
in calculations of Steps 4 through 6. The result of Step 3 is a division of the data
series into two equal sets (halves) of data.

For each equal set or halfof data fi'om Step 3, calculate the mid-date and draw a

dashed vertical line through it. The mid-date is calculated by repeating the

59

process described in Steps 2 and 3 for each halfof the data (for each of the two
sets in the data series).

5. Calculate the mid-rate for each half of the data series and draw a horizontal
dashed line through the mid-rate that intersects with the dashed vertical line
through the mid-date. The mid-rate is calculated by counting the number of
datum points in each half, dividing by 2, and adding 0.5 to the quotient.

NOTE: Frequently, when calculating the mid-date and mid-rate, the answer to
calculations will not be a whole number.

6. Draw a straight line through the two sets of intersecting dashed lines at their
point of intersection. This straight line is known as the quarter-intersect line.

7. Draw a line parallel to the quarter-intersect line that has 50% of the datum points
on or above it and 50% of the datum points on or below it. The resulting line is
the split-middle line of trend estimation.

This technique allowed analyses of present levels of performance in addition to
predicting future performances. The split middle analysis is a process used to descnhe
change in behavior rather than a way of determining statistical significance (Barlow &
Hersen, 1984). Statistically significant change in behavior can be determined after the
celeration line is calculated. This is done by computing the split middle slope of the
baseline and the split middle slope of the intervention and looking at the level of changes

that occur across those phases (Barlow & Hersen, 1984).

60

Deciiion Rule for Effective IntervenLorj

It was hypothesized that the weight-training program would lead to improved
strength and increased work productivity among the participants. The investigator also
examined gain scores to further determine the effectiveness of the intervention on the
measures of strength and work productivity. The mean of the baseline and intervention
scores were compared to determine improvements in strength. The researcher considered
the intervention to be successful if there were strength gains of at least 40 to 50 pounds in
the mean composite strength of participant’s 1-RM lifts exercises performed between the
baseline and intervention phases of the study. The intervention was considered effective
for the simulated work tasks if participants' mean time to completion to stack the 8 boxes
and to push the hand truck the distance of 160 feet decreased by at least 6 to 8 s for each
of the simulated work tasks. In addition, there was a positive treatment effect if the
majority of the data points in the intervention phase fall on or above the celeration line for
strength data and on or below the line for simulated work tasks indicating an improvement
of scores fiom baseline data. The distance of the data points fi'om the celeration line
might also add to the level of significance.

For visual reference, the level and trend changes were also used to filrther determine
the effectiveness of the intervention. Wolery and Harris (1982) indicated “an
experimenter can conclude that a treatment is effective when the following situations exist
concurrently. There must be either no changes or very minor changes within experimental
conditions and a clear change in level, trend or both level and trend must occur when the
treatment is introduced” (p. 447). More detailed data for on-site work productivity may

be found in the results section of the paper.

61

Increased work productivity and positive comments from job supervisors were the
criteria used to determine a successful intervention effect for the on-site jobs. On-site job
productivity rates were dependent upon the specific jobs held. For example, assembly,
packaging, and material handling jobs were evaluated on the amount of work participants
completed for the indicated hours as detailed by the job supervisors. Pay rates varied for
the various assembly and packaging jobs for two of the participants. The intervention
effect for the cleaning tasks and mail sorting tasks were determined to be significant if the
job supervisorsreported positive comments or gave a rating of “good” or “great.” It
should be noted that data on on—site work productivity was difficult to obtain. However,
the investigator attempted to interpret the data and comments given as accurately as
possible. More detailed data for the on-site work tasks may be found in the results section

of this study.

62

CHAPTER FOUR
RESULTS

The only hypothesis supported by the results of this study was the prediction that
muscular strength would improve as a result of a resistance exercise program. Support for
the hypotheses was based on score (strength or time to completion) improvements, level
and trend changes, and celeration line scores for all of the participants, as outlined in the
methods section. Each of the participants showed significant strength improvements of at
least 20 to 40 lb in composite strength. Partial support was obtained for the hypothesis
that performance of simulated job tasks would improve as the result of resistance exercise
training. The hypothesis that performance of on-site job tasks would improve yielded
non-significant results in relation to mean scores across pluse, level and trend changes,
and celeration line data. Table 6 provides a summary of the significance of the progressive
resistance-training pro gram for each of the dependent variables.

Hymthesis 1

It was hypothesized that participants would improve their strength. As expected,
participation in the progressive resistance-training program did increase the muscular
strength of all participants. The strength data support the first hypothesis that
participation in a progressive resistance-training program would increase muscular
strength and endurance in biceps curl, leg curls, leg extension, triceps extension,
abdominal curl, and chest press exercises among the participants. The strength gains
experienced were greater than expected by the investigator. Mean composite strength
scores for each participant are listed in Table 7. Jacob showed the greatest overall

improvement from baseline through intervention that continued into the retention period.

63

Table 6

Effects of the Interven_tion on Performance of the Depgpdent Variables

 

 

Shane Jacob Jim Bob
Trend/Level
Strength Increased 15 lb Increased 0 lb Increased 20 lb Increased 20 lb
(5.2%) (0%) (5%) (6%)
Hand truck Increase 35 Decrease .27 s Decreased 1 s Decreased 3 s
(8%) (.8%) (2%) (7%)
Box stack Increase .91 s Decrease 6 5 Increase 2 s Decrease 2 s
(2.4%) (14.4%) (5 %) (4%)
On-site job’ No Data No Data No Data No Data
Cgleration Line
Strength Significant Significant Significant Significant
Hand truck NS NS NS Significant
Box stack Significant Significant Significant NS
On-site jobb No Data No Data No Data No Data

 

Nat; Increases and decreases are based on the score for the final week of baseline and the
first week of intervention for each dependent variable. ( ) = Percentages are listed for
level changes based on the final week of baseline to the first week of intervention. Trend
changes are based on the slope of the baseline compared to that of the intervention. NS =
Non Significant and is based on the decision rule of the majority of data points in
intervention being above (strength) or below (simulated work tasks) celeration line.

ll’b’No level and trend or celeration line calculations were made for the on-site job tasks.

Table 7

Mean Commsite Strength Scores for Baseline. Interven_tion, and Retention

 

 

Participants Phase of Study

Baseline Intervention Retention
Shane 292 352 485
Jacob 403 537 749
Jim 353 . 447 550
Bob 302 374 480

 

Note. Scores are listed in lb and represent the mean composite strength of participants’ 1-
RM lifts for all exercises (leg extension, leg curl, chest press, biceps curl, triceps curl, and

abdominal curl). Scores are rounded to the nearest whole number.

65

Shane and Jacob demonstrated more baseline stability than did Jim and Bob.
Comparisons of high and low baseline scores for each of the participants showed baseline
variations of no more than 45 lb for composite strength. Shane demonstrated the least
variance with 12.5 lb and Jim showed the greatest difference of 45 lb.

Figure 1 shows a visual comparison of composite strength scores for all participants
during the baseline, intervention, and retention phases of the study. Jacob had the highest
rate of increase throughout the study. Shane, Jim, and Bob showed similar rates of
increase throughout all phases of the study. Additional comparisons of participants’
composite muscular strength scores and raw data for each of the six exercises can be

found in the data files located in Appendix D.

Level a_n_d Trend Changes for Commsite Strength

 

Level and trend changes provided visual reference on the treatment effects of the
progressive resistance-training program. Level and trend changes involve comparisons of
the data patterns of the baseline and intervention scores, as mentioned in the methods
section of this study. Three of the four participants experienced noticeable level and trend
changes across baseline, intervention, and retention phases. The changes in level and
magnitude of the trend lines for the data points of each participant are described for each
participant.

Mg Figure 2 shows that Shane had changes in both level and trend between the
baseline and the intervention. Shane’s strength scores for the final week of baseline and
the first week of intervention were 290 and 305 lb respectively. Shane’s scores during
intervention show some variability; however, the trend line of the data points during this

phase shows a projected increase in strength. There were also level and trend changes

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recorded from the intervention to the retention phase. Shane’s final strength measurement
during intervention was 425 lb, and the first week of retention showed another increase
with a score of 460 1b. It was shown that his strength continued to increase well into the
retention phase. That is, the trend line data during this phase in on an ascending slope.

M There were minimal changes in level and drastic changes in the trend of the
intervention data points (see Figure 3). Jacob’s composite strength measure for the final
week of baseline was 410 lb. This was maintained for the first two weeks of the
intervention. In contrast, the trend of Jacob’s strength scores during intervention shows a
drastic upward slope with a projected increase in strength. His score during the final week
of the intervention was 670 lb, which increased by 25 lb during the first week of the
retention phase. The trend line for Jacob’s scores during the retention phase shows an
increase; however, it is not as drastic as in the intervention phase. His final composite
strength score during the last week of the retention plmse was 750 lb. It would be
expected that Jacob’s scores would begin to level off and decrease after the removal of the
intervention.

Ian; Changes in trend and level of strength scores for Jim can be seen in Figure 4.
Baseline to intervention scores showed little change in level and trend of the data series.
However, there was an increase 20 lb across the two phases. Jim’s final strength score
during the baseline phase was 375 lb. His initial score during the first week of the
intervention was 395 lb. The slight increase in level between the intervention and
retention plmse predicts a continual increase in strength scores. In addition, the trend line

of the data for the retention phase shows an increasing slope; however, it is not as drastic

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as in the intervention phase. Jim’s final score during retention was 550 lb, which was a
decrease fi'om the two previous weeks of the retention. It would seem from the data that
Jim’s strength was beginning to level off. This would be the expected outcome once the
weight- training program was stopped.

_Bo_b. The level and trend changes for Bob were minimal (see Figure 5). His scores
for the final week of baseline and the first week of intervention were 320 and 340 lb
respectively. The slope of the trend line for the intervention shows an increase in scores
with a greater magnitude than the baseline trend line. There is little variability in
intervention scores. Bob’s score of 445 lb during the final week of intervention was his
highest for that phase. The change in the level from the intervention to retention showed
an increase of 25 lb. The magnitude of the trend line during the retention phase is similar
to that of the intervention phase, which indicates that Bob’s strength continued to
increase. His final score during the retention phase is 485 lb. Bob’s results should be
interpreted with caution due to some variability in his baseline scores.
leer_a_t@n Line for Ctnrmosite Strengm

Celeration line projections allowed the investigator to predict the trend of the scores
after the baseline scores have been established. As with the level and trend, calculation of
the celeration line produced varying results. Table 8 provides a summary of the data
points above the celeration line. The majority (5) of the intervention scores should be on
or above the celeration line to be classified as a significant change. In addition, the
distance of the intervention points away fiom celeration line may also add to the
significance of the results. That is, the data points above and farther away fi'om the

celeration line are higher than that closer to the line for composite strength data.

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Table 8

Number of Points On or Above the Celeration Line for Comppsite Strength

 

Intervention Retention
(Maximum 9 data points) (Maximum 6 data points)

 

Shane 9 6
Jacob 9 6
Jim 9 6
Bob 9 6

 

74

_SLan; As seen in Figure 6 all scores during the intervention phase were above the
celeration line. This is a good indication of a positive treatment effect of the resistance-
training program. Some of the composite strength scores increased as much as 100 lbs. or
more during the intervention. Weeks 6 and 7 of the intervention phase showed some
variability in scores (305 and 330 lb respectively). Retention scores for Shane were also
well above the celeration line. Retention scores for Slmne continually increased for the
first 3 weeks of that phase, and then started to level off by the end of the phase.

._l§§0_b. Figure 7 shows that all intervention scores were either on or above the
celeration trend line. This would indicate a possible treatment effect by the progressive
resistance-training program for strength. The highest score for Jacob during the
intervention phase was 670 lb. In addition, his strength continued to improve after the
intervention had ceased. The highest score received throughout the course of the study
was 790 lb on the third week of the retention phase. Jacob improved in strength by an
average of 355 lb fiom baseline through the retention phase.

