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M.L:.BRARY
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" University

This is to certify that the
thesis entitled

EFFECT OF EXPLOSIVE UPPER BODY EXERCISES ON
BIOMECHANICAL PARAMETERS IN MALES 18-30 YEARS
OF AGE

presented by

KRIS WILLIAM KOTRLA

has been accepted towards fulfillment
of the requirements for the

MS. degree in Kinesiolog

 

 

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Date

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EFFECT OF EXPLOSIVE UPPER BODY EXERCISES ON BIOMECHANICAL PARAMETERS IN
MALES 18-30 YEARS OF AGE

By

Kris William Kotrla

A THESIS
Submitted to
Michigan State University

in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE
Department of Kmesiology
2005

ABSTRACT

EFFECT OF EXPLOSIVE UPPER BODY EXERCISES ON BIOMECHANICAL PARAMETERS IN
MALES 18-30 YEARS OF AGE

By
Kris Mlliam Kotrla

The purpose of this study was to examine the relationships that exist between selected
upper body exercises (push-up and medicine ball throw) and biomechanical parameters (force,
maximal rate of force development (MRF D), and average peak power output) in males who are
currently resistance training. Relationships were expected to exist between biomechanical
parameters in response to the demand of exercise methods (concentric only, countennovement,
and plyometric) performed with a push-up and throwing a 3 kg medicine ball. The design was a
cross sectional, descriptive study with repeated measures. In this study individuals were randomly
assigned into one of two groups. The results of this study indicated that push-up exercises require
a significantly higher peak force and MRFD to perform more explosively than 3 kg medicine ball
throws. The average peak power output was greater for the 3 kg medicine ball throws for the
countennovement and plyometric method, but no significant difference was found between the
exercises. In addition, explosive upper body exercises that rely on the stretch shortening cycle
(880) were shown to develop higher magnitudes of force in comparison to concentric only
methods. The MRFD and average peak power output were significantly greater when the
plyometric method was compared to the concentric only and countennovement method. This study
and future studies of this type could help bridge the gap between exercise scientists and coaches

in determining which exercises would be the most beneficial for athletes.

ACKNOWLEDGEMENTS

Thank you to me participants who volunteered their time and effort for this study. I also
want to thank Adam Bruenger, Erin Hess, Tony Moreno, Miguel Narvaez, and Tom Tanaka for
their help with setting up the lab and testing participants. Miguel Narvaez has a great
understanding of the lab equipment that was used and was essential to testing participants. I really
appreciate the work of Dennis Gilliland who took out considerable amounts of time to meet with me
on a regular basis to simplify and guide the statistics of this study. In addition, I would like to thank
Dr. Dummer and Dr. Womack for serving on this thesis committee and for their insight, advice, and
encouragement. I would also like to thank my advisor, Dr. Brown, who spent many hours in helping
me develop this thesis and working through the details of this paper. I want to thank our family who
gave support in numerous and immeasurable ways. I would also like to thank my wife, who has
made many sacrifices for me while in school, and has provided encouragement and support during

this project Thank you Lord for making this possible and providing all of the above mentioned.

iii

TABLE OF CONTENTS

LIST OF TABLES .............................................. viii
LIST OF FIGURES ................................................................................................................. ix-xii
CHAPTER 1
INTRODUCTION .................................................................................................................... 1
Overview of Problem .............................................................................................................. 1
Significance of Problem ........................................................................................................ 1
Purpose ................................................................................................................................. 2
Need for Study ...................................................................................................................... 2
Hypotheses ............................................................................................................................ 4
Assumptions .......................................................................................................................... 4
Definitions of Terms Used ...................................................................................................... 5
Assumptions ......................................................................................................................... 23
Limitations .............................................................................................................................. 23
CHAPTER 2
LITERATURE REVIEW .......................................................................................................... 24
Concentric Only Exercise Method .......................................................................................... 24
Training Studies of Concentric Only Exercises ................................................................... 24
7 Guidelines for Concentric Only Exercises ........................................................................... 25
Summary of the Concentric Only Exercise Method ............................................................. 26
Countennovement Exercise Method ...................................................................................... 26
Studies of Upper Body Countennovement Exercises ......................................................... 26
Guidelines for Countermovement Exercises ....................................................................... 27
Speed of Movement and Load ............................................................................................ 28
Gender and Race ................................................................................................................ 30
Summary of Countennovement Exercise Method ............................................................... 31
Plyometrics ............................................................................................................................ 31
Neuromuscular Response to Plyometrics ........................................................................... 31
Guidelines for Plyometric Exercises .................................................................................... 32
Biomechanical and Training Studies of Plyometric Exercises ............................................. 33
Summary of Plyometric Exercise Method ........................................................................... 33
Comparisons of Exercise Methods ......................................................................................... 34
Comparison of Biomechanical Performance Parameters Among Exercise Methods .......... 34
Gender Comparison of Biomechanical Performance Parameters on Training Methods ..... 36
Summary of Exercise Methods ........................................................................................... 37
Measurement of Pertinent Biomechanical Parameters .......................................................... 37
Peak Force ......................................................................................................................... 38
Maximal Rate of Force Development .................................................................................. 38
Average Peak Power Output .............................................................................................. 39
Implications of the Literature Review for the Current Study .................................................. 39

iv

CHAPTER 3

METHODS ............................................................................................................................. 42
Research Design .................................................................................................................... 42
Participants .............................................................................. g .............................................. 44
Selection Criteria ................................................................................................................. 44
Recruitment ....................................................................................................................... 45
Sample Size ........................................................................................................................ 45
Assignment of Participants to Groups ................................................................................ 46
Exercise Conditions ............................................................................................................... 46
Push-ups ............................................................................................................................. 46
Medicine Ball Throw ............................................................................................................ 48
Instrumentation ...................................................................................................................... 50
Demographic Questionnaire ............................................................................................... 50
Anthropometry .................................................................................................................... 50
Length ............................................................................................................................. 50
Height ........................................................................................................................... 50
Upper Extremity Length ................................................................................................ 51
Width ............................................................................................................................... 51
Weight ............................................................................................................................. 52
Total Body Weight ........................................................................................................ 52
Exercise Position .......................................................................................................... 53
Peak Force ...................................................................................................................... 54
Maximal Rate of Force Development ............................................................................... 58
Average Peak Power Output ........................................................................................... 61
Additional Equipment Used in this Study ............................................................................ 67
Push-up Platform ............................................................................................................. 67
Medicine Ball and Support ............................................................................................... 67
Meter Stick ....................................................................................................................... 68
Mouse Pads ..................................................................................................................... 69
Data Collection Procedures .................................................................................................... 69
Orientation Session ............................................................................................................. 69
Test and Retest Sessions ................................................................................................... 74
Data Collection Personnel and Qualifications ..................................................................... 75
Data Management .............................................................................................................. 75
Data Analysis ......................................................................................................................... 76
Participant Characteristics .................................................................................................. 76
Test of Hypotheses ............................................................................................................. 76
Test of Assumptions ........................................................................................................... 77
CHAPTER 4
RESULTS .............................................................................................................................. 79
Participants ............................................................................................................................ 79
Descriptive Data for Test of Hypotheses ................................................................................ 80
Test of Hypotheses ................................................................................................................ 80
Concenh'ic Only Method ..................................................................................................... 81
Countennovement Method ................................................................................................. 84
Plyometric Method .............................................................................................................. 87

Descriptive Data for Test of Assumptions .............................................................................. 91

Tests of Assumptions ............................................................................................................. 91
Peak Force ......................................................................................................................... 91
Maximal Rate of Force Development ..................................... ~ ............................................. 92
Average Peak Power Output .............................................................................................. 93

CHAPTER 5

DISCUSSION ......................................................................................................................... 95

Contributions to the Research Literature ................................................................................ 95
Hypotheses ......................................................................................................................... 95

Hypotheses for Peak Force ............................................................................................. 95
Hypotheses for Maximal Rate of Force Development ...................................................... 95
Hypotheses for Average Peak Power Output .................................................................. 96
Patterns of Force and Acceleration ..................................................................................... 96
Assumptions ........................................................................................................................ 100
Assumptions for Peak Force ............................................................................................ 100
Assumptions for Maximal Rate of Force Development .................................................... 101
Assumptions for Average Peak Power Output ................................................................. 101

Implications ............................................................................................................................ 102

Implication for Strength Coaches ........................................................................................ 102
Order of Exercise ............................................................................................................. 102
Exercise Mechanics ......................................................................................................... 103
Kinetics of Performance ................................................................................................... 104

Implications for Exercise Scientist ....................................................................................... 105
Exercise Differences in Biomechanical Variables ............................................................ 106
Specificity of Training ...................................................................................................... 106

Implications for Personal Trainers and Individuals Who Perform Resistance Training ....... 107
Effects of Plyometric Exercises ....................................................................................... 107
Risk of Injury .................................................................................................................... 108

Recommendations ................................................................................................................. 108

Scientific Knowledge ........................................................................................................... 108
Exercise Methods ............................................................................................................ 108
Influence of Training on Performance and Sport Skill Efficiency ..................................... 109
Analysis of Other Biomechanical Parameters .................................................................. 109
Relationship of Plyometric Upper Body Exercises to Rehabilitation ................................ 109

Methodology ....................................................................................................................... 110
Homogenous Population ................................................................................................. 110
Additional Coaching and Practice .................................................................................... 111
Standard Method of Recording Biomechanical Parameters ............................................ 111

Practice ............................................................................................................................... 111
Number of Force Platforms .............................................................................................. 112
Identifying the Concentric Phase with an Accelerometer during Medicine Ball Throw ..... 112
Influence of Medicine Ball of Various Weights on Biomechanical Parameters ................ 112

Conclusions ........................................................................................................................... 113

APPENDICES ........................................................................................................................ 1 15

vi

REFERENCES ....................................................................................................................... 143

vii

LIST OF TABLES

Table 1. Procedures for the Testing Sessions for Group 1 and Group 2 ................................ 43
Table 2. Overview of Orientation, Test, and Retest Sessions for Group 1 and 2 ................... 73
Table 3. Anthropometric and Strength Measurements ........................................................... 79

Table 4. Differences in Peak Force, MRFD, and Average Peak Power Output for
Push-up and Medicine Ball Exercises Performed as Concentric Only (CO),
Countennovement (CM), and Plyometric (PLY) Methods ...................................................... 8O _

Table 5. Summary of T-test Results related to Peak Force, MRFD, and Average
Peak Power Output for Push-up and Medicine Ball Exercises Performed as

Concentric Only (CO), Countennovement (CM), and Plyometric (PLY) Methods .................. 91

Table 6. Training Studies of Concentric Only Exercise .......................................................... 116
Table 7. Biomechanical and Training Studies of Countennovement Exercise ....................... 118
Table 8. Biomechanical and Training Studies of Plyometric Exercise .................................... 124
Table 9. Biomechanical and Training Studies Comparison of Exercise Methods ................... 128

viii

LIST OF FIGURES

Figure 1. Concentric only push-up and medicine ball throw...... ............................................. 5
Figure 2. Countennovement push-up and medicine ball throw .............................................. 10
Figure 3. Plyometric push-up and medicine ball throw ........................................................... 16
Figure 4. Push-up platform built to help protect participants during the

performances of the plyometric push-ups. ............................................................................ 47
Figure 5. Two push-up platforms built for the push-up exercises ........................................... 47

Figure 6. Anthropometric measurements taken of standing height using long
anthropometer (a), upper extremity length using short anthropometer (b), and
biacromial width using bow caliper (c). .................................................................................. 51

Figure 7. Weight experienced by the force platform measured for the total body (a),
front leaning position in the push-up (b), and back lying weight for the medicine
ball exercises (c). .................................................................................................................. 53

Figure 8. Force platform on the right used to record data in this study .................................. 55

Figure 9. Typical force patterns of the countennovement push-up for participant
05MB (front leaning push-up position = 44 kg). The same process of calculation
was also used on the concentric only and plyometric methods for the push-up. ................... 56

Figure 10. Typical force patterns of the countennovement medicine ball throw for
participant 05MB (back lying weight = 51 kg). The same process of calculation was
also used for the concentric only medicine ball throw. .......................................................... 57

Figure 11. Typical force patterns of the plyometric medicine ball throw for
participant 05MB (back lying weight = 46 kg). ....................................................................... 57

Figure 12. Typical RFD and force patterns of the countennovement push-up for

participant 05MB (front leaning push-up position = 44 kg). The same process of

calculation was used for all methods of exercise during the push-up and medicine

ball throw. For this graph a larger window of time was used (20 ms) to calculate the

RFD and smooth the data line. MRFD indicates the maximal rate of force

development. ......................................................................................................................... 59

Figure 13. Typical RFD and force patterns of the countennovement medicine ball

throw for participant 05MB (back lying weight = 51 kg). The same process of

calculation was used for all methods of exercise during the push-up and medicine

ball throw. MRFD indicates the maximal rate of force development. .................................... 60

ix

Figure 14. Typical RFD and force patterns of the plyometric medicine ball throw for
participant 05MB (back lying weight = 46 kg). The same process of calculation was
used for all methods of exercise during the push-up and medicine ball throw. For
this graph a larger window of time was used (20 ms) to calculate the RFD and

smooth the data line. MRFD indicates the maximal rate of force development. .................... 61
Figure 15. Accelerometer used to help determine the average peak power output .............. 62
Figure 16. Process used to attach the accelerometer to the chest for the push-up .............. 63

Figure 17. Medicine ball and accelerometer configuration for the medicine ball throws ........ 63

Figure 18. Typical average power output and force patterns of the

countennovement push-up for participant 05MB (front leaning push-up

position = 44 kg). The same process of calculation was used for all methods of

exercise during the push-up and medicine ball throw. . ......................................................... 65

Figure 19. Typical average power output and force pattems of the

countennovement medicine ball throw for participant 05MB (back lying weight =

51 kg). The same process of calculation was used for all methods of exercise

during the push-up and medicine ball throw. . ........................................................................ 66

Figure 20. Typical average power output and force pattems of the plyometric

medicine ball throw for participant 05MB (back lying weight = 46 kg). The same

process of calculation was used for all methods of exercise during the push-up

and medicine ball throw. ....................................................................................................... 67

Figure 21. Setup used for the medicine ball throws ............................................................... 68

Figure 22. Typical force patterns of the concentric only push-up and medicine ball

throw for participant 11PU (back lying weight = 30 kg). MRFD indicates the

maximal rate of force development The same process of calculation was also

used for the concentric only medicine ball throw. .................................................................. 82

Figure 23. Typical rate of force development (RFD) patterns of the concentric only
push-up and medicine ball throw for participant 11PU (back lying weight = 30 kg).
MRFD indicates the maximal rate of force development. ...................................................... 83

Figure 24. Typical average power output patterns of the concentric only push-up
and medicine ball throw for participant 11PU (back lying weight = 30 kg). MRF D

indicates the maximal rate of force development. ................................................................. 83

Figure 25. Typical force patterns of the countennovement push-up and medicine
ball throw for participant 15PU (front leaning push-up position = 28 kg, back lying
weight = 35 kg). MRFD indicates the maximal rate of force development. ............................ 85

Figure 26. Typical rate of force development (RFD) patterns of the

countennovement push-up and medicine ball throw for participant 15PU (front

leaning push-up position = 28 kg, back lying weight = 35 kg). MRFD indicates the

maximal rate of force development. ......................................... . ............................................. 86

Figure 27. Typical average power output patterns of the countennovement push-up
and medicine ball throw for participant 15PU (front leaning push-up position = 28 kg,
back lying weight = 35 kg). MRFD indicates the maximal rate of force development. ........... 87

Figure 28. Typical force patterns of the plyometric push-up and medicine ball throw
for participant 15PU (back lying weight = 37 kg). MRFD indicates the maximal rate
of force development. ............................................................................................................ 88

Figure 29. Typical rate of force development (RFD) patterns of the plyometric

push-up and medicine ball throw for participant 15PU (back lying weight = 37 kg).

MRFD indicates the maximal rate of force development. For this graph, 60 ms

were examined instead of 125 ms to help display markers. .................................................. 89

Figure 30. Typical average power output of the plyometric push—up and medicine

ball throw for participant 15PU (back lying weight = 37 kg). MRFD indicates the

maximal rate of force development For this graph, 60 ms were observed instead

of 125 ms to help display markers. ........................................................................................ 90

Figure 31. Comparisons of the groups' peak force values for the push-up and
medicine ball throw methods. ................................................................................................ 92

Figure 32. Comparisons of the groups’ maximal rate of force development values
for the push-up and medicine ball throw methods. ................................................................ 93

Figure 33. Comparisons of the groups’ average peak power output values for the
push-up methods. ................................................................................................................. 94

Figure 34. Typical acceleration and force patterns of the concentric only push-up
for participant 15PU. ............................................................................................................. 97

Figure 35. Typical acceleration and force patterns of the concentric only medicine
ball throw for participant 15PU (back lying weight = 28 kg). .................................................. 98

Figure 36. Typical acceleration and force patterns of the countennovement
push-up for participant 15PU (front leaning position = 28 kg). .............................................. 98

Figure 37. Typical acceleration and force patterns of the countennovement
medicine ball throw for participant 15PU (back lying weight 32 kg). ...................................... 99

Frgure 38. Typical average acceleration aid force patterns of the plyometric
push-up method for participant 15PU. ................................................................................... 99

xi

Figure 39. Typical acceleration and force patterns of the plyometric medicine ball
throw method for participant 15PU. ....................................................................................... 100

xii

CHAPTER 1
INTRODUCTION

Overview of Problem .

This study was conducted to show selected relationships between biomechanical
parameters and explosive upper body exercises. Exercise science professionals agree that
analysis of performance parameters associated with upper body exercise is lacking (Davies &
Matheson, 2001; Knudson, 2001). Unparalleled to the amount of research on exercise involving the
lower body are relatively few studies conducted to investigate upper body movements and
variables that are influenced by them (Bloomfield, Blanksby, Ackland, & Allison, 1990; Cronin,
McNair, 8 Marshall, 2000; 2002; Newton et al., 1997).

Studies that have been conducted on upper body movement during various exercise
techniques have provided some insight into the specifics of how they influence biomechanical
parameters (Cronin et al., 2000; 2002; Newton et al., 1997) and sport skill efficiency (Bloomfield et
al., 1990; Crowder, Jolly, Collins, 8 Johnson, 1993; Newton & McEvoy, 17994; Vossen, Kraemer,
Burke, & Vossen, 2000). However, not all of‘the common variations of upper body exercise training
methods (e.g., concentric only, countennovement, and plyometric) have been thoroughly
investigated.

Since various exercise methods are used in a wide range of training settings (e.g.,
rehabilitation clinics, health-fitness facilities, athletic training, training camps, and sport specific
clinics), it would be ideal to know which exercises are the most beneficial to intended outcomes for
individuals of different abilities, ages, and genders, and for the performance of different sports skills.

Significance of Problem
Since variations in how exercise movement is performed (e.g., range of motion and

variation of body position) can cause significant changes in biomechanical parameters, it is

important to establish a good understanding of variations in movement with respect to commonly
used exercises (Bobbert, Huijing, 8 van lngen Sheneau, 1987a; Escamilla et. al., 2001; Lee,
Huang, Wang, 8 Lin, 2001). These biomechanical parameters include peak force, the maximal rate
of force development (MRFD), and average peak power output. Although these parameters have
been used to compare performances of different types of lower body exercise, they have not been
thoroughly applied to the study of various upper body exercises.

In addition the plyometric method is an area where a lack of research exists in regards to
upper body exercises (Davies 8 Matheson, 2001; Knudson, 2001; Wilk et. al., 1993). Plyometric
activities sequence movements in a combination that involves the lengthening and shortening of a
group of muscles (i.e., stretch shorten cycle (SSC). Plyometric training is often associated with
certain strength aspects (e.g., agility, acceleration, speed, force production, and power) that are
desirable for athletes to develop for a sport.

Purpose

The purpose of this study was to identify how selected biomechanical parameters (i.e.,
peak force, MRFD, and average peak power output) differ in the performance of the push-up and
medicine ball throw (Figures 1-3) in males using different training methods (i.e., concentric only,
countennovement, and plyometric). A secondary goal of this study was to provide information that
would contribute to future studies of different populations and specificity of training. In addition, this
study was intended to advance scientifically based information that already exists on exercise
training methods for the upper body.

Need for Study

At the many fitness and training settings throughout the United States, a broad spectrum of

training protocols are used to enhance health, strength, and performance from the general strength

of the beginning weight trainer to the sport specific training of the elite athlete. Basic foundational

strength training guidelines, aimed at benefiting the health and performance of participants, have
been established by research (ACSM, 2002), are taught through certification programs, and are
passed on by experienced exercise leaders in various exercise settings. Even though there are
some scientifically supported guidelines, numerous professionals train individuals with different and
unstudied protocols. These include working the same body parts differently (e.g., variation of
training method, position, movement, equipment, intensity a muscle group is worked, and the
extent to which muscle groups are developed). Various training methods are used to optimize
sports performance and not all of the methods have been thoroughly researched, especially with
respect to the upper body. In addition, most of the strength training research has focused on
analyzing the lower body and not as many studies have been conducted on upper body training
methods. The current study of selected upper body exercise methods was somewhat similar to
previous studies of the upper body (Cronin, et al., 2000; 2002; Newton et. al., 1997). Results from
the current study are intended to provide comparative biomechanical performance parameters to
better understand selected upper body exercises.

The intention of conducting this study is to contribute knowledge to an area of exercise
science that has not been thoroughly investigated. lnforrnation gained would lend evidence for
sport specific training and future studies. This study is also practical and applicable to various
movements and training methods used by exercise specialists. Individuals who participated in this
study were instructed on proper technique to perform exercises which could be incorporated into
their workout regiment. lnforrnation gained from this study was provided to the participants. In
addition, further publication of the results will provide knowledge that can be used by exercise

specialists and researchers.

Hypotheses
The results of this study there were expected to show specific relationships of
biomechanical parameters in response to the concentric only, countennovement, and plyometric
methods performed between the push-up and medicine ball throw (Figures 1-3). Some of the
results expected to occur were:
0 Concentric Only (Push-up vs. Medicine Ball Throw)
o Push-off force generated by college aged males will be greater while performing the push-
up versus the medicine ball exercise.
. MRFD and the average peak power output generated by college aged males will be less
while performing the push-up compared to the medicine ball exercise.
0 Countennovement (Push-Up vs. Medicine Ball Throw)
. Push-off force generated by college aged males will be greater while performing the push-
up versus medicine ball exercise.
0 MRFD and the average peak power output generated by college aged males will be less
while performing the push-up compared to the medicine ball exercise.
0 Plyometric (Push-Up vs. Medicine Ball Throw)

. Peak forces, MRFD, and average peak power output will be similar for both exercises
performed by college aged males.

Assumptions
In addition, assumptions were made about biomechanical parameters associated with different
exercise methods used to perform the push-up and medicine ball throw.
0 Push-off force in the push-up and medicine ball throw will have a hierarchical order with
respect to method of exercise (concentric only < countennovement < plyometric) (Bobbert,

et al., 1987a; Newton et al., 1997).

o MRFD in the push-up and medicine ball throw will have a hierarchical order with respect to the
method of exercise (concentric only < countermovement < plyometric).

0 Average peak power output in the push-up and medicine ball throw will have a hierarchical
order (concentric only < countennovement < plyometric) (Bobbert, et al., 1987a; Cronin, et al.,

2000; Newton et al., 1997).
Definitions of Terms Used

Absolute Strength - the maximal amount of force one is able to exert for a given task.

Amortization Phase -— period of time between the eccentric and concentric phases of a
countennovement.

Concentric Contraction- movement involving shortening of the muscle where the force of the
muscle contraction is greater than resistance (Hall, 1999). Positive work is exhibited with this type
of contraction due to the muscle's “moment and angular velocity of the joint being in the same
direction" (Winter, 1990). The lower the external resistance is compared to the muscle force the
higher the movement velocity the muscle will be able to produce in the concentric contraction.
Figure 1 includes the push-up and medicine ball throw exercise

Push-up

Start

 

 

 

 

(Figure 1 continued)

 

ric Contraction

Concent

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(Figure 1 continued)

 

End

Medicine Ball Throw

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(Figure 1 continued)

 

 

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(Figure 1 continued)

End

 

 

Figure 1. Concentric only push-up and medicine ball throw

Countennovement - an eccentric contraction followed immediately by a concentric contraction of
the same muscle group (Figure 2).

