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A COMPARISON OF BILATERAL ASYMMETRIES IN THE GAIT PATTERNS OF SUBJECTS WITH AND WITHOUT POSTERIOR CRUCIATE LIGAMENT INJURIES presented by Saidon Amri has been accepted towards fulfillment of the requirements for M.S. KinesioIogy Jegree in amflflflm/ / Major pro cssor MJ/y? f 0-7639 MS U is an Affirmative Action/Equal Opportunity Institution PLACE IN REI'URN BOX to remove this checkout from your record. , TO AVOID FINE return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE use chIRODatoDmpGS—p.“ A COMPARISON OF BILATERAL ASYMMETRIES IN THE GAIT PATTERNS OF SUBJECTS WITH AND WITHOUT POSTERIOR CRUCIATE LIGAMENT INJURIES By Saidon Amn’ A THESIS Submitted to Michigan State University In partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Kinesiology 1 999 ABSTRACT A COMPARISON OF BILATERAL ASYMMETRIES IN THE GAlT PATTERNS OF SUBJECTS WITH AND WITHOUT POSTERIOR CRUCIATE LIGAMENT INJURIES By Saidon Amri The purpose of this study was to compare bilateral asymmetries associated with kinematic parameters of the lower extremities in walking gait patterns within and among individuals with and without a Grade II posterior cruciate ligament (PCL) injury. Comparisons were made using bilateral gait patterns and Symmetry-Asymmetry lndices (SAL’s). The PCL injured subjects displayed greater levels of asymmetry than noninjured subjects. For the SAL'S, significant differences were found for linear and temporal parameters between the injured and noninjured subjects. However, comparisons of SAL’ s for the angular parameters showed no significant difference between the two groups. Dedicated to my wife and sons who have sacrificed a great deal to see me through this challenging process. ACKNOWLEDGEMENTS My special and sincere thanks to: Dr. Eugene W. Brown, my advisor who provided many hours, guidance, knowledge and encouragement for the completion of this thesis; Dr. Dianne Ulibarri for serving on my committee and her knowledge and guidance during my master's program; Dr. Julie Dodds from MSU Sports Medicine Clinic for serving on my committee and her advice Dr. VWnifred erten from Eastern Michigan University for lending me the two video cameras which were helpful during data collection; and Dr. John Haubenstricker, Dr. Steve Niergarth, athletic trainers in Department of Intercollegiate Athletic, and friends for their assistance in data collection. TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES Need forthe Study Statementofthe Problem Hypotheses" Limitations of the Study Definitions... REVIEW OF LITERATURE” Gait Analysis" Methods of Studying Gait Kinematic Measurements” Linear measures Angular measures Hip motion” Knee motion. Ankle and foot motrarj. Gait Symmetry... Factors Affecting Gait Patterns Pathological gait" Knee Joint Structure" Function of the knee Collateral Ilgamentg .. Cruciate ligaments" Knee Injury.. PCL Injury Classification Of PCL Injury Knee Injury and Gait Evaluation. Subjects lnstrumentation......... . .. . . Data oonecuon........f..'.If.If..f.’.II..'.'I.'.'IIIIIIIIIII.’IIIIIIIIIIIIIIIIIIIIII.’XIII." Data Analyses RESULTS AND DISCUSSION. Walking Velocity” Limb Segment Length Peak Torque for Knee Flexion and Extensron Temporal and Linear Variables” Sagittal Plane Variables” Frontal Plane Variables. Symmetry-Asymmetry Index Level (SAL)) fOr Feet and Preferred Walking” vii viii QVQGUIA 47 48 49 51 53 66 83 91 Summary Suggestions LIST OF REFERENCES vi 99 104 108 109 119 LIST OF TABLES Table 1 - Range of Forward-Walking Velocrty Table 2- Range of Motion for the Hip, Knee, and Ankle In the Sagittal and Coronal Planes During Normal Walking” . .. .. Table 3 - Subject Information Table 4 - Velocities of Walking for Preferred and Fast Trials .. Table 5 - Symmetry-Asymmetry lndices (SAL’s) for Limb Lengths... Table 6 - Symmetry-Asymmetry lndices (SAL’s) for Peak Torque for Selected Angular Velocities for Right and Left Knee Flexion and Extension Table 7 - Stride Lengths for Preferred Walking Speed Table 8 - Stride Lengths for Fast Walking Speed Table 9 - Number of Variables Ranked 5th or 6th for SAL's for Temporal and Linear Variables and Their Temporal Elements... Table 10- Chi-square Tests for Two Categories of SAL Ranking (5 or Greater and Smaller than 5) for Temporal and Linear Variables... . Table 11 Number of Variables Ranked 5"1 or 6th for SAL’s for Sagittal Plane Variables... Table 12- Chi-square Tests for Two Categories of SAL Ranking (5 or Greater and Smaller than 5) for Sagittal Plane Variables... . Table 13 - Number of Variables Ranked 5"1 or 6th for SAL’s for Frontal Plane Vanables Table 14- Chi-square Tests for Two Categories of SAL Ranking (5 or Greater and Smaller than 5) for Frontal Plane Variables... . Table 15 - Comparison of SAL's between Prefened and Fast Walking Trials for Temporal and Linear Variables and Their Temporal Elements ......... Table 16- Comparison of SAL’s between Preferred and Fast Walking Trials for Sagittal Plane Variables. Table 17- Comparison of SAL’ s between Preferred and Fast Walking Trials for Frontal Plane Variables... Table 18 - Gait Patterns with Greater Bilateral Asymmetries in Injured Subjects. vii 17 23 39 49 50 52 58 58 66 66 83 83 90 90 98 98 99 106 Table 19- Linear and Temporal Variables With Greater SAL’ s “(rankedu 5th or W6“) inlnjured Subjects” . .. 107 viii LIST OF FIGURES Figure1-Phasesand componentsofwalking cycle Figure2-Exampleofplanesofmotionofthe knee Figure3-Jointanglesdefinitionofthelowerextremity.................................. Figure 4 - Example of hip joint rotation patterns in a gait cycle: (a) normal hip flexion-extension, (b) normal hip abduction-adduction (compilation of Murray, etal., 1964; WInter, 1987, Chaoetal.; 1990, ”Ounpuu, Figure 5 - Example of knee joint rotation patterns in a gait cycle: (a) normal knee flexion-extension, (b) normal knee abduction-adduction (compilation of Murray, et al., 1964; WInter, 1987; Chao et al.; 1990 Ounpuu, 1995)... Figure 6 - Example of ankle joint rotation patterns in a gait cycle: (a) normal ankle plantar-dorsiflexion, (b) normal ankle abduction- adduction (compilation of Murray“, et al.,1964;WInter,1987;Chao et al.; 1990, Ounpuu, 1995).. ... Figure 7 - Bones, ligaments, and cartilage ofthe knee FigureB -Testing setup Figure 9 - Calibration frame Figure 10 - Position and digitizing order of markers Figure 11 - Standing position and joint angles definition, m(a) Isagi‘ttal plane, (b) frontal plane... . . .. Figure 12 - Ranking of SAL’s for limb length measurements... Figure 13 - Ranking of SAL’s for peak torque for knee flexion and extension ...... Figure 14 - Temporal elements of various phases of the preferred walking cycle and horizontal position of the ankle, knee, and hip for the injured (P) and noninjured (N) subjects Figure 15 - Ranking of SAL’s for temporal variables for preferred waking... .. Figure 16 - Temporal elements of various phases of the fast walking cycle and horizontal position of the ankle, knee, and hip for injured (P) and noninjured (N) subjects Figure 17 - Ranking of SAL’s for temporal variables for fast waking... .. 11 18 19 21 22 24 3O 41 41 43 45 50 52 54 55 56 57 Figure 18- Percentages gait cycle of various phases of preferred walking and vertical position of the ankle, knee, and whip” for injured (P)m and noninjured (N) subjects... . .. Figure 19- Percentages gait cycle of various phases of fast walking and vertical position of the ankle, knee, and hip for injured (P) and nonInjured (N) subjects... .. . .. Figure 20- Horizontal velocities for preferred walking for injured (P) and noninjured (N) subjects... .. .. Figure 21 - Horizontal velocities for fast walking for injured (P) and noninjured Figure 22 - Ranking of SAL’s for linear variables and their temporal elements for preferred waking Figure 23 - Ranking of SAL’s for linear variables and their temporal elements for fastwaking.... Figure 24— Ankle plantar—dorsiflexion angles for preferred walking for injured (P) and noninjured (N) subjects... Figure 25 — Ankle plantar-dorsiflexion angles for fast walking for injured (P) and noninjured (N) subjects Figure 26- Ankle plantar-dorsiflexion angular velocities for ”preferred walking for injured (P) and noninjured (N) subjects... . Figure 27- Ankle plantar—dorsiflexion angular velocities for fast walking for injured(P)and noninjured(N)subjects... Figure 28 - Knee flexion-extension angles for preferred walking for injured (P) and noninjured (N) subjects Figure 29 - Knee flexion-extension angles for fast walking for injured (P) and noninjured (N) subjects Figure 30 - Knee flexion-extension angular velocities for preferred walking for injured (P) and noninjured (N) subjects... Figure 31 - Knee flexion-extension angular velocities for fast walking for injured (P) and noninjured (N) subjects... Figure 32- Hip flexion-extension angles for preferred walking for injured (P) and noninjured (N) subjects... . . .. Figure 33 - Hip flexion-extension angles for fast walking for injured (P) and noninjured (N) subjects 59 60 62 63 64 65 67 68 70 71 72 73 75 76 77 78 Figure 34 - Hip flexion-extension angular velocities for preferred walking for injured (P) and noninjured (N) subjects... Figure 35 - Hip flexion-extension angular velocities for fast walking for injured (P) and noninjured (N) subjects Figure 36 - Ranking of SAL’s for sagittal variables and their temporal elements for preferred walkIng Figure 37- Ranking of SAL’s for ”sagittal variables and their temporal elements for fast walking... Figure 38- Hip abduction-adduction angles for preferred walking for injured (P) and noninjured (N) subjects for injured (P) and noninjured (N). subjects. Figure 39- Hip abduction-adduction angles for fast walking for injured UP)” and noninjured (N) subjects... Figure 40- Hip abduction-adduction angular velocities for preferred walking for injured (P) and noninjured (N) subjects... Figure 41- -I-Iip abduction-adduction angular velocities for fast walking for injured (P) and noninjured (N) subjects... Figure 42 - Ranking of SAL’s for frontal plane variables and their temporal elements for preferred walking Figure 43 - Ranking of SAL’s for frontal plane variables and their temporal elements forfast walkIng Figure 44 (a)- Comparisons of SAL’s between preferred and fast walking for subject N1. . . Figure 44 (b)- Comparisons of SAL’s between preferred and fast walking for Figure 44 (c)- Comparisons of SAL’s between preferred and fast walking for subject N3. .. .. . . .. Figure 44 (d)- Comparisons of SAL’ s between preferred and fast walking for subject N4. . .. Figure 44 (e)- Compan'sons” of SAL’ s between preferred and fast walkIng for subject P1 . .. Figure 44 (f)- Comparisons of SAL’ s between preferred and fast walking for subject P2.. . . xi 80 81 82 82 85 86 87 88 89 89 92 93 94 95 96 97 INTRODUCTION This chapter contains a general background and discussion on why this study should be conducted. The eariy part of this chapter includes information on the importance of the posterior cruciate ligament (PCL) and the need to study PCL injury. A presentation of the present PCL injury evaluation techniques and the possibility of utilizing bilateral gait analysis as an additional supplementary technique in assessing PCL injury are also included. In the study of knee ligament injuries more emphasis has been given to the anterior cruciate ligament (ACL) than posterior cnIciate ligament (PCL). This difference is primarily because of the predominance of ACL injuries in both the athletic and general population (Clancy, 1983). But, as more information is gathered about the ACL, the functional importance of the posterior cruciate ligament (PCL) has become increasingly apparent. Just as the ACL is considered to be the primary restraint to anterior translation of the tibia relative to the femur, the PCL is the primary restraint to posterior translation of the tibia throughout the full range of knee motion (Hamer et al., 1995). Compared to ACL injuries, the natural history data on PCL injuries was sparse and has not been well defined (Morgan 8 Wrobble, 1997). As a result, treatment of PCL injuries remains varied because of the lack of understanding regarding the natural history of this injury (Keller, Shelboume, McCarroll, & Rettig, 1993). Some investigators recommend surgical construction, especially when other ligamentous structures are damaged (Lipscomb, Anderson, Norwig, & Brown, 1993; Shelboume 8 Rubinstein, 1994). However, with isolated PCL ruptures, many authors recommend nonoperative treatment (Fowler 8 Messieh, 1987; Trbone, Antich, Perry, 8 Moynes, 1988). In contrast, some researchers have demonstrated continuing deterioration in their patients’ knees after nonoperative treatment of isolated PCL ruptures (WIIk, 1994; Parolie 8 Bergfeld, 1986; Keller et al., 1993). This deterioration was evident in a reduction of patients’ athletic ability, over time, as a result of these injuries (Richter, Kiefer, Hehl, 8 Kinzl, 1996). Ninety percent of nonoperatively treated patients who had isolated PCL mptures also reported knee pain, six years after the injury (Keller et al. 1993). Presently, varieties of methods are available in assessing PCL injuries. While recent technical advancements in the application of magnetic resonance imaging (MRI) may assist in identifying PCL injuries, the Posterior Drawer Test remains as the most sensitive technique for diagnosis (Miller, Johnson, Hamer, 8 F u, 1993; Rubinstein, Shelboume, McCarroll, VanMeter, 8 Rettig, 1994). However, the present evaluation techniques are performed under a static situation, which do not allow active participation of the patients. For that matter, emphasis should be given to dynamic physical examination techniques to develop prognostic indicators in patients who have a PCL deficient knee. Additional evaluation techniques, such as a kinematic gait analysis, could be valid methods to assess a PCL deficient knee in a dynamic situation. Walking gait can be defined as the manner of moving the body from one place to another by alternately and repetitively changing the location of the feet, with the condition that at least one foot is in contact with the walking surface (Smidt, 1990). Walking patterns displayed by healthy individuals are often considered as normal human gait (Hamill, Bates, 8 Knutzen, 1984; Nakhla 8 King, 1985; Herzog, Nigg, Read, 8 Olsson, 1988). It can be characterized by symmetric kinematics and kinetics between the left and the right sides of the body. If a subject were to walk in a consistent direction, the configuration of gait components elicited by the right side approximately would be the mirror image of those elicited by the left side (Gowitzke 8 Miller, 1988). However, minor quantitative movement differences among people account for the various distinctive ways in which people walk (Chao 8 Cahalan, 1990). For example, differences in joint range of motion could be found between individuals, and between different age groups (Murray, Drought, 8 Kory, 1964). While each person is different, there are certain attributes to the gait of healthy subjects that are consistent or consistent within a normal range. Wrthin this context, investigators in the field of biomechanics strive to understand human musculoskeletal function, both in normal and pathological states. Many gait analyses have focused on the biomechanical aspects of the right limb, assuming similarity with the contralateral limb (Sadeghi, Allard, 8 Duhaime, 1997). However, there have only been a few studies that have dealt with symmetry in simultaneous bilateral three-dimensional gait analyses (Hannah, Morrison, 8 Chapman, 1984; James, Nicol, 8 Hamblen, 1994). Using three-dimensional electrogoniometers on both lower extremities in each of twelve able-bodied subjects, Hannah et al. (1993) have shown joint motion symmetry in all three planes in their subjects” hips during natural walking and in their knees in the sagittal plane. If bilateral symmetry can be used to study walking in able-bodied individuals, can it be used to clinically evaluate problems in gait? If normal gait displays similar bilateral qualitative patterns of movement, patterns that vary from that of normal gait would suggest structural or functional deficiencies. Wrthin this context, the study of gait is important to unequivocally clarify levels and types of gait abnormality, measure the degree of departure from normal, and determine progressive changes resulting from therapeutic intervention (Smidt, 1990). Injuries may alter individual gait patterns. For example, injuries to the PCL of the knee may affect its ability to maintain balance and stability (Kreighbaum 8 Barthels, 1981). Kinematic changes would likely occur in the injured knee clue to its increased laxity. It may also result in kinematic changes in adjacent joints or the other extremities due to compensatory actions. These kinematic changes will likely precipitate kinematic asymmetries between the injured and the noninjured lower extremity. By finding the difference or dividing a measurement associated with one side of the body by a measurement for the same variable associated with the other side of the body, an index of symmetry can be obtained (Smidt, 1990). These differences and ratios between variables in the injured and the noninjured leg can be used as a measure of symmetries or asymmetries. In many studies of gait, it has been assumed that comparison of pathologic gait parameters in an individual or group of individuals, to nonpathologic unilateral gait data, obtained from others, is a valid technique for assessing limb abnormalities (Hannah et al., 1984). Such comparisons were influenced by a wide range of parameters affecting both the measured gait and the selection of measurement technique (Smidt, 1990). For example, quantitative difference in joint range of motion can be due to different walking speed, or because of various distinctive ways in which people walk. For that matter, the use of symmetry as an analytic method for pathologic gait removes many error sources inherent in the comparison with nonpathologic unilateral data. The measure of symmetry is maintained independently within an individual and is free of inter-subject variations. The remainder of this chapter will address the need for the study, statement of the problem, hypotheses of the study, and definition of the terms used. Need for the Study In the evaluation of PCL injuries, the posterior drawer and posterior sag signs are the most sensitive and specific clinical tests (Rubinstein et al., 1994). The grade of injury is determined by quantifying the relative translation of the tibia to the femur. This system relies on qualitative observation and quantitative measurement. In this system, a comparison of total posterior tibial excursion is made between a suspect knee and the contralateral knee, which is assumed to be normal. Medically trained personnel or experience athletic trainers are required to accurately make this type of assessment. However, quantitative assessment of grading knee laxity has been shown to be poorly reproducible among examiners (Daniel, 1988). Examiners in a study by Rubinstein et al. (1994), although agreeing on the overall diagnosis in the type of knee injury, did not agree on the grade of posterior and anterior laxity in 19% and 30% of the cases, respectively. In addition, such tests are also unable to give information on the movement of the injured knee in a dynamic situation (i.e., walking or running). Thus, there is a need to develop and use multiple and combined subjective and objective evaluation criteria to formulate an accurate and reliable assessment of knee laxity via static and dynamic diagnostic techniques. Many studies have shown the effectiveness of dynamic gait analysis techniques to bring out distinct gait abnormalities, typical of specific diseases or functional limitations (Mechelse et al., 1984; Robinson, Herzog 8 Nigg, 1987; James at al., 1994). However, these dynamic analyses have