Jil_n._ As illustrated in Figure 8, all scores during the intervention phase were close to
or above the celeration line. Jim’s predicted strength gains from the celeration line and
actual strength gains were relatively similar. His actual strength was slightly higher.
Variability of scores throughout the intervention was virtually non-existent. There was a
steady increase in strength with more significant gains coming during the end of the
intervention and into the retention phases respectively. There was an increase of 195 1b
fiom the lowest baseline score (330 lb) to the highest intervention score (525 lb).
Although not as high as the previous participants, analysis indicates a significant treatment

effect due to the intervention.

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Bop Extension of the celeration line for Bob’s strength scores shows a predicted
increase in strength scores (see Figure 9). Bob’s baseline scores show some variability
with an upward trend of the celeration line. Although all scores during the intervention
are above the celeration line, the majority of them are closer to the celeration line than for A
the other participants. Bob experiences an acceleration of compo site strength the last two
weeks of the intervention. This is an indication that the actual rate of increase is similar to
the predicted rate. Intervention scores show some variability in scores with the last two
weeks showing increases of 420 and 445 lb respectively. Scores in the retention phase
were filrther fi'om the celeration line than for the intervention, indicating still more
increases in strength after stopping the intervention.

Percent Performance Changes for Strength

Percent changes are outlined in Table 9 for each lifting exercise across baseline and
intervention and baseline and retention phases. Increases in strength among exercises
ranged from 5% to 65% between baseline and intervention to 26% to 138% between
baseline and intervention. Jacob showed the greatest increase fiom baseline to retention
with an increase of 113% on the leg extension exercise. Conversely, Bob received the
lowest overall percent change from baseline to retention on the leg curl exercise. Overall
percent changes were positive for all participants. The improvement in strength may be
due to the progressions used in the study. The gradual changes in the amount of weight
lifted allowed for optimal and safe muscle increases. Additionally, participants worked out
two days a week. They were not accustomed to this type of regime and their muscles

responded positively.

79

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Table 9

Percent_age Cha_nge in Mean l-RM Scores for Strength Data for Each Exercise

 

 

Shane Jacob Jim Bob

Exercises
fig Extension
Baseline (B) 76.0 124.0 96.0 80.0
Intervention (I) 96.7 191.1 121.1 101.7
Retention (R) 158.3 265.0 165.8 158.3
% Change B-I 27.2 54.1 26.1 27.1
% Change B-R 108.3 113.7 72.7 97.9
Leg Curl
Baseline (B) 38.0 64.0 51.0 3.0
Intervention (I) 40.0 67.8 53.9 45.0
Retention (R) 51.7 95.0 64.2 47.5
% Change B-I 5.3 5.9 5.7 21.6
% Change B-R 36.1 48.4 25.9 28.4
Chest Press
Baseline (B) 80.0 74.0 96.0 79.0
Intervention (I) 87.8 101.1 1 13.3 96.7
Retention (R) 106.7 145.0 125.0 110.8
% Change B-I 9.7 36.6 18.0 22.4
% Change B-R 33.4 95.9 30.2 40.3
Bic_eps Curl
Baseline (B) 39.0 47.0 43.0 34.0
Intervention (I) 48.3 55.0 54.4 44.4
Retention (R) 50.0 80.0 65.0 55.0
% Change B-I 23.8 17.0 26.5 30.6
% Change B-R 28.2 70.2 51.2 61.8

81

Table ‘9

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Shane Jacob Jim Bob
Exercises
Tricgps Extension
Baseline (B) 31.0 43.0 35.0 37.0
Intervention (I) 38.9 57.8 57.8 40.6
Retention (R) 53.3 75.8 65.0 52.5
% Change B-I 25.5 34.4 65.1 9.7
% Change B-R 71.9 76.3 85.7 41.9
Abdominal Curl
Baseline (B) 28.0 51.0 32.0 35.0
Intervention (I) 45.6 64.4 46.1 45.6
Retention (R) 66.7 88.3 65.0 55.8
% Change B-I 62.9 26.3 44.1 30.3
% Change B-R 138.2 73.1 103.1 59.4

 

Note. The baseline, intervention, and retention scores are listed in lb. Baseline,
intervention, and retention percent changes are calculated based on the means of each

respective phase.

82

Visual inspection of the data for composite strength shows that participation in the
progressive resistance exercise pro gram produced increased composite strength for all
participants. The rate at which participants increased varied. Two of the four
participants’ actual rates of increase were consistent with their predicted rate fi'om
extension of the celeration line. Three of the four participants showed strength increases
prior to participating in the intervention. Although strength improvements were evident,
results fiom participants with unstable baselines should be cautioned.

Hymthesis 2

Results of the simulated work tasks provided partial support of the hypothesis
regarding work productivity of hand truck push and box stacking task. The investigator
expected all participants to have sizeable improvements in completion times. All
participants showed some improvement in their mean scores for both the hand truck push
and box stacking tasks from baseline through intervention. Level and trend changes
among the baseline, intervention, and retention phase varied among participants. The
celeration line results were significant (only for Bob with the hand-truck push and Shane,
Jacob, and Jim with the box stacking tasks. Additional comparisons and raw data of
participants’ mean hand truck push and box-stacking scores can be found in the data files
located in Appendix D. Additional level and trend changes and celeration line results will
be described for the simulated work tasks to provide for further interpretation.
Con_lpm' n of Particm’ ts’ Hand TruckfiPush Scores

Score comparison shows varying levels of significance among the participants. Mean
scores for the hand-truck push are listed in Table 10. The mean time to completion varied

for each participant, with Shane and Jacob having the lowest (fastest) mean scores

83

Table 10

Mean Scores for Time to Corrfltion of the Hand-Truck Push

 

Time to Completion in Seconds)

 

Parti lpant' 3

Baseline Intervention Retention
Shane 37.01 31.94 30.22
Jacob 38.68 31.29 30.34
Jim 49.87 43.89 38.92
Bob 45.66 38.26 33.53

 

Note. Scores are rounded to the nearest whole number in the text. Scores represent the

participants’ mean productivity scores measured by time to completion.

84

during the intervention. However, Jacob and Bob showed the greatest improvement fi‘om
baseline to intervention with improvements of about 7.4 s each.

Figure 10 shows a comparison of hand truck push scores for all participants. Visual
inspection shows baseline variability and slopes that are not level for Shane, Jacob, and
Jim. That is, each of the data series within baseline illustrates a downward rather tlmn a
horizontal trend. The most noticeable change in baseline scores occurred between Shane
and Jacob who showed score decreases of 5.4 and 5.2 s respectively during the last week
of baseline. These changes may be due participants becoming more familiar with the tasks
as the weeks progressed. Further visual inspection of Figure 10 illustrates that all
participants showed improvements in their completion times during intervention. The rate
of those improvements and the magnitude of the data series also varied for each
participant. By viewing the slope of the data series, it can be observed that scores for Jim

and Bob show the greatest rate of improvement during the intervention phase.
Level a_n_d TrendChgges for the Hand Truck Push Task

The level changes across baseline, intervention, and retention phases were relatively

 

minor for all participants on the hand truck push The trend of the data series on the other
hand showed more noticeable changes across the three phases. Descriptions of those
changes for each participant are detailed below. As mentioned previously, the level and
trend changes involve comparing the baseline and intervention data. In addition the
researcher also described the change in the intervention to retention phase.

Shara Hand-truck push scores for Shane showed small change in level of the data
across the baseline and intervention phase (see Figure 11). His score during the final week

of baseline and the first week of intervention was an increase of 2.8 5. Shane

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demonstrated a more dramatic change in the slope of trend line between baseline and
intervention. The trend of the data for Shane’s intervention scores seems to level off more
than shown in baseline. In addition, scores fiom intervention to retention showed more
variation in the trend of data than level. Shane’s score in the last week of intervention was
29.8 s, and his score during the first week of the retention phases was 28.2 s.

m. The level and trend changes for Jacob showed mixed results (see Figure 12).
The trend of the data pattern for baseline predicts decreasing scores. There was minimal
change in level of the data pattern fi'om the end of baseline to the start of intervention.
That is, Jacob’s score for the last week of baseline and his first week of intervention was
33.5 and 33.3 s respectively. The slope of the intervention data series is not as prominent
as for the baseline trend. There is no major change in level between the intervention and
retention phases. However, there is an increasing trend of the retention data points.

m There were no drastic changes in level and trend of Jim’s score between baseline
and intervention phases (see Figure 13). His score for the final week of baseline and the
first week of intervention was a difference of l s. In addition, the trend of the data series
for intervention was similar to that of the baseline phase. Jim’s score during the first week
of retention was 40.9 8; this was a 1.1-s decrease from the final week of the intervention
phase. The trend of the data for the retention phase, as with the intervention, shows a
descending pattern.

1391), As illustrated in Figure 14, there was not a major level change between the
baseline and the intervention or between the intervention and the retention phase. Bob’s

score for the last week of baseline and the first week of intervention showed a 3.4-5

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difference. The trend of the data during intervention has more of a descending slope than
the trend of baseline scores. Bob’s time to completion score during the final week of
intervention was 32.4 8. His score increased by .80 s for the first week of the retention
phase. There was also a change in the trend of the data pattern for the retention phase
with the scores showing an ascending pattern. This trend was similar to Jacob’s retention
scores and is the desired effect when the intervention is removed.

Celmtion Line for the Hand Truck Push Task

”i“

Table 11 shows the number of hand truck push data points that fall on or below the
celeration line. Points that fall below the celeration line in the intervention phase show a
significant rate of improvement from the baseline phase. As with the strength data, the
distance of the intervention points away from celeration line may also add to the
significance of the results. That is, the data points below and farther away fi'om the
celeration line are better than those closer to the line for simulated work productivity data.

M None of Shane’s intervention phase scores fell below the celeration line. The
trend of the celeration line shows predicted decreases in time taken to complete the hand
truck push (see Figure 15). The actual decreases in time to completion were not as the
celeration line predicted. The celeration line forecasted a more drastic change in scores
than what Shane achieved. Although scores do show improvements throughout
intervention, the rate of those improvements is not considered significant because the
completion times recorded during the intervention phase were above the celeration line.
For significance to occur, more than halfof the scores in the intervention plmse have to

fall below the celeration line extended from baseline.

92

Table 11

Number of Points On or Below th_e Celeration Line for the Hand-Truck Pugh Task

 

Intervention Retention
(Maximum 9 data points) (Maximum 6 data points)

Shane 0 0
Jacob 6 6
Jim 0 0
Bob 9 6

 

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The peak (lowest time to completion score for Shane during the intervention phase
was 30 s, which was recorded during week 8 of that period. His high score for the
intervention phase was 35 s, which was recorded on week 5 of the intervention.

All retention scores were above the celeration line. In addition, the scores for this
phase are further away from the celeration line than in the intervention phase. The highest
score for Shane during the retention phase was 33 s, which was recorded during the final
week of the study. It is expected that the scores during the retention phase would be
higher than in the intervention phase.

Jac_ob_. As illustrated in Figure 16, the majority of Jacob’s intervention scores are
above the celeration line. Jacob’s final baseline score was 33.5 s, which was a decrease of
9.6 s from the first week of baseline. However the introduction of the weight-training
program caused the scores to level off, and the slope of the data series is not as extreme as
predicted in the baseline. The peak score for the intervention phase was 28.5 s, which was
achieved on the final day of intervention. This score was a 14.6 s improvement for from
the first week of baseline. All data points in the retention phase also are above the
celeration line.

Inn. No significant treatment effect was observed for J irn. Analysis of the celeration
line in Figure 17 shows all of his data points were above the celeration line. The data
series had at least lmlfof his score close to the celeration line during the intervention
phase. Jim’s highest scores during the intervention phase were 49.3 s on the second week
and 47.2 8 recorded on the first week. As expected, scores in the retention phase are
firrther away from the celeration line tlmn those in the intervention. Jim’s high score

throughout retention was 40.9 3 during the first week. His best time or lowest score was

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36.8 s that was conrpleted during week 19 of the study.