Push-up

Start

Eccentric Contraction

 

 

10

 

 

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End

 

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(Figure 2 continued)

 

13

 

 

 

(Figure 2 continued)

 

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(Figure 2 continued)

End

 

 

Figure 2. Countennovement push-up and medicine ball throw

Eccentric Contraction - movement involving lengthening of the muscle where the force of the
muscle contraction is less than resistance (Hall, 1999).

External Validity - the extent to which research findings are truthful or generalizable to other
populations, other times, and other settings.

Force - product of mass and acceleration; force = mass x acceleration.

History- anything that happens during the period of time between one measure of a dependent
variable and a subsequent measure of the same dependent variable.

Internal Validity - the quality of the research design; the ability to claim that difference (if any) are
caused by the independent variable rather than an intervening, extraneous, or attribute variable.

lsokinetic Contraction - muscular shortening in which the angular velocity about a joint is kept
constant by an external torque (typically generated by an lsokinetic dynamometer) equal and
opposite to the internal torque (generated by the contracting muscle).

lsokinetic Dynamometer- motorized equipment designed to provide an accommodating resistance
to the concentric torque generated by the contraction of muscles.

15

Isometric Contraction - external resistance equal to the internal force produced by contracting
muscle causing no movement to occur about a joint and no change in length of contracting muscle.

lsotonic Contraction — most common type of muscle contraction in which a muscle or group of
muscles moves a specified load through a range with varied force of muscular contraction and
varied angular velocity of movement.

Maturation — progress of a biological system toward a mature state that influences a dependent
variable.

Maximal Rate of Force Development (MRFD) - the greatest amount of force that can be produced
in the shortest amount of time, represented by the steepest slope of the force-time curve. (“The
ability of the neuromuscular system to develop high action velocities” (Schmidtbleicher 8 Komi,
1992).

Multiple Treatment Threat - one treatment influencing the effects of another treatment.

Plyometric - a type of countennovement that involves a high force, high speed, and low amplitude
eccentric contraction followed by a forceful concentric contraction. This process relies on the
stretch shorten cycle (SSC). Plyometrics include drills aimed at linking strength with speed of
movement to produce power (Chu, 1998) (Figure 3).

Push-up

Start

 

 

Eccentric Contraction

 

     

 

(Figure 3 continued)

 

(Figure 3 continued)

  

Concentric Contraction

 

(Figure 3 continued)

 

End

 

Medicine Ball Throw

Start

 

 

(Figure 3 continued)

 

20

 

 

(Figure 3 continued)

 

858580 22880

 

(Figure 3 continued)

 

End

 

 

Figure 3. Plyometric push-up and medicine ball throw

Relative Strength — ones maximum amount of strength in a task that made in comparison to their
body weight

Repetition Maximum (RM) - exercise that an individual can perform no more than a designated
number of repetitions under the load imposed (e.g., 1RM is an exercise that an individual can only
perform one time under the load imposed).

Sport Ski/I Efficiency - ability to enhance the performance of a skill within a sport as a result of
training effectively.

Stretch Shorten Cycle (SSC) - eccentric movement prior to concentric movement that utilizes
muscle elasticity and muscle spindle response during the eccentric phase of an exercise to
facilitate force of muscle contraction during the concentric phase.

Training Methods — different muscle contraction patterns (e.g., lsokinetic, isometric, isotonic,
concentric only, countennovement, plyometric) used in exercise regimes.

Training Specificity - enhancement of performance resulting from a training regime in which the
movement pattern or exercise is similar or identical to the outcome to be evaluated.

22

Variations in Movement - alternative motions that may occur in the performance of an exercise
(e.g., speed of movement, range of motion, positioning of body parts).

Assumptions

Assumptions of this study include:

Participants were healthy and trained in a resistance program for a minimum 6 weeks on a
consistent basis immediately prior to the study.

Participants gave their maximal effort during exercises.

Participants exerted equal amounts of force from each hand when performing the push-up
on the force platform and when performing the medicine ball throw.

The accelerometer gave a true reading and experienced little rotation during the push-up
and medicine ball throw exercises.

Limitations

Limitations of this study include:

The sample size for this study was 17 participants.

Take-off velocity in the performance of the push-up and medicine ball throw was indirectly
measured through the use of an accelerometer.

The vertical ground reaction force was measured in the push-up exercise via single force

platform located under the right hand.

23

CHAPTER 2
REVIEW OF LITERATURE

Selected pertinent research on exercise training from the previous 30 years was used in
this review. An examination was made of different types of exercise methods (i.e., concentric only,
countennovement, and plyometric) and the training duration, frequency, and intensity on post
training results. In addition, biomechanical parameter comparisons of movement and skill
performance were made between the different types of exercise methods. Even though the upper
body is the focus of this study most of the information available is from studies of the lower body.
After comparisons are made, biomechanical parameters (i.e., force, MRFD, and power output) will
be discussed on how they are influenced by the different exercise methods. Finally, implications
will be made from pertinent literature sources available for this study.

Concentric Only Exercise Method

There are a number of studies involving concentric only exercises. However, concentric
only exercises are rarely used at training settings. Articles that review the concentric only training
method show how participants who trained at various constant angular velocities have different
training effects. Training regiments used in the various concentric only exercises will be identified in
this review of literature.

Training Studies of Concentric Only Exercises

Studies of concentric isokinetic contractions have primarily focused on the ability to
produce greater amounts of torque in knee flexion and extension in association with training at
different constant angular velocities (Caiozzo, Perrine, 8 Edgerton, 1981; Coyle et. al., 1981;
Kanehisa 8 Miyashita, 1983; Prevost, Nelson, 8 Maraj, 1999). These studies tend to show training
specificity. Biomechanical properties of various exercises were influenced by the force and speed

in which the muscles contract. For example, training the knee extensors at relatively high angular

24

velocities (i.e., 4.19, 4.71, and 5.24 rad/s) improved torque production the most at faster velocities
(Caiozzo, et al., 1981; Coyle et al., 1981; Kanehisa 8 Miyashita, 1983; Prevost, et al., 1999).
Similarly, slower angular velocity training (i.e., 0.52, 1.04, 1.05, and 168 rad/s) of the knee
extensors improved post training torque production the most at the slower tested velocities and
post training torque production more than the higher angular velocity training through out the range
of exercise velocities tested (Caiozzo, et al., 1981; Coyle et. al., 1981; Kanehisa 8 Miyashita, 1983;
Prevost, et al., 1999). In another study using an isokinetic dynamometer, Behm and Sale (1993)
trained participants’ dorsiflexors. Participants trained one ankle with fast force developing isometric
dorsiflexions set at 0 rad/s and the other ankle with fast isokinetic dorsiflexions set at 5.23 rad/s.
The post test training results of their study for both ankles were similar for peak force and rate of
force development. Their conclusion was training movement speed might not be as important as
training the rate in which force is developed. The results from this study do not support training
specificity.
Guidelines for Concentric Only Exercises

Studies which incorporated the isokinetic dynamometer as the method of training varied in
their use of the number of sets and repefitions in which the training was performed (Behm 8 Sale,
1993; Caiozzo et al., 1981; Coyle et. al., 1981; Kanehisa 8 Miyashita, 1983; Prevost, et al., 1999),
making it difficult to compare and draw generalizafions across studies. Typically the number of sets
performed during training ranged from two to five, and the number of repetitions per set ranged
from 6-50. Rest between sets also varied from 1-3 min (Behm 8 Sale, 1993; Kanehisa 8 Miyashita,
1983; Prevost, et al., 1999). Studies from the literature review used training frequencies of 2-6 days
per week. Duration of the training in the isokinetic studies ranged from 2 days to 16 weeks.
Participants in these studies (Caiozzo, et al., 1981; Coyle et. al., 1981; Kanehisa 8 Miyashita, 1983;

Prevost, et al., 1999) ranged from 19-38 years of age with the majority of participants in their lower

25

20’s. Age was not mentioned as being significant to the outcome of the various studies or
determined to be significantly different between groups. Even though most of the studies were
conducted on males, studies including both male and female participants reported no difference
between genders in post test strength gains (Behm 8 Sale, 1993; Caiozzo, et al., 1981).
Summary of the Concentric Only Exercise Method

Unfortunately, because isokinetic dynamometers are not available at most training facilities
and are typically used in rehabilitation, their use in strength training is not practical. More recent
studies have used training with free weights to evaluate concentric contractions in comparison to
the countennovement exercise (Cronin, et al., 2000; 2002; Newton et. al., 1997). However, no
literature was found in which the body, free weight, or machine weight was used for training with
concentric only movements, to explore the effects of training. Appendix A provides a summary of
the concentric only review of literature.

Countennovement Exercise Method

The majority of strength training studies involve countennovement exercises using
resistance created by the body, free weight, or machine weight. Countennovement training is
typically performed in most training facilities. However, there is a paucity of countennovement
studies of the upper body that are available to be highlighted in this review of literature. lnforrnation
reviewed on countennovement exercise includes the types of upper and lower body exercise used
in training, provides basic strength training guidelines, examines the training effect of speed of
movement and load has on the lower and upper body, and examines what differences were found
between gender and race.

Studies of Upper Body Countennovement Exercises
Studies of upper body countennovement exercises focus on the chest (push-ups, bench

press, and chest flies), back (lat-pull down), shoulder (overhead press and behind the head press),

26

and arm (bicep curl and triceps press) (Blackard, Jensen, 8 Ebben, 1999; Bloomfield, et al., 1991;
Fields, et al., 1997; Jones, Hunter, Gleisig, Escamilla, 8 Lemak, 1999; Newton, Kraemer, Hakkinen,
Humphries, 8 Murphy, 1996). Testing of countennovement exercisesof the upper body in previous
studies had participants perform three trials with a 2-5 min rest between sets and 2-4 days before
retesting (Blackard, et al., 1999; Fields, et al., 1997; Newton, et al., 1996). Usually an orientation
session was given prior to testing to familiarize subjects with testing and the following session was
used to initiate data collection.
Guidelines for Countennovement Exercises
The foundation of resistance training is stated by governing bodies such as the American
College of Sports Medicine (ACSM) and the National Strength and Conditioning Association
(NSCA) as part of their certification processes. General guidelines vary little between these two
organizations. Therefore, this review will be limited to the inclusion of the guidelines stated by
NSCA (Baechle 8 Earle, 2000). Usually the same number of sets and repetitions for both the upper
and lower body are used during training.
0 If the objective is to develop strength, two to six sets of one to six repetitions at an intensity
greater than 85% of maximal strength with a 2-5 min rest between sets is recommended.
0 For developing power, three to five sets with one to five repetitions at 75-90% of maximal
strength taking 25 min of rest between sets is recommended.
0 To enhance muscle size, three to six sets with 6-12 repetitions at 67-85% maximal
strength with 30—90 s of rest between sets is recommended.
0 For endurance two to three sets of 12 or more repetitions at less than 67% of maximal

strength with less than a 30 3 rest between sets is recommended.

27

0 Duration of the countennovement training should last 7-9 weeks, which has been reported
to be a sufficient amount of time for physiological changes to occur, especially in sedentary
individuals (Wilmore 8 Costill, 1999).

Varying training loads cause different “acute metabolic, hormonal, neural and
cardiovascular responses” (ACSM, 2002). Variation in force of muscle contraction has been
attributed to the muscle’s neural adaptations, cross-sectional area, pennation of fibers, length,
contraction velocity, type of action, strength to mass ratio, as well as the body size, joint angle, and
joint angular velocity (ACSM, 2002; Baechle 8 Earle, 2000; Wilmore 8 Costill, 1999).

Speed of Movement and Load

The following studies examine the effects manipulation of frequency of contraction and
magnitude of resistance (load) has on sport or skill performance. Training studies of the lower body
have used various speeds of motion in either the eccentric and/or the concentric phase of the
countennovement. The speed of motion during training is affected by the load imposed or the pace
that is set by the investigators for the participants. A study by Harris, et al. (2000) investigated the
effect of load on training collegiate football players. Three groups trained at different percentages
of their maximal strength using the same number of sets and repetitions. The groups consisted of a
high power group (30-45% 1RM), high force group (80% 1RM), and combination group, which
used both methods of training. All groups performed strength, skill, and sports tests pre- and post
training. The high power group improved more in the skill and sports performance test where the
high force group’s improvement was demonstrated more in the strength tests. The combination
group improved in more skill and sports performance tests than the other groups. Another
investigation by Blazevich and Jenkins (2002) found no substantial difference in the significant
improvements in strength or 20 m acceleration time between fast (30-50% 1RM) or slow (70-90%

1RM) training in the concentric phase for trained collegiate sprinters. Other studies with non-

28

resistant trained participants have used squat exercises and modified tempo between groups,
using similar repetitions and sets for training (Morrissey, et al., 1998; Young 8 Bilby, 1993). In
these studies it was found that the fast and slow training groups improved significantly in force,
MRFD, and power output. There were differences noted in the extent that biomechanical variables
were increased between the fast and slow training groups.

Results from these studies become less clear when looking at what implications they have
on a type of sport performance (i.e., vertical or long jump). Results of these studies indicate that
both types of training are can improve jumping ability. Limitations of these studies could include not
allowing a full range of motion during the concentric phase, which has been shown to affect
biomechanical variables (Newton, et al., 1996). Also in the two mentioned studies, groups
performing the squat faster had to develop force faster in the concentric movement to keep up with
the set training pace. Behm and Sale (1993) stated in their study that the attempt to produce
ballistic movements might be more important to improving the speed of movement than training at
high speeds. Another limitation was that the results from these studies could have varied due to the
use of non-resistant trained participants. With non-trained participants training effects are going to
have more variation compared to a more homogenous resistant trained population.

There are few studies of the upper body that have investigated the effect of training.
Bloomfield, et al. (1990) investigated whether anthropometric or upper body training had the
biggest impact on the ability of experienced water polo players to throw overhand at high velocities.
Results from this study indicated that limb length and body width were significantly related to
throwing velocity compared to the resistance training which did not produce any significant
changes. However, the number of repetitions and sets used in the training protocol were more
designed to develop muscle endurance and size than improve strength or power. Jones, et al.,

(1999) studied football players in an off-season 14 week training program using either conventional

29

countennovement training or countennovement training with higher concentric accelerations.
Results from this study indicate that using higher concentric accelerations in the countennovement
increased strength and power performance (i.e., distance of a medicine ball throw) to a greater
extent than traditional countennovement training.

Gender and Race

Countennovement exercises are effective in producing physiological and biomechanical
adaptations in males and females in non-resistance and resistance trained individuals. Two studies
were reviewed to see if the training effects and biomechanical variables were different by gender
and race. One study (Staron et. al., 1994) involved post training comparisons of the lower
extremities between men and women of similar age and background. Some differences were found
in regards to the rate at which men or women improved strength on the leg extension and leg press.
But, both men and women improved strength significantly and had similar changes in muscle
adaptation during the beginnings of strength training. Differences did occur in regard to hormone
levels during the initial phase of training. Testosterone levels increased and cortisol levels were
lower in men in comparison to women.

In 1997, Fields, et al. observed the differences between race on muscle strength and
power. The two groups consisted of African Americans and Caucasian Americans performing
maximal strength and power lifts for the bench press and leg press exercise. In comparison of
maximal strength no differences existed between either race. The ratio of strength between the
upper and lower body was slightly higher for the African American group than the Caucasian group.
No racial differences existed for the upper or lower extremity muscles between the strength-power

relationships.

30

Summary of Countennovement Exercise Method

The countennovement is often used with many types of exercises and strength training
guidelines have been established for this type of training. However the effects of training are shown
to vary according to study and there are few upper body studies conducted. Refer to Appendix A
for the summary of the countennovement review. Another area of interest for further investigation
is upper body is plyometrics exercises. Note that plyometric exercises incorporate a
countennovement. Plyometrics will be discussed next.

Plyometrics

Plyometrics are used in rehabilitation, sport activities, and training. Performing upper body
plyometric training may enhance the upper body's ability to perform explosive movements used in
sports such as golf, softball, tennis, football, track, and baseball (Baechle 8 Earle, 2000). In training,
plyometrics are used to give individuals an advantage for developing specific skill performance and
explosiveness. However, most studies of plyometric exercise involve the lower body (Bobbert,
Huijing, 8 van lngen Schenau, 1987b; Hakkinen, Komi, 8 Alen, 1985; Hewett, Stroupe, Nance, 8
Noyes, 1995; Matavulj, Kukolj, Ugarkovic, Tihanyi, 8 Jaric, 2001; Young, Wilson, 8 Byme, 1999a;
1999b). Because of the lack of upper body research reported for plyometrics, most information
included in this review of literature will be of the lower body. This review covers the neuromuscular
system during plyometrics exercise, guidelines for the types of exercises used for plyometric
training, and biomechanical and training studies that have used plyometric exercises.

Neuromuscular Response to Plyometrics

Plyometrics rely on an eccentric-concentric sequence of movement, sometimes referred to
as the stretch shortening cycle (SSC). The $80 consists of three phases of muscle contraction that
occur in the following order: eccentric, amortization, and concentric. During the eccentric phase of

contraction, muscle lengthening and rate of length change stimulate the muscles and nerves.

3]

During this phase, energy is absorbed into the muscles due to their elasticity. At the same time, the
stretch and rate of stretch of the muscle stimulates muscle spindles. The duration and amplitude of
the eccentric phase during plyometric exercise determines the magnitude of biomechanical
variables in the initial concentric phase. Larger amplitudes of movement in the eccentric phase
decrease the ability of biomechanical variables to be enhanced during the initial part of the
concentric phase. A longer duration and amplitude attenuate the nerve response and dissipate the
stored energy of the muscles. At the end of the eccentric phase, a quick explosive translation is
made in the concentric phase. The change in direction of movement is called the amortization
phase, which identifies the change in muscle contraction from eccentric to concentric.
Guidelines for Plyometric Exercises

Specific recommendations for the number of repetitions and sets for plyometric exercises
are few (Davies 8 Matheson, 2001). Chu (1998), who has worked with the conditioning of many
elite athletes in different sports, has set some guidelines and recommendations for plyometric
training. He divided up plyometrics into five types of exercises: jumps in place, standing jumps,
multiple jumps and hops, box drills, and depth jumps. The intensity level of plyometric exercises
has a general rating of low to high in the previously listed order of exercises. The amount of work
done when performing plyometrics depends on the type of plyometric activities. Typical plyometric
activities use the number of foot contacts per session to estimate the amount of work done (Chu,
1998). The number of foot contacts can vary from 60-450 per training session depending on the
experience level of the athlete and the training season (Chu, 1998). From the literature review 24-
30 jumps were performed 3 days a week (Matavulj, et al., 2001; Young, et al., 1999a). Another way
to estimate the amount of work done in certain plyometric exercises, called bounding (similar to
skipping or exaggerated running movements), is through distance. An exercise work to rest time

interval ratio of 1:5 or 1:10 in time is recommended when performing plyometrics. Rest periods

32

from the literature review from plyometric training studies use a 3—5 min rest between exercise trials.
Knudson’s study (2001) used a 30 3 rest between each plyometric movement when testing the
upper body’s biomechanical variables. Hrysomallis and Kidgell’s study (2001) used a 3 min rest
period but used more repetitions in a set prior to testing.
Biomechanical and Training Studies of Plyometric Exercises

Studies of lower body plyometric training usually involved a combination of types of
plyometric exercises (Hakkinen, et al., 1985; Hewett, et al., 1996; Matavulj, et al., 2001; Young, et
al., 19993). Plyometric training has been shown to improve the rate of force development (Matavulj,
et al., 2001; Hakkinen, et al., 1985), force production, power output, and the ability to jump higher
(Hakkinen, et al., 1985; Hewett, et al., 1996; Matavulj, et al., 2001; Young, et al., 1999a). This
improvement in biomechanical variables is important when correcting for muscle imbalance
(Hewett, et al., 1996). Plyometric training has also helped to decrease the impact force individuals
encounter when landing from jumps as well as decrease the amount of unwanted knee movement
(Hewett, et al., 1996). Biomechanical studies that test the performance of the lower body are
primarily from plyometric depth jumps (Bobbert, et al., 1987b; Young, et al., 1999b). Plyometric
exercises that involve depth jumps indicate that higher falling heights increase the amount of
negative work and ground reaction force encountered (Bobbert, et al., 1987b). Yet increasing the
height of the fall, to a certain extent, has been shown to augment concentric biomechanical
variables (Bobbert, et al., 1987b).

Summary of Plyometric Exercise Method

lnforrnation from the plyometric review is useful to understanding how the neuromuscular
mechanisms work, providing guidelines to consider with plyometric training, and describing the
benefits and observations of plyometric training. Similar to the concentric only and

countennovement exercise methods discussed previously, there is little information in regards to

33

upper body plyometric exercise. Even exercise professionals have stated that there is a lack of
upper body plyometric studies (Davies 8 Matheson, 2001; Knudson, 2001; Wilk et. al., 1993).
Refer to Appendix A for a summary of the plyometric exercise method.
Comparisons of Exercise Methods

The final part of this review will compare the previously reviewed concentric only,
countennovement, and plyometric methods. Most research on exercise testing or training
compares the effects of using different exercise methods on biomechanical variables. Using
different exercise methods will cause the results of biomechanical parameters to differ (Lee, et al.,
2001). In addition this exercise method review will compare biomechanical parameters between
genders.

Comparison of Biomechanical Performance Parameters Among Exercise Methods

Results from testing the performance of the upper or lower body during a concentric only
exercise show the measured performance (i.e., jumping height, force production, and power output)
to be lower than for countennovement or plyometric exercises (Cronin, et al., 2000; Komi 8 Bosco,
1978; Newton et. al., 1997). Since the concentric only method has not been shown to augment
sport skill variables or biomechanical parameters to the same extent as the countennovement or
plyometric methods, it is usually overlooked in research and training. Cronin, et al. (2002) identified
the concentric only average power output as the “best predictor for SSC power production” in the
bench press. They concluded that there may be merit in training the ability to develop concentric
force. There were no studies reviewed that compared the effects of training the concentric only
method to the countennovement or plyometric method.

Based on testing of the lower body, countennovement and plyometric exercises differed in
biomechanical output parameters. Typically plyometric movements produce higher values for

biomechanical variables than those for countennovement. Participants’ centers of gravity were

34

shown to achieve greater maximum height with plyometric (depth) jumps in comparison to
countennovement jumps (Komi 8 Bosco, 1978). Likewise during the countennovement jumps, the
participants’ centers of gravity achieved greater maximum height in comparison to the concentric
only jumps. A later study by Bobbert, et al. (1987a) indicated higher force production, moment, and
power output in the plyometric jumps compared to countennovement jumps. However, the jumping
heights and take-off velocities were lower during plyometric jumps compared to countennovement
jumps.

Studies comparing the effects of plyometric and countennovement training typically are in
agreement but the extent of agreement varies. As a result of lower body exercises, both methods
of training have demonstrated the ability to improve the maximum height participants are able to
jump (Delecluse et. al., 1994; Newton, et al., 1999; Wilson, Newton, Murphy, 8 Humphries, 1993).
Upon further examination in the studies by Newton, et al. (1999) and Delecluse, et al. (1994), only
the plyometric training groups exhibited a change in jumping performance; whereas, in erson, et
al. (1993) all groups (i.e., those that used traditional training, plyometric training, or power training)
had this experience. Results of these studies also showed that participants had greater gains in
strength during countennovement training. In addition, the MRFD improved with the
countennovement and plyometric method of training when performing isometric tests (Wilson, et al.,
1993) and only with the plyometric training when performing the squat jump (Newton, et al., 1999).
Other variables influenced by plyometric training include significant improvements in power,
velocity, displacement for the plyometric power squat, force production of the squat jump, and force
and power output during the countennovement jump (Newton, et al., 1999). In the same study the
countennovement group improved the power, velocity, and displacement of the bar for the
plyometric power squat only at 30% 1RM, the velocity of the countennovement jump, and peak

force and power output during the heaviest loaded squat jump (an additional 40 kg to participant’s

35

body weight). Other interesting results of plyometric training include improvements in initial
acceleration and a decrease in 100 m time (Delecluse et. al., 1994), decrease in ground contact
time, and a higher flight to foot contact ratio with plyometric training (Newton, et al., 1999).