not been applied to an assessment of PCL deficient knees. The utilization of gait analysis techniques as cliniml tools may offer an accurate supplementary alternative to static techniques of diagnosing PCL injuries. If this dynamic method of assessing knee injuries is accurate, valid, and reliable; biomechanists may be included as consultants for investigation and evaluation of PCL knee injuries. It may also provide additional information to the understanding of PCL injuries and guidance for treatment decisions. Statement of the Problem Injury to the PCL would likely result in kinematic changes in the injured limb due to increased laxity. These changes may result in kinematic asymmetries between the injured and the noninjured lower extremity. One of the methods that can be used to investigate these asymmetries is bilateral gait analysis. Utilizing this method, bilateral asymmetries for temporal and kinematic parameters of the PCL injured lower extremities could be determined and compared to those without PCL injury. The purpose of this study was to compare bilateral asymmetries between individuals who had PCL injury to those without PCL injury. This study also examined the possibility of using bilateral kinematic analysis of gait as a supplementary and additional method for dynamically evaluating PCL knee injuries. Hygheses Hypothesis 1: Persons with a Grade II PCL injury will demonstrate greater bilateral asymmetries in gait patterns than persons without a PCL injury in the following: horizontal and vertical displacements of the ankle, knee, and hip; horizontal velocities of the ankle, knee, and hip; sagittal plane angular displacements and velocities of the ankle, knee, and hip; and frontal plane angular displacement and velocity of the hip. Hypothesis 2: Persons with a Grade II PCL injury will demonstrate greater Symmetry-Asymmetry Index Level (SAL) than persons without a PCL injury in the following parameters: temporal measures of gait cycle time, stance time, and weight acceptance time; positional measures of midstance, and midswing; stride length; vertical displacements of the ankle, knee, and hip; and horizontal velocities of the ankle, knee, and hip. Hypothesis 3: Persons with a Grade II PCL injury will demonstrate greater Symmetry-Asymmetry Index Level (SAL) than persons without a PCL injury in the following angular parameters: sagittal plane angular displacements and velocities of the ankle, knee, and hip; and frontal plane displacement and velocity of the hip. Mm of the Study The comparisons made in this study were limited to a small number of subjects; four with no injuries, and two with PCL injuries. The smaller number of injured subjects was due to the difficulty of getting subjects with unilateral Grade II isolated PCL injury. Due to limited equipment availability, the analyses were restricted to temporal and kinematic analyses only. The joint angular measurements examined were for the hip, knee, and ankle in the sagittal plane; and for the hip in the frontal plane. There were some difficulties in determining the bony landmarks that served as the endpoints for the measurement of each segmental length. Finally, the measurements involved were a limitation to all biomechanics studies: using relatively gross measures to identify very small differences. Utilization of the Ariel Performance Analysis System (APAS) software and procedure was subjected to digitizing errors. Wrthin this context, random error was caused by quantification inherent in the digitizing process which transformed the target point image coordinates into their numerical values. A small difference in the point of digitization between each video frame would cause greater difference in results of the displacement measurements and increased error with velocity. Within this limitation, it was assumed that the same point on the markers was digitized for different video frame of each trial. D_efimti_0r£ Coronal (Frontal) Plane - A vertical plane that divides the body into anterior and posterior parts. Gait Cycle TIme (GCT) - The period between the first heel contact to the next heel contact of the same foot. Grade II Posterior Cruciate Ligament (PCL) Injury — Injury to the PCL in which the anterior tibial border is flush with the femoral condyle. Heel Contact (Strike) - The first field of video when the heel of the foot is observed to make initial contact with the ground. Kinematics - Study or description of motion dealing with linear and angular positions, displacements, velocities, and accelerations. Midstance (MS) - Position of the lower extremity at the middle of the time period between the first heel contact and toe off of the same foot. Mid Swing (MSW) - Position of the lower extremity at the middle of the time period between toe off and ending with heel contact of the same foot. Mid Swing Time (MSWI') - The time at the middle of time period between toe off and ending with heel contact of the same foot. Sagittal Plane - A vertical plane that divides the body into right and left parts. Stance time (ST) - The period when the foot is in contact with the ground, measured from the first heel contact to toe off of the same foot. Step Period - The time period between the first heel contact to the next heel contact of the contralateral leg. Stride length (SL) - The distance covered by the ankle markers between the first heel contact to the next heel contact of the same foot. Swing TIme (SWT) - The period when the foot is not in contact with the ground; beginning with toe off and ending with heel contact of the same foot. Symmetry-Asymmetry Index Level (SAL) - Values for bilateral symmetries or asymmetries between the left and right variables of the lower extremities. Toe Off (T O) - The first field of video when the toe of the foot is observed to leave the ground. Transverse (Horizontal) Plane - A plane cutting through the body at right angles to the sagittal and coronal planes. Weight Acceptance Trme (WAT) - The period between heel contact and the field of video in which maximum knee flexion of the same limb is observed. REVIEW OF LITERATURE In normal walking, a gait cycle begins at the time the heel of one foot strikes the ground. Subsequently, the heel of the opposite foot swings fonrvard and strikes the ground, at which point one step is completed. A stride is completed when a second subsequent heel strike of the original foot occurs. Thus, a step is one-half of a stride (Figure 1). For natural wdence, the stance phase consumes 58 to 61 percent of the gait cycle and the swing phase 39 to 42 percent (Winter, 1987). This breakdown seems to hold primarily for the moderate-fast and fast walking velocities with stance percentages being larger at the slowest walking velocities. As cadence and walking velocity increase, the double stance time progressively diminishes. During normal gait, the majority of motion occurs in the sagittal plane, whereas in pathological gait, this type of motion is reduced while motion in the coronal and tranverse planes increases. The increase in motion in these two planes indicates coping responses to deviations in the sagittal plane. Gait Analysis The topic of gait has attracted the interest of researchers for a variety of reasons. Fundamental processes of movement, from a mechanical and physiological point of view, are studied in gait because walking is cyclic in nature and among the most 10 11 M. Right heel Left Right Left Left heel Right Left Right Right heel contact toe off midstance midswing contact tee off midstance midswing contact I I I l i l l l l I l l I l . 0 % 50% 100 % Gait Cycle Percentage (a) Order of Events L .L .r F Right Stance Time 'I‘ Right Swing Time 'I (b) Time i‘” T "‘ " "LeifétEB‘Ie’n‘gth ’ i ” ’i“ “T "" Righi SEE Ee'ngth fl" ‘ Ti L -I " Stride Length 'l (c) Distance Figure 1. Phases and components of walking cycle. 12 highly automated gross human movements. These movements display widespread synergy involving interaction between central and peripheral nervous system processes in the context of whole body musculature and skeletal system. The movements have inter individual generality because the walking act is mastered more completely than any other skill (Smidt, 1990). In addition to using the walking act to study underiying movement principles, gait analysis has also been used in clinical situations. Many clinical studies have shown that this analysis can clarify levels and types of gait abnormalities through measurements of the degree of departure from normal gait. Well defined and clinically meaningful parameters of gait have to be measured and analyzed in quantitative values (Olsson, 1990). Gait analysis that merely describes a walking pattern may not be sufficient. Wrthout quantitative information, comparisons of patients” walking patterns from one study to another, would be difficult and unreliable. According to Brand and Crowninshield (1981), gait analysis should fulfill six criteria if it were to gain clinical acceptance: 1. the measured parameters must correlate well with the patient's functional capacity; 2. the measured parameter must not be directly observable and semi quantifiable by the physician or therapist; 3. the measured parameters must distinguish cleariy between normal and abnonnak 4. the measurement technique must not significantly alter the performance of the evaluated activity; 5. the measurement must be accurate and reproducible; and 6. the results must be communicated in a form that is readily identifiable in a physical or physiological analog. 