Bop Figure 18 shows that all of the data points during the intervention phase are
below the celeration line. This is an indication that the scores during the intervention
phase were significant. The actual rate of improvement is better than predicted by the
celeration line. That is, not all the scores are close to the extended celeration line for the
intervention phase. The last 3 weeks of the intervention show drastic improvements with
scores of 36.1, 34.6, and 32.4 s respectively. There was an improvement of
approximately 9 5 during the 9-week intervention period. The split middle line calculation
for the retention phase shows an increase in the amount of time to complete the hand
truck push after the treatment is stopped. The scores within the retention phase were also
below the celeration line of trend estimation extended from baseline. Scores in the
retention phase start to move closer to the celeration line at about week 4. This pattern
gave some confidence that that treatment was effective for Bob. When the intervention
was removed the participant’s performance started to decrease.

The celeration line data basically indicates non-significant results. However, the level
and trend data for the hand truck push suggest that the intervention had a small positive
effect. Shane and Jacob had better overall scores than Jim and Bob. The mixed results
did not provide conclusive evidence for complete support of work productivity for the
hand truck push task.

Comparison of Partic' ants’ Box Stac ' Scores

Mean scores showed improvements across all phases of the study for all participants

(see Table 12). Jacob was the only participant that had a drastic treatment effect with

level and trend changes, celeration, and improved time to completion by more than 5 s.

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Table 12

Mean Time to Completion of Box Stacking Task

 

 

Participants Time to Completion (3)

Baseline Intervention Retention
Shane 39.78 37.93 35.22
Jacob 41.73 35.30 34.44
Jim 42.06 38.49 37.31
Bob 40.90 35.21 36.44

 

Note. Scores are listed in s and represent the participants’ mean productivity scores

 

measured by time to completion.

100

As with the hand truck push score, the comparison shows varying levels of
significance among the participants. The mean time to completion varied for each
participant, with Jacob and Bob having the lowest (fastest) box stacking mean scores
during the intervention. These two participants also demonstrated the best improvements
in completion times.

Initial visual inspection of baseline data shows variability throughout all phases of the
study for some of the participants (see Figure 19). Comparison of the trend of the data
points indicates that all participants showed improved times from baseline to intervention;
however, the level of significance varied. Shane and Jim recorded the most stable baseline
scores for the box stacking tasks. Bob showed the most extreme variation during baseline
of all the participants.

Level a_n_d Trend Chgges for Box Stackng' Task

Changes in level and trend of the data series varied for each of the four participants
on the box stacking tasks. Only one of the four participants had significant level and trend
changes in completion times. More detailed descriptions of change for all participants are
provided below.

_S_h_an_e_. Figure 20 illustrates that there was no change in the level of the data pattern
fi'om baseline to intervention. Shane’s scores on the last week of the baseline and the first
week of intervention were 38.5 and 39.5 s respectively. Intervention scores show some
variability with extreme scores recorded on weeks 3, 7, and 9 of that phase. Shane’s peak
intervention score was 33.2 s and was not reached until the final week of intervention. In
addition, the trend of the data series is relatively level, indicating not much overall

improvement in box stacking scores. On the other hand, there is a noticeable level and

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trend change between the intervention and retention phase. The trend line for the
retention phase shows increasing scores. A more stable retention and scores returning
back close to baseline measures would have been the desired effect.

1% There is an extreme change in the level between the baseline and intervention
phase (see Figure 21). The trend of the data within the intervention phase is different fiom
that in baseline. That is the data pattern for the intervention shows a slight upward trend.
Jacob’s box stacking scores are variable throughout the intervention phase. However,
there were improvements from the baseline phase to the intervention phase. There seemed
to be an immediate effect during the first few weeks of the weight-training program The
first three weeks of the intervention phase produced decreases in scores fi'om the final
week of baseline. The scores recorded for those 3 weeks were 38.7, 34.8, and 31.9 s
respectively. There are not consistent improvements after week 3 of intervention. That is,
scores started to increase fi'om week 4 through week 7 of the intervention phase. Lastly,
there was a change in level between the intervention phase and the retention phase.

_J_'_rrn No major changes in level or trend were observed for Jim between the baseline phase
and intervention phase (see Figure 22). In fact, there was a 2.1 3 increase in scores fi'om
the final week of baseline (40.8 s) to the first week of the intervention phase (42.9 3).
Data in the intervention phase were relatively stable. The trend of the data series for the
intervention phase shows a slight descending pattern with scores showing little variability.
There is a minor change in level of the data trend between the intervention and retention
phase. The difference from the final week of intervention and the first week of retention is
only 1.4 s. The trend of retention scores shows an upward pattern, indicating increasing

scores when the intervention is stopped.

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391;, There were no significant level changes between baseline phase and the
intervention phase or for the intervention and retention phase. Bob’s level and trend
changes for all phases are pictured in Figure 23. There were changes in the trend of data
for both the intervention and the retention phases of the study. Scores during the
intervention phase showed a downward trend indicating improvement in Bob’s box
stacking scores. The trend of the data pattern for the retention phase showed scores on
the increase.

Mon Li1_1e for Box Stacking Task

Table 13 outlines the number of data points that fall at or below the celeration line for
the intervention and retention phases of the box stacking scores of all participants. As
with the hand truck push, visual inspection of the celeration line is a way of determining
the effectiveness of the progressive resistance-training program. Results are significant if
the majority of the data points fall below the celeration line. Three of the participants had
the majority of their intervention scores fall below the celeration line.

gm The celeration trend line derived fiom baseline measures predicted a slight
decrease in scores throughout the intervention and retention (see Figure 24). Shane has
the majority of his intervention scores below the celeration line. One can interpret by
looking at the celeration line across intervention and retention that changes seemed to be
minor, therefore, leading one to conclude that the significance of the treatment may be

minimal.

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Table 13

Number of Points On or Below the Celeration Line for the Box Stacking Task

 

Intervention Retention
(Maximum 9 data points) (Maximum 6 data points)

 

Shane 5 5 3?"
Jacob 9 6 1
Jim 5 2 ‘”
Bob 0 0

 

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M As illustrated in Figure 25, all data points during the intervention phase fell
below the celeration line. This was a good indicator that there was an overall improvement
in Jacob’s scores fi'om the baseline to retention. Score variability was a concern during
the intervention phase. Extreme score increases occurred during week 6 and 7 of the
intervention and started to decline again by the week 8 of the phase. The aforementioned
scores moved closer to the celeration indicating a rise in scores. The treatment effect for
Jacob was significant fiom baseline to intervention and subsequently fiom baseline to
retention.

lir_n._ The majority of the data points in the intervention were on or below the
celeration trend line (Figure 26). This was a good indication the treatment effect was
significant. The scores in the intervention phase were quite stable. Improvements in
productivity did not occur until week 2 of the intervention. The low score for Jim during
intervention was 35.8 s, which was attained during the fourth week of the phase. Jim’s
results were evidence that participation in the weight-training program can improve work
productivity for the box-stacking task. Data points in the retention phase do not show
significant increases in scores when the intervention is stopped.

B_o_b_. All data points in the intervention phase were above the celeration line (see
Figure 27). This indicates that there was no significant treatment effect. Box stacking
scores for Bob showed continued increase throughout the intervention phase. Data points
within the intervention phase continued to move away from the celeration line as the phase
progressed. The high scores for Bob during the intervention phase were 37.5 and 37.8 s

recorded during weeks 3 and 6. These scores were about a 5-s difference fiom his

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best score of 32.9 5 recorded on week 5 of intervention In addition, the retention scores
were also a distance away fiom the celeration line. This increase during the retention
phase was somewhat anticipated with the removal of the treatment.
Percent Performance Changes for Simu_lated Work Ta_s_ks
The improvements in completion times for the hand truck push task were modest and
less robust than for the strength data. Percent changes for the simulated work tasks are
outlined in Table 14. The percent changes for the hand truck push ranged from 12% to
1 9- 1% baseline to intervention and 18.3% to 26.6% baseline to intervention. Jacob and
Bo b experienced the greatest percent change between baseline and intervention for the
hand truck push. Jim and Bob demonstrated the greatest percent change from baseline to
the retention phase with decreases in time of 22% and 26.6% respectively.
The percent changes for the box-stacking task were not as prominent as for the hand
truck push. The lowest percent change of 4.7% was by Shane in the baseline to

intervention phase. Jacob had the greatest percent change in scores between baseline and

retention for the box-stacking task.

W
This hypothesis postulated that participation in a progressive resistance-training
Program would improve work productivity of on-site job tasks. It was expected that there
Would be increases in work productivity, however, the researcher was unable to get any
SLIbstantial quantitative data regarding the participants’ actual job performance. The
Cll-lfillitative data provided for this section were derived from supervisors’ ratings using a 4-

point Likert scale (poor, average, good, great) and comments. Examples of the work data

115

Table 14

Percent Change in Mean Scores for Simulated Work Ta_sks

 

 

 

Shane Jacob Jim Bob
Hand Truck Push
Baseline (B) 37.01 38.68 49.87 45.66
Intervention (I) 31.94 31.29 43.89 38.26
Retention (R) 30.22 30.34 38.92 33.53
% Change B-I 13.7 19.1 12 16.2
% Change B-R 18.3 21.6 22 26.6
mm
Baseline (B) 39.78 41.73 42.06 40.90
Intervention (I) 37.93 35.30 38.49 35.21
Retention (R) 35.22 34.44 37.31 36.44
% Change BL-I 4.7 15.4 8.5 13.9
% Change BL—R 11.5 17.5 11.3 10.9

‘

m Percentages are expressed as a decrease in time to completion between the designated

phases of baseline to intervention and baseline to retention.

116

 

forms may be found in Appendix K Job supervisors recorded the participants’ work
productivity data, and the investigator had no control over the data. Comments and ratings
for all participants should have been recorded on a weekly basis; however, supervisors did
not provide consistent data. The investigator was able to get quantitative data on two of
the participants, as well as qualitative data on all participants.

The supervisor’s comments fiom the workshop ratings for Shane and Jacob did not
correspond to the amount of hours worked or the amount that they were paid. That is, on
weeks when the participants worked more hours at a high pay rate their performance
ratings may have been only “average” or “good”. The lack of correspondence between

objective and subjective indicators of performance made it virtually impossible for the
investigator to draw conclusions regarding the effect of the progressive resistance-training
pro gram on work productivity for the on-site job tasks. Jim and Bob had only one job
d‘J-ring the course of the study.
%

Shane worked at a sheltered workshop performing light assembly, packing, and
Iraterials handling tasks. Table 15 provides a summary of work performance results for
Shane’s workshop job task. He was paid for the number of assemblies he completed. The
job supervisors reported the data in two-week intervals, according to the workshop pay
Sol'leclule. No data were given on the number of specific assemblies performed by Shane.
TIIere was no data recorded for the last two weeks of the study. He took time off the job

at the workshop to work only at the high school. The supervisor at the workshop

bdicated that he would return to the workshop after the summer.

117

 

Table 15

 

Productm' ' Data for Shane’s Workshop Job

 

 

 

 

 

.__——— Hours x Rate = Pay Ratings/Comments
Week 1 & 2 30.25 x $2.78 = $84.10 Average
Week 3 & 4 07.50 x $3.79 = $28.43 Average
Week 5 & 6 28.25 x $1.60 = $42.30 Average
Week 7 & 8 28.50 x $1.73 = $49.31 Average
Week 9 & 10 28.50 x $1.70 = $48.45 Average
Week 11 & 12 No Data Average
Week 13 & 14 11.50 x $1.30 = $14.95 Average/Good
Week 15 & 16 10.50 x $2.09 = $21.95 Good
Week 17 & 18 09.50 x $0.80 = $07.06 Good
Week 19 & 20 No Data No Rating

M. Productivity recorded according to pay schedule of workshop contract.

118

0

Supervisor comments for Shane’s high school job were provided a total of 11 weeks
and can be found in Table 16. He transferred to another school for a period of 3 weeks in
weeks 13, 14, and 15 of the study. There were no comments made during this time. The

investigator contacted the new job supervisor and explained the form; however, only

ratings and job task information were provided.