Upper body studies conducted by Crowder, et al. (1993); Newton and McEvoy (1994); and
Vossen, et al. (2000) explore the differences between the plyometric and countennovement
methods. Crowder's, et al. study (1993) conducted on the effects of plyometric push-ups in
comparison to traditional push-ups (countermovement) disclosed that plyometric training improved
power production significantly and to a greater extent than did countennovement training. Newton
and McEvoy’s study (1994) contrasted the effects of plyometric medicine ball overhead throws and
the traditional countennovement bench press on the upper body’s strength and capability to
improve the throwing velocity of a baseball. Throwing velocity was increased considerably by
traditional countennovement weight training compared to plyometric training. Both types of training
significantly improved strength. In Vossen's et al. study (2000) the distance a medicine ball was
thrown improved in both plyometric and traditional push-up training, but the plyometric group
improved to a greater extent. The traditional group’s improvements were greater in chest strength
than in the plyometric group.

Gender Comparison of Biomechanical Performance Parameters on Training Methods

Some literature was found that compared the influence of exercise methods (i.e.,
concentric only, countennovement, and plyometric) between men and women. Men jumped higher
than women for all three jumping methods (Komi 8 Bosco, 1978). But, women were more efficient
in transferring the elastic energy of the eccentric phase to the concentric phase during the
countennovement jumps. However, Cronin et al. (2002) found no significant difference between
gender when examining the predictors of power absorption and production for the concentric only

and countennovement bench press.

36

Summary of Exercise Methods

Even though the results of studies that have made comparisons between the concentric
only, countennovement, and plyometric exercise methods are not consistent, some general
conclusions can be made from the literature. An eccentric phase performed before a concentric
phase enhances potential performance of the concentric phase (i.e., jumping height, force
production, and power output) compared to the concentric only method. Strength is improved more
with countennovement than with comparable plyometric training. Usually the plyometric method
increases biomechanical parameters (i.e., higher force production, power output, and moment) and
explosive performances (i.e. jumps, sprints, and medicine ball throws) to a greater extent than a
comparable training using a countennovement method. See Appendix A.

Measurement of Pertinent Biomechanical Parameters

Since the objective of this study was to compare selected biomechanical output variables
(force output, MRFD, and power output) in the push-up and medicine ball throw under similar
exercise methods (concentric only, countermovement, and plyometric), studies that incorporated
similar variables were reviewed for the methods they employed. The magnitude of biomechanical
variables has been shown to have relationships to the level of sports performance (ACSM, 2002;
Garhammer, 1985; Kanehisa 8 Miyashita, 1983; Morrissey, Harman, 8 Johnson, 1995;
Schmidtbleicher 8 Komi, 1992; Stone, Byrd, Tew, 8 Wood, 1980; 8 Young 8 Bilby, 1993). Some of
these variables, relating to the current study, include peak force, MRFD, and average peak power
output. Typically, when these biomechanical variables have been incorporated in research on
physical performance, they have been measured via force platforms and strain gauges. The
following studies provide examples of how these biomechanical variables have been measured. In
addition, these studies have provided a basis for selecting methods to measure the peak force,

MRFD, and average peak power output in the current study.

37

Peak Force

Previous studies of various exercises performed via different exercise methods have used
force platforms sampling at frequencies from 500-1000 Hz during fast explosive movements. (Baca,
1999; Bobbert, et al., 1987a; Newton, et al., 1996). Since the push-up and medicine ball throw
were done in an explosive manner and the force platform had the ability to be sample at a high
frequency, 1000 Hz was selected for recording during exercise trials in the current study. During
the orientation session, 100 Hz was selected for the sampling frequency to record the participants'
weight.

When comparing how precise the various ways of using force platforms and other
equipment to simultaneously record biomechanical parameters during a jumping exercise, Baca
(1999) concluded that the double force platform was the “reference method" for analyzing drop
jumps. However, when comparing the results of recording with only one force platform (i.e., one
force platform under both feet) to the use of a double force platform (i.e., one force platform under
each foot), results were similar. But, the use of one force platform was not considered practical in
this study due to the size of the force platform available and the space needed for the drop jump.
Only one force platform was used to record force data of the push-up and medicine ball throw
exercises in the current study. It was assumed that the force-time history experienced by right hand
in the push-up was similar to that experienced by the left hand.

Maximal Rate of Force Development

The maximal rate of force development (MRFD) has been determined directly from
computer readouts of the force applied to a force platform. Two methods have been used to
determine the MRFD. Kovacs, et al., (1999) measured the rate of force development (RFD) by
'dividing peak force (Fv1 and M) by the time elapsed from the onset of increasing force to the

peak.” The RFD can also be calculated in smaller time intervals (e.g., 5 ms) that allow one to

38

determine the maximal rate at which the force is being developed (Young 8 Behm 2003). From
Young and Behm’s study (2003) the recordings of force were taken over a period time in which the
force levels were rising during the exercise movement. In the current study a similar method was
used to that of Young and Behm’s study (2003). Since participants were performing these
exercises explosively and the sampling frequency was at 1000 Hz during these exercises, small
intervals of time (5 ms) were used to evaluate the rate of change in the force curves. This method
was selected to identify the sudden changes in the magnitude of force application.
Average Peak Power Output

No information was found in the literature that used an accelerometer in conjunction with a
force platform to determine average peak power output. Power is a product of force and velocity. In
the current study, velocity was determined through the use of an accelerometer by dividing
acceleration values by small intervals of time (5 ms). Acceleration values represent the change in
velocity over a period of time. In comparable methods of exercise the acceleration values from the
push-up exercise (accelerometer attached to the sternum of the chest) were expected to be less
than the acceleration values of the medicine ball (accelerometer attached to a plastic mount
inserted into the top of the ball) since the skin is a more pliable material and the chest is more
massive in comparison to the medicine ball (Nigg 8 Herzog, 1994). Note that the outputs from the
accelerometer and force platform were synchronized during the test and retest sessions.
Synchronizing these instruments allowed both force and acceleration values to be evaluated
simultaneously during the same time period providing a means to calculate average peak power
output.

Implications of the Literature Review for the Current Study
How biomechanical variables are collected and the interest in these variables to exercise

specialists and researchers has set a foundation for examining how those variables compare

39

between exercise methods. The literature review has also helped to confirm that there is a lack of
scientifically based biomechanical information on exercise methods used for the upper body,
especially in relation to plyometric exercises. Therefore the exercises tested in this study are the
push-up and medicine ball throw performed with the concentric only, countennovement, and
plyometric method. The following paragraphs will state similar protocols from past studies and how
those considerations were used for the current study.

From the literature, when biomechanical parameters are measured for an exercise, a
comparison is made between variations of exercise methods (i.e., concentric only,
countennovement, and plyometric). When using the plyometric method, a general recommendation
from the NSCA is that participants should have a foundational base of strength through resistance
training prior to participation. For studies of upper body plyometric repetitions, two to three trials
have been used per testing session with a rest period of 5—30 s with 1-3 min between different
types of exercise methods with 2-4 days of recovery. (Blackard, et al., 1999; Cronin, et al., 2000;
2002; Fields, et al., 1997; Knudson, 2001 ; Newton, et al., 1996, Newton et. al., 1997; Vossen, et al.,
2000; Young, et al., 1999b).

Since upper body exercises need to be further researched, comparisons of the
biomechanical parameters in performing the push-up and medicine ball throw (Figures 1-3) were
selected to be study. For the current study, two to three trials were used to collect information on
the exercise methods selected and data was collected on 2 days separated by a 48 hour rest
period. Two days were selected, by the investigator and participant, to test and retest participants
and to have a total of five trials per each exercise method. Thirty seconds of rest was given
between each trial and 2 min of rest between the push-up and medicine ball throw exercises.

The previously mentioned implications established a foundation to test if significant

differences in kinetic and kinematic parameters are present when using various upper body

40

exercise methods. Modifying the exercise method to differentiate biomechanical parameters was

used to establish hypotheses.

4r

CHAPTER 3
METHODS

This chapter describes the methods that were used in this study and their purposes. For
these methods information is presented on their relationships to the research design, participants,
exercise conditions, instrumentation, data collection procedures and data analysis. In addition, the
purposes for selecting the methods used in this study are provided.

Research Design

This was a descriptive, non-experimental, cross sectional study of biomechanical
perfdrrnance parameters under different conditions of upper body exercise. There were two
independent variables identified in this study. The two independent variables were based on
methods (i.e., concentric only, countennovement, and plyometric) and the two upper body
exercises (i.e., push-up and medicine ball throw). A comparison was made on how the same
method used for the two exercises (i.e., concentric push-up versus concentric medicine ball throw,
countennovement push-up versus countennovement medicine ball throw, and plyometric push-up
versus plyometric medicine ball throw) influenced the dependent variables (i.e., biomechanical
parameters). The dependent variables included the peak force, MRFD and average peak power
output.

Each participant completed an orientation session, testing session, and retesting session.
Participants were randomly assigned to two groups. The order of task presentation was

counterbalanced across the two groups during the testing sessions as illustrated in Table 1.

42

Table 1. Procedures for the Testing Sessions for Group 1 and Group 2

 

 

Group 1 Group 2
Wann-up Warm-up
Medicine Ball Throw Push-ups

. Concentric Only

0 Countennovement

. Plyometric
Medicine Ball Throw

o Concentric Only

. Countennovement

. Concentric Only

0 Countennovement

o Plyometric
Push-ups

- Concentric Only

0 Countennovement

. Plyometric o Plyometric
Stretching Stretching

 

The counterbalanced order of task presentation and the random assignment of participants

to groups was a strength of the research design because it minimized group threats and interaction

effects of selection bias and experimental treatment. Other efforts to strengthen the research

design and minimize threats to internal and external validity were calibration of instruments before

sessions and familiarization of participants to the testing procedures, exercises, and environment.

A homogenous group, males 18-30 years of age who were healthy and currently participating in

resistance training, were selected to minimize history and maturation. In addition, not allowing

participants to view another participant’s performance addressed on stage effects. Two testers

were used in measurement, instruction, and motivation to account for expectancy. Participants also

performed the exercises in a standard randomized order which reduced the threat of reactive or

interactive affects of testing. Providing a familiarization session, having the participants perform

methods in a random order, and preventing participants from observing others perform was a

strength because it minimized reactive effects of experimental setting. Another strength of the

study was providing adequate rest (48 hours between sessions, 1-2 min between conditions, and

15-30 s between trials), having a standard randomized order of exercises, and using a different

number of trials with each exercise per testing session which minimized multiple treatment threat

(Table 1). In this study there was no pre testing, intervention, and post testing.

Participants

Selection Criteria

Four criteria were used to determine eligibility for participation in this study:

Men 1830 years of age insured that growth and development was complete or nearly
complete. Younger individuals might have been at risk of possible damage to their growth
plates during the plyometric push-ups. Once individuals reach an age in years around their
mid 30’s, 3 natural decline in muscular strength starts to occur.

Participants had to have been currently been resistance training (minimum of 6 weeks
training immediately prior to this study). This requirement allowed an appropriate amount
of time for basic neuromuscular and physiological adaptations through resistance training
to have occurred and potentially reduced the variability of their performance on the
dependent variables associated with earty teaming in the performance of various exercises.
In addition strength is a characteristic that is recommended to have before starting
plyometrics.

Participants had to be free from upper extremity injury. Requirements for participants
included no acute, chronic muscle or joint problems in the shoulders, elbows, wrists, and
back. This measure was taken to help reduce potential risk of injury from the performance
of exercises.

A written informed consent (Appendix B) was provided to participants who met the
previously mentioned criteria and agreed to participate in this study. Participants signed a
written informed consent after a demonstration of the exercises and they had an

opportunity for questions and answers.

44

Recruitment

Upon approval from the University Committee on Research Investigating Human Subjects
(UCRIHS) an announcement to recruit participants was sent out to kinesiology undergraduate and
graduate students at Michigan State University (Appendix C). Flyers (Appendix D) were also
posted at local gyms in order to secure individuals who met the study’s requirements. Interested
individuals who responded to the announcements were contacted. Through email or phone
conversation an overview of the testing procedures was explained to each potential participant in
regards to the purpose, participation requirements, and the possible implications of the study. If
individuals wished to participate in this study, they were scheduled to arrive at the Biomechanics
Research Station at Michigan State University on a Saturday for an orientation session. At the
orientation, a demonstration of the exercises, to be performed by participants in the study, was
given. After the demonstration, the informed consent and a questionnaire (Appendix E) were given
to the participants who wanted to participate. Only participants who signed the UCRIHS informed
consent forms were permitted to continue their involvement in the study. Participants were given an
orientation session. No payment was provided to participants for their involvement. However,
participants were promised their specific results and general group results for comparison.

Sample Size

The total number of participants in this study was 17 - 9 in Group 1 and 8 in Group 2.
Significance was determined with a paired t-test at p < .05 level and conducted with a two sample
t-test assuming equal variance. It was expected that differences between the two exercises were
going to be large. Therefore, a larger number of participants were not required. Once the study was
under way, if the results would have shown that the population size was not adequate for analysis,
an effort would have been made to recruit more participants. In addition, repeated measures were

taken during the test and retest sessions within 1 week. Since there were no significant differences

45

in results between the two testing sessions, the data of both sessions were combined for each
group to add power to the analysis.
Assignment of Participants to Groups

Assignments to groups were made after the orientation session (T able 1). Due to the
strength requirements of the plyometric exercises, performing two different exercises, and possible
fatigue; two groups were formed to help counterbalance the effect of multiple exercises and
possible fatigue. Participant's names were randomly drawn to determine assignment to group.
Then, before the test session, each participant was randomly assigned into Group 1 or 2 (e.g., MB
or PU), during the test and retest sessions according to the exercise method they were performing
first.

Exercise Conditions
Push-ups

Push-ups were performed in this study with the concentric only, countennovement, and
plyometric methods. See Figures 1-3. Each of these methods consisted of the participant giving
maximal effort during the concentric contraction.

The concentric only method (Figure 1) started from the position with the chest on the push-
up platform, shoulders over the hands, and the elbows and shoulders flexed over the force platform
(Figures 4). The hands were located at the same position in the countennovement method. The
exercise began when a push-off was performed quickly by concentric contractions of the muscles
of the upper body to elevate the body as high as possible and land with the hands on the push-up
platform. This was the same objective for the countennovement and concentric only method. For
the concentric only and countennovement method a push-up platform was used that was

approximately 15 ‘/2 cm high from the top surface of platform to the floor, Figure 5).

46

 

Two mouse pads stacked on each
side of the force platform

Active
force
platform

 

Figure 4. Push-up platform built to help protect partrcrpants dunng the performances of plometric push-ups

Push-up platform for the Push-up platform for the
concentric only and plyometric push-up

countennovement push-ups

 

The countennovement push-up (i.e., standard push-up; Figure 2), involved starting with
the upper extremities extended and hands on the force platforms on each side of the push-up
platform. The hands were located approximately in the middle of the force platforms on the stacked
pairs of mouse pads. When cued the participant would lower the body down from the starting
position as quickly as possible until immediately before the chest touched the push-up platform.
Once this position was reached the concentric phase of the push-up was performed forcefully to

elevate the upper body as high as possible. The push-up platform served as a reference point for

47

participants to know when to convert the downward motion of the push-up to the upward motion
during the countennovement. If the push-up platform or bench with cushioning were touched by the
participant in the performance of either the countennovement or plyometric push-up during the
eccentric phase during the test or retest session, the trial was not counted and a retrial was
performed.

The plyometric push-up (Figure 3) started with the upper extremities extended with the
hands directly below the chest on the push-up platform (top surface of push-up platform around 20
cm high from the floor; Figure 5). To begin the exercise, the hands released the push-up platform
and then fell onto the mouse pads located on each side of the push-up platform. One stacked pair
of mouse pads was located on an active force platform and another stacked pair was located in a
similar position on the inactive force platform on the opposite side of the push-up platform. When
falling, the hands were positioned under the shoulders with the arms slightly bent. Once the hands
made contact with the stacked pairs of mouse pads, eccentric contractions of the upper body
occurred. This was followed by the amortization phase and then concentric contractions to push-off
with the intent to elevate the upper body high as possible.

Medicine Ball Throw

Medicine ball throws were performed in this study with the same methods as the push-ups.
See Figures 1-3. Like the push-up each of these methods for the medicine ball throw consisted of
the parficipant giving maximal effort during the concentric contraction. The beginning position for all
methods was with the participant lying on the force platform; shoulder blades in the center of the
force platform, head off of the force platform, knees bent, and feet on the floor.

The concentric only method started with the arms horizontally abducted (i.e., around 90
degrees), the elbows flexed, and the medicine ball positioned in the participant’s hands to where

the ball was resting on the participant’s chest. (Figure 1). Once signaled the ball was to be thrown

48

as high as possible, same for the countennovement and plyometric methods. A spotter was on
hand to catch the ball once it was propelled into the air for all methods of throwing the medicine
ball.

The countennovement method (Figure 2) started out with the ball in both hands of the
participant at arms length above the chest. The hands were slightly cupped, wrists hyper extended,
and the palms facing up. On the count of three the ball was lowered down quickly by the upper
extremity toward the chest. Right before the ball hit the chest a push-off was generated by the
upper body to throw the ball straight up as high as possible. If the ball touched the chest during the
countennovement or plyometric method a retrial was performed

The plyometric method (Figure 3) started with the ball positioned 1 m above the palms of
the hands when the wrists were hyper extended and the elbows were fully extended. The drop
height of 1 m is approximately the height recommended for this exercise by Baechle, Earte (2000),
and Chu (1998). A 1 m drop height was shown previously in the Biomechanics Research Station to
fall within a range that augmented the biomechanical parameters the most. Heights higher and
lower than this decreased the ability to increase kinetic variables. A tester measured the distance
from the participant’s palm to the bottom of the ball being held by a tester. On the count of three
the rope and‘attached ball were released by the tester from the 1 m height directly over the
participant's chest. The participant started with the arms extended and slightly bent with the palms
facing up prepared to catch the ball. Once the ball made contact with the participant’s hands, the
impulse of the medicine ball was countered by an eccentric contraction of the upper extremities.
The upper extremities continue to push against the medicine ball, eventually changing its direction
of motion (concentric phase of muscle contraction). The intent is to throw the ball as high as

possible using this SSC pattern.

49

Instrumentation
Demographic Questionnaire

Participants took a demographic questionnaire prior to participation in the study. The
questionnaire consisted of information about the participant's age, training and sports background.
Refer to Appendix E.

Anthropometry

Anthropometric measures were taken of body length, width, and weight. Typically two to
three measurements were taken for each of these anthropometric variables. Values of a particular
variable were recorded when two measurements were similar (Appendix F). Equipment used for
taking these measurements was the anthropometer (long and shortened), bow caliper, physician’s
weight scale, and force platform.

Length

The anthropometer was calibrated by measuring an object of a known length. The long
anthropometer was used to measure standing height (Figure 6a) and the shortened anthropometer
was used to measure upper extremity length (Figure 6b). After calibration, standing height and the
upper extremity length (i.e., combined length of arm, forearm, and hand) were measured with the
anthropometer. Both height and length were measured to the nearest centimeter. The
anthropometer provides a direct measurement of length which has face validity.

height.

Participants did not wear shoes for the measurement of their height (Figure 6a). During the
measurement of height, the participants stood against a wall with the posterior aspects of their
heels against the wall and their head in the Frankfort position (i.e., head facing straight forward with
eyes and ears forming a horizontal line). Measurements of height were taken from the floor to the

highest peak of the head.

50

upper extremity length.

The upper extremity length was recorded with the shortened anthropometer (Figure 6b).
Measurements were taken on the right side of the participants’ acromion process to the tip of their
middle finger with the upper extremity fully extended.

Width
Biacromial width is the distance between the outer edges of the right and left acromion

process. A bow caliper was used to measure biacromial width (Figure 6c). The bow caliper was
calibrated by first closing the calipers until the olive tips were touching. At this point, the
measurement was checked for zero reading. Then a ruler was positioned between the olive tips of
the calipers to determine if the readout on the bow caliper matched the known length. The bow

caliper is a device that is used to directly measure width and has face validity.

 

51

(Figure 6 continued)

 

(C)
Figure 6. Anthropometric measurements taken of standing height using long anthropometer (a), upper extremity length
using short anthropometer (b), and biacromial width using bow caliper (c)

Weight

Each participant’s weight was measured and compared through the use of a physician’s
scale and a force platform. The physician's scale and force platform were calibrated by taking all
objects off the scale and platform and setting the output to zero. Then a known weight was put on
the scale and the force platform to see if the weight displayed on each instrument matched the
known weight. Participant's total and upper body weights were measured on the force platform.
Both the physician's scale and force platform have face validity when used correctly.

total body weight.

Participant’s total body weight was recorded to the nearest quarter pound (0.113 kg) while
they stood on a physician’s scale (Health 0 Meter’s 402KLS physician balance beam scale).
Participant's total body weight was recorded in kilograms while they stood on the force platform.
The two measures of total body weight were compared (Figure 7a). Participants did not wear

shoes for the measurement of their total body weight.

52

exercise position.

In addition, measurements of weight of each participant's upper body were taken using the
force platform for the push-up and medicine ball throw. For the push-up participants positioned
themselves in a front leaning push-up position with their hands directly under their shoulders in the
middle of the active and inactive force platforms. Their legs were extended in a straight line out
from their body. They held this position and weight was recorded (Figure 7b). Another weight
measurement of the participants was taken for the medicine ball throw. For this measurement, the
participant laid on his back with his legs extended out from the force platform. His head, abdomen,
and lower extremities were off the force platform and his shoulder blades were centered and in

contact with the force platform (Figure 7c).

 

53

(Figure 7 continued)

 

(C)
Figure 7. Weight experienced by the force platform measured for the total body (a), front leaning position in the push-
up (b), and back lying weight for the medicine ball exercises (0)

Peak Force

The AMTI force platform (Figure 8) used in this study was a strain gauge type device that
provided analog data to the Ariel Performance Analysis System (APAS) software where vertical
force data were sampled, converted to digital values, and stored on a computer. Ground reaction
forces from the exercise movements were measured by the force platform in kilograms, which has
face validity. The sampling frequency selected for this study was 1000 Hz for recording force
associated with the subjects’ exercises and 100 Hz for recording the weight of the subjects. One
’ force platform was used in data collection for the push-up and medicine ball throw exercises.
Vertical force values enabled calculations to be made of peak force, MRFD, and average power
output. Only force values were displayed on the computer, the other two variables were later
calculated later. These three variables were analyzed in the push-off phase of both exercises.

Calibrations of the force platforms were previously described for weighing the participants.

54

Inactive force
platform spacer

Active force
platform

Figure 8. Force platform on the right used to record data in this study

 

For the force output calculations for the push-up exercises, each participant’s push-up
front leaning position weight was measured directly from the force platform. To calculate force, in
Newtons, the amount of weight, in kilograms, applied to the platform during the trial was multiplied
by the acceleration due to gravity (Figures 911).

Force (N) = ((absolute (recorded weight from force platform (kg))*9.81 mlsZ)*2)
Absolute refers to the making a positive value from a given negative value.

However, for each participant in the medicine ball throw, the vertical force recorded via the
force platform and APAS system was equal to the weight of the participant on the force platform in
the back lying position plus the forces associated with the acceleration of the mass of the medicine
ball when in contact with the participant's hands and the acceleration of the mass of the upper
body segments. To determine the force applied by the upper body in the medicine ball throw, the
weight of the individual on the platform was subtracted from the force reading (Baca, 1999; Young,
Wilson, 8 Byme, 1999i).

Force (N) = (absolute ((weight of participant in the back lying position plus ball (kg)) *9.81 mlsz)—
(recorded weight of participant in the back lying position (kg))*9.81 mlsZ)

Absolute refers to the making a positive value from a given negative value.