13 In studying pathological gait, analysis may only be useful if the variables that reflect the cause of the walking pattern are differentiable. According to Vaughan and Sussman (1993), gait analysis may provide insight into the basic mechanism underlying injury and disease processes. Thus, understanding of this underlying mechanism would allow investigators to accurately assess the efficiency of a specific intervention and to develop a more reliable treatment. Methods of Studying Gait Gait analysis is frequently used to analyze normal walking conditions as well as abnormal or inefficient walking patterns caused by a variety of medical conditions. In the several thousand papers published on human gait, the measures reported and the measurement techniques vary considerably (Winter, 1987). In his review, he found that each paper appeared to be characteristic of the understanding and interests of the investigators. A similar view was also presented by Olsson (1990), who cited differences in the focus of gait analysis between various types of investigations. Clinical investigators tend to look at output measures such as stride length, cadence, and joint angles; neurological researchers focus in electromyographic (EMG) measures; and biomechanists analyze kinematic, and kinetic parameters. Gait parameters can be categorized into four basic groups: the time-distance factors, ground reaction forces, joint kinematics, and electromyography (Chao, 1986). Different types of measures in gait analysis gather different information. Electomyographic signals, moments of force, and power provide the cause of a movement; while kinematics, momentum, stride length, cadence, and ground reaction forces merely reflect many output integrated effects (Winter, 1987). 14 Time-distance variables are frequently included in gait analysis because of the importance to relate forces, muscle activity, or joint motion to the phase of gait cycle. Time-distance measurements provide useful information concerning the patient’s walking ability, which objectively complements and reinforces the clinical evaluation and patient impressions of the procedure (Olsson, 1990). The kinetic parameters of gait describe the forces produced by muscular contraction and body weight during the course of movement. The ground reaction forces are a direct reflection of the accelerations of the mass of the body and its segments, a key to the study of human locomotion. The purpose of using EMG during gait is to determine the mode, timing, and intensity of the action of muscles. Timing of the contraction of the muscles within the gait cycle is the most common determination made from the EMG record (Olsson, 1990). Deviations from normal timing are classified as premature, prolonged, and out- of-phase action. This information is used to differentiate normal from abnormal function within muscle groups. Because of differences of height, body mass, age, cadence, and gender, investigators are challenged to identify methods that will normalize their measures so as to give them less variability and more universal patterns (Winter, 1987). For example, the moment of force and power patterns can be normalized by dividing these parameters by body mass, and walking velocities can be normalized by dividing the distance by body height and report velocity as statureslsecond. Tall subjects with long extremities would be expected to take longer strides than used by their counterparts of shorter stature; the step or stride length can be normalized to standing height or, more appropriately, to lower extremity length. 15 In gait studies, information on walking velocity is very important. It is an independent variable for which control can be made. Joint angular movements, ground reaction forces, stride lengths, and energy expenditures are all related to walking velocity. Therefore, the greater the velocity, the greater the tendency for the temporal values to decrease and the requirements for kinematic and kinetic parameters to increase. As such, in group studies, differences between groups or changes in one group over time may be due to changes in walking velocity alone (Smidt, 1990). Almost every gait variable changes with changes in walking speed. Therefore, gait information is useful when considered in relationship to walking speed. The free walking speed of patients is a measure of overall effectiveness of their physiological efficiency (Waters 8 Yakura, 1990). At this preferred speed, walking taxes less than 50 percent of the maximum oxygen consumption (VOzmax) in normal subjects in all age groups and does not require anaerobic activity. This oxygen consumption accounts for the perception that the walking speed requires minimal effort. Individuals with a specific trauma to the lower limb may be able to compensate for their disability by modifying their pattern of gait (Poulis 8 Soames, 1994). Such modification may be so successful as to be almost undetectable, particularly when these individuals walk at their preferred speed. However profound changes may become apparent at higher velocities due to problems of coordination and stability. Kinematic Measurements Kinematic studies concern descriptions of movements of the body, body segments, or relative motion between body segments in different planes. Because gait is a repetitive event, one cycle is used to represent the overall movement of walking. These movements include linear and angular displacements, linear and angular 16 velocities, and linear and angular accelerations. Through imaging systems, using cameras and a defined spatial reference system, a full kinematic description of gait can be obtained (Winter, 1987). Currently, one of the most successful techniques for obtaining joint motion data for clinical evaluation is the use of reflective marker systems (Ounpuu, 1995). Reflective joint markers are aligned with respect to specific bony landmarks on the pelvis and both lower extremities. Joint angle definitions are dependent on the marker set used to collect the data and thus are laboratory dependent. Linear measures Displacement data of the stride can be presented in two ways. Trajectory plots portray the movement in space on a plot of vertical versus horizontal position. Time is indicated by showing the position of each segment by a stick figure or each anatomical landmark by a point. A second way of presenting kinematic descriptors is on a time plot. Such graphs depict displacement, velocity, and/or acceleration of anatomical landmarks over the walking period. Walking velocity is the rate of linear forward motion of the body. For example, average velocity can be calculated by measuring the distance between the initial location of a foot placement, designated by the heel or toe, and a subsequent placement of the same foot. The displacement of the selected body part is then divided by the associated elapsed time to obtain a velocity parameter. Another method of calculation is to multiply the average step length by cadence, in steps per second, or to multiply the stride length by strides per second. Table 1 shows six ranges of forward walking velocity that were reported by Smidt (1990). He also cited a difference between men and 17 women during preferred walking velocities, with average velocities of 137 cm/s and 123 cmls respectively. Table 1 Range of Forward-Walking Velggty’ Rate Velocity (cm/s) Very slow g 40 Slow 41 - 70 Slow-moderate 71 - 100 Moderate 101 - 130 Moderate fast 131 - 160 Fast 161 - 190 Very fast > 190 Walking velocities of individuals are also influenced by situations and/or environments in which they walk. For example, the same individual may have different walking velocities in different settings (i.e., commercial area, shopping center). However, these differences were found to be small, and the range was between 124 cmls to 135 cmls (Finley 8 Cody, 1970). Angular measures Angular measurements of segments are based on their movement about an axis of rotation. In the knee joint, for example, the flexion-extension angle occurs about the mediolaterally directed axis fixed to the femoral condyle, and abduction-adduction is measured about an anterior-posterior axis (Figure 2). 18 plane Of __ axrs of motion ' rotation adduction 4__ __.p abduction Frontal plane motion axis of rotation plane of motion flexion extension 2 Sagittal plane motion Figure 2. Example of planes of motion of the knee. A convention for calculation of segmental displacements in space was presented by Winter (1987). He proposed that the distal end of the segments be chosen as the origin of segmental rotation because it meant that the shank, thigh, and trunk would oscillate either side of 90° rather than 270°. As part of his proposal, segments are measured in a counter-clockwise direction from the horizontal. Measurements of joint angles are determined by the relative positions of the segments composing them. 19 Therefore, joint angles do not provide the absolute angle of each of the adjacent segments in space. In joint angular measurements, the hip angle represents the position of the thigh relative to the trunk, knee angle represents the position of the shank relative to the thigh, and ankle angle represents the position of the foot relative to the shank (Figure 3). For the purpose of determining joint angular displacements, angles measured are compared to a reference position; the anatomical or the neutral position. This position is defined as the position where the body is standing erect with feet together, arms at the side, and palms facing toward. trunk hip angle thigh knee angle " —— shank ankle angle . Figure 3. Joint angles definition of the lower extremity. 