Jacob

 

Jacob also held a job at a workshop setting performing light assembly, packing, and

Inaterial handling tasks. Data were recorded in two-week intervals, according to the

workshop pay schedule (see Table 17). No data were given on the number of specific

assemblies performed by Jacob. Jacob had no data recorded for weeks 15 and 16 of the

study for his workshop job because he was sick on those days. A summary of the

CO rrlrnents from Jacob’s supervisor at the restaurant can be found in Table 18. Jacob
reedeived comments for only eight weeks of the study. The comments provided for Jacob
gave general descriptions of his work performance and not the amount of work
c"'OIfltlxileted. One of the major concerns for supervisors at the restaurant was the speed at
which Jacob worked. Due to the nature of the business, completing work in a timely

M was important. Jacob’s co-workers and supervisors were generally pleased with
his performance.

Lila;

A summary of comments from Jim’s supervisor may be found in Table 19. It was
Climcult to get consistent comments from Jim’s supervisors. The mailroom supervisors
did provide ratings; however, comments were scarce. Jim received comments on 7 of the

20 Weeks. Comments were generally descriptive indicating what Jim had done and how

119

 

Table 16

Shane’s Weekly Job Performance Ratmgl’ Comments for High School Job

 

 

 

 

 

Ratings Comments
Baseline
Week 1 Good None
Week 2 Good None
Week 3 Average “Shane staying on task and doing less wandering out
of work area.”
Week 4 Average “Continue to remind Shane to stay in his work area.
Does a great job when he remains focus.”
Week 5 Good “Improved attention to tasks. Very pleasant to work
with.”
I 111: ervention
Week 6 No Rating None
Week 7 Good “Shane is expressing his need to improve. He wants
to transfer to the new kitchen so he has a goal.”
Week 8 Good “Garbage disposal down so a lot less work this
week. Shane did other cleaning duties. He was
overly excited about his transfer this week! Is
showing signs of displaying too much affection
with employees. We’re working on this.”
Week 9 Good “Shows signs of improvement with appropriate
contact with fellow employees. He worked closer
with Sheri (not real name) to share work load,
particularly pots, pans, and rotating sprayer/catcher.”
Week 10 Great “Staying in work area-assisting with other duties not

expected of him.”

120

Table 16 (cont’d).

 

—.———

 

Ratings Comments
Intervention
Week 11 Good “In absence of co-worker Shane displayed
enthusiasm for being capable of performing on his
own. We did use disposable trays which saved a lot
of labor.”

Week 12 Good “You can see when Shane is putting away dishes that i
he wants to come and visit, but refiains fiom doing
so most of the time. Continue working on less
wandering and visiting the oflice! He expressed '1
concern of not knowing anyone at Elmer School (not
actual name)-We stress he will need to stay in the
kitchen area!”

m
Week 13 Average None
Week 14 Average None
Week 15 Good None
Week 16 Good “Shane is doing well after coming back fi'om the
other school”
Week 17 Good None
Week 13 Average Week 18: “He had trouble with staying in his work
areathisweek. Wehadatalkwithhisjobcoachthis
week.”
Week 19 Great None
Week 20 Average None
\

 

121

Table 17

Productimy' Data for Jacob’s Workshop Job

 

’7

I

Week 1 &2
Week 3 &4
Week 5 & 6
Week 7 & 8
Week9&10
Week 11 & 12
Week 13 &14

Week 15 &16
Week 17& 18
Week 19 & 20

Hours x Rate = Total Pay

24.00 x $1.31 = $31.44
22.50 x $1.04 = $23.40
43.00 x $0.81 = $34.83
35.50 x $0.56 = $19.88
42.50 x $0.56 = $23.80
41.00 x $0.46 = $18.86
43.00 x $0.46 = $17.78
No Data

27.00 x $0.80 = $21.60
47.00 x $0.94 = $44.18

Rating/Comments

Average
Average
Average
Average
Average
Average
Great

No Rating
Good
Good

M Productivity recorded according to pay schedule of workshop contract.

122

 

Table 18

Jacob’s Weekly Job Performance Ratmgl' Comments for Restaurant Job

 

 

 

 

 

Rating Comments
m
Week 1 Average “Jacob is getting better at completing the dishes
quicker. He sometimes has a difficult time staying
on task.”
Week 2 No Rating None
Week 3 Good None
Week 4 Average None
Week 5 Average “Jacob is not feeling well this week and is not alert as
he usually is.”
Intervention
Week 6 Average “Doing better with completing tasks on time this
week. He is coming off of a cold.”
Week 7 Average “Jacob was very distracted today. He will be going
to visit his father this weekend to go to a concert.
We had to keep reminding him to gather the dishes.”
Week 8 Poor “Went home sick on Tuesday complaining of
stomach pains. He only worked for 2 hours.”
Week 9 Average None
Week 10 Average None
Week 11 Average “Got all of the dishes done, but forgot to take out all
of the garbage.”
Week 12 Average None
\

 

123

Table 18 (cont’d).

 

 

 

 

 

Rating Comments
Intervention
Week 13 No Rating None
Week 14 Poor None
Retention -
Week 15 Good “Jacob worked very hard today we had a busy day.
He washed all the dishes and took out the garbage. ,4
Still working on being faster.”
Week 16 Poor None
Week 17 No Rating None
Week 18 Average None
Week 19 Good “Jacob is doing a good job. He is learning to use the
new dishwasher and is getting better with putting
away all of dishes”
Week 20 Average None
124

Table 19

Jim’s Wee Job Performance Rat' Comments for MaL Room Job

 

/

 

 

 

Rating Comments
Baseline
Week 1 Good “Jim did all of his work this week. There was a lot
of mail to sort. He also was a big help with stacking
packages for delivery to the other buildings on
campus.”
Week 2 Good None
Week 3 Good “He sorted all of his morning packages this week.
He is very happy with his job.”
Week 4 Good None
Week 5 Good None
Week 6 Average None
Week 7 Good None
Intervention
Week 8 Poor “Jim seemed to be distracted this week. His mom
said they were changing his medication this week.”
Week 9 Average None
Week 10 Great “This week was very good for Jim. He has worked
very lmrd and was able to help with other jobs in the
mailroom. He gets excited when he does a good
job.”
Week 11 Great None
Week 12 Average None
\

 

125

Table 19 (cont’d).

 

/

 

Rating Comments
Week 13 Great “Jim had an excellent week at sorting and some
delivery of mail. He works very fast, but we tell him
to slow down so he won’t make any mistakes.”
Week 14 Great None
w 11‘:
l
Week 15 Good “Jim wants to start delivering mailbags and packages .
to other buildings. We told him we will think about ‘
it and he needs to keep working hard.” “Good week, '
He is working har .”
Week 16 No Rating None
Week 17 Good “Had a chance to help deliver mail to other buildings.
He wastoldthathehadto doallofhisworkandhe
may be able to go out again later.”
Week 18 Average None
Week 19 No Rating None
Week 20 Good None

 

126

well he was getting along. Overall Jim’s ratings were positive which is an indication that
his supervisors were generally satisfied with his work performance.
ggla
An overview of the ratings and comments from Bob’s supervisors can be found in
Table 20. The ratings and comments for Bob were obtained from several individuals due
to the fact he had various supervisors throughout the course of the study. Although the

ratings for Bob were relatively consistent, the supervisors provided comments for only 8

 

weeks of the study. The positive ratings that are offered by Bob’s supervisors indicated a

general satisfaction with his job performance.

127

Table 20

Bo b’s Weefly Job Performance RatingZComments for Health Club Job

 

I

 

 

 

Rating Comments
Baseline
Week 1 Average None
Week 2 Average “Bob has been working very hard. He sometimes
rushes through his cleaning and spills water.”
Week 3 Average None
Week 4 Good None
Week 5 Good None
Interventigx
Week 6 Good “Bob cleaned all of the machines and worked in the
locker room some this week. He was really busy,
because he worked during the afiemoon rush.”
Week 7 Average None
Week 8 Average None
Week 9 Average “Bob did okay this week. We want him to be able to
get his work completed without rushing and missing
some machines.”

Week 10 Average “He was cleaning up after construction this week. It
was difficult for him to stay on tas .”

Week 11 Average “Bob was not feeling well this week, but he did okay
working. Most of his cleaning was in the aerobic
exercise room.”

Week 12 Great None

\

 

128

 

Table 20 (cont’d).

 

 

 

 

Rating Comments
Intervention
Week 13 Great None
Week 14 Good “Very good week. Bob worked in the exercise room
and the locker room this week. He mopped floors
and cleaned counter tops in the locker room.”
Retention
Week 15 Good None
Week 16 Average None
Week 17 Good “Good job this week. He had to do some cleaning in
the locker room and the windows in the
cardiovascular room.”
Week 18 Good None
Week 19 No Rating None ,
Week 20 Good “Bob worked hard this week. We had some

remodeling done and he worked extra time.”

129

CHAPTER FIVE
DISCUSSION
There were three hypotheses offered in this study; namely that participation in
progressive resistance training by young adult men with mental retardation (MR) would
result in increased muscular strength, work productivity in simulated work tasks (hand
truck push and box stacking), and work productivity at the participants’ on site jobs. The
only hypothesis supported in this study was the one regarding strength. There was partial
support for increased work productivity of simulated work tasks. Lastly, the hypothesis
for increased work productivity for on-site jobs was not supported.
Strength Gains
The strength gains experienced by the four participants during the intervention in this

study are comparable to other findings in the research literature for both persons with and
without MR.

Non-Disabled Persons

 

The use of the progressive overload principle is essential for optimal muscular
Strength and endmance development (ACSM, 1998; Edstrom & Grimby, 1989; Fleck &
Kraerner, 1997). The intervention phase of this study used progressive overload with
Positive results. Shane, Jacob, Jim, and Bob were subjected to gradual increases in
Strength as they improved and as the weeks progressed. These increased resistances were
based on percentages ranging from 30 to 80% according to their weekly l-RM lifts.
B’ZYCki (1995) mentions that the increases in resistance for progressive training programs
did not need to be in large amounts, but need to represent a challenge for the individual.

Therefore, the progressions were individualized to the strength of each participant.

130

This study has further demonstrated that noticeable strength gains are possible by
participating in a progressive resistance training program for as little as 9 weeks. In
conjunction, several researchers (Brzycki, 1995; Braith, et al. 1989; ACSM, 1991, 1998)
[gave conducted studies and reported that 8 to 14 weeks of resistance training is sufficient
to produce significant gains in strength for adults. Although the aforementioned studies
involved non-disabled participants, persons with MR have the potential to benefit as well.

The strength gains experienced in this study were similar to those observed in past

research. For example, Braith et al. (1989), Fleck and Kraemer, (1997), and Pollock et a1.

( 1 989) have reported strength gains ranging fiom 16% to 100% on various resistance
exercises. Similar to previous studies, participants in this study had strength gains ranging

fi‘om 5.3% to 65.1% baseline to intervention and 25.9% to 138.2% baseline to retention

on various exercises.

Persons with Mental Retardation

The results of this study confirm other findings in the literature that persons with MR
have the potential to respond to progressive resistance training similar to persons without
disabilities. Although not all persons increased their l-RM at the same rate, there were
n0ti<>eable strength gains for each participant. The findings are consistent with past
reSearch indicating that there can be significant muscular strength increases among
indi‘fiduals who have mental retardation with the use of reinforcement-based exercise
(CrOce & Horvat, 1992) and progressive resistance training (Rimmer & Kelly, 1991).
Participants in the previously published studies showed increases in strength ranging from
aboltt 11% to 35% (Croce & Horvat, 1992) and from 42% to 121% on upper body

Stl"’tlgth measures and from 42% to 52% on lower body strength measures (Rimmer &

131

F—‘n-I

 

IO:

Kelly, 1991) from baseline through intervention phases. These increases are similar to the
strength gains in this study where the participants lified two days a week on non-
consecutive days for 9 weeks. Young adult males with MR who decide to use a resistance

training protocol similar to the one used in this study could expect 5% to 113% gains in
strength in as little as 9 weeks.

S core Variability

Shane and Jacob had the least variable baselines for composite strength Stability
within baseline may have been due to the fact that Shane and Jacob are faster learners and
W opportunities to practice the weight lifting exercises prior to the study. This was done
to allow them to become familiar with the setting and the use of the weight machines.