55

A separate calculation had to be made for the plyometric medicine ball throw since the ball did not

start out as a part of the initial weight on the force platform.

Force (N) = (absolute (recorded weight (kg))*9.81 m/s2) - (recorded weight of participant in the

back lying position (kg))*9.81 m/sZ)

Absolute refers to the making a positive value from a given negative value.

The highest force value from each exercise trial was taken as peak force and used for data

analysis. There was no manufacturer’s information reported in regards to the reliability of the force

platform measuring dynamic forces.

Force (N)

1650

 

 

 

 

 

 

 

 

Calculated Force
1443 N
1450 - - - — -Vertical Force of Front -10
Leaning Push-up (868 N)
—Recorded Weight
1250 4 1 -20
105° 4 Isornetrlc Contractlon ’ '30
A A
f N O
850 d __ ¥ -1 .40 5
Concentric Contraction 3.0:,
650 - " “5° g
450 - -- so
250 ~ \ J -70
Y
Eccentric Contraction '73 *0
50 ~ Peak Weight * 4’"
-150 fi r Y r r ‘r r T -90
0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30
Time (s)

Figure 9. Typical force patterns of the countermovement push-up for participant 05MB (front leaning push-up position =
44 kg). The same process of calculation was also used on the concentric only and plyometric methods for the push-up.

56

 

900‘

700*

Force (N)

 

 

 

Calculated Force Peak Force
N
- - - Vertical Force of Medicine Ball (29 N) 888
-—Reoorded Weight
Eccentric Concentric
Contraction Contraction

 

 

 

 

-100 .
-3oo - .
438 kg
Peak Weight
-500 r a 1 . . .
0.80 0.90 1.00 1.10 1.20 1.30 1.40
Time (a)

40

0 .60

Weight (kg)

-- -120

- -140

-160

Figure 10. Typical force patterns of the countennovement medicine ball throw for participant 05MB (back lying weight =
51 kg). The same process of calculation was also used for the concentric only medicine ball throw.

 

 
  

 

 

 

 

 

 

 

 

 

1000
—Calculated Force Peak Force
- - - Vertical Force of Medicine Ball (29 N) 842 N
800 ‘ —Recorded Weight
Concentric
Contraction Begins
600 1.” "ma-x _ - -
A Ball Makes Contact with Hands, \
‘2' 40° ‘ Eccentric Contraction Begins '
0
2 i
a 200 ~
0 ' - "1:17-31”; — TTTTTTTTTTTTTTTTTTTTTTTT
'200 i 432 kg
Peak Weight
400 T Y I I V I
1.00 1.10 1.20 1.30 1.40 1.50 1.60
Time (s)

Weight (kg)

-~ -140

-160

Figure 11. Typical force patterns of the plyometric medicine ball throw for participant 05MB (back lying weight = 46 kg).

57

Maximal Rate of Force Development
To determine the MRFD (i.e., N/s), calculations of force output and time were required
from the force platform. Since the sampling of the force platform was set at a 1000 Hz, small
windows of time were taken to examine the change in force. These windows were divided up into 5
ms intervals. Two points of force (i.e., N) were examined in that window of time (T 1 to T5) -the first
point of force (i.e., F1) and the fifth point of force (i.e., F5).
RFD (N/s) = (F5-F1)/(T5-T1)
This process was continued using the corresponding force values for T2 and T6 to calculate the
next value of RFD. From all calculated values of RFD, a MRFD was determined. This represented
the force curve where the slope was the greatest. This approach has been used by others (Young
8 Behm, 2003). Since there are changes in force over very short periods of time (Figures 12-14),
taking small intervals of time (i.e., 5 ms) allowed an accurate reading of the RFD and subsequent
determination of MRFD compared to an overall reading when force output is initiated and when it
peaks. However, when examining the RFD graph there are sudden changes in magnitude. These
sudden changes in magnitude are due to large changes in force being magnified when the force
interval is divided by time (i.e., first derivative) causing error components to magnify. Although not
published, Young and Behm (2003) reported the intra-class correlation using these methods as .92

on separate days of testing.

58

 

20000 1 700

 

 

 

 

 

 

 

 

 

Calculated RFD Peak Force
-—Calculated Force MRFD 1443 N -- 1500
15000 1 13505 We
— - - - Vertical Force of Front
Leaning Push-up (868 N) . fl 1300
10000 -
Eccentric -- 1100
Contraction Begins
g ml - 900 i
E “ §
l A
E 0 700 '2
- 500
-5000 1
1. 300
Concentric
49°09 ‘ Contraction Begins
100
'1m 1 r T r l r r r '1m
0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30
Time (s)

Figure 12. Typical RFD and force patterns of the countermovement push-up for participant 05MB (front leaning push-
up position = 44 kg). The same process of calculation was used for all methods of exercise during the push-up and
medicine ball throw. For this graph a larger window of time was used (20 ms) to calculate the RFD and smooth the
data line. MRFD indicates the maximal rate of force development.

59

 

 

 

 

 

 

 

 

Calculated RFD Concentric
25000 . Calculated Force Contraction Begins Peak Force ‘* 1000
888 N
— — - Vertical Force of Medicine Ball (29 N)
MRFD .
Eccentric " 800
14093 MI!
15000 Contraction Begins
~~ 600
? A
2 5000 l E.
‘ it
D .
u. i 40° 0
a: n.
-5000 ~
.. 200
45000 22:21:.4 - 1 ———————————————————————————————————— I“
( 0
'25000 f I r r 1 T "1 -200
0.80 0.90 1.00 1.10 1.20 1.30 1.40

Time (s)

Figure 13. Typical RFD and force patterns of the countennovement medicine ball throw for participant 05MB (back
lying weight = 51 kg). The same process of calculation was used for all methods of exercise during the push-up and
medicine ball throw. MRFD indicates the maximal rate of force development.

60

 

 

 

 

 

 

 

 

—Calculated RFD Concentric Peak Force
Contraction Inc ..
25°00 ‘ -—Calculated Force 809 842 N 900
- - - Vertical Force of Medicine Ball (29 N)
MRFD
Bell flakes Contact with Hands, 15267 We
15000 4 Eccentric Contraction Begins -~ 700
3 ma . «» 500 .2.
2
v 0
e g
a: in.
45000 - 100
. ___________ _ ___________________________________ E
'25000 I I I 1 r fl ' -100
1.00 1.10 1.20 130 1.40 1.50 1.60

Tlme (s)

Figure 14. Typical RFD and force patterns of the plyometric medicine ball throw for participant 05MB (back lying weight
= 46 kg). The same process of calculation was used for all methods of exercise during the push-up and medicine ball
throw. For this graph 3 larger window of time was used (20 ms) to calculate the RFD and smooth the data line. MRFD

indicates the maximal rate of force development.

Average Peak Power Output
A force platform and accelerometer (Figure 15) were used to determine the average peak
power output (W). A uniaxial accelerometer (Microtron) was calibrated by setting the long side of
the accelerometer parallel and perpendicular on a horizontal surface parallel to the floor.
Calibration occurred for the accelerometer in a stationary position. The computer graph displayed

the accelerometer experiencing 9.81 m/sZ, which is equivalent to the force of gravity.

61

  

Figure 15. Accelerometer used to help determine the average peak power output
The recorded time histories of acceleration were synchronized with time histories of the
force-time curves. The accelerometer was strapped to the sternum (Figure 16) for the push-up
exercises and mounted to a plastic device which was inserted into a hole on top of the medicine
ball (Figure 17) for the medicine ball exercises. The sampling frequency of the accelerometer was
1000 Hz. These set ups of the accelerometer allowed the values of acceleration of the chest and
the medicine ball to be determined in the vertical direction. Since the accelerometer was attached
to different surfaces (i.e., skin over the sternum and a plastic mount over the medicine ball), the
acceleration values were expected to differ from a more accurate acceleration reading. Force
readings (i.e., N) were recorded in conjunction with the acceleration readings (i.e., mlsz) to
determine the average peak power output during the push-off phase for each exercise method

(Figures 18-20).

62

Accelerometer on Chest

   

(a) (b)
Accelerometer Taped and Stra ed

    
  

(C)
Figure 16. Process used to attach the accelerometer to the chest for the push—up

‘ 't" Accelerometer

Figure 17. Medicine ball and accelerometer configuration for the medicine ball throws

For the push-up and medicine ball throw exercises all three methods used the same
formula.

Power (W) = (force‘distance)/time = (force)'(distanceltime) = (force)'(velocity)

63

Velocity wasn't able to be directly measured since participants were unable to entirely fit their
whole body on the active force platform. Therefore, an accelerometer was used since velocity is
the product of acceleration (A) and time (T).
Average velocity (mls) = ((A5+A1)l2)*(9.81 m/s’)*(T 5-T1)
This value of velocity was multiplied by the average force.
Average force (N) = absolute ((F5+F1)/2)

Absolute refers to the making a positive value from a given negative value.

Average power output (W) = ((A5+A1)/2)*(9.81m/s’)*(T5-T1)* (absolute ((F5+F1)/2))
This provided a window of time similar to the calculation of MRFD. Similar to the MRFD
calculations, the next window evaluated average power output 1 ms later. The highest average
peak power output from these windows was used for data analysis. No information found in the
literature review incorporated accelerometers in conjunction with force platforms to determine the
average power output. If each of these parameters is accurately measured and their time histories
are synchronized, their resulting product should be accurate and valid. The force platform and the
accelerometer both have face validity for measuring their respective variables.
Identification of Concentric Contraction during the Countennovement and Plyometric Methods

For the countennovement method, the eccentric contraction was identified from the force
readings by the initial fluctuation of force due to the unloading of weight when lowering the body
during the push-up or the medicine ball during the throw. The beginning of the concentric
contraction was determined when the magnitude of force returned to the magnitude of force
immediately prior to the participant beginning the exercise while on the force platform (Figures
9&10). In addition, the accelerometer was able to provide information on when the eccentric
contraction ended and the concentric contraction began for the plyometric methods. When the

value of acceleration reached zero during the exercise trial, it identified when the motion of the

64

chest and ball for an instant was stopped on the way down before being pushed up. Therefore the

beginning of the concentric contraction was determined when the acceleration value was zero for

 

    
 

 

 

 

 

 

 

the plyometric methods.
120 1600
-—Calcuated power OU‘PUt Concentric Peak Force
Contraction Begins 1443 N

100- -—-Calcuiated Force 0 1400
'0 ----- Vertical Force of Front Leaning
5 so Push-up (868 N) " 1200
A P k P
E r trlc ea ower Output
.5 a Contraction Begins -- 1000
5' v 60 JWL 2
a g - - - - - -------------------------------------------------------- v
0 .2 d 800 R
a. an 2
g 2 o
O 3 40 IL
0- 8 «- 600
O 0
D <
8 20 4
g ‘ 4 400
<

0 s 200
'20 I I I I I T I T o
0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 ' 1.30
Time (s)

Figure 18. Typical average power output and force patterns of the countermovement push-up for participant 05MB
(front leaning push-up position = 44 kg). The same process of calculation was used for all methods of exercise during
the push-up and medicine ball throw.

65

500 1100

 

 

 

 

 

 

 

 

 

 

—Cak=ula‘ed Pmr output concenmc Peak FOTCQ
450 . Contraction Begins 882 N
Calculated Force 9‘“ PW" «» 900
Output
400 r - — - Vertical Force of Medicine Ball (29 N) 335 w
t .
g 350 . Eccentric .. 700
E Contraction Begins
«A
'4 30° * «» 500
g E
3 E 250 « .2.
,_ E 300 §
§ 0 200 « °
— IL
0
n.
g 8 150 - .c 100
g < efficit- .4 ———————————————— -
b
O 100 1
> - —100
<
50 ..
-300
0
-50 r I r 1 I -500
0.80 0.90 1.00 1.10 1.20 1.30 1.40

Time (a)

Figure 19. Typical average power output and force patterns of the countennovement medicine ball throw for participant
05MB (back lying weight = 51 kg). The same process of calculation was used for all methods of exercise during the
push-up and medicine ball throw.

66

 

 

  
   
      

 

 

 

 

 

 

 

 

~ ”fl— ,5 k 1ooo
ea
—Calculated Power 0 ut
550 utp Concentric For“?
Calculated Force Contraction 8'9"“ 842 N
.- 800
- — — Vertical Force of Medicine Ball (29 N)
450
'5
Ball Makes Contact with Hands
: ' Peak Power
1 Eccentric Contraction Begins Output -_ 600
E «1‘ 350 - 320 w
05 L”
e .5,
3 g 400 E
O O < "'
h ‘3 250 8
g E u
o -‘-’ o
n. 3 » 200 u.
¢ 0 150
c» <
E
0
> . __________ . _ ___________________ _ _ _ _ _ .. _ _ ._ - .
< 50 i ‘ 0
ii
-50 . w —— 4v WW WT- . 4 . ~2oo
1.00 1.10 1.20 1.30 1.40 1.50 1.60

Time (s)

Figure 20. Typical average power output and force patterns of the plyometric medicine ball throw for participant 05MB
(back lying weight = 46 kg). The same process of calculation was used for all methods of exercise during the push-up
and medicine ball throw.

Additional Equipment Used in this Study
Push-up Platform.

Push-up platforms (Figure 5) were built for the participants to initiate their plyometric push-
ups. Using a set of platforms insured that all participants started from the same drop height,
allowed them more hand room, and provided excellent stability. The highest push-up platform used
for the plyometric push-up was well cushioned. Because of the cushion, its height was determined
to be approximately 20 cm tall and the second platform was similarly built and used for the
concentric only and countennovement push-ups. Its height was approximately 15 ‘/2 cm.

Medicine Ball and Support.
A 3 kg medicine ball was used for the throws (Figure 17). The weight of the ball was

selected due to typical recommendations provided by experts (Baechle & Earle, 2000; Chu, 1998).

67

This ball was purchased from Power Systems, inc. (2527 Westcott Blvd. Knoxville, TN 3793). The
open ball used for the throw is rubberized on the outside. The ball is spherical with a narrow
column passing through its center and forming a diameter. A rope passed through the column of
the medicine ball. It was attached to a wooden beam directly above the center of the force platform
by the rope. The wooden beam was secure. As a safety precaution, the length of the rope was
adjusted for each participant so that, when the ball fell, it would stop short of making contact with

the participant's chest (Figure 21).

Full length of

rope to prevent
Support for medicine ball
medicine from striking
ball throw participant

Medicine ‘
ball

 

Figure 21. Setup used for the medicine ball throws

Meter Stick

For the plyometric medicine ball throw, the participant assumed a supine back lying
position with the upper extremities extended in a vertical alignment. The wrists were hyper
extended in preparation to receive the medicine ball. A meter stick was used to insure a 1 m

distance from the interior point on the medicine ball to the palms of the cupped hands.

68

Mouse Pads

For plyometric push-ups absorbing surfaces are recommended to help significantly
decrease landing impact forces and to aid in the prevention of injury (Hewett, et al., 1996; McNitt-
Gray, 2001). The use of elastic surfaces has been proven to help reduce the contact time and
augment the forces used to project the body (Krug, Minow, & Jassmann, 2001). However, using
surfaces too thick (15 cm) will attenuate force generation (Baechle & Earle, 2000). Other
recommendations include mats of 7.62-10.16 cm in thickness placed shoulder width apart (Chu,
1998). Preliminary evaluations of the plyometric push-up helped determine that two stacked mouse
pads per hand was a safe landing surface without unnecessary attenuation of ground reaction
forces. Two mouse pads were stacked and then placed over the center of each force platform (i.e.,
active and inactive) for the participants as targets to land on (Figures 4 & 8).

Data Collection Procedures

There were three data collection sessions, the orientation, test, and retest session. Each
session. was an individual session separated by at least 24 hours. Data was collected at the
Biomechanics Research Station. The Biomechanics Research Station consists of two primary
components: the deck and the computer room. The deck consists of a raised platform with two
embedded force platforms whose locations are adjustable. The deck is approximately 15.5 by 4
meters with an additional film/video access at the level of the deck and from overhead. The
computer room is a 4 by 3 meter space with additional storage room that houses computer
software and hardware, amplifiers, and video and cine cameras.

Orientation Session

Prior to each orientation session the force platform and anthropometric devices were

calibrated as previously described under Anthropometry the accelerometer was calibrated as

previously described under Average Peak Power Output by the author and doctoral or graduate

69

student. Individuals interested in participating arrived at the Biomechanics Research Station for an
orientation session and were required to dress in comfortable athletic shorts or pants, and athletic .
shoes for all sessions. Once the individual arrived he was given a demonstration of the exercises
that were to be performed during the testing sessions by the author. Refer to Table 2 for a

summary of the orientation, test, and retest sessions.

In the orientation session a demonstration of push-up and medicine ball throw exercises to
be performed, as previously described under Exercise Conditions, by the participants in the test
and retest sessions was given by the author. Individuals who wished to participate read and signed
a consent form (Appendix B). In addition, a questionnaire was given (Appendix E), following the
signing of consent forms, to gain information about the participants’ resistance training and sports
background. Following the consent and questionnaire anthropometric measurements (Appendix F)
were taken.

Anthropometric measurements of the participant’s upper extremity length, biacromial width,
height, and weight were recorded and kept on a form (Appendix F) and taken by the author,
graduate and doctoral students as previously described under Anthropometry. Participants were
first weighed on a physician’s balance beam scale. Then they were weighed on the force platform
in three different body configurations: standing, in a push-up position with their hands on the force
platform (front leaning position) and lying on their back with their shoulder blades on the force
platform and their heads slightly off the force platform (Figure 7). When they were weighed in the
front leaning push-up position, a piece of tape was placed where there shoes were in contact with
the floor. A measurement was then taken from the closest edge of the force platform to tape and
was kept as a record for future data collection sessions to assist in configuring the subjects in
approximately the same position. Standing height was measured with the long anthropometer from

the floor to the apex of the head (Figure 6 a). Next, a measurement was taken with a short

70

anthropometer of the upper extremity length (Figure 6 b). Measurements were taken with a bow
caliper of the biacromial width (Figure 6 c). Following anthropometric measurements, the upper
body strength was tested.

The strength testing protocol used was derived from NSCA’s guidelines for a 10 repetition
maximum load (Baechle & Earle, 2000). The strength tests were conducted by the author,
graduate, and doctoral students. Participants started with a non-challenging weight, a weight they
selected that they normally used before lifting heavier loads that they could easily perform 10 times.
The second set was more difficult because a judgment was made about adding 10-20 pounds
(4.54-9.08 kg), yet permitting the participant to complete 10 repetitions. After the first and second
sets, a 1 min rest was given. The same process was followed in the third, fourth, and fifth sets
where typically 510 pounds (2.27-4.54 kg) were added. The test was terminated and the weight
and repetitions recorded when the participants were to the point of total fatigue on the tenth
repetition or during the set when participants were unable to achieve 10 repetitions. Two minutes of
rest were given between the third and fourth sets if those sets were necessary. Spotters were used
to insure safety during all bench press sets. With the use of a table from the NSCA (Baechle &
Earle, 2000) maximum upper body strength was estimated based on the weight and the number of
repetitions participants were able to achieve on their final set. After recording and determining each
participant’s maximal strength, each subject was then familiarized to each exercise.

Participants practiced each method for the push-up and medicine ball throw used in the
study as described under Exercise Conditions. For each exercise participants were coached by the
author and practiced until they demonstrated an ability to perform the exercise correctly and felt
comfortable. Usually each exercise method involved no more than three practices. During the
practices, a verbal count to three was given to the participant to let them know when to begin the

exercise. This count was used to accustom them to the testing sessions that followed. The push-up

71

exercises involved a push-up platform and a cushioned bench beneath the body for safety
purposes (Figure 4). A pad, built onto the push-up platform, was positioned between the right and
left shoulders. A bench with cushioning was placed beneath, and perpendicular to the length of the
body, under the trunk. All three methods of the medicine ball throw involved the participants lying
down on their back, centering their shoulder blades on the active force platform and positioning
their heads off of the force platform (Figure 7 c). An accelerometer was attached to a mount fixed
on top of the medicine ball. A mounting device was used to protect the accelerometer from being
hit and to provide a stable area to attach the accelerometer (Figure 17). The recommended
medicine ball weight used for this exercise ranges from 0907-3629 kg (Baechle & Earie, 2000)
and data from our lab showed that a 2.722 kg produced optimal biomechanical variables when
compared to lighter balls. A 3 kg was chosen for the previously mentioned reasons. The medicine
ball was attached by a rope to a fixed beam directly above the force platform (Figure 21). The full
length of the rope was adjusted to prevent the ball from hitting the chest during the plyometric
method.

The orientation sessions ended with the author directing standing static stretches directed
(30 s for each stretch) for the chest, shoulders and triceps. The first stretch involved grabbing a
towel with both hands wider than shoulder width. Keeping the hands in the same position on the
towel the arms were pulled upwards over the head and then back behind the head and held. The
other stretch involved taking the right arm straight up over the head bending the elbow to where the
forearm and hand hung down behind the back. Then with the left hand the right elbow was grabbed
and pulled towards the floor (the opposite for stretching the left side). Static stretching as part of
the wann-up performed before exercise trials has been reported to reduce the ability to generate

maximum force (Young and Behm, 2003).When the stretching exercises were completed, future

72

dates were scheduled for testing the participants. Once the orientation sessions were over for that
day, participants were randomly assigned into either Group 1 or Group 2.

Table 2. Overview of Orientation, Test, and Retest Sessions for Group 1 and Group 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Orientation Session
Orientation, initial measurements, and @up formation
1. Orient subjects to study
2. Signing of consent form and survey
3. Take selected measurements
4. Test subjects upper body strength
5. Familiarize subjects to exercise methods
6. Stretch
7. Assiqp participants into groups
Test Session
1. Wann-up with push-ups
Group 1 2. Perform medicrne ball tnals (x 3)
3. Perform push-up tnals (x 2)
4. Stretch
1. Warm-up with push-ups
Group 2 2. Perform push-u) tnals (x 3)
3. Perform medicrne ball tnals (x2)
4. Stretch
Retest Session
Group 1. Warm-up with push-ups
2. Perform medicine ball trials (x 2)
Group 1 3. Perform push-up trials (x 3)
4. Stretch
1. Warm-up with push-ups
Group 2 2. Perform push-up tnals (x 2)
3. Perform medrcrne ball tnals (x3)
4. Stretch

 

 

 

73

Test and Retest Sessions

Before the test or retest sessions the force platform and accelerometer were calibrated
and synchronized by the author, graduate and doctoral students. During the test and retest
sessions, each participant was tested separately at the Biomechanics Research Station, around
the same time of the day. A 48 hour rest period between the orientation and testing sessions was
given. Participant’s dressed in athletic shorts and shoes. The warm-up sessions for these two
testing sessions involved participants performing two sets of 10 standard push-ups without an
explosive concentric component. Refer to Table 2 for a summary of this section.