20 Hip motion. Kinematic analysis of the hip joint involves relative motion between the pelvis and the femur with three degrees of freedom. Gait patterns for the hip in the sagittal and frontal planes are presented in Figure 4. In the sagittal plane, at heel strike, the hip is at or near maximum fiexion and beings to extend just after the start of double support (Winter, 1987; Chao et al., 1990). The hip continues to extend throughout the stance phase and maximum extension at about 85 percent of the gait cycle (Munay et al., 1964). At this point, the hip begins to flex, and continue through out the swing phase, again reaching maximum flexion just before heel strike. In the frontal plane, the hip is in neutral or slight adduction at the time of heel strike. Adduction occurs through foot flat and heel off, reaching maximum adduction at 65 percent of the stance phase period (Chao et al., 1990; Ounpuu, 1995). There is a rather sharp inclination toward abduction, which peaks shortly after toe off. Knee motion. Rotation of the tibia relative to the femur takes place in three planes. Figure 5 depicts a normal gait pattern for the knee in the sagittal and frontal planes. In the sagittal plane, the knee is just short of full extension at heel strike (Murray, et al., 1964; Winter, 1987; Chao et al.; 1990, Ounpuu, 1995). The knee then begins to flex as the foot accepts more body weight. As the body is progressing over the foot, from the foot flat until heel-off, the knee is extending. Flexion occurs through toe-off, continues during eariy swing phase, and reaches maximum extension just before heel strike. In the frontal plane, small adduction occurs at heel strike and remains essentially stable through foot fiat (Chao et al., 1990). The knee then begins to abduct and remains stable through most of the stance phase. At the end of the stance phase, the knee adducts until the early period of the swing phase, returning to the neutral position. The knee then abducts until the midswing and finally adducts for the next heel strike. 21 Right Right Right HS TO HS 25 - . . 154 V I i (a) Extension-Flexion (degrees) t'h -15 _ -25 J 0 20 40 60 80 100 % of gait cycle Sagittal Plane Movement Right Right Right (b) Adduction-Abduction 0 20 40 60 80 100 % of gait cycle Frontal Plane Movement Figure 4. Example of hip joint rotation patterns in a gait cycle: (a) normal hip flexion- extension, (b) normal hip abduction-adduction (compilation of Murray, et al., 1964; Winter, 1987; Chao et al.; 1990, Ounpuu, 1995). 22 Right Right Right HS TO HS 80 n 60 s 5 .5 a E if“ (a) a 3 20 - 0 T I T 0 20 40 60 80 100 % of gait cycle Sagittal Plane Movement Right Right Right HS TO HS 20 i a s 23 10 ~ «.3 it? E g 0 f \‘ m '13 a V b ( ) § 40 - -20 - 0 20 40 60 80 100 % of gait cycle Frontal Plane Movement Figure 5. Example of knee joint rotation patterns in a gait cycle: (a) normal knee flexion- extension, (b) normal knee abduction-adduction (compilation of Murray, et al., 1964; VVInter, 1987; Chao et al.; 1990, Ounpuu, 1995). 23 Ankle and foot motion. Normal gait patterns of the ankle for sagittal and frontal planes are presented in Figure 6. In the sagittal plane, the ankle angle is usually near the neutral position as in standing at heel strike, (Murray, et al., 1964; Winter, 1987; Chao et al., 1990; Ounpuu, 1995). During this period, there is initial plantar flexion to get the foot flat on the ground. From foot flat to heel-off, there is dorsiflexion, followed by rapid plantar fiexion associated with push off. During the swing phase, dorsiflexion brings the ankle back to neutral, so the foot will clear the floor and be prepared for the next heel strike. In the frontal plane, the ankle slightly adducts at heel strike, followed by a rapid abduction during the eariy stance phase. It then gradually adducts and reaches maximum at toe off (Chao et al., 1990). The ankle then abducts throughout the swing phase. The range of motion for the hip, knee, and ankle in the sagittal and frontal planes during normal walking are summarized in Table 2. Table 2 Range of Motion for the Hip, Knee, gm Ankle in the Sagittal and Coronal Planes During Normal Walking Planes of motion SAGI'I'I’AL FRONTAL (deLrees) (degrees) Authors Hip Knee Ankle Hip Knee Ankle Murray et al. (1964) 40 - 43 65 -68 28 - 30 Winter (1987) 33 - 36 65 29 Chao et al. (1990) 41 7o 30 9 10-12 Ounpuu (1990) 43 60 30 13 24 Right Right Right HS TO HS 25 c l 31 15 — 5 ~\/\¥ '3 s - - . * F '0 (a) EV -5 - OJ 0. -15 - .25 g 0 20 4O 60 80 100 % of gait cycle Sagittal Plane Movement Right Right Right HS TO HS 5 l ,5 ‘5 a A E 3 J\\ / a; %0 T a I "g 3 L’ (b) g < _5 .- 0 20 40 60 80 100 "/0 of gait cycle Frontal Plane Movement Figure 6. Example of ankle joint rotation patterns in a gait cycle: (a) normal ankle . plantar-dorsiflexion, (b) normal ankle abduction-adduction (compilation of Murray, et al., 1964; VVInter, 1987; Chao et al.; 1990, Ounpuu, 1995). 25 Gait Symmetry Gait symmetry has been generally assumed in normal human gait (Chao, 1986; Winter, 1987). This measure can either be determined through statistical analysis or through indices of symmetry. For mathematically derived indices of symmetry, a quotient is obtained by dividing a measurement associated with one side of the body by a measurement for the same variable associated with the other side of the body. Robinson, Herzog, and Nigg (1987) quantified ground reaction force asymmetries using the following Symmetry Index: 2 (Xn - Xi) Symmetry Index (SI) = .100. (Xn + Xi) where X.1 is a gait variable associated with the noninjured side and X, is the corresponding variable for injured side. Values of zero indicate that there is no difference between the variables Xn and X, and, therefore, perfect gait symmetry for the measured variables. James, Nicol, and Hamblen (1994) also calculated gait asymmetries using an identical formula: (X left - X right) Asymmetry = o 200. (X left + X right) Investigation of bilateral symmetry of the lower limb using indices of symmetry from kinematic analysis was rarely done. An attempt by Hannah, Morrison, and Chapman (1984) applied a correlation coefficient to kinematic data collected on the right and left lower limbs. They found a high level of symmetry for the linear and angular sagittal plane motions of hips and knees. High levels of symmetry of the motion of the hip was also observed in the tranverse and coronal planes, but symmetry of the motion 26 of the knee was lower for these planes. Nakhla and King (1985) observed no significant differences in the patterns between the left and the right foot for overground gait, suggesting bilateral symmetry in normal gait. Zuniga and Leavit (1974), in their analysis on human gait reported a similar finding of temporal symmetry in normal gait. In comparing normal subjects with those with prosthetic limbs, they found similar swing- stance phase time ratios for both normal men and women indicating temporal symmetry of the normal gait. However, the amputees showed a decrease in the swing-stance ratio, indicative of compensatory action for gait stability. Murray, Drought, and Ross (1964), in their study on walking patterns of normal men, found each movement pattern was strikingly similar for repeated trials of the same subjects and for subjects in the various age and height groups. Numerous other studies have also shown symmetry of selected temporal, kinetic, and kinematic parameters for normal gait patterns. Nakhla et al. (1985), in their study to determine relationships between the left and right lower extremity, also observed no significant difference in ground reaction force between the two limbs for overground gait. Hamill, Bates, and Knutzen’s (1983) study of ground reaction force symmetry in walking and jogging also found no significant differences between the left and the right foot in any of their descriptors. The symmetry between the preferred and nonpreferred limb in both locomotor conditions also indicated that both limbs were used equally. Although the results of this study may be limited, due to the small number of subjects, the clinical contribution of these results cannot be overtooked. They further suggested that normal healthy subjects should exhibit a symmetrical gait pattern when performing at a submaximal effort. In the previous discussion on gait symmetry, normal human gait was considered symmetrical when there was no significant difference in temporal, kinetic, and kinematic 27 parameters between the right and the left lower extremity. However, Herzog, Nigg, Read, and Olsson (1989), using a symmetry index to analyze ground reaction force pattern, found asymmetries for 34 variables associated with normal human gait. In their study, they defined gait symmetry as completely similar ground reaction force patterns between the left and the right lower extremity. With this definition, normal human gait was found not to be symmetrical, but indicated a range of asymmetries describing normal gait pattern. The upper and lower limit of normal gait symmetry range from four percent to over 13,000 percent. This wide range of symmetry was found to be attributed to the formula adopted to calculate the symmetry index. Values of the upper and lower limit of the symmetry indices were large if the differences in a variable from the right to the left leg were large compared to the absolute values of that variable. They also suggested that limits for normal gait asymmetry are variable specific and it is not valid to use one criterion value to assess gait symmetry for several gait variables. In other words, in normal gait, different variables have different levels of asymmetries Factors Affecting Gait Patterns Many factors affect the biomechanics of the lower extremity during walking. For example, in abnormal walking, the heel may not be the first part of the foot to make floor contact. As discussed earlier, normal human gait is characterized by symmetrical gait patterns between the right and left lower extremity. Variation to such patterns shown by large asymmetric values between the limbs can be used to highlight anomalies and/or pathologies. An important factor to be taken into consideration when assessing pathologic gait is whether or not any differences observed are due to pathology or are merely due to environmental factors, and therefore are within normal range. Factors such as stride length and cadence influence gait pattern (Soamess 8 Richardson, 28 1985). Since velocity of walking is the product of stride length and cadence, an increase in velocity may be achieved by increasing either or both of these components. It might be expected that joint angles, range of motion, and ground reaction forces increase with increasing gait velocity due to greater propulsive forces associated with higher velocity. Rodger (1993), comparing two