Score variability experienced by participants could be due to the fact that some

individuals respond better to resistance training than others do. Therefore, the rates at

which participants improved varied throughout the study. Brzycki (1995) mentions that

unprovement in strength can be observed in as little as two weekly sessions for some

individuals. In addition, participation in l-day per week resistance training has the
potential to improve muscular strength comparable to 2-days per week and 3-days per
week programs. With this in mind, it is possible that the l-RM exercises performed
during the baseline phase were suflicient enough to improve the participants’ strength in as
little as two weeks. If this is the case, variability in scores is probably inevitable. It is also
Possible that the strength gains may have just occurred by chance. More research needs to
be Conducted to further examine the possible causes of strength gains. This is important

because 3 of the 4 participants showed composite strength increases ranging from 10 to

20 lb fi'Om the first week to the second week of baseline.

132

The variability in week-to-week strength scores throughout the intervention and
retention phases can possibly be attributed to minor illness, lack of motivation, and/or
stressful events in the participant’s life. Two of the four participants indicated at least one
of the aforementioned factors. Changes in variability of scores for Shane during the
intervention may have been due to him not feeling well. Shane became ill during Weeks
1 l and 12 of the study. Lack of motivation rmy also been a factor affecting score
variability. In addition, Shane contemplated dropping out of the study in order to play
Softball during Weeks 6 and 7 of the intervention. The investigator assured him that there
would be no harsh feelings if he decided to drop out of the weight-training program. He
later decided that the softball schedule would interfere with his work schedule and
continued to participate in the weight-training program. Shane has a short attention span
and had to be constantly reminded to remain on tasks while in the weight room. It should
be noted that Shane was the most difiicult to motivate of all the participants.

Jacob had the greatest strength gains of all participants. However, he did experience
sorne score variability at about Weeks 5 and 6 of the intervention phase. His scores
actually decreased from the previous two weeks. His erratic scores may have been due to
minor complications from the medications he was taking. Jacob’s mother indicated that
the doctor was experimenting with the dosage of his medications to better control his
seizures and stomach ailments. There were a few occasions during this time when he
Cattle to sessions complaining of being tired. On those days he was encouraged to do
What he could. By the end ofthe exercise sessions he usually reported that he felt much
better. It is important to note that Jacob experienced no adverse effects from the weight-

training and simulated work tasks during his medication changes.

133

Jim and Bob did not reveal any major situations in their lives that may have caused
concern regarding score variability. A few minor issues involved sickness and
transportation. Although Bob became ill during week 2 of the intervention phase, his
strength scores did not reflect any major changes for week 3. Another minor concern for
Jim and Bob involved transportation to and fi'om the weight training sessions during the
retention phase. There were times when the participants were unsure of how they would
get to the training sessions. Jim and Bob’s attendance was not affected and they were not
absent from any sessions due to transportation difficulties. The scores during the retention
phase did not seem to be effected. As a matter of fact, the scores during retention were
on the increase for the first few weeks of that phase.
Demmg' ' Effects
The strength retention experienced by the participants, afier completion of the
intervention, may be explained by the detraining effect, which is consistent with the
literature. The ACSM (1998), Graves et al. (1988), and Lemmer et al. (2000) have
reported tlmt strength can be maintained anywhere fi'om 12 to 31 weeks detraining.
However, in order for strength to be maintained, the individual must sustain the intensity
of the resistance training for at least one-day a week. The participants in the present study
perform were tested using the l-RM exercises once a week after the intervention was
concluded. Although not at the same intensity as the intervention, participants were still
Performing some type of resistance training.
As with the baseline, it is possible tlmt the once a week testing during retention was
enough to maintain the muscular strength of the participants. The trend of the data series

for the retention phase showed some decrease and leveling off during the last three weeks

134

of the retention phase. This may be an indication that more time is needed to accurately
measure the detraining effect to determine if the participants’ scores would regress toward
baseline strength levels. Pitetti and Tan (1991) mentioned, “there are no reported studies
of MR individuals that evaluated detraining effects following the conclusion of the training
period” (p. 594). Pitetti and Tan (1991) further implied tint by not looking at detraining
effects, it would be diflicult to determine if the intervention led to any positive lifestyle
Inodifications and lead these persons to independently continue participating in an exercise
program. For this study, no formal analysis was done to determine the detraining efi‘ects
o f the resistance-training program post intervention.
The literature (Croce & Horvat, 1992) also supports strength retention for several
weeks post intervention for a person with MR As with the study by Croce and Horvat
( 1 992), all participants in this study had significant strength gains that were above the
celeration line. In addition, the participants in the present study had scores above the
celeration line for all 6 weeks of the retention phase. This is a positive sign in that persons
with m may have the potential to maintain their strength afier participation in a
structured resistance-training program similar to person without disabilities.
Tm. ° Protocol and Euipment
The strength training protocol used in this study seems to be quite appropriate for
young adult males with MR. The type of training, muscle fiber types, and overloads are a
few of the factors that come into play when setting up strength training programs. The
individualized weight training programs used in the present study were determined by each
pal'tiCipant’s l-RM lifis. Participants lified on non-consecutive days and were given ample

r est periods to minimize the likelihood of fatigue. The ACSM (1991) and Braith et al.

135

(1989) confirm that strength training two to three times a week on non consecutive days
should allow muscles to have sufficient recovery time, which would reduce fatigue and
provide for optimal strength gains.

The protocol used in this study was designed for optimal strength gains across
participants and to limit injury. However, it is poss1ble that fatigue could have been a
factor in regards to strength gains. Prior to the study, Jacob was the only participant who

was involved in some type of regular physical activity (martial arts). The only complaints
received fiom the participants were regarding muscle soreness during the first three weeks
0 f baseline. None of the participants complained of soreness throughout the remainder of
the study.

The personalized resistance-training program used in this study allowed for an
efl‘ective progression that produced noticeable strength gains. The protocol also seemed
to be acceptable to the participants in this study. In an effort to minimize the possibility of
il'lj ury, the lifting program in this study did not start until participants had a chance to
practice each of the strength exercises. When participants started baseline trials they
shellld have been familiar with all aspects of the lilting exercises. This aforementioned
protocol rmy have added to improvement in strength. It was similar to the protocol used
by Combes and Jansma (1990), Rimmer and Kelly (1991), and Croce and Horvat (1992).

The participants had very positive attitudes toward the intervention. They seemed to
look forward to attending the sessions. The presence of the investigator may have
contributed to the positive attitudes and improvements of the participants. They seemed
to enjoy the company of the investigator. This could be because each time the participants

lifted, they were given verbal praise and encouragement fi'om the investigator. The verbal

136

statements for Shane, Jacob, Jim, and Bob varied and could have been a motivational
factor. In addition, participants related well to the investigator and often talked about the
happenings of their day and jobs. It was apparent by their attendance that they looked
forward to the interaction. They also appeared to recognize the benefits of the
progressive weight-training program. For example, Shane and Jacob often stated that the
weight lilting was making them stronger and they can lift heavier objects at work and
around the house.

Jacob experienced the greatest composite strength gains across all exercises. He was
the largest of the four participants and in my opinion exerted the most efi‘ort during the
weight training exercise. Jacob also participated in martial arts and showed more
discipline and commitment when performing the lifting tasks. In addition, he often asked
for increases in weight before the designated dates. It should be noted that all weight
irlcreases were based upon the percentages of 30-40%, 50-60%, and 70-80% of
participants’ l-RM liits. The progressive nature of the weight-training program allowed
for safe increases in strength. Each of the increases and adjustments of the weight
mchines were conducted or supervised by the investigator.

There were three brand names of weight machines used in this study. Although
Possible, it would seem unlikely that the different types of weight machine could have
aflécted the rates and amount of strength improvements among participants. All
Participants in the study used weight machines at facilities that were convenient to them.
Although there were three types of machines used, they all worked the same muscle
gr ODDS. For safety reasons, none of the participants performed exercises on free weights.

The investigator nude every effort to insure the consistency of exercises.

137

Lastly, two of the four participants involved in the present study continue to be
involved in some type of physical activity, however, not consistently. Jacob is involved
with martial arts and Bob participates in weight training once a week. As mentioned
previously, the investigator did not formally evaluate participants exercise routines after
completion of the study. The data about continued involvement in physical activity were
obtained fiom the participants and their parents. Major deterrents to continued
participation seemed to be transportation, lack of facilities, and/or lack of equipment.
None of the four participants engage in resistance training at the same intensity and
fi-equency as in this study. However, it is encouraging to know that participants are
actively involved in some type of consistent physical activity.
Performce on Simulated Worl_(_T_aak_s
Only one of the four participants showed significant improvements on box stacking
and one on the hand truck push. Overall they improved about 25% in hand truck and 15%
on box stacking compared to a 60% gain in composite strength. However, each
participant did show minor improvements in time to completion on both of the simulated
work tasks. The results regarding simulated work tasks are consistent with the literature
(Croce & Horvat, 1992; Zetts et al., 1995) in that participants showed improvements in
conmletion times while engaging in a progressive resistance-training program.
mmvements on Simulated Work Tasks
There may have been several reasons why some participants were successful and
others were not in the simulated work tasks. Bob was the only participant to have

Significant results on the hand truck push. Jacob produced significant results for the box-

138

stacking task. That is, they met the criteria for the celeration line, level and trend changes,
and score improvements. 1
Participant motivation and experience with the tasks may be factors ofl‘ered that
contributed to success for Bob and Jacob. For the most part, participants seemed to be
motivated throughout the course of this study. They were enthusiastic during the training
and testing sessions. Each of the participant’s parents indicated that their son was
enthusiastic about the workout program used in this study. It could be that participants
found the investigator’s attention a motivating factor that encouraged them to work hard
dining the study.

Muscular strength and coordination also are possible factors that may have
contributed to the results of the simulated work tasks. Both the hand truck push and the
box stacking required a certain level of strength. It was shown that Jacob had the highest
increases in strength and improvement in box stacking scores. It is possible that muscular
strength is a major factor in the improvement of box stacking scores. This is logical in
that each of the boxes weighted 25 lb and a certain level of muscular strength and
endurance was needed to place them onto the table

Coordination also could have been a factor in the results of the hand truck push and
box stacking tasks. The investigator did not observe any noticeable problems with
coordination during the hand truck push task, which required participants to be able to
balance the hand truck while moving a distance of 160 it. They had to maintain control of
the hand truck while pushing it around the designated course. It is likely that the lack of
coordination could have created problems for some of the participants. Participants

pet'fOI‘Ining the box-stacking task had to bend, pick up a box, walk a few steps, and place

139

it on a table or platform. The bending, lifting, and walking required to perform the box
stacking requires a certain level of coordination.

Other factors that may have affected the improvements include participants’
experience and the complexity of the task. Zetts, Horvat, and Langone (1995) also
alluded to these factors as possible reasons for participants’ scores in their study. It is
very likely that the hand truck push task was unfamiliar to the participants in the present
study. Jim was the only participant who possibly would have had experience using a hand
truck push. He worked in a mailroom and may have used a hand truck. However, Jim’s
results on the hand truck push and box stacking were not significant, which shows his past
experience may not have helped his work productivity. The participants with possibly the
most experience performing the box stacking would have been Shane, Jacob, and Jim due
to the nature of their jobs. However, Jacob was the only participant with significant
results for the box-stacking task.

An additional reason why some participants did not improve may be that they were
still learning the skill during baseline, producing unstable data, which in turn affected the
calculation of the celeration line. Participants were given an opportunity to practice prior
to starting the study. It could be that more practice time was needed in order to assure the
participants were comfortable with performing the simulated work tasks. The simulated
work tasks required a certain level of cognition. The participants had to remember how to
balance the hand truck and push it for a desigmted distance. The box stacking required
the participants to place the boxes in a certain pattern on a table. Each participant had to
be verbally reminded to stack the boxes properly during the baseline and about the first

three weeks of the intervention phases of the study. This could have easily caused a

140

distraction and impinged upon participants’ completion times. No verbal prompting was
needed during the retention phase for any of the participants. On the contrary, Crouch et
al. (1984) reported that verbal prompting prior to performing work tasks improved work
productivity. It should be noted that the Crouch et al. (1984) study was conducted using
the participants’ actual jobs and their improvements were required in order for them to
keep their jobs. The jobs in the present study were simulated and there were no
consequences if participants did not improve which could have affected the participants’
motivation to work hard.