Prior to testing participants in the push-up exercise, the accelerometer was attached to
their skin exterior to the sternum (Figure 16) by the author. Before the medicine ball trials, an
accelerometer was attached to a hard plastic cylinder firmly inserted into the hole that ran through
the center of the medicine ball (Figure 17) by the author. Depending on which group a participant
was in, they began with either the push-up or medicine ball trials. The exact same methods
described under Exercise Conditions and practiced by the participants in the orientation session for
the push-up and medicine ball throw were performed. The concentric only method was tested first,
. and then the countennovement, followed by the plyometric method fer the push-up and medicine
ball throw in both groups. Group 1 started with the medicine ball exercise methods and then the
push-up exercise methods. For the participants in Group 1, three trials were performed for each
medicine ball throw method and two trials for each push-up method for the first testing seSsion.
During the retest of the participants in Group 1, only two trials were performed for each medicine
ball throw method and three trials were performed for each push-up method. For the first test
Group 2 performed the push-up exercises first, completing three trials for each method, followed by
two trials for each medicine ball throw method. For the retest, Group 2 started with two trials for

each push-up method followed by three trials for each medicine ball throw method. Each exercise

74

trial was initiated by a tester, either a graduate or doctoral student, counting to three, which
signaled the participant to begin the exercise. On two, a tester started recording the synchronized
force and acceleration data for 4 5. Two minutes of rest was given .by the author to the participant
between each exercise (i.e., push-up and medicine ball throw) and 30 s of rest occurred between
each trial within each exercise. The author kept time of the rests with a watch to insure rest time
was sufficient and not exceeded. At the end of each session, individuals performed the same static
stretches for the chest, shoulder, and triceps as they had performed for the orientation session.
Data Collection Personnel and Qualifications
This author's responsibilities included setting up and calibrating equipment before
orientation and testing sessions occurred. All exercise methods performed by the participants were
administered and spotted by the author. This could be accomplished since the trigger to initiate the
recording devices had the ability to be positioned where testing was performed. In addition, a time
lapse occurred between the initiation of recording and the exercise trial. The primary investigator,
who is a departmental adviser for sports biomechanics, oversaw orientation, testing, and retesting
sessions on a periodic basis to insure proper testing procedures and provide insight. Assistants
who participated in the testing of this study were graduate and doctoral students in sports
biomechanics who had experience with the equipment and/or exercises. These students were
involved with triggering the recording equipment, observing the force patterns displayed on the
computer screen, and providing feedback on the participant’s performance.
Data Management
Participants were coded according to a numbering and lettering system for privacy and
identification of participant, group, exercise method, exercise performed, and trial. A number was
used to code for the participant based on the chronological order of their participation (e.g., 01 for

first). Another set of letters was designated; CO for the concentric only, CM for the

75

countennovement, and PLY for the plyometric method. Then, based on which trial it was (five total)
a letter was assigned (i.e., A-E) according to the number of trials they performed. For example if
. the first person was in the push-up group and performing the countennovement push-up for his
third trial the code would be 01PUCMPUC. AII recorded information was stored on a computer that
was housed in the locked biomechanics office accessible only to selected graduate students and
the primary investigator. Information gathered from this study will be destroyed 5 years post
publication.
Data Analysis

Participant Characteristics

Information about the participants' age, weight, height, shoulder width, upper extremity
length, strength, and exercise performance were recorded. From this information, means and
standard deviations (Table 3) of the population were made.

Tests of Hypotheses

A three-step analysis was conducted to compare the groups’ performances in determining
statistical significance of the hypothesized results. The purpose of these calculations were to
determine if the test and retest sessions could be analyzed together for the final statistics. Group
differences were not a focus of this study. Groups were formed only to increase internal validity of
this study. Statistics were conducted on a combined sample. '

The first assessment was a non-parametric procedure that involved ranking the third trial
to the first and second to determine if there were major differences in the participants’ trials. This
analysis determined the effects of the groups performing a different number of repetitions during
the sessions. Following analysis of the participants’ performances, a trim mean (i.e., elimination of
the highest and lowest scores and an average of the remaining scores) was conducted on

biomechanical parameters. Using the trim means helped to eliminate extreme scores that were

76

recorded and was used for the following analysis. The second assessment involved analyzing
session-to-session differences for both groups using a paired t-test (p<. 01). Following that analysis,
a calculation with a paired t-test was conducted to determine if significant differences existed
between the two exercises measured parameters at p<. 05. The final data analysis tested the
previously stated assumptions made in this study. A paired t-test was used to check if there were
major differences between the type of methods (concentric only and countennovement,
countennovement and plyometric, concentric only and plyometric) within each exercise (push-up or
medicine ball) at p<. 05.
o Hypothesis 1 - Concentric method, push-up versus medicine ball throw

. Push-up > medicine ball throw for peak force.

a Push-up < medicine ball throw for MRFD.

. Push-up < medicine ball throw for average peak power output.
0 Hypothesis 2 - Countennovement method, push-up versus medicine ball throw

0 Push-up > medicine ball throw for peak force.

. Push-up < medicine ball throw for MRFD.

o Push-up < medicine ball throw for average peak power output.
0 Hypothesis 3 — Plyometric method, push-up versus medicine ball throw

. Push-up = medicine ball throw for peak force.

. Push-up = medicine ball throw for MRFD.

o Push-up = medicine ball throw for average peak power output.

Tests of Assumptions
. Peak force in concentric only < countennovement < plyometric method for both the push-

up and medicine ball throws.

77

MRFD in concentric only < countennovement < plyometric method for both the push-up
and medicine ball throws.
Average peak power output in concentric only < countennovement < plyometric method for

both the push-up and medicine ball throws.

78

CHAPTER 4
RESULTS

The results of this study will be discussed in the following paragraphs. These results

provide a statistical analysis of the participants, hypotheses, and assumptions.
Participants

There were 17 participants in the study whose anthropometric measurements and strength
were recorded and analyzed. Comparisons between the groups showed no significant differences
in the height, weight, biacromial width, upper extremity length, absolute strength, and relative
strength (Table 3). Nine participants were in Group 1. This was the group that performed the
medicine ball exercises first during the testing sessions. In Group 2 there were 8 participants and
they performed the push-up exercises first.

Table 3. Anthropometric and Strength Measurements

 

 

Sample
Participants (n) 17
Age (yrs) 24.00 :t 3.02
Height (cm) 179.14 :l: 6.01
Weight (kg) 76.99 1: 12.28
Biacromial Width (cm) 41.68 i 2.00
Arm Length (cm) 75.93 1 3.59
Absolute Strength (kg) 104.24 :t 23.83
Relative Strength 1.35 i .22

 

79

Descriptive Data for Test of Hypotheses

Table 4. Differences in Peak Force, MRFD, and Average Peak Power Output for Push-up and
Medicine Ball Exercises Performed as Concentric Only (CO), Countennovement (CM), and

 

 

 

Plyometric (PLY) Methods _
Medicine
Push-ups ball throw
M :I: SD M 1 SD tits) p
Peak Force (N)
Entire Sample (n=17) CO 1003.25 :l: 217.04 371.04 1 171.73 17.54 .00*
Entire Sample (n=17) CM 1224.63 :l: 196.11 455.15 :1: 158.77 20.50 .00*
Entire Sample (n=17) PLY 1254.90 :t 235.11 602.98 1: 167.51 13.98 .00*
MRFD (N/s)
Entire Sample (n=17) CO 11244.47 :l: 3028.08+ 6965.83 :1: 3023.98 4.86 .00*
Group1 (n=9) 00 9690.85 1 2053.99 7002.96 :t 3515.05 2.47 .02*
Group 2 (n=8) CO 12992.30 1 3089.02 6924.06 1 2603.29 5.16 .00*
Entire Sample (n=17) CM 12468.08 5: 2183.38 6954.83 :1: 2058.78 9.56 .00*
Entire Sample (n=17) PLY 20739.92 1: 7506.88+ 12600.72 1 4349.10 3.85 .00*
Group1 (n=9) PLY 16518.26 :1: 5797.22 13307.81 :l: 5568.56 1.33 .11
Group 2 (n=8) PLY 25489.29 :1: 6457.97 11805.23 1 2535.51 5.63 .00"
Average Peak Power Output (W)
Entire Sample (n=17) CO 106.75 :t 31 .72+ 90.68 1 59.01 1.09 .29
Group 1 (n=9) CO 91.55 d: 32.94 86.26 :1: 68.97 .19 .43
Group 2 (n=8) CO 123.85 1: 20.72 95.66 :t 49.68 2.18 .03*
Entire Sample (n=17) CM (W) 125.19 1: 51.76 132.73 1 66.77 .33 .74
Entire Sample (n=17) PLY 167.58 1: 5986+ 209.93 3: 101.85 1.55 .14
Group 1.(n=9) PLY 133.71 1 36.76 242.26 1 124.61 3.17 .01*
Group 2 (n=8) PLY 205.69 1 59.25 173.56 1: 55.79 1.31 .12

 

Significant difference in the biomechanical parameters beMen the push-up and medicine ball throw at the .05 level.
+Signilicant difference in the biomechanical parameters between Group 1 8 2 at the .05 level.

Test of Hypotheses

Predictions were made of how the push-up and medicine ball throw exercises peak force,

MRFD, and average peak power output differed when performing the concentric only,

countennovement, and plyometric methods. Typical patterns of the biomechanical parameters are

displayed in Figures 22-30 and discussed in the following paragraphs. In this study the predictions

made varied in comparison to the results.

80

Concentric Only Method

Table 4 indicates the differences in biomechanical parameters between the push-up and
medicine ball throw exercises for the concentric only method. The peak force and MRFD were
found to be significantly greater during the concentric only push-up compared to the concentric
only medicine ball throw. However, there were no significant differences when examining the
average peak power output for the concentric only push-up and medicine ball throw. In addition
there were significant differences found between the groups’ values of MRFD and average peak
power output for the push-up exercise.

Figure 22 displays typical force patterns of the concentric only push-up and medicine ball
throw exercises. From the force pattem graph the beginning of the concentric contraction was able
to be determined from the increasing rise of force. In this graph not only is it shown that the peak
values for these exercises differ, but also the duration of these exercises differ. When events occur
and the attributes of these exercises are also displayed in figures for the results of the
countennovement and plyometric methods. Figures 23 and 24 display the RFD and average
power output. Figures that show RFD patterns are more jagged compared to the other
biomechanical parameters. This is from the change in force occurring over a very small amount of
time which produces an error component. The same is seen in the analysis of other biomechanical

parameters that look at displacement over time.

81

 

1150 < CONCOM'“: Peak Power Peak Force
Output (1013 N)

Con n l
tractlo Beg ns Peak Power

Output

   
   
 
 

950 ~ MRFD

MRFD

.-.......—_.~«——-n——-—

Force (N)

—Push-up

_____________ ,. _ _ —-Medicine Ball Throw

 

 

 

 

 

 

 

 

-50 < i ----- Vertical Force of Front
I Leaning Push-up (249 N)
j - - - Vertical Force Medicine Ball
: (29N)
-250 . . T . .
0.60 0.70 0.80 0.90 1.00 1.10 1.20

Tlrne (s)

Figure 22. Typical force pattems of the concentric only push-up and medicine ball throw for participant 11PU (back
lying weight = 30 kg). MRFD indicates the maximal rate of force development. The same process of calculation was
also used for the concentric only medicine ball throw.

82

 

Concentric Peak Force Peak Force

 

 

 

 

 

 

 

 

 

Contraction Begins
Peak Power Output
MRFD
< 1 1 NI
12000 ‘—Push-up ( 096 5) Peak Power
Output
—Medicine Ball Throw
7000 ‘ MRFD
A (6263 N/s) _
Q
.2.
0
1L
1 2000 -
-3000 _
0.60 0.70 0.80 0.90 1.00 1.10 1.20
Time (s)

Figure 23. Typical rate of force development (RFD) patterns of the concentric only push-up and medicine ball threw for
participant 11PU (back lying weight = 30 kg). MRF D indicates the maximal rate of force development

 

 

 

 

 

 

 

 

 

 

 

9°“ P k P P k P
Concentric OI OWOI‘ ea ower Peak Force
110 Contractions Begln\ Force _. DMD“t Omput
(93 W) (102 W) /
MRFD
9° MRFD
—Push—up
—Medicine Ball
A 70 ‘ Throw
E
E
50 *
O
O.
30 <
10 z, “A
/ I
0.60 0.70 0.80 0.90 1.00 1.10 1.20

“me (s)

Figure 24. Typical average power output patterns of the concentric only push-up and medicine ball throw for participant
11PU (back lying weight = 30 kg). MRFD indicates the maximal rate of force development.

83

The hypotheses made for the concentric only push-up and medicine ball throw and
the results of this study varied. Peak force was predicted and found to be significantly greater for
the push-up compared to the medicine ball throw. The hypothesis that the MRFD would be
significantly greater during the medicine ball throw was incorrect. The MRFD was actually
significantly greater during the push-up. No significant difference was found in the average peak
power output between the push-up and medicine ball throw.

Countennovement Method

Table 4 indicates the differences in biomechanical parameters between the push-up and
medicine ball throw exercises for the countennovement method. The peak force and MRFD were
found to be significantly greater during the countennovement push-up compared to the
countennovement medicine ball throw. However, there were no significant differences found when
comparing the average peak power output of the countennovement push-up to the medicine ball
throw. For the countennovement method no significant differences were found to exist between
groups’ biomechanical parameters for both exercises.

Figure 25 displays typical force patterns of the concentric only push-up and medicine ball
throw exercises. Like the concentric only method the duration of the exercises differed for the
countennovement method. Figures 26 and 27 display the RFD and average power output patterns

during the countennovement method for both exercises.

84

 

1500

       
  
  

“Push-up Concentric Peak Force
1300 . —Medicine Ball Throw “"mcyQM'" “291 N)
----- Vertical Force of Front Leaning
1100 , Push-up (551 N) MRFD
—— Vertical Force of Medicine Ball / \.
(29 N)
900 1 Eccentric
Contractions Begin
5 700 ~ I
0
2
O
ll.

 

 

 

 

 

 

 

 

 

 

1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80
Time (s)

Figure 25. Typical force patterns of the countennovement push-up and medicine ball throw for participant 15PU (front
leaning push-up position = 28 kg, back lying weight = 35 kg). MRFD indicates the maximal rate of force development

85

 

 

 

 

 

 

 

 

 

 

 

 

 

 

20000
-P l p Concentric Contractions Begin Peak Force
T / \ Peak Power
15000 J Medicine Ball hrow M RF D Output
(12918 le) \\ Peak Force
Eccentric Contractions Begin MRFD
10°00 ‘ (3512 mi Peak PowerOutput
g 5000 x
.2. r
e i .
m 0 fl ‘
-5000 . ‘ V
-10000 «
45000 I I I I T r
1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80

Time (s)

Figure 26. Typical rate of force development (RFD) patterns of the countennovement push-up and medicine ball throw
for participant 15PU (front leaning push-up position = 28 kg, back lying weight = 35 kg). MRFD indicates the maximal

rate of force development.

86

225

 

 

 

 

 

 

 

 

 

 

 

 

 

_push,up Concentric Contractions Begin Peak Force
. / \.
E tric c tractl r "RFD "88 w’
1754 ccen on onsBegn ‘/ \
Peak Power Output
(142 W)
E 125 T
i
O
a. 75 .
25 EWXZ/
‘25 I I r I I I
1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80

Time (s)

Figure 27. Typical average power output patterns of the countennovement push-up and medicine ball throw for
participant 15PU (front leaning push-up position = 28 kg, back lying weight = 35 kg). MRFD indicates the maximal rate
of force development.

; The hypotheses made for the countennovement push-up and medicine ball throw and the
results of this study varied. Peak force was predicted and found to be significantly greater for the
push-up compared to the medicine ball throw. The hypothesis that the MRFD would be significantly
greater during the medicine ball throw was incorrect. The MRFD was actually significantly greater
during the push-up. No significant difference was found in the average peak power output between

the push-up and medicine ball throw.

Plyometric Method
Table 4 indicates the differences in biomechanical parameters between the push-up and
medicine ball throw exercises for the plyometric method. The peak force and MRFD were found to
be significantly greater during the plyometric push-up compared to the plyometric medicine ball

throw. However, there were no significant differences found when comparing the average peak

87

power output of the plyometric push-up to the medicine ball throw. For the plyometric method
significant differences were found to exist between groups’ MRFD and average peak power output
during the push-up exercise.

Figure 28 displays typical force patterns of the concentric only push-up and medicine ball
throw exercises. From Figure 28 the eccentric contraction was determined by the initial increase in
force from the contact of the hand to the force platform during the push-up or the contact of the
hands to the medicine ball during the throw. The beginning of the concentric contraction was
identified when acceleration values equaled zero, indicating the change in direction of movement.
Like the other methods the duration of the exercises differed for the plyometric method. Figures 29

and 30 display the RFD and average power output patterns during the plyometric method for both

 

exercises.
Concentric Contractions Begin —Push-up
2500 ~ Peak impact Force ——a ‘/ \‘ —Mediche Ball Throw
(2489 N)
MRF D MRFD
200° ‘ Eccentric Contractions Begin P932221?" 9““ POW" OWN"
\
Peak Force
1500 , (1279 N)

./

2

{'2’ [M P kF
0. on.

I2 1000‘ N“ (858 N)

r
- A
v vwv -
-

 

 

 

 

 

 

 

 

 

 

 

 

 

1.00 1.20 1.40 1.60 1.80 2.00 2.20
Time (s)

Figure 28. Typical force patterns of the plyometric push—up and medicine ball throw for participant 15PU (back lying
weight = 37 kg). MRFD indicates the maximal rate of force development

88

 

175000 . . .
Concentric Contractions Begin Peak Force 9.“ Force
Eccentric Contractions Begin Peak W“ PW"
. Output
\ 2 Power
125000 ~ 3 Output Concentric
PUSh'W i Contractions Begin
—Medic'ne Ball Throw :
75000 < § MRFD
3 (1683 His)
é” : MRFD
D
l v‘x I 7%
m M: ._#‘ ‘7? J %
-25000 « ‘
-75000 -
-125000 . T i . . .
1.20 1.30 1.40 1.50 1.60 1.70
Time (s)

Figure 29. Typical rate of force development (RFD) patterns of the plyometric push-up and medicine ball throw for
participant 15PU (back lying weight = 37 kg). MRFD indicates the maximal rate of force development For this graph,

60 ms were examined instead of 125 ms to help display markers.

 

 

 

 

 

 

 

 

 

 

 

 

89

 

325

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Eccentric Contractions Begin P.“ Force
3 Concentric “mm
275 ‘ "“PUS'HJP i Contractions Begin Contractions Begin Peak Power
—M°did"° 33" ““0" MRFD Peak Power
. I Output
225 / (214 w)
Peak Force
175 7
i125 (
O
n.
75 i
25 1
L T
-25 i
'75 W If r I I
1.20 1.30 1.50 1.60 1.70 1.80
Time (s)

Figure 30. Typical average power output of the plyometric push-up and medicine ball throw for participant 15PU (back
lying weight = 37 kg). MRFD indicates the maximal rate of force development. For this graph, 60 ms were observed
instead of 125 ms to help display markers.

Based on previous laboratory work biomechanical parameters were expected to be similar
when comparing the plyometric push-up to the medicine ball throw. Peak force and MRFD were
found to be significantly greater for the push-up compared to the medicine ball throw. No significant

difference was found in the average peak power output between the push-up and medicine ball

throw.

90

Descriptive Data for Test of Assumptions

Table 5. Summary of T-test Results related to Peak Force, MRFD, and Average Peak Power
Output for Push-up and Medicine Ball Exercises Performed as Concentric Only (CO),
Countennovement (CM), and Plyometric (PLY) Methods
CO vs CM CO vs PLY CM vs PLY
t. P I. P t. P
Peak Force
Push-ups (n=17) trs = 9.69, p = .00* hr, = 10.41, p = .00" hr) = 1.16, p = .27
Medicine Ball Throw (n=17) trs = 3.05, p = .01* t15 = 6.43, p = .00* hr, = 4.74, p = .00*
MRFD
Entire Sample Push-ups (n=17) trs = 2.04, p = .06+ tis = 5.48, p = .00*+ 115 = 4.75, p = .00*+
‘ Push-ups Group 1 (n=9) is = 3.70, p = .00" is = 4.40, p = .00* ta = 2.70, p = .01“
Push-ups Group 2 (n=8) t7 = .33, p = .37 t7 = 4.15, p = .00* t7 = 4.73, p = .00*
Medicine Ball Throw (n=17) hr, = .02, p = .98 in = 5.97, p = .00* t15 = 5.75, p = 00*
Average Peak Power Output
Entire Sample Push-ups (n=17) t15 = 1.53, p = .15+ t15 = 4.04, p = .00*+ trs = 2.19, p= .04*+
Push-ups Group 1 (n=9) is = 1.12, p = .15 is = 2.76, p = .01* is = .83, p =.22
Push-ups Group 2 (n=8) t7 = .92, p = .19 t7 = 3.06, p = .01* t7 = 2.14, p = .04"
Medicine Ball Throw (n=17) t15 = 3.97, p = .00* t15 = 5.50, p = .00* t15 = 4.07, p = .00*
*Significant difference in the biomechanical parameters between the exercise methods at the .05 level.
+Significant difference in the biomechanical parameters between Group 1 8 2 at the .05 level.

 

Tests of Assumptions

Assumptions were made of how the peak force, MRFD, and average peak power output
differed between the concentric only, countennovement, and plyometric methods. The results of
the differences in biomechanical parameters are displayed in Table 5 and in Figures 31-33, and
discussed in the following paragraphs. In comparison the assumptions made were similar to the
results of this study.

Peak Force

Table 5 shows that a greater peak force was generated when using the plyometric method
compared to the concentric only and countennovement methods to perform the push-up and
medicine ball throw exercises. (Figure 31). However, there was no statistical significance for the
push-up exercise between the countennovement and plyometric methods. In addition, results from

this study indicate that the peak force values for both groups were significantly greater for both the

91

countennovement compared to the concentric only method when performing the push-up and
medicine ball throw. These results tend to support the assumptions made that peak force is going
to be the greatest for the plyometric method and significantly greater for the countennovement
compared to the concentric only method for the push-up and medicine ball throw. Only for the
push-up exercise were there no statistical differences in peak force between the countennovement

and plyometric method.

 

1400 .

Push-u 12 5

p (1225 i 2355)

IMedicine Ball 1 196)
row

(1003
t 217)

10001

800‘

600‘

Peak Force (N)

we

200

  

 

 

   

Concentric —_—— Countennovement
Only

Plyometric

Figure 31. Comparisons of the groups' peak force values for the push-up and medicine ball throw methods.
Maximal Rate of Force Development
Table 5 indicates a significantly greater MRFD when using the plyometric method
compared to the concentric only and countennovement methods to perform the push-up and
medicine ball throw exercises (Figure 32). There were no statistical differences between the
concentric only and countennovement methods for both exercises. These results support the

assumption made that MRFD is going to be significantly greater for the plyometric compared to the

92

countermovement and concentric only methods. However, the assumption that significant
differences in MRFD would exist between the concentric only and countennovement methods were
not shown in the results of this study. The only significant difference found between the
countennovement and the concentric only methods was found in the push-up exercise for Group 1.

There were also significant differences between the groups’ MRFD for the concentric only and

 

plyometric push-ups.
30000
I Push-up 62
IMedicine Ball Throw (25m
1 3453)
25000 1
A 20000 «
0
Z
a
07: oz
5 15000 I (129,, P
:l: 3089) (12460
a 2183)
10000 1
5000 -

 

 

      

 

Concentric Countennovement
Only

Figure 32. Comparisons of the groups’ maximal rate of force development values for the push-up and medicine ball
throw methods.

G1 represents data from the medicine ball group for the push-up methods.

62 represents data from the pushop group for the push-up methods.

P represents data from the entire population.

Plyometric

Average Peak Power Output
Table 5 indicates a significantly greater average peak power output when using the
plyometric method compared to the concentric only and countennovement methods to perform the

push-up and medicine ball throw exercises (Figure 33). The average peak power output was

93

statistically different between the concentric only and countennovement methods for the medicine
ball throw but not for the push-up exercise. During the push-up, the assumption that significant
differences in average peak power output would be significantly greater for the plyometric
compared to the concentric only and countennovement method was shown in the results of this
study. However, the assumption that peak forces were going to be significantly different between
the concentric only and countennovement push-up was not a result of this study. These results
support the assumption made that average peak power output was going to be significantly greater
for the plyometric compared to the countennovement and concentric only medicine ball throws and
for the countennovement compared to the concentric only medicine ball throw. There were also

significant differences between the groups' average peak power output for the concentric only and

 

plyometric push-ups.

250
I Pushoup 62 :10
IMedicine Ball Throw (ace 1‘ 102)

. 2 as)
200 1
p
150 . 62 P (133

(124 (125 t or)

1001

Average Peak Power Output (W)

3

 

 

 

 

Concentric Countermovement Plyometric
Only

Figure 33. Comparisons of the groups' average peak power output values for the push-up methods.
G1 represents data from the medicine ball group for the push-up methods.

62 represents data from the push-up group for the push-up methods.

P represents data from the entire population.