styles of gait, found significant differences in the ground reaction force patterns due to different velocities and anthropometry, such as limb length. Similar results were also reported by Soames et al. (1985), stressing that the effect of increasing cadence was more pronounced in changing the gait pattern than increasing stride length. Mechanics of the foot during floor contact can also be influenced by the construction of the running shoes worn by subjects for gait analysis. With different types of running shoes, subjects exhibited different angle of pronation of the foot (Nigg, Luethi, Denoth, 8 Stacoff, 1983). Furthermore, changes in the compliance of the foot and ankle, due to wearing shoes or barefooted may influence ground reaction forces of walking (Poulis 8 Soames, 1994). In other words, walking barefooted for gait analysis would control any discrepancies due to unusual footwear. Pathological gait Gait patterns that vary from normal would suggest structural and/or functional deficiencies (Luttgen, Deutch, 8 Hamilton, 1992). This problem may be associated with the compensatory action of opposing limbs and/or adjacent joints to maintain balance and stability. For example, a smaller ankle moment together with a larger hip moment was found in patients with hereditary motor and sensory neuropathy (Mechelse, Pompe, Best, Pronk, 8 Einjhoven, 1985). The smaller ankle moments in these patients were due to the weakness of the leg muscles, but the explanation of the larger hip moment 29 was not obvious. Perhaps, the decreased ankle moment was compensated by the increased hip moment. Katoh, Laughman, Schneider, and Morrey (1983), in their study of the weight bearing extremity among patients who had heel pain, indicated a presence of compensatory action to increase gait stability. The injured extremity tended to alter the action of the normal contralateral extremity during gait. Weidenhielm, Svensson, and Brostrom (1995), in their study of unilateral medial knee osteoathrosis of patients, found increased adduction moments about the knee and hip joints during midstance in the uninvolved leg when compared to normal subjects. James et al. (1994) found asymmetry of flexion-extension movements between the two hips in unilateral hip athritis patients, and suggested the use of gait symmetry measurements as the most effective method in assessing the need for surgery. Knee Joint Structure The knee joint is a synovial joint between the lower end of the femur, the patella, and the upper end of the tibia (Figure 7). It has a joint cavity which contains a small amount of synovial fluid (Lumley, Craven, 8 Aitken, 1995). The synovial membrane lines the joint capsule which covers the non-articular parts of the femur and tibia. The femur is the large bone of the thigh. The shank consists of two bones; the large bone is the tibia and the small bone is the fibula. The patella is the fourth bone of the knee joint. The patellar tendon connects the patella to the tibia. This tendon covers the patella and is continuous with the quadriceps tendon and quadriceps muscles of the thigh (Wells 8 Luttgen, 1976). 3O Femur -— I Lateral condyle of femur Lateral meniscus L Lateral collateral Medial condyle of femur Posterior cruciate ligament __ Anterior cruciate ligament Medial meniscus Medial collateral ligament the... it“ *9 Ir “ “l Fibula \ T Anterior View Femur Medial condyle ligament 4— Tibia Lateral condyle of femur of femur 7’ , tiiltal ’4“ Posterior cruciate l ) ligament ‘ Medial collateral ligament s.. Anterior cruciate ligament Lateral collateral ligament Fibula Tibia _— . i T Posterior View Figure 7. Bones, ligaments, and cartilage of the knee. 31 Function of the knee Two structures called menisci sit between the femur and the tibia. These structures are sometimes referred to as the cartilages of the knee (Lumley et al., 1995). Two ligaments are found on either side of the knee joint; the medial collateral ligament and lateral collateral ligament. The popliteal ligament passes upwards and laterally from the medial tibial condyle across the posterior surface of the capsule. Inside the knee joint, two ligaments (ACL and PCL) stretch between the femur and the tibia. The ACL is attached to the anterior tibia and crosses the posterior femur (Kreighbaum 8 Barthels, 1985). The PCL attaches to the lateral side of the medial condyle of the femur. The tibial attachment begins one centimeter below the tibial plateau on the posterior surface of the proximal tibia. The PCL is larger and stronger than the ACL (Wells et al., 1976). It consists of a large anterolateral and a smaller posteromedial bundle. Its orientation is from anterior, at the femoral attachment, to posterior, at the tibial attachment. The knee joint functions primarily to provide stability in weight bearing and mobility in locomotion. It depends on its ligaments and muscles to maintain its stability (Thomson, 1985). The ligaments of the knee joint act as primary stabilizers and guide the movement of the bones in proper relation to one another. The movements which occur at the knee joint are primarily flexion and extension (Wells et al., 1976). A slight movement of medial and lateral rotation can take place when the knee is in the flexed position and the foot is not supporting the body. During knee extension, the tibia glides anterioriy on the femur. The gliding of the tibia on the medial condyle of the femur causes the tibia to externally rotate during the last 20 degrees of extension (Amheim, 1994). During knee flexion, the tibia glides posteriorly on the femur. From a position of full knee extension, posterior tibial glide begins earlier on medial condyles than the lateral condyles, causing tibial intemal rotation (Wells et al., 1976). 32 Collateral ligaments Stability on the medial and lateral sides of the knee joint is provided by the medial and lateral collateral ligaments (Amheim, 1994). The medial collateral ligament is tight throughout the full range of motion, although there is a greater stress placed on different parts of the ligament as it goes through the range of motion because of the shape of the femoral condyles. The lateral collateral ligament provides protection to the lateral aspect of the knee. Cruciate ligaments The cruciate ligaments are the primary rotary stabilizers of the knee (Magee, 1987). The ACL's main functions are to prevent anterior movement of the tibia on the femur, check external rotation of the tibia in flexion, and to a lesser extent, check extension and hyperextension of the knee. The PCL is a primary stabilizer of the knee against posterior movement of the tibia on the femur, and it checks extension and hyperextension. The orientation of the PCL enables it to perform its function: preventing fonrvard displacement of the femur on the tibia (Kreighbaum et al., 1985). The PCL also helps to stabilize the flexed knee during weigh bearing, prevent internal rotation, and guide the knee in flexion (Magee, 1987). Knee Injury The knee joint is particularly susceptible to traumatic injury because it is located at the ends of two long lever arms: the tibia and the femur (Kreighbaum et al., 1985). The apparent increase in knee ligament injuries in sports has played an important role in focusing attention on this joint. Keller, Shelboume, McCarroll, and Rettig (1993), in their study of patients with isolated PCL injuries, reported 75% of the injuries were sports related. The most commonly disrupted ligament in the knee is the ACL (Clancy, 1983). 33 An abundance of literature has focused on this type of injury. This is primarily because of the predominance of ACL injuries in both the athletic and general populations. PCL injury Injury to the PCL has received less attention than the ACL, despite being recognized by many investigators as the primary stabilizer of the knee joint (Hamer et al., 1995). Just as the ACL is considered to be the primary restraint to anterior translation of the tibia, the PCL is the primary restraint to posterior translation of the tibia throughout the full range of knee motion. The PCL is most susceptible to injury when the knee is flexed to 90 degrees. A fall on a bent knee with the foot plantar flexed or a hard blow to the front of the knee can tear the PCL (Morgan & Wroble, 1997). A rotational force and hyperextension can also injure this ligament. It is well documented that PCL insufficiency can lead to progressive laxity of secondary stabilizers of the knee such as the minisci, resulting in localized pain, swelling and instability (Hamer et al., 1995). Wilk ( 1994) cited functional disability to PCL deficient knee, and this disability was secondary to pain and inflammation from articular cartilage degeneration. Under radiographic evaluation, PCL insufficiency has been shown to lead to degenerative changes in both medial and patellofemoral compartment (Lipscomb et al., 1993). Keller et al. (1993) found that patients with isolated PCL injuries suffer continued deterioration of the involved knee based on radiographic, subjective, and functional criteria at reevaluation. The deterioration appeared to begin, and can be detected, less than five years after injury and was not reduced by maintaining excellent quadriceps strength. Similar finding was also reported by Wilk (1994), citing degeneration process occurred over a period greater than five years. The patients with isolated PCL injuries 34 may maintain enough muscular strength to remain active. However, they are usually unable to return to their preinjury activity level, and they continue to show objective and subjective evidence of knee deterioration with increasing time from the injury. lsokinetic strength analysis revealed quadriceps muscle deficits of the PCL injured leg, especially at low angular velocities (Richter et al., 1996). For that matter, rehabilitation program of PCL deficient knee should emphasize aggressive quadriceps strengthening and full range of motion maintenance. The patients would have full pain free range