Jacob was the only participant that had all intervention data points fall below the
celeration line for the box stacking tasks. Again he really worked hard when performing
the box-stacking task. Additionally, all the participants seemed to enjoy the box stacking
tasks more than the hand truck push. As with the hand truck push, participants had a
chance to practice the box stacking prior to starting the study. They were motivated to
perform the task and would periodically ask for additional attempts after their testing was
done.

Score Variability of Simiated WorlLasks

Baseline measures for the hand truck push scores were not entirely stable. This
variability afl'ected the celeration line scores. Although results of the box stacking
celeration line showed significance for three of the four participants, the level and trend
changes were significant only for Jacob. It should be noted that the participants’ unstable
baselines possibly confounded the results and contributed to less reliable and valid
celeration line scores. Baseline stability needs to be established prior to starting the

intervention. This should lead to a more valid and reliable celeration line analysis.

141

The reason for the variability early in baseline my be due to participants’ difficulty in
understanding the concept of pushing the hand truck around the designated course. There
were occasions during baseline and intervention when participants had trouble completing
the mm. It may have been difficult for the participants to comprehend the concept of
pushing and lifting as quickly as they could. As with participants in the Zetts et al. (1995)
study, the men in the present study sometimes stopped or slowed down before completing
the course. They hesitated at times and had to be verbally prompted to complete the
course. The investigator in this study used only verbal prompting to get participants to
complete the course. No physical prompting was permitted during any of the simulated
work tasks.

Limitations

A major limitation of the present study involved baseline instability. None of the four
participants achieved a stable baseline for the hand truck push task. On the other hand
relatively stable baselines were achieved for three of the four participants (Shane, Jacob,
and Jim) for the box stacking tasks. The unstable baselines may possrbly have affected the
celeration lines, which in turn may have compromised the validity and the reliability of the
results. The trend of the celeration baseline scores for each of the participants had a
drastic downward slope and did not start to stabilize until the intervention. The
participants could have been experiencing a learning effect into the intervention phase.
Therefore, more time needs to allow to establishing baseline stability.

Recommendations for firture research on solving the problem of baseline instability
includes establishing stable baselines before starting the intervention, allowing more

practice time, and using more visual cues to assist with completion of the simulated work

142

tasks. Participants may luve benefited from more practice sessions to increase familiarity
with the task. It may have been also possible to allow participants to have more practice
trials prior to starting the study. As for the visual cues, the course for the hand truck push
was rectangular and the perimeter was marked with colorfirl cones. It may have helped to
include some type of taped and colored line and arrows to show the direction of the
course. Although the investigator demonstrated the hand truck push weekly, it may not
have been sufficient for optimal learning.

Baseline instability for the simulated work tasks may be attributed to several factors.
Baseline scores for the box-stacking task were stable for Shane, Jim, and Bob. This was
an indication that they understood the tasks and were performing as predicted. Jacob on
the other hand demonstrated some variability near the end of baseline. As previously
mentioned, Jacob was experiencing some minor illness during various times during the
study. Bob had stable scores but the trend of his baseline data showed a drastic
downward slope tlmt suggest the scores he experienced were not as prominent as the
celeration line predicted. The results of the box stacking tasks were more stable than the
hand-truck push. This was consistent with results from Zetts et al. (1995).

Me of the Simulated Work Tasks

The simulated jobs used were typical of those performd by persons with mental
retardation (ARC 1994, Wehman et al. 1985a). The hand truck push and box stacking
tasks used in this study were modifications of those used by Zetts et a1. (1995). Although
the simulated jobs may have been novel tasks for some the participants, they are
appropriate for this and future studies designed to test work productivity in adult males

with MR. In addition, the investigator contacted several professionals who have several

143

years of experiences working with adult with Nflt and they agreed the task are appropriate
for person with MR.

The box-stacking task appeared to be the most difficult and strenuous of the
simulated jobs. This particular task could potentially have caused the most injury to
participants because the boxes were weighted and they had to travel a short distance to
put them on the table or platform. Fortunately no one was injured. Participants viewed a
training video and received demonstrations fiom the investigator that detailed proper box
lifting techniques. However, they still had to be consistently reminded to maintain proper
posture by using the legs to lift and keeping the back straight and head up. The verbal
cues seemed to distract participants from the lifting task. For example, when the verbal
cues were given, the participants would either stop momentarily or put the box back down
on the floor and lift again. Because the cues seemed distracting, they were kept to a
minimum and mostly given at the start and end of each trial whenever safety was not
compromised.

Improvements at On;site Work Tasks

The results for the on site work tasks were non-significant, probably for two reasons.
There was inadequate instrumentation, and the some of the on site jobs did not require the
same level of muscular strength as others.

Instrumentation Concerns

The instrumentation used in this study was not sufficiently sensitive to determine the
effects of the progressive resistance-training program on the work productivity at
participants’ actual jobs. Results regarding work productivity of on site job tasks were

inconclusive due to insufficient data from job supervisors. This finding is not consistent

144

with the literature. Previous studies have been able to successfully measure work
productivity using participants’ onsite jobs of bench assembly tasks in a workshop setting
(Serr et al. 1994; Beasley, 1982) and general cleaning task of sweeping and mopping in a
food service setting (Crouch et al. 1984). For the present study, supervisor’s comments
were not provided with enough frequency or detail to be helpful. It was a challenge to
determine the extent of the participants’ improvement at their on-site job tasks. Many of
the tasks did not allow for consistent data collection to track improvement. In addition,
there were several different supervisors who recorded participants’ work data. Having
more than one person recording the data may have caused some inconsistencies. The job
supervisors were responsible for recording work productivity data. The investigator’s role
was to communicate with the job supervisors and request that work productivity data be
recorded and submitted on a regular basis.

The use of objective methods of assessing productivity such as amount paid and
pieces of work completed did not work in this study. The recording instruments used did
not allow the investigator to get accurate measures of the participant’s productivity levels
in relation to the intervention. This could be due to a lack of understanding about the
research project by the job supervisors and/or to the nature of the jobs held by the
participants. For example, the workshop productivity data were recorded for Shane and
Jacob involved their supervisors listing the hours and pay rates and conducting
performance ratings with comments at 2-week intervals. The total pay does not provide
an accurate prediction of the amount of work completed for Shane and Jacob. The
supervisors indicated that the amount received depended on the job contract held by the

workshop. That is, participants may work long hours but the pay may be minimal. In

145

addition, the hours and pay rates were not consistent. Attempting to use total pay to
determine productivity in relation to participation in the resistance-training program would
not provide a reliable measure.

Some of the participants’ on-site jobs may not have required as much strength as
others did. Each participant performed various tasks at their respective jobs, which made
accurate data recording difficult. Shane performd various assemblies and packaging
tasks as well as general maintenance and cleaning. Jacob also performd assembly and
packaging tasks, was employed as a dishwasher, and performed general cleaning at a local
restaurant. Jim sorted mail and assisted with the delivery of packages at a local university.
Lastly, Bob performed general cleaning duties at a health club. The various tasks made
data analyses and comparisons difficult. Logically, the intervention is likely to be effective
only if the jobs required a higher level of strength. The investigator did not obtain
adequate data here because of instrumentation problems.

Performance Ratmg' s

The nmjority of the comments provided by the supervisors were relatively positive or
neutral. Although not directly stated, one can determine fiom the supervisors’ comments
that they were generally satisfied with the participant’s performances on the job. This is
consistent with the past literature (Wehman, 1993).

Data regarding job ratings of work performance for all participants ranged from
“poor” to “great.” The rating of “poor” was only recorded three times during the study,
twice by Jacob’s supervisors at the restaurant and once by Jim’s supervisors in the

mailroom. Jacob’s rating was followed by comments of “Went home sick on Tuesday

complaining of stomach pains, he only worked 2 hours.” The other rating had no

146

comment. The “poor” rating for Jim was supported by the comment that he seemed to be
distracted and was having a medication change that week. The comments from
supervisors generally revealed legitimate reasons for poor job performance.

Attempting to retrieve data on the amount of work participants performed was not
practical for the jobs they held. Although encouraged to do so, job supervisors did not
provide many open-ended comments. The only supervisors that were forthcoming with
this type of information were for Shane (high school) and Jim (mailroom). The
investigator contacted all the job supervisors at least twice a month throughout the study.
He also encouraged the supervisors to contact him if they had any finther questions or
concern. None of the job supervisors communicated with the investigator outside of the
scheduled contact times. It can be concluded that for this dependent variable, the data
have questionable validity and reliability and therefore do not serve as a good basis for
statistical analysis. A more feasible method of data collection needs to be developed

Conclusion and Recommendations

This study provides strong support that a 9-week progressive resistance-training
program resulted in increased strength for adults with mental retardation. This
information confirms earlier findings in the literature. The results in this study are useful
to service providers who design exercise programs for this population, employers,
parents/guardians, and for the individuals themselves, especially those who are responsible
for making their own employment decisions.

The results of this study provide partial support for the hypothesis that increased
strength can lead to better performance on simulated work tasks that involve strength.

However this study needs to be replicated using a longer and more stable baseline period

147

prior to intervention. Nevertheless, it seems reasonable to conclude that strength gains
can be generalized to “real worl ” tasks for persons with mental retardation. This study
did not provide support for the hypothesis that increased strength would lead to increase
work productivity at the participants’ on-site jobs. The failure to find significant results
does not mean that the hypothesis is necessarily untrue. Limitations in research methods
made it impossible to fairly evaluate all the hypotheses. This research should be repeated
with more valid and reliable ways of assessing productivity.

The practical significance of this study is that there were improvements in muscular
strength, partial improvements on work productivity, and positive comments fiom
employers. In addition, participant motivation was high. Although not formally assessed,
participants in the study showed great motivation. As previously mentioned, past studies
have reported lack of motivation for person with mental retardation. Motivation was not
lacking in this study. They attended all sessions and had good weight training sessions.
That is, they seemed to make very effort to complete the necessary exercises and
simulated work tasks. The investigator made every effort to create a good rapport with
the participants. This was done by encouraging and listening to participants when they
arrived at their respective exercise and testing sessions. The special attention given to the
participants could have further encouraged their participation.

Past researchers have also reported that exercise adherence for this population is
difficult. Reasons for this include problems with understanding the task and attention
deficits. The participants in the present study attended all weight training and test
sessions. The investigator made every effort to make the weight training protocol easy to

use. The investigator was always cordial to each of the participants. This may have added

148

to their desire to continue to partake in the investigation. The environment was conducive
to a safe and fun weight-training program.

All sessions were conducted in facilities that allowed accessible to the public. This
may have made the participants feel as if they were important. They were closely
supervised throughout the study and they seemed to become quite familiar with the
workout and testing routine by the end of baseline. That is they were able to move to the
next exercise on their own and at times verbalized the amount of weight the needed to
complete their lifts. Participants also showed etiquette in that they had to remain aware of
others who may have been using the equipment ahead of them.

Participants were made aware of their results during all weight training exercises and
testing sessions. They often wanted to do better than their previous performance and
were excited to come back each week. This is important in that allowing participants with
mental retardation to view their scores and results on a consistent basis may encourage
them to want to improve each performance. Persons who coordinate exercise programs
for these individuals should allow for viewing of data. However, the data given should be
understandable to the participants. The investigator in the present study also verbally
cormnunicated participants’ scores weekly.

Recommendations

Several suggestions/recommendations are offered for firture research on strength
training and work productivity for adults with MR. These recommendations include the
following:

1. Improved instrumentation is needed especially for on-site work tasks. Research

needs to be completed that uses valid and reliable methods of determining the effects of

149

progressive resistance training on work productivity. It may be necessary to have the
investigator collect work productivity data or to compensate the job supervisors. If the
investigator were to collect the data he would have been able to control for erratic
recording. In addition, the investigator would have been able to get the exact data he/she
required.