94

CHAPTER 5
DISCUSSION

Contributions to the Research Literature
Hypotheses

The results from this study show that there were significant differences in the
biomechanical parameters between the two upper body exercises. However, the results and what
was predicted for the study did not exactly match. Of the biomechanical parameters studied
significant differences shown to occur were in peak force and MRFD, but not in average peak
power output.
Hypotheses for Peak Force

The differences in the magnitude of the peak force experienced in the two exercises
support the hypotheses made (Table 4). Push-up exercises performed for the three exercise
methods required a significantly greater amount of explosive force compared to the 3 kg medicine
ball throw. This result is supported by previous literature (Newton et. al., 1997; Schmidtbleicher 8
Komi, 1992); heavier resistive loads require a greater amount of peak force.
Hypotheses for Maximal Rate of Force Development

When considering the MRFD, results of this study differed somewhat from the hypotheses
made about the exercises used in this study (Table 4). For all but one of the three methods of
exercise, the MRFD was significantly greater in the push-up exercises compared to the medicine
ball throw. Group 1 did not show a significant difference in MRFD during the plyometric push-up
compared to the plyometric medicine ball throw. According to previous literature, exercises that use
lighter loads rely more on the rate of force development than absolute strength to explosively
perform and a substantial resistive load is required to sufficiently stimulate the MRFD

(Schmidtbleicher 8 Komi 1992). In addition, it may be beneficial to further investigate which

95

exercises require individuals to develop force at a higher rate, since the MRFD is reported to be
trainable (Matavulj, et al., 2001; Newton, et al., 1999; Young 8 Bilby, 1993).
Hypotheses for Average Peak Power Output

For the biomechanical parameter of average peak power output, there were no significant
differences found between the two exercises. Significant differences in average peak power output
were expected between these two exercises because of the load differences between the two
exercises. Values of the average peak power output from this study were similar to those of Fields,
et al. (1997). The biomechanical parameters of peak force and acceleration offset one another;
forces were significantly higher for the push-up exercises (Table 4), while acceleration values were
higher for the medicine ball exercises (Figures 34-39). In Newton’s, et al. (1997) biomechanical
analysis of the bench press, there were higher velocities obtained with lighter loads. The results of
Newton's, et al. study (1997) are compatible with the current study since acceleration is a
derivative of velocity. However, acceleration values were not statically analyzed in the current
study. In addition, acceleration values were larger for the medicine ball flirow since the
accelerometer was attached to a relatively smaller mass, in comparison to the much larger mass
represented by the attachment of the accelerometer to the chest (Nigg 8 Herzog, 1994). Even
though no significant differences were found in explosive power in this study, acceleration may be
another cmcial variable in understanding movement and its application to training the upper body,
especially with plyometrics methods. '

Paftems of Force and Acceleration

Vertical force and accompanying acceleration in the push-up and in the medicine ball
throw should have similar patterns since force is a product of mass and acceleration and in both
exercises the maSs remains constant. Differences in force and acceleration patterns could be

attributable to the different locations of the recording equipment during the push-up and medicine

96

ball throw exercises (Figures 34-39). For the push-up exercise force was detected through the
force platform, which was located at the participant’s hands, while the accelerometer was attached
to the chest of the participant. Similariy, for the medicine ball throw, the force platform was

underneath the participant’s shoulder blades while the accelerometer was attached to the top of

 

 

the medicine ball.
90 1000
Push-up Acceleration Peak Force
(891 N)
80 « —Push-up Force Concentric .. goo
Contractions Begin
- ~ - - Vertical Force Front

7 — ..

0 Leaning Push-up (234 N) 300
60 n 700

2
§

A

.2.

.. O

Acceleration 500 2
2 O

(28 mls ) ll.

Acceleration (mls 2)
8 8
9

3
§

-3
O
t

 

 

 

 

-~ 200
0 - .. 100
‘10 I I I I I I I 0
0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50
Time (s)

Figure 34. Typical acceleration and force patterns of the concentric only push-up for participant 15PU.

97

 

 

 

 

 

 

90 1000
—-Medicine Ball Acceleration
. . Acceleration
80 1 ——Medrcrne Ball Force Concentric (73 m’55:,
- - - Vertical Force of Medicine Contractions “9'" ~» 800
70 1 Ball (29 N)
A 60 d
"a Peak Force ‘* 500
E 50. 1324 N1 ,.
g a
a 40 .. 400 §
g o
_ ll.
01 30 1
8
.. 200
< 20
10 ‘ -—___ +__ —*—f ________ '_ v... WA, ________________ _
at 0
0 .4
-10 , . , . —e -200
0.80 0.90 1 00 1.10 1.20 1.30 1.40
Time (s)

Figure 35. Typical acceleration and force patterns of the concentric only medicine ball throw for participant 15PU (back
lying weight = 28 kg).

 

     
 

 

 

 

 

 

 

 

 

 

 

 

1600
85 , —Push-up Acceleration Concentric
Contractions Begin
—P“3h'“9 F°r°° Peak Force .. 1400
- 2 -- - Vertical Force of Front Leaning "291 N)
Push-up (551 N)
65 1 ~~ 1200
Eccentric
.7" Contractions Begin
g 1 1000
v 45 A
g Acceleration 5
3 (31 mlszj 800 g
E o
2 u.
0
o 25 1 .
O . _ t _- 600
“ “K
~ 400
5 ,
200
'15 I I I I 7 ‘1' I g—_ h o
0.90 1.00 ' 1.10 1.20 1.30 1.40 1.50 1 60 1.70 1.80 1.90

Time (s)

Figure 36. Typical acceleration and force patterns of the countennovement push-up for participant 15PU (front leaning
position = 28 kg).

98

‘1
O
I

 

3?

8

Acceleration (mls 2)
8 S

L

—— Medicine Ball Acceleration
I—Medicine Ball Force

—— Vertical Force of the Medicine Ball

(31 N) Concentric

Contractions Begin
Eccentric
Contractions Begin

 

 

 

   
  
   
 
  
   

Acceleration

.,pv”” (79'nh9)

Peak Force
(560 N)

 

 

1 000

r 800

>600

a
Force (N)

- 200

 

 

 

2° ..
10 >
1» 0
0 a
-10 Y , I ' r r I 1 T ‘200
0.90 1.00 1.10 1.20 1.30 1.40 1.50 1 60 1.70 1.80
Time (s) .

Figure 37. Typical acceleration and force patterns of the countennovement medicine ball throw for participant 15PU
(back lying weight 32 kg).

 

   
    

 

 

 

 

 

Force (N)

 

 

2550
——push.up Acceleration Concentric Contractions Begin
100 1
—Push-up Force
Acceleration . 2050
(53 mrs’)
80 1
A Peak Force
"a (1279 u) * 155°
E 60 " /
V Eccentric
g Contractions Begin ——t
3 . 1050
a 401
.2
0
8
1- 550
‘ 20 «
q
0 1 50
'20 I I I I I I I '450
1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80
Time (s)

Figure 38. Typical average acceleration and force patterns of the plyometric push-up method for participant 15PU.

99

 

 

 

 

 

 

 

 

2550
-—Medicine Ball Acceleration Concentric Contractions Begin
100 A a Acceleration
— - Acceleration (0 W52) (79 mlsz)
1+ 2050
—Medicine Ball Force
80 1
af‘ .. 1550
O
3 6°‘
: Eccentric Contractions Begin 2
33° 1050 3
i! 401 :5
2 u.
o
8
a. 550
< 20 ~
. - k Force
42 N
0‘ ‘ ' -~_'--’ 'J‘H_-£-l--. .—._;’50
‘20 I I I 'I I I T I “450
1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80 1.90 2.00
Time (s)

Figure 39. Typical acceleration and force patterns of the plyometric medicine ball throw method for participant 15PU.
Assumptions

Past research shows that exercise methods that utilize the SSC are going to enhance the
biomechanical parameters (i.e., force and power output) in the concentric phase to a greater extent
than in the concentric only method (Bobbert, et al., 1987a; Cronin, et al., 2000; Newton, et. al.,
1997). In addition, plyometric exercises typically generate biomechanical variables in the
concentric phase to a greater extent than countennovement exercises. In the current study, the
influence of exercise methods on biomechanical parameters (i.e., peak force, MRFD, and average
peak power output) supports past research.
Assumptions for Peak Force

Results of the current study indicate peak force was different between all methods of
exercise. The plyometric push-up exercise produced a greater peak force compared to the

countennovement push-up exercise and both methods had significantly higher peak forces

100

compared to the concentric only method. However, for the push-up exercises, no significant
differences existed in peak force between the plyometric and countennovement method for both
groups (Figure 31). In both groups, the highest peak force duringthe medicine ball throw exercise
was for the plyometric method (Figure 32). From this information, it could be generalized that
explosive upper body exercises that rely on the SSC are going to develop higher magnitudes of
force in comparison to concentric only methods.
Assumptions for Maximal Rate of Force Development

Significant differences in MRF D were found when using different types of exercise
methods. During the push-ups, results varied according to group. Group 1 showed significant
difference in the MRFD for all methods, with the plyometric method producing the greatest MRFD.
Group 2’s differences in the MRFD were only significant between the plyometric and
countennovement method, and between the plyometric and concentric only method. However
during the medicine ball throw, significant differences were found with the plyometric method when
it was compared to the countennovement or concentric only methods for the subgroups. Since
upper body plyometric exercises require a greater MRFD, plyometric exercises could be beneficial
in training athletes who require a high rate of force development during sports activities.
Assumptions for Average Peak Power Output

For both the push-up and medicine ball throw significant differences eXisted in average
peak power output when different methods of exercise were used. The average peak power output
was significantly greater during the plyometric method when compared to the countennovement
and concentric only methods (Figures 35 8 36). Exercise trials with the plyometric movement for
either exercise required a greater amount of power to explosively perform compared to the

concentric only or countennovement methods. Plyometric push-ups, performed in conjunction with

101

upper body training, have been shown to improve performance (i.e., distance of medicine ball
throw) more so than traditional training (Crowder 8 Jolly, 1992).

The eccentric phase of countennovement exercises typically results in enhanced
performance during the concentric phase in comparison to the performance parameters during the
concentric only method. Even though the biomechanical variables measured in this study were
higher during the countennovement method for both exercises, only the peak force was
consistently and significantly higher during the countennovement method (Figures 31 8 32)
compared to the concentric only movement. According to literature (Cronin, et al., 2000; Newton, et.
al., 1997), exercises that involve the SSC. produce higher average velocity, force, power output,
and electromyography (EMG) activity than concentric only movements. To produce higher levels of
force, a countennovement or SSC. is required.

Implications

The goals of this study were to provide practical and scientific information to strengfli
coaches and exercise scientists, as well to personal trainers and individuals who perform
resistance training.

Implications for Strength Coaches
, lnfonnation gained from this study holds implications that are practical for coaches who
train athletes. This relates to the order, mechanics, and kinetics of eXercise.
Order of Exercise

One idea that the results of this study suggests is that the order in which upper body
exercises are completed may significantly affect an individual’s performance during a testing or
training session. This idea is based on significant differences between the group’s biomechanical
performance parameters (i.e., MRFD and peak average power output) during the push-up

exercises (Table 4), even though the groups were homogeneous on physical parameters (i.e.,

102

anthropometric and strength measures; Table 3). Group 2 (i.e., group that performed push-up
exercises first) was able to achieve a greater rate of force development and produce a greater
average peak power output compared to Group 1 (i.e., group that performed medicine ball throw
exercises first). Group 1 may have been, to a certain degree, fatigued after the medicine ball
exercises resulting in decreased performance during the push-up exercises. In this study, it might
have been beneficial to give longer rest intervals between exercise trials, so if fatigue were a factor
to biomechanical performance parameters it would be of a lesser extent. Note that the push-up
exercises placed a heavier load on the upper extremities than the medicine ball exercises.
lnfonnation in the scientific literature on order of exercise is mixed. One study, that involved the
use of isometric training before a power movement, found mat the participants' power output was
enhanced (Gullich 8 Schmidtbleicher, 1996). Another training study that used heavy dynamic
resistive training (i.e., 5 RM bench press) or explosive push-ups prior to testing the power output of
explosive push-ups found no significant difference in power output (Hrysomallis 8 Kidgell, 2001).
Whether or not the order of exercise influences training adaptations over a period of time needs to
be further investigated. Information on how the order of upper body exercises influences
biomechanical performance parameters could be important to how training programs are designed.
Training programs that prevent athletes from optimal performance could interfere with their
improvement or possibly their sport skill performance if the theory of training specificity holds true.
The order of exercise during training could also help protect athletes from potential injury. In a
training session, if athletes are vigorously training their chest and upper extremities, plyometric
push-ups at the end of the training session could be difficult to perform and potentially injurious.
Exercise Mechanics

In this study it was observed that it was easier (i.e., from a skill perspective) for participants

to perform the mechanics of the plyometric push-up compared to the plyometric medicine ball

103

throw. This could be due to the difference in load (i.e., upper body weight in the push-up is
considerable greater than the 3 kg medicine ball). With the plyometric push-up, when participant’s
hands made contact with the mouse pads, they were unable to immediately stop the downward
motion and were forced to descend a short distance before the concentric motion started. This
motion seemed to be more natural and less skill dependent compared to the plyometric medicine
ball throw. During the plyometric medicine ball throw, participants demonstrated uncertainty about
when to start pushing against ball. Typically the participants took one of two approaches. They
would either try to “bump” the ball upward or let the ball descend down close to their chest before
moving it upward. Due to the shape of the ball and the ball not being as stable as the ground, this
may have affected the participants’ performances. During some of the trials, there was a noticeable
rotation on the ball after the throw. In these cases the data was not used. However, rotation of the
ball could possibly indicate the ball being received in an awkward position (i.e., not in the center of
the chest) for participants to catch and subsequently project upward. Or, maybe one hand was
compensating for the other hand when receiving the ball because of the position of the hands on
the ball, causing one hand to push more than the other. Possible solutions to help prevent
mechanical problems and variations in the medicine ball throw include: more clearly explaining the
movement pattem.associated with plyometric exercise, providing additional practice in the
medicine ball throw before testing, providing a target directly above the chest, and using a
medicine ball of sufficient weight heavy enough to stimulate an appropriate SSC response.
Kinetics of Performance

Another result of this study that may be beneficial to coaches who strength train athletes,
is to consider the significant kinetic differences between the push-up and medicine ball throw
methods. These kinetic differences clearly indicate that push-ups, regardless of the methods used,

require significantly more peak force and a higher MRFD to perform than supine medicine ball

104

throws with a 3 kg ball (Table 4). This lnfonnation could be of value in two ways. First, athletes who
are beginning plyometric training should start with exercises that have less impact force. Using an
exercise that requires less force (i.e., less massive medicine ball throw) should be easier for the
beginner to manage and it will likely be safer. It also may be beneficial to train novice exercisers in
a progressive order of exercise methods beginning with the concentric only, progressing to a
countennovement, and, finally, to the plyometric method. On the other hand, the plyometric push-
ups may be more beneficial to the experienced weight trainers who have developed considerable
upper body strength. In addition, plyometric push-ups requiring high levels and rapid development
of force may be more compatible to the demands of sport. One study that used highly trained
athletes from different sports showed that each athlete group had a maximum power output under
different load conditions. (lzquierdo, Hakkinen, Gonzalez-Badillo, Ibanez, 8 Gorostiaga, 2002). If
the principle of “specificity of training” holds for exercise training, then appropriately selecting
exercises and methods of performing these exercises may be beneficial. In addition, research has
shown that the load and type of training used can influence athletic performance (Harris, et al.,
2000; Wilson, et al., 1993).
Implications for Exercise Scientist

It is important for exercise scientists to find and show the relevance of science in sports
and sports training to those who coach and train. Results from this study should be beneficial to
exercise scientists investigating sports biomechanics. This study provides a base of lnfonnation on
the biomechanical differences between two similar explosive upper body exercises (i.e., push-up
and medicine ball throw) performed under three methods (i.e., concentric only, countennovement,
and plyometric method) that are used in physical training. There is a need to further explore the

specificity of training.

105

Exercise Differences in Biomechanical Variables

This study implies that biomechanical parameters differ in the performances of similar
explosive upper body exercises. This finding supports past research (Cronin, et al., 2000; 2002;
Newton, et al., 1996; Newton et. al., 1997). Two parameters from this study exhibited significant
differences between the exercises when using the same exercise method (Table 4). Peak force
and MRFD were significantly higher in the push-up exercise when compared to the medicine ball
throw. This difference is probably attributable to the load used. This supports the results of
Blackard, Jensen, and Ebben’s study (1999). In addition, the current study and studies of others
(Cronin, et al., 2000; 2002; Newton, et al., 1996; Newton et. al., 1997) agree that methods of
exercise influence magnitudes of biomechanical parameters and when maximum values occur
within phases (i.e., concentric and eccentric) of performance. Although acceleration values were
not statistically analyzed in this study, they appear to be different when comparing the methods
used for the push-up and medicine ball throw exercises (Figures 34-39). lnfonnation gained from
research on methods of training may be important in scientifically establishing training methods.
Specificity of Training

The exercises used in this study, compared to exercises used in most other research and
forms of training allowed individuals to accelerate through the full range of motion, similar to that of
actual explosive sports movements of the upper body (e.g., golf drive, softball throw, tennis serve,
football pass, javelin throw, and baseball pitch). In traditional exercises (i.e., countennovement
resistive training) the amount of time to complete a repetition is typically shorter than in the
plyometric exercise. If training adaptations are specific to movement and an athlete's sport skill
efficiency specific to training, the effect of using the plyometric method in training may enhance
one’s skill effiCiency to a greater extent (e.g., a weight Iifter's ability to press more weight during a

bench press, a football player's upper body force production during a block, a shot putter's throw

106

for distance). However training specificity exercises, intended to enhance one’s sport skill efficiency,
are likely to differ biomechanically from the actual sport movement. If exercises require the use of
, movement patterns or biomechanical parameters that are more closely associated with the
biomechanical patterns associated with movement in sport skills, then sport skill efficiency maybe
enhanced to a greater extent. Even though most research supports one’s performance or skill
efficiency being enhanced to a greater extent through the use of sport or movement specific
training, there still remains debate (Blazevich 8 Jenkins, 2002; Bloomfield, et al., 1990; Harris, et
al., 2000; Jones, et al., 1999; Matavulj, et al., 2001; Newton 8 McEvoy, 1994; Newton, et al., 1999).

Implications for Personal Trainers and Individuals Who Perform Resistance Training

Information from this study may be useful to personal trainers and those who engage in
upper body resistive training. The plyometric exercises used in this study may be of interest to
those who use resistance training because of the possible training effect on performance and in
this study they did not cause any injuries in the participants.
Effects of Plyometric Exercises

For healthy individuals interested in starting these exercises, as previously described in the
section on Implication for Coaches, an order of progression of methods (i.e., from concentric only,
to countennovement, to plyometric), going from least to greatest force demands, may be ideal
(Figures 3489). Plyometric exercises require a greater amount of force and a faster rate of force
development than other traditional exercises. There is support for upper body plyometric training or
training with faster concentric accelerations enhancing force production to a greater extent than
traditional methods (Jones, et al., 1999; Vossen, et al., 2000). Again, more research is needed to

understand how various methods of exercise influences performance.

107

Risk of Injury

This is an important finding because of concern for injury in plyometric exercises.
Exercises were found to be relatively safe in experienced weight trainers if proper exercise
techniques were used. Out of the 17 healthy resistant trained participants in this study, only one
reported a temporary mild pain in the wrist during testing of the plyometric push-up. No other
problems were reported or observed during testing. Before starting these exercises it would be
important to seek proper training on exercise technique.

Recommendations

Recommendations from the conduction of this study are directed toward improving future
studies looking to replicate this study or aspects of this study. Recommendations that future
studies should consider are based on ways to contributions to scientific knowledge, methods and
practice.

Scientific Knowledge

Based on the review of literature and the results of this study there-are additional
suggestions that may help future studies contribute to the scientific body of knowledge in exercise
science. Scientific knowledge could be advanced in exercise science by focusing research on
various exercise methods, the influence of training on performance and sport skill efficiency, the
analysis of other biomechanical parameters, and the relationship of plyometric upper body
exercises to rehabilitation.
Exercise Methods

This study took a step toward the understanding of ways in which kinetic variables are
influenced by differentst of exercises and methods. Results from this study indicate distinct
differences in biomechanical parameters between two similar exercises. Future studies should

investigate how different training methods (e.g., concentric only, countennovement, eccentric and

108

plyometric) affect performance. In addition, it would be interesting to know how changes in the
mass of the medicine ball would influence patterns of biomechanical output parameters.
Influence of Training on Performance and Sport Skill Efficiency .

Lower body training studies have shown biomechanical parameters and sport skill
efficiency (i.e., jumping ability) to be altered through training (Hewett, et al., 1996; Matavulj, et al., .
2001; Newton, et al., 1999). In regards to further development of the current study on upper body
exercises, it would be of interest to determine the influence of training programs using various
methods of training on biomechanical variables and sport skill efficiency. Additional biomechanical
studies may enhance the body of knowledge in exercise science and help bridge the gap between
researchers and practitioners.

Analysis of Other Biomechanical Parameters

Researchers have shown that biomechanical parameters are significantly influenced by
different exercises (Blackard, et al., 1999; Blazevich 8 Jenkins, 2002; Bobbert, et al., 1987a;
Cronin, et al., 2000; 2002; Delecluse et. al., 1994; Escamilla et. al., 2001; lzquierdo, et al., 2002;
Newton et. al., 1997; Young, et al., 19993). On the other hand, Bloomfield, et al. (1990) showed
that the results of performance were more closely associated with anthropometric measures than
exercise training in elite water polo players. Additional research on the importance of
biomechanical performance parameters in comparison to anthropometry is warranted.
Relationship of Plyometric Upper Body Exercises to Rehabilitation

It was reported (Davies 8 Matheson 2001) that, especially for the upper body, there is a
lack of biomechanical lnfonnation in regards to plyometrics. Future studies that provide
biomechanical information of upper body plyometrics may be of value to those in rehabilitation or .
preventive injury training. Providing biomechanical information (e.g., acceleration, impact force,

torque) on the shoulder girdle and upper extremity during exercise may be useful to therapists for

109

their selection or rejection of plyometric exercises for rehabilitation. This might be beneficial to
athletes who need to progress too more intense exercises before returning to sport activities.
Methodology

Continuing research in this area should aim at minimizing variance of the results. From this
study there were three ways in which variance could have been reduced. Suggestions for reducing
variance relate to the population studied, participants receiving more practice and coaching prior to
data collection, and a standard method in which biomechanical parameters are recorded.
Homogenous Population

To statistiCally enhance the ability to obtain differences between exercises, it would have
been ideal to have a larger sample size. However, in some biomechanics studies, where data
collection and coding are time consuming, relatively smaller sample sizes have been acceptable.
The number of participants in this study is similar to that of, other studies of biomechanical variables
(Newton, et al., 1996; Newton et. al., 1997). In addition, the population used in this study was
homogeneous on selected anthropometric and strength measures; no significant differences were
found between anthropometrical and strength measurements in the two subgroups and their
performances were similar in each of the two exercises. Although for future studies it would be
ideal to have a more homogenous population (i.e., sport and resistant training background).
Backgrounds between the participants differed; some had participated in collegiate sports
(plyometric training experience) and even though there were similarities in their training regiments
(i.e., number of repetitions and sets) there were differences (i.e., types of exercises they used and
training duration). Even though there were no significant differences found between the two groups,
differences in measurements taken in weight and relative strength between the two groups were

relatively high.

110

Additional Coaching and Practice

To those who are looking to do additional research with the plyometric medicine ball throw,
additional coaching and practice would be beneficial to those who have no previous experience
with plyometric exercises. The plyometric medicine ball throw appeared to require more skill to
perform than the plyometric push-up. Bobbert’s, et al. previous study (1987a) affinned that two or
three practice trials were sufficient for participants to correctly perform plyometric jumps and the
same was found in this study for the plyometric push-ups. However, when using lighter loads for
plyometric exercises, more practice and coaching may be needed to help individuals who are
inexperienced.
Standard Method of Recording Biomechanical Parameters

From the review of literature and this study it would be ideal to have a standard method to
further develop the area of exercise science and help minimize error. It was difficult to make a
comparison of the reviewed studies” results and the results of this study, since different recording
methods were used to calculate biomechanical parameters. For instance, in other studies the
participant would be on the force platform while the force platform was set to zero. This in turn,
affects the value of force output recorded during the exercise trial since the weight of the
participant is subtracted out of the force calculation. Having a standard method to record
biomechanical parameters may increase the body of knowledge in biomechanics by helping
exercise scientist build on to previous research.