of motion of the knee joint and equal strength in the quadriceps and hamstrings muscle after completing the program (Waller, 1995). Majority of athletes with isolated PCL injuries who maintained muscular strength returned to sports without functional disability (Parolie et al., 1986). In contrast, Keller et al. (1993) reported continued deterioration of nonoperatively injured knee although the patients maintained excellent quadriceps strength. Classification of PCL injury According to Amheim (1994), the following conditions are major indicators of an injured PCL: 1. the athlete reports feeling a pop in the back of the knee, 2. there is a feeling of tenderness in the back of the knee, and 3. testing will reveal a posterior knee sag. Other methods have also been used to evaluate PCL injuries. These evaluations include symptoms of pain, swelling, instability, and the patient’s inability to perform specific tasks in various activity levels (Keller et al., 1993). In the assessments, patients are asked about limitations of their activity, feeling whether their knee has 35 recovered, and ascertaining whether braces are used for sports. Their post and preinjury activity levels are also compared. Several tests aid in the diagnosis of PCL injuries. The most commonly performed tests include the Posterior Drawer, Posterior Sag, Lachman's, Quadriceps Active, and the Reverse Pivot Shift (Amheim, 1994). In all tests, the physician or certified athletic trainer also examines the contralateral uninjured knee for comparison. Currently, arthrometer and MRI have also been used to assist in assessment of PCL injury. Among all these tests, the Posterior Drawer Test was found to be the most sensitive and specific clinical test for PCL injury (Miller et al., 1993). Using this test, the sensitivity for grading high grade PCL tears (grade I and II) was 97 percent, and 70 percent for the lower grade (Rubinstein et al., 1994). The arthrometer was found to be relatively accurate in detecting and grading the grade II and Ill posterior laxities but was not sensitive enough to detect the grade I laxities (Rubinstein et al., 1994). Magnetic resonance imaging (MRI), on the other hand, can be useful in pinpointing the PCL tear and identifying other injuries (Miller & Hamer, 1993). The Posterior Drawer Test is done with the patient supine, the knee flexed 90 degrees, and the foot flat on the table. The physician first observes the resting position of the tibial plateau in relation to the femoral condyles (Magee, 1987). With the knee flexed 90 degrees, the medial tibial plateau normally lies approximately one centimeter anterior to the medial femoral condyle. The Posterior Drawer Test is graded by the amount of posterior subluxation. A Grade I PCL injury was defined as increased posterior tibial displacement but with the tibia not being flush with the femoral condyles. Tibial translation is between one to five millimeters. A Grade II PCL injury exists when the anterior tibial border is flush with the femoral condyles. Posterior tibial translation for this grade is between five to ten millimeters. Any further posterior subluxation is 36 considered a Grade lll PCL injury. This is seen when the tibia posteriorly translates more than ten millimeters, and the tibia lies posterior to the femoral condyles (Rubinstein et al., 1994). Knee Injury and Gait Evaluation Injury to any of the knee ligaments will reduce the stability and ability of the knee in weight bearing. The body tends to lose its ability to maintain equilibrium and, as a result, movement reflex will try to prevent the loss of balance by shifting the weight to the other base of support, the other limb (Kreighbaum et al., 1981). This compensatory action of the noninjured other limb to maintain balance and stability are important factors in the smoothness of the gait. In human walking, single stance time indiwtes the weight bearing ability of each limb. This time has proved more accurate than total stance time because the latter measurement is a mixture of single and double stance time (Olsson, 1990). According to Winter (1987), weight is effectively accepted by the supporting limb between the period of initial heel contact and the time of maximum knee flexion. This period is called the weight acceptance time (WAT). Winter (1983) also reported that potential wear damage at the knee and hip joint increases with increases in knee flexion. As knee flexion increased during stance, the extensors at the knee must contract to limit knee flexion and to cause the knee to extend again during midstance. Such muscle activity results in drastic changes in the bone-on- bone forces at the knee. The ratio between the injured and uninjured legs can be used as a measure of asymmetry or limp, although the ranges of normal symmetry have not yet been identified. The irregularities and asymmetries in time-distance factors have been used in 37 attempts to find gait abnormalities typical of specific diseases or functional limitation (Olsson, 1990). Chao, Laughman, and Stauffer (1980) described eight significant gait variables, providing discriminative power in separating total knee replacement patients from a control group of normals using time-distance, force plate, and the electrogoniometer measurements. Simon, Trieschman, and Burdett (1983) compared patients, who had total knee replacement, with normals and found differences in WAT, cadence, knee flexion in stance, and external moments of the knee joint. Compensatory alterations in gait seem to be imposed by abnormal knee mechanics due to ligament injuries. Patients with ACL deficient knees demonstrated decreased mediolateral translation, increased adduction during midstance, and increased external rotation during the transition from swing to stance (Shiavi, Limbird, & Frazer, 1987). Trmoney et al. (1993), found gait differences between individuals who had ACL reconstruction and those with normal knee. Those with ACL reconstructed knee demonstrated decreased quadriceps strength, increased hamstrings activity, prolonged activity in the hamstrings, and decreased anterior shear forces. Although no study has been reported on gait analysis due to PCL injury, an adverse effect might occur in the PCL deficient knee. METHODS Midi Six males, 19 - 23 years of age participated in the study. They were divided into two groups, the noninjured (uninjured group) and those who had suffered a Grade II PCL injury (injured group). From the six participants, four were without any injury history and two had a history of being diagnosed with a unilateral isolated Grade II PCL injury. Both injured subjects had PCL injuries to their left leg. For confidentiality, noninjured subjects were labeled N1, N2, N3, and N4; while the injured subjects were labeled P1 and P2. The selection of PCL injured subjects was made through consultation with physicians of the Michigan State University (MSU) Sports Medicine Clinic and athletic trainers in the Department of Intercollegiate Athletics at MSU. Another criteria considered for each subject’s involvement in this study was that they were free from injury to the other parts of the lower extremities, upper extremities, and the axial region of the body, except for the PCL injury in the injured group. In accordance with the University policy, approval from the University Committee on Research Involving Human Subjects (UCRIHS) was obtained prior to the subject selection. All noninjured subjects and one of the injured subjects were involved in recreational physical activity (jogging, fitness activity workout, or playing soccer at least once a week) at the time of the study. The other injured subject was a member of the MSU cheerleading squad. Both injured subjects were involved in rehabilitation programs. Subject P2 went through a full rehabilitation program one hour everyday for 38 39 two months immediately after sustaining the injury five years ago. Although Subject P1 suffered the PCL injury two and a half years ago, it was only diagnosed two weeks prior to the testing. This subject had ultra sound treatments and participated in a weight training program three times a week at the time of the study. However the type of activities involved in the weight training program was not indicated. Subject P1 also reported pain and swelling of the injured knee under strenuous activity. All subjects reported the right leg as their dominant leg based on their preferred leg used for kicking. On the day of the testing, the subjects signed an informed consent form (Appendix A) and completed a personal information sheet (Appendix B). Subjects were then tested via Posterior Drawer Test on both knees (Appendix C). This test was performed by an orthopaedic surgeon from the MSU Sports Medicine Clinic. For the injured subjects, the test was performed to determine the grade of the injury. For the noninjured subjects, it was performed to assure the healthy condition of their knees. Results for the Posterior Drawer Test and other information on the subjects are presented in Table 3. Table 3 Subject Information Subject Age Weight Height Posterior Drawer Test Age of Injury Dominant k (yea rs) (EL (cm) (grade) (years) LeL Noninjured Left knee Right knee N1 23 60 172 0 O - right N2 22 73 167 0 0 - right N3 21 60 170 0 0 - right N4 21 68 182 0 0 - right PCL injured P1 19 95 177 + 2 0 2.5 right P2 23 68 177 + 2 O 5 right 4O Instrumentation Four Panasonic S-VHS video cameras, two on each side of a walkway were used for the video taping procedure (Figure 8). The cameras recorded at a speed of 60 hertz per second (60 Hz). Cameras with portable lights on each side, were placed on each side of the walkway at approximately 60 degree angles to each other and to the axis of the walkway. This provided the best view of all markers as the subjects moved in the sagittal plane within the calibrated space. Cameras 1 and 2 were used to record the right side of the subject; while cameras 3 and 4 recorded the left side. For synchronization of fields from independent cameras during data reduction, timing lights synchronized to each other were placed in the field of view of both cameras on each side of the walkway. A calibrated test volume of 4 meters long, 1.5 meters wide, and 1.25 meters high was placed at the center of a walkway (Figure 9). The calibration structure consisted of 16 control points, four points distributed at each vertical of the rectangular volume. The spacing of the points on each vertical axis was the same: 15 centimeters, 50 centimeters, 90 centimeters, and 125 centimeters from the floor. The calibration structure was then removed from the walkway after being recorded by the cameras. Use of the calibration structure was to define the volume of the walkway. Using a Cybex Il isokinetic dynamometer, subjects were also tested for peak torque for knee joint flexion and extension at three angular velocities: 60 deg/sec, 180 deg/sec, and 360 deg/sec to indicate joint strength (Appendix D). The test was supervised by a certified athletic trainer from the Department of Intercollegiate Athletic at MSU. The athletic trainer had considerable experience in the use of the Cybex ll equipment to measure knee flexion and extension torques. 