2. There is a need for longer baselines and use a multiple baseline approach where
participants must show stability on all measures before proceeding to the intervention. A
S-week baseline period was set prior to the study and the investigator continued with the
intervention regardless of baseline stability. Although Barlow and Hersen (1984)
mentioned that a minimum of three data points is needed to establish baseline data, more
time was needed in the present investigation. Extending the baseline until scores are stable
would allow for more valid and reliable results from the trend, level and celeration line
data. In addition, the use of multiple baselines would allow the investigator to be more
confident that the intervention had an effect on the variables. On the other hand, longer
baselines and multiple baselines may be difficult because the variable being tested is
strength. There is likely to be improvements just by the nature of the testing. Lastly,
motivation and fatigue may be additional factors that make extending the length of the
study a difficult task.

3. To promote more efficient strength gains, firture investigations should use a
protocol that has participants perform 1 set of resistance exercise instead of multiple sets
for each lifting exercise for the 9-week period. This may also assist in preventing fatigue
and to minimize the risk of injury. To help increase strength efficiency, Brzycki (1995)

emphasized that completing 1 set of resistance at capacity at a high level of intensity has

150

 

the capacity to increase strength. This type of protocol may be warranted for because
persons with MR are known to have limited attention span and adherence in participating
in strength training exercises.

4. This study should be repeated with participants of different ages and gender to
expand the generalization of the results. If further studies are conducted using other age
groups and females, the results can be generalized to assist a larger population of persons
with MR.

5. More attention needs to be given to assessing the dependent variables during the
retention phase. Extending the retention plmse until scores become stable will help to
determine the detraining effect and better explain the continued strength gains.

6. Future studies should be done to examine employer attitudes, which may provide
additional explanations of participants’ productivity levels and overall perceptions of their
jobs. It would be beneficial to know how the employers perceive the worker with mental
retardation. Results from this data have the potential to provide insight into the hiring and
retention practices of employers who have employees with mental retardation

The results of the present study provide some valuable information for those who
work with persons who have MR. It is imperative that we seek ways to better prepare
persons with MR for the work force and come to the realization the majority of the jobs
they have require some type of physical labor. If persons with mental retardation can
benefit fi'om increased strength it would seem imperative that they be given the
Opportunity to do so. If properly supervised and motivated these persons can become
involved in a program that has implications for employment, physical health, self esteem,

socialization. The present study has contributed to the research literature by providing a

151

rationale for the use of progressive resistance training to improve the muscular strength
and work productivity of young adult males with MR. Much research is still needed to
understand the factors that enhance strength and work productivity of working persons

with mental retardation.

 

152

APPENDIX A

Informed Consent

153

CONSENT TO PARTICIPATE IN A WEIGHT TRAINING AND WORK TASK STUDY

Dear Parent/Guardian,

My name is Lorenzo Parker. I am a doctoral student at Michigan State University in the
Department of Physical Education and Exercise Science. I currently hold the position of Assistant
Professor at Chicago State University in the Department of Health, Physical Education, and
Recreation. I am writing to ask your permission for your son
(NAME: ) to participate in my dissertation
research.

The purpose of my study is to examine the effects of weight training on the work productivity
of adult males with mental retardation. Although no beneficial effects of the weight training
program are guaranteed, I expect that the weight-training program will have a positive effect on the
participant's health and work productivity. Other benefits may include the following:

1. Your son may learn how to lift weights using Nautilus equipment and be
able to improve his muscular strength and endurance.

2. The results of this study may allow your son to learn effective strength
training tips.

3. Lifting weights may help your son's health and make him feel and look
better.

4. Lifting weights may help your son do his job better.

Participants in this research will be tested once a week during a 5-week baseline period, a
9-wwk treatment period, and a 6—week retention period (a total of 20 weeks) on the following
measures:

0 Records will be maintained of his maximum lifts on seven weight-lifting exercise using
Nautilus equipment.

0 He will be timed as he lifts eight 25-pound boxes from the floor to a table.

0 He will be timed as he pushes a hand truck weighted with 85-pounds of boxes around a 160-
foot course in a gymnasium.

o I will consult with his job supervisor to obtain records of his work productivity (e.g., number
of items produced).

During the 9-week treatment period, participants will attend a twice-a-week weight-lifting
class. Each session will begin with light cardiovascular exercise and stretching, continue with
weight-lifting exercises, and end with cool-down exercises. Participants will be instructed and
reminded as needed about correct posture and lifting technique.

The duration of each testing session (maximal lifts, box stacking, and hand truck push) and
each weight training class will be approximately 90 minutes. All testing sessions and classes will
be conducted in a weight room and gymnasium at a local facility. I will supervise all testing
sessions and weight-training classes. 1 am an experienced weight-training instructor and am a
certified instructor of first aid and CPR. Transportation to and from the weight training facility

will be the responsibility of the family or group home.

154

The risk of injury (e.g., muscle soreness or strain) during this project is no greater than the
risk when participating in a weight-training program offered by a health club or gym. The risk
may be lower because of the supervision and instruction that is provided. "If your son is injured
as a mutt of his participation in this research project, the following steps will be taken. If any
minor injuries occur, I will administerflrsl aidand will nonfiyou or the group home
supervisor. If the injury is serious, I will request emergency medical services. The family will be
responsible for the costs of any emergency medical services.

I will respect your son's privacy by treating all information with strict confidence. The data
obtained during this study will be kept in a locked file cabinet in my office and will be seen only by
me, the students who assist with data collection, and my dissertation committee. I will not use
participants' names in presentations or publications related to this research. In addition, please note
that your son’s results will only be shared with you if he agrees to this on the assent form.

I will obtain written consent from the parent/guardian (you) and written assent from your son
before beginning this research. Before asking for your son's assent, 1 will explain the purpose of
the study to him and will show a videotape of an adult male performing the weight-lifting exercises
and testing tasks involved in this study. Your son will also have an opportunity to ask questions.
You may request to see the videotape and you should feel welcome to ask questions before signing
this consent form.

Participation in this study is voluntary. Your son may choose not to participate in certain
exercises or tasks or may discontinue his participation at any time. Similarly, you may withdraw
your permission for your son to participate at any time. There are no penalties for choosing not to
participate or for withdrawing from the research.

If you have any questions about this research, you may contact me, my dissertation director,
research supervisor or UCRIHS Chair.

Lorenzo Parker (Investigator)

Health, Physical Education & Recreation
Chicago State University

Iacoby Dickens P.E. & Ath. Center / 216
9501 S. King Drive

Chicago, IL 60628-1598

Phone: (773) 995-3647

E-mail: L—Parker@csu.edu

James H. Rimmer (Research Supervisor)
Physical Education

Northern Illinois University

Anderson Hall 232

Dekalb, IL 60115-2854

Phone: (815) 753-1401

Gail M. Dummer (Dissertation Director)
Physical Education & Exercise Science
Michigan State University

132 IM Sport Circle

East Lansing, MI 48824-1049

Phone: (517) 355-4744

E-mail: dummer@msu.edu

David E. Wright (UCRIHS Chair)

Office of Research and Graduate Studies
Michigan State University

246 Administration Building

East Lansing, MI 48824-1046

Phone: (517) 355-2180

Please sign and return the form below to Lorenzo Parker at the address listed above.
You may keep the description of the study for your records.

 

155

I have received a copy of the consent form for Lorenzo Parker's dissertation study on the
Eflects of a Weight-Training Program on the Job Productivity of Adult Males with Mental
Retardation. By signing this form, I voluntarily agree to the provisions of this eoment firm
for my son's participation in this study.

Signature of Parent/ Guardian Date

 

Name of Participant Date

 

Check the box below if you would like a copy of the results upon completion of this
research

[I I Do want a copy of the individual/ study results. '”Please note that results will
only be shared with you if your son has given me permission to do so by checking the “Yes”
box on his assent form.

156

Assent Form

Participant’s Name Date of Birth / /
month day year

This assent form will be read aloud to potential participants. They will also be provided with a
written copy of the form and will be given an opportunity to ask questions before they are
requested to assent to participation.
Lorenzo Parker told me about this research study and he showed me a videotape about
the study. He wants to know ifI will get stronger from lifting weights. He also wants
to know if lifting weights will help me do more work at my job.
I agree to go to weight-training classes two times a week.
I agree to do the box-lifting test every week.
I agree to do the cart-pushing test every week.

I agree to do the weight-lifting tests every week.

I give permission to Lorenzo Parker to talk to my boss every week. I know that
Lorenzo will ask my boss about how much work I did that week.

I can decide if I want to participate in this weight-training study. I know that I can
quit at any time. I can say no to doing any of the tests. No one will get mad at me if
I say no or quit the study.

Signature of Participant Date

Name of Participant Date
(Please Print)

By checking the “YES” box, I give permission to Lorenzo Parker to show or tell my

parents/guardians how I did on the lifting and working tasks during the study
[ IYES

l57

 

 

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September 10. 1997

TO: Gail M. Dummer .
132 IM Sports Circle

 

RE: IRE”: 97-601
TITLE: EFFECTIVENESS OF A PROGRESSIVE RESISTANCE
TRANING PROGRAM ON WORK PRODUCTIVITY AND
MUSCULAR STRENGTH AMONG ADULT MALES WITH MENTAL
RETARDATION
REVISION REQUESTED: N/A
CATEGORY' FULL REVIEW

APPROVAL oars: 09/08/97

 

The University Committee on Research Involving Human Subjects'(UCRIHSl
review of this project is complete.. I am pleased to adVise that the
rights and welfare of the human subjects appear to be adequately
rotecced and methods to obtain informed consent are appropriate.
Therefore. the UCRIHS approved this project and any reVisions listed
above.
PLEASE ADD DR. DAVID WRIGHT'S NAME, ADDRESS, AND PRONE NUMBER TO THE
CONSENT FORM AS A CONTACT PERSON FOR SUBJECTS WHO HAVE QUESTIONS ABOUT
THEIR PARTICIPATION IN THIS STUDY.

RENEWAL: UCRIHS approval is valid for one calendar year, beginning with
the approval date shown above. Investigators planning to
continue a project be ond one year must use the green renewal
form (enclosed with c e original approval letter or when a_
project is renewed) to seek u date certification. There is a
maXimum of four such expedite renewals possible. Investigators
wishing to continue a prejecc beyond that time need to submit it
again or complete reView.

REVISIONS: UCRIHS must review any changes in procedures involving human
subjects. rior to initiation of t e change. If this is done at
the time o renewal. please use the green renewal form. To
revise an approved protocol at any other time during the year.
send your written request to the. CRIBS Chair, requesting revised
approval and referenCing the prOJect's IRB # and title. Include
in your request a description of the change and any revised
instruments, consent forms or advertisements that are applicable.

PROBLEMS]

CHANGES: Should either of the followin arise during the course of the
work. investigators must noti UCRIHS promptly: (1) roblems
(unexpected side effects, comp aincs. e c ) involving uman
subjects or (2) changes in the research environment or new
information indicating greater risk to the human sub eccs than
eXisted when the protocol was preViously reviewed approved.

If we can be of any future help, lease do not hesitate to contact us
at (517)355-2180 or FAX (517)4 2- 171.

vid E. Wright, Ph.D

CRIHS Chair
DEW:bed

Sincerely,

  
     
  

 
 

cc: Lorenzo Parker

158

APPENDIX B

Data Collection Forms

159

Employment Observation Form

 

 

 

 

 

 

Subject #

Name: Date
Date of Birth: Gender: Male Female
Living Environment: Group Home___ Community Living Other

If Other Please Explain
Job Site:
Job Supervisor/Job Coach:
Telephone:

 

Participants Employment Background Information.
How long have you been at your current job?
How did you hear about this job?
Did you have to have a job interview?
What do you do at your job?
How do you get back and forth to work?
Do you or have you used public transportation to get back and forth to work?
On average how many days of the week do you work?
How many hours per week do you work at your job?
Do you like your job?
What type of job training program were you involved in?