Practice

There were valuable experiences gained from this study that would be of benefit to future

. biomechanical research on upper body exercises. Practices to consider are the number of force

platforms used, identification of the concentric phase during the plyometric medicine ball throw with

111

an accelerometer, and the influence of medicine balls of various weights on biomechanical
performance parameters.
Number of Force Platforms

With the size of force platform used in this study getting an individual to perform push-ups
with both hands on one force plate would have been difficult. It has been recommended (Baca,
1999) to use two platforms to allow a more accurate reading of force impact and production.
Therefore, the use two force platforms, if they are available, or use one, if the size of the force
platform is big enough to accommodate the width of both hands during the exercise is
recommended.
Identifying the Concentric Phase with an Accelerometer during Medicine Ball Throw

The accelerometer was accurate and reliable, but it was difficult to determine when the
concentric phase started during the plyometric medicine ball throw. The accelerometer had
perturbation when the ball made contact with the hands from the 1 m drop. Two suggestions may
help future studies. Attach the accelerometer to a place other than the ball. It may be ideal to
attach the accelerometer to the wrist or create a device that would connect to the hands during the
exercise trial. Another option would be to film each trial with a high-speed camera and timing lights.
This may allow one to examine ball movement and acceleration recordings simultaneously.
However this suggestion may also be problematic since positional errors are magnified when
calculating velocity and subsequently calculating acceleration.
Influence of Medicine Balls of Various Weights on Biomechanical Parameters

Finally, for the upper body it would be of interest to understand how biomechanical
variables correlate to different upper body exercises and loads. Using a heavier weighted ball will
likely require the production of biomechanical variables that are more similar to that of the push-up

exercise (Blackard, et al., 1999). A lighter medicine ball was chosen on the basis of common

112

guidelines (Baechle 8 Earle, 2000; Chu, 1998) and concern for safety. If training specificity occurs,
then varying the loads of the medicine ball for exercises may help coaches select a weight that
would augment certain biomechanical variables to a greater extent in athletes who are of different
abilities and participate in different sports.

Conclusions

There are several conclusions that can be drawn from this study. The conclusions made
relate to the results of this study, the implications the results have to those in the exercise science
field, and recommendations for future studies.

Push-up methods are going to generate a greater peak force and MRFD when compared
to the same methods of the 3 kg medicine ball throw when performing explosively. When
comparing methods, the methods that use the SSC are going to generate significantly greater
biomechanical variables. The only exception to this was when the MRFD was compared between
the concentric only and countennovement methods. Between the methods that use the SSC the
plyometric method is going to produce significantly greater biomechanical variables than the
countennovement method, except for the peak force during the push-up.

In addition, implications were made for c0aches, exercise scientists, and personal trainers.
For strength coaches, when performing multiple explosive exercises in a training session,
consideration should be taken to the order in which explosive exercises are performed. Because
there were participants in this study that had never performed plyometric exercises it may be
beneficial to provide additional coaching and practice to athletes who are new to plyometrics,
especially for the lighter weight medicine ball throw. Coaches should also consider the age and the
level of athlete they are working with when choosing which upper body plyometric exercises to use.
Some exercises that cause higher impact forces and require higher peak forces may not be

suitable for athletes whose strength has not yet developed. For exercise scientists, this study

113

shows that there are significant differences in biomechanical parameters when comparing these
two exercises and exercise methods. There should be further investigation to see if there is a
training effect and if that training effect carries over into efficiency of sport skill when using these
exercises and exercise methods. For personal trainers, upper body plyometric exercises may be
beneficial to enhancing a client’s strength parameters. In this study, these exercises were shown to
be safe for those who had been participating in weight training for an extended period of time when
shock absorbent surfaces were used. In addition, an order of progression may be beneficial when
starting clients with these exercises.

In closing recommendations to improve the quality of similar future studies, researchers
should consider how their work is going to contribute to the body of knowledge in exercise science
and the methods and practices that are being implemented. The body of exercise science would
benefit from future investigation of the effects of training on sports skill efficiency and analysis of
other biomechanical variables as they relate to performance. Methods to implement would be to
include larger and more homogenous populations who have used the exercises in the study if the
intention of the study is based on performance rather than coaching. In practice, careful
consideration must be taken when selecting the use of equipment for recording biomechanical
information and the interpretation of that lnfonnation or the results of the study and its contribution

to exercise science may be inconsistent.

114

APPENDICES

Appendix A

Table 6. Training Studies of Concentric Only Exercise ................ g .......................................... 116
Table 7. Biomechanical and Training Studies of Countennovement Exercise ....................... 118
Table 8. Biomechanical and Training Studies of Plyometric Exercise ................................... 124
Table 9. Biomechanical and Training Studies Comparison of Exercise Methods .................. 128
Appendix B

Consent Form ........................................................................................................................ 136
Appendix C .

Listserv for Recruitment ......................................................................................................... 138
Appendix D

Flyer for Recruitment ............................................................................................................. 139
Appendix E

Questionnaire ........................................................................................................................ 140
Appendix F

Anthropometric Recording Form ............................................................................................ 142

115

Table 6. Trainin r

    

Studies of Concentnc Onl Exercise
{2:14- 91:92,; (WW ,-~~ :. .

‘ 3;. ”311532112 i' ‘ " .. .. ..
‘Table abbrevrations are as follows.
an= between. A: change. deg/s= degrees per second. 1

= increase. ISOK = isokinetic.
ISOM = isometric. max = maximal. PE = physical educatidn. rad/s = radians per second. reps =
repetitions. SIG = significant. ’

 

 

 

 

 

Author, Year Participants Methods Results
Caiozzo, et a 12 male and Tested max” knee Slow training 1 torque
al., 1981 5 female, extension torque pre/post— at all speeds by 14%
sedentary, testing @ 4 velocities (0- (0 8.082 rad/s) by 8%
20-38 yrs 5.03 rad/s) (1.68-3.35 rad/s) 8
Assigned to 1 of 3 groups: 5% (4.19 rad/s)
control, slow (1.68 rad/s), 8 Fast training
fast (4.19 rad/s) improved torque by
2 sets of 10 max reps, 5% @ most speeds
3xlwk, 4 wk except ISOM 8 by
8.8% @ training
speed
Coyle. et. al., 0 22 physically Performed knee extensions, Placebo group 1
1981 active, 3xlwk, 6 wks, kept work torque by 8% ISOM
college age, same by changing sets and Slow group 1 peak
males 21-27 reps for various speeds torque by 20, 31, to
yrs Slow, 60 deg/s, 5 sets of 6 10% @ 0, 60 8 180
o No previous max reps deg/s
training 2 yrs Fast group, 300 deg/s, 5 Mixed group 1 peak
0 5 groups, sets of 12 max reps torque by 19, 23, 8 8
(control, Mixed group did half work 16% @ 0, 60, 180 8
placebo, fast, of slow 8 fast group 300 deg/s
slow 8 mixed) Fast training 1 peak
torque by 24, 15.1,
16.8 8 18.5% @ 0,
' 60, 180, 8 300 deg/s
Kanehisa 8: o 21 males ~24 Measured max knee Slow group T SIG
Miyashita, yrs extension torque 8 power power @ all speeds,
1983 . Assigned to 1 @ 5 speeds (1.05 - 5.24 T was less as speed
of 3 groups, rad/s) T, 22, 15.8, 7, 7, 8
slow (1.05 Calculated work 8 power 7% from 105-5.24
rad/s), 3 sets, 2 min rest, slow rad/s
intermediate group 10 reps, intermediate lntennediate group
(3-14 rad/s) & group 30 reps 8 fast group similar results 15, 15,
fast (5.24 50 reps 19, 21 8 21%
rad/s) 6 days/wk, 3 wks from1.05- 524 rad/s
Fast group 1 at fast
speeds 7, 17, 20%
from 3.14-5.24 rad/s

 

 

 

 

116

 

(Table 6 continued)

 

 

 

Behm 8 8 male 8 8 Perform max dorsiflexion Both types of training
Sale, 1993 female PE ISOM or ISOK produced high
students, ~20 Trained 16 wks, 3 days/wk, velocity response to
yrs 8 wks, 3 wk break, 8 wks training
One group, Performed 3 (131), 4 (20d) T MRFD by 26%
opposite leg and 5 sets (remaining 1 peak torque by 38%
served as weeks) 10 max ballistic
control movements, 2—3 min rest
btwn sets
Prevost, et 18 males, 19- Tested knee extension No SIG A in peak
al., 1999 35 yrs peak torque 3x torque btwn groups
Beginning Wann-up of 10 reps at 1.57 btwn 2 tests
weight rad/s Test 3 fast group SIG
training Peak torque measured at t (22.1%) mean peak
students, 3 4.71, 2.62, 8 0.52 rad/s, 3 torque at training
wks of max effort contractions @ speed
training each speed 20 3 rest btwn
2 groups, fast reps and minute rest btwn
(4.71 rad/s) 8 sets
slow (0.52 Each group performed 3
rad/s) sets of10 reps for 2 days

 

 

 

 

117

 

   
 

Table 7. Bromechanrcaland Trainin

*Table abbrevratrons are as follows:

Studies of Countennovement Exercrse f _

 

A: change. 1RM= 1 repetition maximum. Ila = Type Ila muscle fibers. Ilb = Type llb muscle
fibers. AA= African American. BP= Bench press. btwn: between. CON= concentric. CA- -

Caucasian American. 1: -.decreased ECC= eccentric. Fri= Friday. 1:

isokinetic. ISOM=

increased. ISOK -

Isometric. max: maximal. ms= millisecond. min= minute. Mon= Monday.
PLYO = plyometric. PU = push-up. reps = repetitions. s = second. SIG = significantly. wk =
week(s). yr(s) = year(§) .

 

 

 

 

Author, Year Participants Methods Results
Bloomfield, o 21 men, 12 - upper body resistance Anthropometrical
et al., 1991 under 19 training for 8 weeks, 3XIweek variables of length,
men’s Others served as control width, mass signify
water 9010 Continued swimming routine 3 "31315003111910
teams ~ Xlwk throwing velocity
13-5 399 Nautilus machines, overhead N0 relationship 0'
press, behind head press, "IIOWIIIQ VGIOCItY WI
decline bench, pullovers, mesomorphy,
latpulls, flys, bicep curt and flexibility. or skin folds
tricep press Upper body strength
1215 reps / 3 sets for primarily tests related to
upper body throwing velocity
Camera measured throwing N0 change in
velocity at 100 frames! 5 overhead "WWIIIQ
Recorded anthropometrical V9100“)!
variables of weight, biacromial
width
Young 8 o 18 male Pre/post-test1 RM machine Both groups 1 SIG in
Bilby, 1993 subjects , squat measures of 1RM,
19-23 yrs 2 groups, 8 in fast power, hypertrophy
o No Trained 3X/wk, 7 ‘/2 wks., 812 No SIG differences
previous reps, wI8-12 1RM load, 4 btwn the groups in
resistance sets, 3 min rest gains
training Both groups, ECC movement Fast group did 1
was in a slow controlled MRFD to a greater

 

 

manner, 90 degrees knee
flexion

Fast group CON movement
explosively

 

extent (68.7 -23.5%)
Slow group improved
strength (31-12.4%)
and vertical jump

Slow group CON movement height (74%) to a
slow greater extent
Measured MRFD (Nlms) 8

peak force from Kistler force

platform ISOM

 

118

 

(Table 7 Continued)

 

 

Staron et.
al., 1994

 

35 healthy
men 8
women
No
previous
resistance
training

13 men
(~23 yrs) 8
8 women
(~20 yrSI

 

9 wks, 2XIwk, every other
week, max on 3rd day

2 warm-up sets .
Mon, 3 sets to failure with 68
reps

Fri, 3 sets 10—12 reps to failure
2 min rest btwn sets
Exercises, squat, leg press
and extension

 

No SIG A in body,
lean or fat mass, or
girths

1RM leg strength
relative to lean mass
1 SIG in men lower
body after 4 wks of
training w/ all
exercises

Women SIG T 1RM in
the leg press in 2 wks
and squat and leg
extension in 4 wks
Similar relative value
T’s

1’s in cross-sectional
area were non SIG

T in Ila and l fibers, 1
llb fibers

In men 1 SIG
testosterone in 4 wk.,
1 SIG in cortisol after

,6wk

Inverse correlation
with i coritsol and t
in llb fibers

 

119

 

(Table 7 continued)

 

 

Newton,
Kraemer,
Hakkinen,
Humphries
8 Murphy,
1996

 

17 healthy
males,
Resistance
training 6
mos, bench
press body
weight

~ 20 yrs

 

2 test sessions separated by 4
days of rest

1st session tested bench press
1RM using PLYO Power
System 8 served to familiarize
45% of 1RM for trials

Held bar at arms length,
lowered 8 pushed up to throw
bar as high as possible

2"d session, warmed up @
45% on bench 2x10, 5 min
upper body stretch, used
throwing motion

Performed same 1RM again

2 movements tested using
45% load for three trials @
each condition 3 min rest btwn
trials

Used Kistler force plate and
EMG

Sampled bar displacement,
ground reaction forces, 8 EMG
@ 876 Hz.

 

ECC velocities
similar, press -0.7m/s
8 throw -0.77 mIs
CON peak 8 average
velocities higher for
the throw (1.31 8 0.84
mls) than the press
(0.96 8 .066 m/s)

, Throw bar

accelerated over
larger portion of CON
phase, peak velocity
later in CON phase
Average power, force
8 peak power higher
for throw (70, 35, 8
67% difference)

After 10% of
movement throwing
velocity 8 force SIG t
mmmw

 

120

 

(Table 7 Continued)

 

 

 

Fields, et 15 CA Performed 1RM 8 power tests No SIG differences
al., 1997 . males ~ 21 on leg press 8 Smith BP, lift btwn. groups of age,
' .yrs weight fast as possible , height, weight, lean
14 AA ~ 21 Legs warm-up w/ weight = to body mass, arm
yrs body weight for 10 reps 8 did 5 length or arm cross
Had less sets to reach max, w/ 2 min sectional area
’ than yr rest Significant differences
previous Upper body warm-up wl 50% in body weight
weight body weight for 10 reps 8 5 (AA>CA), fat weight
training sets to reach max, WI 2 min (AA>CA), % fat
rest btwn (AA>CA) and thigh
Tests repeated 2-4 days later cross sectional area
Power, warm-up with upper (AA>CA)
body at 50% load for 10 reps, No SIG difference in
then did 60% 1RM wl CON strength absolute or
movement relative or power
3 trials w/ 1 minute rest btwn variables upper body
trials and 2 min rest after btwn 2 groups
warm-up for power Average power &
assessment power for 1st 1/3rd for
Power, lower body, perform lower 9091’ in AA
60% of 1RM on leg press higher (168 & 41%)
Piezoresistive accelerometer Difference 00" SIG
sampled @ 100 Hz, on bar 8 b when cross sectional
foot pad, collecting every 2 ms area considered
Relationship strength
8 power differed
among upper or lower
. muscle groups
Morrissey, 21 Women, 7wks, 3xwk, 3 warm-up sets 8 Fast group: long
at al., 1998 ~24 yrs 3 sets of 8RM jump, higher knee
No Fast group trained squats 1 5 peak velocity 8 total
previous up 8 1 5 down body vertical 8
resistance Slow group trained squats 2 s absolute power,
training up & 2 3 down vertical jump, higher
2 groups Used AMTI force platform, average power in
fast (10), record ground reaction forces ankle & hip, T
and Slow Used different force platforms strength @ faster
group (11) pre/post tests, calibrated the speeds 0" ISOK 67-

 

 

same?
Camera filmed at 60 frames! 5

 

82 kg, compared to
57-74 kg

Slow group: vertical
jump most affected by
torque in knee

 

121

 

(Table 7 continued)

 

 

 

 

Blackard, et , 10 males ~ 24 Orientation session practiced No differences in
al., 1999 yrs ' exercises, measured static different exercises w/
weight on force plate in the similar loads (BP w/
extended push-up position, not load 8 PU)
total body weight SIG differences w/
Performed push-ups, bench load used (BP loaded
press wl load = push-up and non-loaded)
extended force from force
platform, 8 w/o weight
5 reps w/ 5 min. rest
Harris, 0 42 Tested 1RM on V4 squat, Heavy resistance
Stone, et al., collegiate parallel squat 8 mid-thigh pull group 1 SIG in 1RM
2000 football Skill 8 power tests involved the (934%) 8 stair
players > 1 countennovement vertical climbing tests (6%) 8
yr jump, standing long jump, stair SIG more high power
~ 19 yrs climbing, 1O yd shuttle, 8 30 m group in ‘/4 squat
Performed sprint High power groupf
high Trained 4 days/wk for 9 wks SIG in ‘/4 squat
volume of All groups same exercises w/ 115-5%). mid thigh
reps before the same number of reps (5) 8 PU“ (225%). vertical
training sets (5) jump (2.3%), stair-
started Heavy group training load @ climbing tests (5%) 8
. Divided approximately 80% of 1RM , the long lump (3%)
into 3 High power group trained @ Combination group T
groups 30.45% of 1RM SIG all areas except
Combination group trained 5 E30 m spring 3‘ 'an
weeks w/ the heavy resistance jump, SIG greater I"
8 then 4 w/ the high power "1959931- 1/4 squat,
intensity mid thigh PU"
compared to high
power group 8 SIG i
greater in the ‘/4 squat
to the high force
group
Jones, et 0 40 NCAA Group 1, trained w/ maximal End of 14 weeks both.1
al., 1999 Division CON acceleration during groups 1 SIG in all
IAA resistance training tests.
Football Group 2 used traditional Group 1 improvement
players, acceleration during lifts SIG to Group 2, BP 8
off-season Each group pre/post-tested w/ medicine ball throw

 

 

medicine ball throw, 1 RM BP,
8 PLYO PU

 

Differences did exist
between groups force
plate reading for
PLYO PU

 

 

122

(Table 7 continued)

 

 

Blazevich 8
Jenkins,
2002

 

10 male
nationally
ranked
college

. sprinters, ~

19 yrs
Sprint
training for
> 5 yrs 8
strength
and power
resistance
training
Running
2XIwk, no
distance
over 600 m
Fast group
8 slow

group

 

4 wks. of pre-training to
standardize subjects, training:
squat, hip extension, leg .
flexion and leg extension, 3
sets of 10 reps

Pre/post - test 20 m sprint
(flying start and standing start),
ISOK torque of hip flexion 8
extension 8 smith machine
squat press

2 training groups w/ sprint
training

7 wk. intervention, 2x/wk both
groups same upper body
weight training

Fast group 30-50% 1RM, fast
CON velocity 8 ECC phase 2x
long, 4 min rest

Slower group 70-90% 1RM
max effort in the concentric
movement, 4 min rest,
ECC/CONC phase ~ 2 s each
Each group 3-10 reps per set
W] the same exercises

 

Both groups had SIG
1 in squat strength 8
hip extension force
Both groups had SIG
I in 20 m acceleration
time

No SIG differences
btwn groups

 

123

 

 

Table 8. Biomechanical and Training Studies of Plyometric Exercise

;There were fewSignificantpost training results fOrgender. ‘

 

*Table abbreviations are as follows:
> = greater than. (-) =negative. 1RM = 1 repetition maximum. avg = average. BP = Bench press.
btwn = between. CM = countennovement. CON = concentric. j. = decreased. DJ = drop jump.
ECC = eccentric. T = increased. IEMG = integrated electromyography. ham = hamstring. ISOM =
Isometric. jr = junior. max = maximal. min = minute. PLYO = plyometric. PU = push-up. quad =
quadriceps. rad = radians. RFD = rate of force development. reps = repetitions. s = second. SIG =
significantly wk(s) = week(s). yr(s = year(s)

 

 

 

 

 

 

Kistler force platform took
readings @ 500 Hz

 

Author, Year . Participants Methods Results
Hakkinen, et 0 10 male, Train 3X/wk for 24 wks SIG T RFD from 34,
al., 1985 previous Jump training included PLYO 000412.000 le (24%)
resistance 8 CM Small T force
training, 20- Perfonned additional production 10.8%
35 YFS" resistance training exercises T avg IEMG time
3Xlwk @ 60-80% 1RM curve
Measured max ISOM force 8 T Fast to slow twitch
force-time variables on muscle fiber area
electromechanical ratio from 09—1
dynamometer
Bobbert, et 0 6 physically Performed Drop Jumps from (-) work larger w/ T
al., 1987b . active 20, 40, 60 cm height, 258, 358-489
males ~ 25 Filmed high speed camera @ J from 20, 40 8 60 J <
yrs 100 Hz No difference in

. duration downward

movement

Ground reaction W: X
force for DJ60 > DJ
40

Knee angle DJ40
(1.76 rad) > DJ 60
(1.67 rad) for push-off
Max moment 8 power
ankle DJ40 (406 Nm/
2,103 W) > DJ60 (350
le 2,287 W) during
push-off

Amplitude of joint
reaction forces T with
height

 

124

 

(Table 8 continued)

 

 

 

Hewett, et al., 11 female Tested on vertical jump 8 Peak landing forces 1
1996 high school height, muscle strength from block shot by
volley ball Multi-component force plate 22%
players, ~ sampled volley ball jump Knee abd/adduction j
15 yrs block with 0.6096 m at 480 50%
2 yrs Hz landing on one foot on the T in ham. : quad.
experience plate @ 120 Hz. peak torque T’s most
6 wks, 3x/wk for 2 hours in non-dominant 26%
30 s of recovery btwn each and in dominant 13%
exercise T power by 44% in
Stretch before jumping, after the hamstring on the
jump training 15 min rest, dominant side and
weight training 21% non dominant
Stretched 3 sets I 30 s side
Weight training 1 set of 12
reps for upper body, 15 reps
for lower body and 45 reps
for think with universal gym
Young, et al., 35 males ~ Tested standing 8 run-up No SIG gains made
1999a 19-34 yrs, 1 vertical jump, arm swing by groups 1 or 2 in
yr exp permitted jumping performance
activities wl Loaded squat jump tests ‘ Group 2 improved
jumping Tested squat jump relative to reactive strength by
Group 1, body weight on force platform 20%
(11) DJ for (1000 Hz for 0.5 3) Group 2 did T in
max height DJ height for max height, standing vertical
Group 2, used progressive order of 30- jump, run-up vertical
(5) DJ for 75 cm @ 15 cm intervals (30 jump, DJ height, DJ
maxheight 3 rest btwn trials) height for minimal
and DJ for max height w/ time
minimal minimum contact time, from Group 1 Tjump force
ground ’ same 4 heights per body weight, drop
0001301 Max strength of legs ISOM jump height and drop
time squat jump height wl
0001“” (9) Trained 3 sessions/wk for 6 minimal 0001301111119
. wks (72-90 jumps/wk) Improvements in both
4 sets of 6 jumps/session, 4-5 groups were non-SIG,
min rest in btwn 3* Group 2

 

 

1st session 4 wks
2"(1 session weeks 586, 5
sets

 

improvements were
larger

 

125

 

(Table 8 continued)

 

 

 

 

 

 

 