Comment regarding work performance and environment (attitude of participant, attitude
of supervisors, work environment, etc).

160

HEALTH HISTORY/BACKGROUND INFORMATION FORM

 

 

 

 

Participant #—

Participant Name Date__
Date of Birth: Date of Verbal Assent

Living Environment: Group Home____ Community Living__ Other

If other, please explain

 

Data to be collected from the participant ’s parent/guardian or group home supervisor.
Do you have or have you had in the past:
Yes No
1. Any health condition that would be harmful if you lift weights
in this study?
2. High blood pressure?
3. Difliculty with physical activity or exercise?
4. History of breathing or lung problems?

5. Muscle, joint, or back problems, or any physical injury still
bothering you?

6. Hernia, or any condition that my be aggravated by lilting
weights?

Please explain any YES answers below:

Please answer the following questions:

Do you like to exercise?

Are you currently taking any medications that could be harmful to you if you lift weights?
How often do you exercise per week?

What type of exercises do you do?

161

Work Task Data Performance Sheet

 

 

Date Box Stacking Hand TruckPush Comments
8 boxes, 25 lb each
Seconds (160 fi, 851b)
Seconds

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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N—N—NHNr—N—‘N-dNr—Nv—N—‘N—Nt—Nr—‘Ng—Nz—gug—Ng—

 

 

 

 

 

 

Participant's Name:

 

162

Workout Schedule
Participants Name:

 

 

DATE: Leg Leg Chest Bicep Triceps Back Abs
Intensity Extension Curl Press Curl Curl Extension Curl

 

Once Wk.
Baseline

 

l-RM

 

l-RM

 

l-RM

 

l-RM

 

l-RM

 

Twice/Wk

 

30—40%

 

30-40%

 

30-40°/o

 

30-40%

 

50—60%

 

50-60%

 

50-60°/o

 

50-60%

 

50—60°/o

 

50-60%

 

 

 

 

 

 

 

 

 

 

163

Workout Schedule (cont’d)

 

70—80%

 

70—80%

 

70—80%

 

70—80%

 

70—80%

 

70-80%

 

70-80%

 

70-80%

 

Once/Wk
Retention

 

l-RM

 

l-RM

 

l-RM

 

l-RM

 

l-RM

 

l-RM

 

 

 

 

 

 

 

Comments:

164

 

 

 

 

Work Performance Forms for Onsite Job Tasks

 

 

 

Name: Job Location:
Week of: Job Task Amount of Job performance ratings
work completed (Check one)

 

 

Poor Average Good Great

 

 

 

 

 

 

 

Weekly Comments Regarding Job Performance

 

Week of: Job Task Amount of Job performance ratings
work completed (Check one)

 

 

Poor Average Good Great

 

 

 

 

 

 

 

Weekly Comments Regarding Job Performance

 

Week of: Job Task Amount of Job performance ratings
work completed (Check one)

 

 

Poor Average Good Great

 

 

 

 

 

 

 

Weekly Comments Regarding Job Performance

 

Week of: Job Task Amount of Job performance ratings
work completed (Check one)

 

 

Poor Average Good Great

 

 

 

 

 

 

 

Weekly Comments Regarding Job Performance

 

Week of: Job Task Amount of Job performance ratings
work completed (Check one)

 

 

Poor Average Good Great

 

 

 

 

 

 

 

Weekly Comments Regarding Job Performance

165

 

 

 

 

 

APPENDIX C

The Abilities Index

166

 

 

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I72

APPENDIX D

Data Files

173

Table 21

Strength Data Files for Shane’s l-RM Lifts for Baseline, Intervention, and Retention

 

 

 

 

 

 

Leg Leg Chest Biceps Triceps Abs
Extension Curl Press Curl Extension Curl
Baseline
February 25 7O 50 80 37.5 35 20
March 4 7O 4O 80 37.5 30 30
March 11 80 4O 80 40 3O 30
March 18 80 30 80 40 30 30
March 25 80 30 80 4O 30 30
Intervention
30-40%-1RM
March 30 80 30 9O 4O 35 30
April 6 9O 30 9O 4O 4O 3O
50-60%-1RM
April 13 9O 3O 9O 40 35 50
April 22 100 50 9O 40 35 50
April 29 90 50 90 45 40 50
70-80%-1RM
May 6 80 30 80 4O 35 40
May 13 9O 4O 6O 45 35 60
May 18 120 50 100 50 50 50
May 27 130 50 100 50 45 50
Retention
June 3 150 50 100 40 50 70
June 10 150 50 110 45 55 70
June 15 160 50 110 55 55 60
June 24 170 60 100 45 55 70
July 1 160 50 110 55 55 60
July 8 160 50 110 50 50 7O

 

Note. Scores are listed in pounds represent the l-RM lifts for each testing session.

174

Table 22

Strength Data Files for Jacob’s l-RM Lifts for Baseline, Intervention, and Retention

 

 

 

 

 

Leg Leg Chest Biceps Triceps Abs
Extension Curl Press Curl Extension Curl
Baseline
February 25 120 60 70 47.5 37.5 50
March 4 120 70 70 47.5 40 50
March 1 1 125 70 70 47.5 45 50
March 18 130 60 80 47.5 47.5 50
March 25 125 60 8O 45 45 55
Intervention
30-40%-1 RM
March 30 130 60 8O 45 45 50
April 6 140 50 80 45 45 50
50-60%- 1 RM
April 13 170 60 100 52.5 67.5 60
April 22 190 60 1 10 52.5 67.5 70
April 29 210 70 80 57.5 55 6O
70-80%-RM
May 6 210 70 80 57.5 55 60
May 13 210 70 110 60 60 80
May 18 230 80 130 60 6O 70
May 27 230 90 140 65 65 80
Retention
June 3 245 90 140 70 7O 80
June 10 260 100 150 80 75 90
June 15 275 110 150 80 75 100
June 24 270 80 140 80 75 90
July 1 270 100 150 85 85 80
July 8 270 90 140 85 75 90

 

Note. Scores are listed in pounds represent the l-RM lifis for each testing session.

175

Table 23

Strength Data Files for Ji_m’s l-RM Lifis for Baseline, Interven_tion. an_d Retention

 

 

 

 

 

Leg Leg Chest Biceps Triceps
Abs

Extension Curl Press Curl Extension Curl
Baseline
May 19 90 50 90 40 3O 30
May 26 90 50 100 45 35 30
June 02 100 55 90 45 35 30
June 09 100 50 9O 45 35 3 5
June 14 100 50 110 40 4O 35
Intervention
30-40%- 1 RM
June 23 105 55 110 45 45 35
June 30 105 50 100 50 50 35
50-60%-1 RM
July 05 120 55 110 50 55 40
July 14 120 55 110 55 60 45
July 21 110 50 110 60 65 45
70-80°/o- 1 RM
July 28 130 55 120 50 6O 45
August 02 120 50 120 55 6O 50
August 1 l 130 50 120 60 60 60
August 18 150 65 120 65 65 60
Retention
August 25 155 65 125 60 7O 60
September 01 165 65 125 65 65 60
September 08 1 7O 65 130 65 65 65
September 15 165 65 120 65 65 70
September 22 l 70 60 130 65 65 70
September 27 170 65 120 70 60 65

 

Note. Scores are listed in pounds represent the l-RM lifls for each testing session.

l76

Table 24

Strength Data F iles for Bob’s l-RM Lifis for Baseline, Intervention, and Retention

 

 

 

 

 

Leg Leg Chest Biceps Triceps

Abs

Extension Curl Press Curl Extension Curl
Baseline
May 19 8O 4O 75 35 35 30
May 26 8O 40 75 35 4O 35
June 02 7O 35 80 30 35 35
June 09 85 35 8O 35 35 35
June 14 85 35 85 35 4O 40
Intervention
30-40%-1RM
June 23 85 45 9O 40 40 40
June 30 85 45 90 4O 45 40
50-60%-1RM
July 05 90 45 9O 40 4O 40
July 14 9O 45 100 45 35 45
July 21 100 50 9O 45 35 45
70-80%- 1 RM
July 28 95 50 100 45 40 40
August 02 100 40 100 45 40 50
August 11 130 40 100 50 45 55
August 18 140 45 110 50 45 55
Retention
August 25 150 45 110 55 50 60
September 01 155 45 1 10 55 50 60
September 08 155 50 110 55 50 55
September 15 160 50 1 10 55 50 55
September 22 160 50 115 60 55 55
September 27 170 45 1 10 50 60 50

 

Note. Scores are listed in pounds and represent the l-RM lifts for each testing session.

 

l77

Table 25

Data Files for Shane’s Avmge Time for Completion of Simulated Work Tasks

 

 

 

Box Stacking Hand Truck
Baseline Dates
February 25 40.92 40.93
March 4 38.89 37.37
March 11 39.10 38.92
March 18 41.44 36.59
March 25 38.54 31.23
Intervention Dates
March 30 39.45 33.98
April 6 37.62 32.61
April 13 40.98 29.98
April 22 37.34 31.68
April 29 36.28 35.00
May 6 1 39.14 32.23
May 13 40.90 31.95
May 18 36.48 30.24
May 27 33.18 29.78
Retention Dates
June 3 34.04 28.15
June 10 32.97 31.65
June 15 35.35 31.40
June 24 33.18 29.00
July 1 35.06 28.09
July 8 40.74 33.03

 

Note. Scores are listed in seconds and represent the mean of two trials for each testing

session.

178

Table 26

Data Files for .Lacob’s Average Tir_n_e for Completion of Simulated Work Tasks

 

 

 

 

Box Stacking Hand Truck
Baseline Dates
February 25 42.51 43.07
March 4 42.1 1 39.18
March 11 40.07 38.93
March 18 38.70 38.69
March 25 45.26 33.53
mmetmn Dates
March 30 38.72 33.26
April 6 34.83 31.03
April 13 31.93 29.73
April 22 33.69 31.89
April 29 35.44 30.25
May 6 38.65 33.65
May 13 39.49 32.26
May 18 32.52 30.98
May 27 32.50 28.52
Retention DLte_s
June 3 29.78 27.39
June 10 31.56 30.86
June 15 35.81 29.65
June 24 36.28 32.56
July 1 36.75 29.73
July 8 36.50 31.88

 

Note. Scores are listed in seconds and represent the mean of two trials for each

testing session.

179

Table 27

Data Files for Jim’s Average Time for Comletion of Simulated Work Tasks

 

 

 

 

 

 

Box Stacking Hand Truck
Baseline Dates
May 19 43.80 50.82
May 26 41.10 51.74
June 02 42.14 50.58
June 09 42.46 48.04
June 14 40.81 48.17
Interven_tipn Dms
June 23 42.86 47.23
June 30 38.82 49.31
July 05 40.05 45.54
July 14 35.84 43.91
July 21 38.28 42.81
July 28 36.91 41.31
August 02 36.97 42.01
August 11 39.04 40.86
August 18 37.63 42.00
Retention Dat_es
August 25 36.20 40.91
September 01 36.99 39.19
September 08 37.30 39.64
September 15 35.45 38.27
September 22 39.20 36.75
September 27 38.71 38.78

 

Note. Scores are listed in seconds and represent the mean of two trials for each

testing session.

180

Table 28

Data Files for Bob’s Average Tim_e for COM of Simalated Work Tasks

 

 

 

Box Stacking Hand Truck
Baseline Dates
May 19 45.97 46.06
May 26 42.13 46.82
June 02 40.24 45.75
June 09 38.80 45.04
June 14 37.36 44.62
Intervention Dates
June 23 35.68 41.23
June 30 36.56 40.54
July 05 37.52 40.71
July 14 34.26 41.27
July 21 32.90 38.73
July 28 37.83 38.78
August 02 35.94 36.06
August 11 33.74 34.61
August 18 32.48 32.43
Reten_tion Dates
August 25 33.11 33.16
September 01 32.76 32.93
September 08 37.91 30.81
September 15 37.61 33.91
September 22 37.09 36.09
September 27 40.16 34.26

 

Note. Scores are listed in seconds and represent the mean of two trials for each testing

session.

181

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