Young, et al., 29 males, 0 Performed 2 jump tests and 5 DJ tests correlated
1999b previously strength tests strongly w/ run-up
involved in 0 Jumps performed w/ arm jumps (07)
' jumping swing, standing and run-up Standing vertical jump
activities, (1 ,3,587 stride approach) correlated strongly
19-34 yrs vertical jump tests (0.8) w/ squat jump
1 yr - o Squat jumps on PLYO power and the DJ for height
experience system
in running . Max dynamic strength
80d relative to body weight (jump
jumping squat on a force platform with
activities bar)
0 DJ for height (30,45,60,75
cm)
a DJ for height] wl minimal time
0 Max ISOM squat tests
0 3 trials for each test
Hrysomallis 8 12 healthy 0 Group 1 performed explosive No SIG differences
Kidgell, 2001 ' resistance PU and then were tested on btwn the groups
trained force plate while performing 3 performance on the
active explosive PU force platform
males 0 Group 2 performed 5 RM BP
8 then 3 explosive PU
Matavulj, et 33 male jr 0 Tested vertical jump height w/ Both experimental
al., 2001 basketball counter movement jump groups experienced
players ~ . Tested max force & MRFD in an i in vertical jump
15—16 yrs knees and hips ISOM, . E50 +4.8 cm 8 E100
7 jr national measured by strain gauge - ' + 5.6 cm
team dynamometer E100 SIG T force
5-8 yrs 0 All groups participated in the ISOM @ hips 8:
experience same mid season training MRFD in the knees,
3 groups, 0 Experimental groups trained E50 1 close 1° 3'9
control, 50 after practice 3xlwk, 6 wks, 3
cm (E50), set of 10 reps, 3 min rest
100 cm
(E100)

 

126

 

(Table 8 continued)

 

 

Knudson 2 male 8 1 Warm-up w/ 2 sets of 10 reps Peak force conelated
2001 female, PU to distance ball was
experience 3 medicine balls of 4.1, 5.4 8 dropped
upper body 6.8 kg, lighter for female 8 Impact force higher 8
plyometrics heavier for male longer on the force
8 strength 2 medicine ball dropped 15 platform compared to
training times from 49-124 cm, individuals performing
randomly power drop
30 3 rest btwn drops 8 5 min Power drop larger
rest btwn change of load contact times than
Performed drops onto that Of the force
platform 8 then w/ subjects platform & force 30%
on bench that was on force lower
platform (600 Hz) Forces produced by
power drop under 8
over estimated fiom
force plate

 

 

 

 

127

 

Table 9. Biomechanical and Training Studies Comparison of Exercise Methods

 

.*There were few Slgnlf cant Observational differences between genders

 

*Table abbreviations are as follows:

(+)= positive. >= greater than < = less than A: change. BDJ= bounce drop jump BP=
bench press. CON= concentric only. CG= control group. CDJ= countennovement drop jump.
CM: countennovement. CMJ= counter movement jump. 006: center of gravrty dev- -
development. DJ= drop jump. ECC= eccentric. exp: experience. EXG= experimental group.
ext = extension. ISOM = isometrically. jr = junior. max = maximum. mos = months. PE = physical
education. PLYO = plyometric. PU = push-ups. Rad = radians. reps = repetitions. SIG =
significantly. SJ = squat jump. VERT = vertical. VJ = vertical jump. VB = volleyball. yr(s) = year(s)

 

 

 

Author, Year Participants Methods Results
Komi, 8 Bosco, o 25 o Performed SJ, CMJ 8 DJ (20- 0 SJ - least T 006
1978 women, 100 cm) DJ — height fall T so
PE*. ~ 20 0 Hands on hips all techniques did T in C06 (26—62
yrs 0 Force platform record vertical cm for men, 20-50 cm
a 16 men, Force for women)
PE, ~ 24 o 006. T’d from SJ,
yrs CMJ to DJ in all
e 16 men, groups
Natl o All techniques men
Finnish jumped highest 40-43
VB team, cm compared to 27
~ 24 yrs cm '

0 Women better able to
use elastic energy
from prestretch in
CMJ by 91%
compared to men
50%

0 Change in (+) energy
btwn DJ 8 SJ higher
in women

 

 

 

 

 

128

 

(Table 9 continued)

 

 

 

Bobbert, Huing, 10 male, CMJ, BDJ, 8 CDJ (3 jumps Duration of movement
et al., 1987a VB for each type) BDJ (0.13 s)<CDJ
players, ~ Order random (0.19 s) <CMJ (0.55
23 yrs Hands on hips 3) '
Vertical force form Kistler Height Jumped 3*
force platform sampled @ vertical velocity BDJ
500 Hz (0.48 cm 8 2.52 mls)
Filmed w/ 16 mm camera @ (CDJ (052 cm & 2-75
100 Hz mls)=CMJ (0.54 cm 8
2.78 mls) ,
Push off vertical force
BDJ (4,099 N) > CDJ
(2,649 N) >CMJ
(2,094 N)
BDJ 8 CDJ joint
moments max @
initial phase of push-
off SIG T
Power output 8
moment of knee 8
ankle SIG T
(DJ’s>CMJ,
BDJ>CDJ)

' Angular velocity j
rapidly during push-
off

Wilson, et al., 64 males, Familiarization session before All training conditions
1993 weight testing 8 training begun T CMJ 8 SJ SIG
training > 2XIwk, 10 wk of training Power group T CMJ
1 W 3—6 sets of 6-10 reps max SIG more than did
10 effort in a squat movement traditional
dropped Groups, drop jumps, squat PLYO group didn't T
out jumps 30% max 8 traditional SJ significantly
21-24 yrs squats Weight group T ISOM
15 in T resistance, height, 8 sets force SIG
traditional throughout training PLYO 8 weight group
13 in Load differed according to T RFD most but not
PLYO 8 groups SIG
max 2 trials each test, sprint, VJ,
power peak power output on cycle,
Olltptll max ISOM squat
group 3 min rest btwn each repeat
14 in CG trial and test

 

 

 

 

129

 

(Table 9 continued)

 

 

 

Crowder, et al., 34 Used medicine ball throw to 0 Significant gain in
1993 college test upper body power upper body power for
males Throw measured to the. PLYO training by
nearest inch 17.03 8 2.05 for
2 groups strength train 3Xlwk traditional PU
for 9 wks o F ratio in power of
Group 1 (17) traditional PU 9024 btwn PLYO 8
before strength training traditional group
Group 2 (17) PLOY PU then
strength training
1it wk started w/ 90% of max
PU
Following wks added 2 PU
each week (16 + PU total)
Same training, reps, sets 8
workout format
Reps depended on max # 8
started out w/ 90% max
Newton 8 _ 24 male Tested max throwing velocity 0 Weight group SIG A
McEvoy, 1994 jr dev, ~ 8 BP 6 RM from pre — post for
18 yrs 2XIwk, 8 wks 8 participated throwing velocity
Previous in regular training 2X wk (31.7 —> 33 mls)
extensive Medicine ball (3 kg) group (8) o . Both groups SIG T in
playing overhead throws 8 chest 6RM BP
eXp pass, 3 sets of 8 reps for 4 0 Weight group T SIG
Throw weeks, and 3 sets of 10 reps different from other
ball at 30 the last 4 wks, 6 sets a groups
m/s session, 3 min rest btwn sets 0 No SIG relationship
No Weight training group (8), found btwn throwing
previous barbell BP and barbell velocity and 6RM BP
weight pullover, 3 sets of 8-10reps
training 1st 4 wks, 3 sets of 6-8 reps

 

 

the last 4 wks

 

 

130

 

(Table 9 continued)

 

 

Delecluse, et.
al., 1994

 

78 male,
PE
students,
~ 18-22
yrs

No
previous
strength
training
program
24
students
to EXG
groups
and 15
students
to each
CG

 

EXG either performed high
resistance or PLYO training
2x/wk with 1Xlwk for running
for 9 wks ’
CG one ran once a week with
other groups 8 the other
group didn’t

All groups tested 100m sprint
speed prior to 8 after
intervention

High resistance free 8
machine weights, upper 8
lower body training 3 sets 6-
15 reps (wks 16) and 4 sets
of 3-5 reps (wk 7-9)
(instructed move as fast as
possible), tested 10RM
PLYO unloaded, executed
jumps quickly, 3 rotations 10
exercises per circuit, sets
3x5,1x15,1x5,1x20,4x5,
tested bounding, hopping and
jumpianrior to

 

Heavy resistance
group T SIG on all 10
RM tests

PLYO group T SIG on
all bounding, jumping,
hopping and throwing
tests

PLYO T SIG to all
groups in initial
acceleration, to the
non-trained CG in
max speed 8 I in
speed endurance
compared to CG 8 I
SIG in 100m time
compared to CG
Heavy resistance
group T SIG in initial
acceleration

 

131

 

(Table 9 continued)

 

 

Newton, et. al.,
1997

 

17
exercise
students,
bench @
least own
weight 8
been
lifting
previous
6 mos

~ 20 yrs

 

2 testing sessions separated
by 4 days

1st session 1RM bench, ~wl
45% of RM with throws

One type of throw was a
CON throw, started 1 cm
above chest and then threw
for max height

Other type was a CM throw,
where SSC was utilized from
extended arm position to
throw for max height

2ml test session warm-up
2x10 with 45% load
Performed single SSC throw
w/ 1RM

CM 8 CON throws tested at
15, 30,45,60,75,90% or 1RM
3 trials for each condition, w/
3 min rest btwn

 

1 height of throw,
velocity wl T in load

T load =>T peak
force, time of CON
movement

Highest mean power
output @ 30845%
SIG difference in
average velocity
between CM < CON
throws

Height thrown no SIG
difference, CM = CON
Peak velocity signif T
for 75%, CM>CON
Average 8 peak force
8 power output SIG T
@ all loads,
CM>CON

CON phase longer for
CON throw

Peak velocity 1 in

, ECC phase w/

heavier load

Time of ECC phase
not effected by load
Avg. force T w/ Ting
load in ECC phase

 

132

 

(Table 9 continued)

 

 

Newton, et al., 16 male, Tested jump and reach, max EXG SIG T jump
1999 V8 NCAA squat 1RM, PLYO Power height standing 8 mn-

players, system ijp tests at 30,608 up vertical jump (6%)

~19 yrs 90% ‘ EXG SIG T PLYO

2 yrs DJ, CMJ and SJ on force Power squat tests all

weight plate loads for bar

training 8 CG; 3 sets each of 6 reps of displacement, velocity

5 yrs of leg press and squats, for 8 8 power output

VB exp wks CG only T those

2 groups EXG; 6 sets of ballistic squat three variables @

same jumps 2 sets at 30, 60, and 30% load .

upper 80% 1RM CM: EXG SIG T force

body (2.1%) 8 power

training, output (8%)during,

leg CG T velocity

ext/curl SJ: EXG SIG T peak

plus pre- force production all

season loads (5-11%) most

training body weight, control
group T peak force @
only heaviest load
Peak power output
SIG T (7.7%) for CG
@ heaviest load
Avg power output SIG
T (18.9%) pre-post
test for EXG @ body
weight
MRFD T SIG (47%) in
EXG compared to the
CG
DJ, EXG, SIG 1
ground contact time
(14.6%) 8 flight to
contact ratio (24.4%)

 

 

 

 

133

 

(Table 9 continued)

 

 

 

 

Vossen, et al., 35, Tested medicine ball put 8 Group 2 T (23 cm)
2000 healthy 1RM chest press SIG more than Group
women, ~ 18 training sessions, 3ka 1 (18 cm) for
17 yrs (3sets of 10 twice, 3 sets of medicine ball put
No 11 reps, 3 sets of 12 reps, 4 Group 1 (4.17 kg) T
current sets of 10 reps, 8 4 sets of 11 more than Group 2
athletic reps) . (2.7'kg) on chest
activities Group 2PLYO PU sitting press
or weight upright on knees
training Group 1 traditional PU w/
Group 1 cadence of 2 up 2 down
CM PU 10 medicine ball puts for
Group 2 distance during test session
PLYO PU with 45 3 rest btwn each trial
Cronin, et al. 27 males, Tested 1RM BP, familiarized CM was optimized by
2000 ~ 22 yrs, wl CON and CM BP on prior ECC (mean
no modified smith machine power output by 8-
previous 2"d session warm-up, 2 sets 15.8%) movement
weight of 10 reps @ 45% 1RM more so @ the
training in 2nd session performed beginning of the CON
previous CON/CM BP phase
5 mos Performed each movement Stronger participants
(twice) wl loads of 40, 60 8 produce greater
80% 1 RM load power in the initial
1 trial per movement type 8 CON phase
load, w/ 1 min rest btwn each Performing W/ 30%
movement 8 2 min btwn A of max load delayed
load peak power in
movement
Lee, et al., 4 male 8 Performed either SJ, CMJ wl Hip angle of grab start
2001 1 female, akimbo 8 swimming grab smaller than SJ
elite start Center of mass for
swimmer Used high speed video the grab start jump
camera (120 Hz) more forward than
synchronized to force plate . CM
(600 Hz) Force, power 8
Used inverse dynamics moment patterns
model to determine force 8 differed btwn 3 jumps

 

 

kinematic data

 

 

134

 

(Table 9 continued)

 

 

Cronin, et al., 27 males Performed bench presses on Rebound motion T
2002 8 27 modified smith press power output
females, 2 sessions, 1 to familiarize 8 T load => T ECC
~21 yrs determine 1 RM phase, ECC
Athletic Performed CON 8 rebound acceleration 8 j ECC
w/ no BP w/o release of bar velocity
weight Warm-up 2"d session 2 sets CON power output
training 10 reps BP @ 40% max load best predictor for
who 2 Trials per type of movement power production
prevrous 8 load w/ 1 min rest between across gender & load
6 mos explosive movements 8 2 Strength best
min btwn changing load predictor power
absorption for both
gender 8 load
No SIG difference
bmjimler

 

 

 

 

135

 

Consent Form:

Effect of explosive upper body exercises on
biomechanical parameters in males 18-30 years Of age

The purpose of this study is to identify the relationships that exist between six different upper body exercises
(medicine ball throw, catch and throw, and push; and the standard push up, drop push up and pushup) and
biomechanical parameters (force output, power output, and rate of force development) in males who are
currently involved with resistance training. Most exercise research is conducted on the lower extremity,
especially with explosive exercises which are called plyometrics.

This study will consist of three sessions lasting approximately 30 minutes. Participation will be needed for all
three sessions for data collection to be complete. Participants should have no past or cunent upper
extremity injuries, especially of the wrist, elbow, shoulder, neck, and/or back.

Data collection will include the following stages:

a. General lnfonnation: You will be given general lnfonnation about this study and a chance to
ask questions.

b. Measurements: All measurements will be collected in private in the Department of
Kinesiology’s Biomechanics Research Station in the IM Sports Circle Building on the campus
of Michigan State University.

i. Body weight will be assessed on a force plate and weight scale.

ii. Upper body weight will be recorded in a pushup position with the shoulders directly
over a force plate and in a position lying on the back with the shoulder blades on the
force plate.

iii. Standing height will be assessed with a standard stadiometer.

iv. Right arm length will be assessed with a short anthropometer.
v. Width of shoulders will be assessed with a bow caliper. .
vi. Upper body strength will be assessed via a ten repetition bench press after a
standardized warm-up.
vii. A digital video camera will be used to record events of the exercises (medicine ball
throw and pushup).
viii. A light weight accelerometer will be taped to the participant's back dunng the last two
sessrons.

ix. Force and power output and the rate of force development will be measured for the
performances of the 6 exercises.

c. Sports and training survey:

t. On the survey lnfonnation will be asked about age, gender, training experience and
sports background.

You are asked to participate in this study because you are 18-30 years of age, healthy, and have been
previously involved with resistance training. There is no economical benefit from your participation. Your
participation is totally voluntary. You may choose to participate or not and discontinue your participation at
any time without any explanation. By participating in this study, you agree that the materials and data
generated (pictures and measurements) may be used for research and academic purposes. You have also
been assured that your privacy will be protected to the maximum extent allowable by law. When this
research is completed, an abstract of the results will be emailed to you. You may also seek personal data of
your results to compare the exercise methods used.

136

(Consent Form continued)

If you are injured as a result of your participation in this research project, Michigan State University will
assist you in obtaining emergency care, if necessary, for your research related injuries. If you have
insurance for medical care, your insurance carrier will be billed in the ordinary manner. As with any medical
insurance, any costs that are not covered or in excess of what are paid by your insurance, including

. deductibles, will be your responsibility. Financial compensation for lost wages, disability, pain, or discomfort
is not available. This does not mean that you are giving up any legal rights you may have.

If you have any questions about this study, please contact Dr. Eugene Brown ((517)353-6491,
ewbrown@msu.edu <mailto: ewbrown@msu.edu>) or Kris Kotrla ((517)267-0011, kotrlakr@msu.edg
<mailto: kotrlakr@msu.edu>) at the Kinesiology Department, 204 IM Sports CIR East Lansing MI 48824-
1049. If you have questions or concerns regarding your rights as a study participant, or are dissatisfied at
any time with any aspect of this study you may contact — anonymously, if you wish - Peter Vasilenko, PhD.,
Chair'of the University Committee on Research Involving Human Subject (UCRIHS) by phone: (517)355-
2180, fax: (517)432-4503, email: ucrihs@msu.edu <mailto:ucrihs@msu.edu>, or regular mail: 202 Olds Hall,
East Lansing, MI 48824.

Your signature below indicates your voluntary agreement to participate in this study.

 

 

 

 

 

Name of participant: Signature:
Date: Mailing Address: .
Phone: Email address:

Date of Birth:

 

137

Listserv for Recruitment:
Dear Kinesiology Students,

My name is Kris Kotrla, I am a graduate student at Michigan State University in the department of
kinesiology. My masters thesis is, “Effect of explosive upper body exercises on biomechanical
parameters in males 18-30 years of age". I am looking for male participants in this study.

If you are 1) currently participating in resistance training 2) 18 to 30 years of age and 3) free of
injury or past injury (especially in wrist, elbow, shoulder, neck and back) then you are the person
for this study.

The purpose of this study is to determine the effects of performing different upper body exercises
on biomechanical variables. This study will involve 3 sessions within a weeks time. An orientation
session will involve a demonstration of the exercises (medicine ball throw, catch and throw, and
push; and the standard push up, drop push up and pushup), a consent form, a short survey (age,
gender, training and sports background), and measurements taken of body height, length and
weight. A 10 repetition maximal bench press will also be performed during this session and
practice with the exercises and equipment used (force plate 8 accelerometer). The following
sessions will involve performing the pushup and medicine ball throws in a selected order on a force
platforrn(s). From these testing sessions lnfonnation will be determined of individuals power output,
force production and maximal rate of force development. Each session will take about 30 minutes.
Athletic shoes, shorts/pants and shirts are required for participation. Once the study starts upper
body resistance training will not be allowed for that week of participation in the study due to fatigue.

The majority of exercises in this study have minimal risks. With explosive (plyometric) exercises
there is naturally more of a potential for injury. Devices, program design, and participant
requirements have been set to help minimize the risk for injury. Benefits that would be received
through this study are certified teaching and instruction in performing plyometric exercises which
could be added to an exercise regimen. Additional benefits to participants will include
biomechanical analysis of the upper body’s ability to exert force and p0wer and the maximal rate in
which force is applied. This study would also contribute knowledge to an area of exercise science
that has not been thoroughly investigated which would help researchers, coaches and weight
trainers.

Orientation and testing sessions will be held at 107 IM Sports Cir, East Lansing MI 48824-1049.
This study will run from 8/14 to 9/3/2004. The orientation sessions will be held on Saturday from 9
am. to 4 pm. Testing sessions will be held the following week on a Monday and Wednesday or
Tuesday and Thursday from 6 pm. to 9 pm.

If you are interested in participating, email me at kotrlakr@msu.edu or call me at (517) 267-0011
for questions and scheduling.

The goal is to have 30 individuals participate in this study.

Your participation in this study will definitely provide help and be greatly appreciated. If you know of
others who would be qualified and willing to participate please inform them too. Thank you for
taking time to read this message.

138

Flyer for Recruitment:

Participants Needed for Weight Training Study

Men who are 18-30 years old, currently involved with resistance training, and free of any past
or current injury to the upper body are needed for this study.

This study is set up with different upper body exercises (medicine ball throw, catch and throw, and
push; and the standard push up, drop push up and pushup) to determine their effect on
biomechanical variables (power output, force production, and ability to develop force at a high rate).

Three testing sessions will be performed within a week's time, each session lasting around 30
minutes. Testing sessions will be held in the Department of Kinesiology’s Biomechanics Research
Station at 107 IM Sports Cir, East Lansing MI 48824-1049, on the campus of Michigan State
University.

The majority of exercises in this study have minimal risks. With explosive exercises (plyometric
exercises) there is naturally more of a potential for injury. Devices, program design, and participant
requirements have been set to help minimize the risk for injury. Benefits that would be received
through this study are certified teaching and instruction in performing plyometric exercises which
could be added to an exercise regimen. There will also be an assessment of the upper body's
maximal strength with the bench press. Additional benefits to participants will include

biomechanical analysis of the upper body’s ability to exert force and power and an assessment of
maximal rate in which force is applied. This study would also contribute knowledge to an area of
exercise science that has not been thoroughly investigated which would help researchers, coaches,
and weight trainers

If you are interested in participating, email me at kotrlakr@msu.edu or call me at (517) 267-0011
for questions and scheduling.

Thank you for taking time to read this message.

 

139

Questionnaire:

Name: Date:

 

Circle the ngmbeflccording to your Qe:

1. Under 18 8. 24-25
2. 18-19 9. 25-26
3. 19-20 10. 26-27
4. 20-21 11. 27-28
5. 21-22 12. 28-29
6. 22-23 13. 29-30
7. 23-24 14. Over 30

Circle the number for vomender:

1. Female 2. Male

Circle the number and letter of all that apply to Resistance Training Background 8 Participation:

 

Types (LExerCises Se_ts Regs Duration
1. Machine Weights 1-3, 35, >5 1-6, 6-12,12-20,>20 <2mon,2—6
- mos, 6mos-1yr,
. . 1-3yrs, >3 yrs
2. Cable Machines 1-3, 3-5, >5 1-6, 6-12,12-20,>20 <2mon,2-6

mos, 6mos-1yr,
. 1-3yrs, >3 yrs
Free Weights 1-3, 35, >5 1-6, 6-12, 12-20, >20 <2mon,2-6
mos, 6mos-1yr,
1-3yrs, >3 yrs
. Body Weight 1-3, 3-5, >5 1-6, 6-12,12-20,>20 <2mon,2-6 mos,
6mos-1yr,
. 1-3yrs, >3 yrs
Plyometrics 1-3, 3-5, >5 1-6, 6-12,12-20.> 20 <2mon, 2-6
' mos, 6mos-1yr,
1-3yrs, >3 yrs

9°

.b

9"

During the Previous 6 weeks circle the type of Resistance Training that applies:

M of Exercises _S_et§ Reps
1. Machine Weights 1-3, 3-5, >5 1-6, 6-12, 12-20, > 20

2. Cable Machines 1-3, 3-5, >5 1-6,6-12,12-20,>20

140

3. Free Weights
4. Body Weight

5. Plyometrics

(Questionnaire continued)

1-3, 3-5, >5
1-3, 3-5, >5
1-3, 3-5, >5

1-6, 6-12, 12-20, > 20

1-6, 6-12, 12-20, > 20

1-6, 6-12, 12-20, > 20

Circle the number and letter that apply to Sports Participation and Level:

1. Baseball

2.
3. Cross Country - H/C
4.

oowspor

a. Catcher- HIC
b. Pitcher- HIC
c. Infield-HIC
d. Outfield - H/C

Basketball - H/C

Football

a. Offensive/Defensive Line - H/C
b. Running back/ Linebacker- H/C
c. Receiver/Defensive back - H/C

d. Quarterback - H/C

Golf - HIC

Ice Hockey - H/C
Lacrosse - HIC
Soccer - HIC

. Swimming
a. Sprints-HIC
b. Endurance- H/C

141

(H — high school 8 C - collegiate level)

10. Tennis - H/C

11. Track 8 Field
a. Throwing Events
i. Javelin - HIC
ii. Shot Put - HIC
iii. Discus - HIC
b. Running Events
i. Sprints (400 yd or less) - HIC
ii. Distance (800 yd or over) - H/C
0.. Jumping Events
1. Triple Jump - HIC
ii. High Jump - H/C
iii. Long Jump - H/C

12. Weight Lifting - HIC

13. Wrestling- HIC

Anthropometric Recording Form:

 

 

‘ Name:
Date:
_Height (cm) _ Back Lying Weight (kg)
_Total Body Weight (lbs) __ Upper Extremity Length (cm)
_Weight Body Weight (kg) _ Biacromial Width (cm)
_ Push-up Weight (kg)

142

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