41 Camera Camera .“‘. Xcalibraudjiniyorumo X: d" “Hm °f /' '\ I '\ walking ]: ..‘éx‘ : 2 ' . optic axis Camera ‘ “““ field of view of a camera Figure 8. Testing setup. 0 1.25 meters 0 I) . . + Z + Y walkway direction of walking --..__‘_..'.‘ v."‘~‘....,."‘ 15% + X A “I 4 meters Figure 9. Calibration frame. 42 Standing and segmental leg length measurements were performed by a qualified and experienced anthropometrist from the Department of Kinesiology at MSU (Appendix E). The standing leg length was defined as the length from the center of the greater trochanter to the floor, thigh length was measured from the center of greater trochanter to the upper edge of the tibia, and shank length was measured from the upper edge of the tibia to the center of the lateral maleolus. For the measurement, subjects were required to stand upright with their hands by their side and feet slightly apart. Points for measurements were first highlighted on the skin of the subjects with markers and then measurements were made by using a long anthropometer. The sets of measurements were repeated a minimum of two times to check reliability of the length recorded. Data Collection The data were collected in the basement Dance Studio located in the Department of Kinesiology at MSU. Testing procedures were conducted by this author/researcher and graduate students specializing in the biomechanical analysis of physical activity. For the purpose of identification of the joints during the digitization process, reflective markers were placed on bony landmarks at the lateral side of the hip (anterior superior illiac spine - ASIS), thigh (greater trochanter and lateral femoral condyle), shank (lateral maleolus), and the foot (5th metartarsal) of each subject (Figure 10). Digitization order of the markers was deterrnlned and used for the input of position data for calculation and analysis of displacement and velocity parameters. Subjects were shorts to facilitate the placement of markers on the bony landmarks of both limbs. Black round paper disks measuring five centimeters in diameter were used as the base of one centimeter diameter spherical reflection markers to allow better contrast between the markers and their background. Subjects were 43 briefed about the testing procedure and allowed to walk along the walkway, and were given ample time to familiarize themselves with the testing procedure. Prior to performing the trials, a standing file was taken for each subject. Subjects performed the trials barefooted, to allow for natural movement of the joints and to avoid any possible effect of shoes on walking performance. Subjects were required to complete five trials each at a preferred walking speed and at a very fast walking speed. For preferred walking, subjects were asked to walk at a speed comfortable for them. In very fast walking, they were asked to walk as fast as possible. In each trial, two consecutive strides were videotaped, with two cameras filming each leg. anterior superior iliac spine pelvis greater trochanter thigh lateral femoral condyle shank lateral maleolus fifth metartarsal 1 = fifth metatarsal 2 = lateral maleolus 3 = lateral femoral condyle 4 = greater trochanter 5 = ASIS Figure 10. Position and digitizing order of markers. Data Anal ses Three-dimensional analysis of the kinematic parameters was performed using the Ariel Performance Analysis System (APAS). Sagittal plane linear and angular displacements and velocities of the hip, knee, and ankle; and frontal plane linear and angular displacements and velocities of the hip, during different phases of walking, were analyzed. The first step in data analysis was the selection of trials to be analyzed. This selection was determined by the visibility of the markers seen in the video images of the trials. \fldeo images with all the markers clearly visible throughout the trial were selected for further analysis. Temporal parameters for heel strike and toe off were also determined from these video images. Based on the markers’ visibility, two trials of each walking speed for each subject were selected to be digitized and analyzed using the APAS software. Established protocols for digitizing data points and subsequent analyses were used (Angeli, 1995). Measurements analyzed were from two consecutive strides of the gait. For both sides of the body, the order of joint digitization was the same for all subjects. The sequential order was fifth metatarsal, ankle, knee, hip, and ASIS. Using the direct linear transformation module of the APAS software, the digitized cartesian coordinates obtained from the two dimensional views were converted into three dimensional coordinates. The three dimensional data were subsequemly smoothed utilizing the cubic spline technique. Upon examining the two trials analyzed, the best trial for each walking speed was selected for further comparison between subjects and between groups. The trial seleded was the one with less asymmetries in the linear horizontal and vertical displacement patterns. This decision was made since normal walking is believed to exhibit bilateral symmetry. In addition, such measure would enable the researcher to obtain more unbiased results. If the trials selected could 45 depict differences in bilateral asymmetries between the injured and the noninjured subjects, the researcher then could be more confident that such results were due to the injury, not the trial used. Flexion-extension and abduction-adduction angle displacements and joint angle displacements, for both the sagittal and frontal planes were defined according to the following joint angle convention shown in Figure 11. Angular displacement was set at zero for the standing position videotaped prior to the trials. Based on this reference point, angular displacement for movement in the sagittal and frontal planes was then calculated from joint angle measurements provided by the APAS software. Anterior Posterior Medial Lateral Hip Angle flexion extension 5 k . abduction ‘ adduction y. ...-4 Knee Angle extension V... ,‘ flexion dorsmmon Ankle Angle ...plantarflexion (a) Sagittal Plane View of Left Lower (b) Frontal Plane View of Left Lower Extremity Extremity Figure 11. Standing position and joint angles definition, (a) sagittal plane, (b) frontal plane. 46 Corresponding gait patterns between the lower limbs of each subject for both preferred walking speed and fast walking speed were compared for bilateral asymmetries. These bilateral asymmetries were then compared between each subject and between the injured and the noninjured groups. Values of the linear and angular parameters for variables investigated were calculated for bilateral asymmetries between the limbs using the following formula: XR‘XL 1/1'(XR"'XL) Symmetry - Asymmetry Index Level (SAL) = where, XR = measured parameter of the right leg XL = measured parameter of the left leg Through the formula adopted, a SAL of zero would indicate perfect symmetry of the right and the left leg. A positive value for SAL indicated that the magnitude of XR was larger than that of XL; negative value indicated that the magnitude of XR was smaller than that XL. As such, the magnitude of the asymmetry was indicated by the absolute value of the SAL. Testing of hypotheses was done by descriptive analysis through comparison of gait patterns and values of SAL’s between the injured group and the noninjured group. Absolute values of SAL’s for the subjects were used to rank these variables. The ranking ranged from one to six, with the larger number indicating a higher level of asymmetry. Finally, the difference in the absolute values of SAL’s between the injured and the noninjured groups was statistically tested using the Chi-square technique. RESULTS AND DISCUSSION In this chapter, velocities of walking for the preferred and fast walking trials are presented, and the gait patterns for bilateral asymmetries within subjects were compared between injured and noninjured groups. Comparisons consisted of temporal, linear, and angular patterns for both sagittal and frontal planes. Symmetry-Asymmetry lndices (SAL's) of segment lengths, peak torque of knee flexion and extension, temporal and kinematic elements of the gait cycle are presented. These indices were calculated to four decimal places so as to bring out distinct differences in bilateral asymmetries between the subjects. The absolute values of the SAL’s were then compared between the injured and the noninjured groups. Because of the convention adopted, the absolute values represented the magnitude of asymmetries between the right and left lower limbs. A value of zero for SAL indicated perfect symmetry. The negative and positive values of the SAL’s indicated relative values of the variables for the right and left lower limbs. As such, a negative SAL indicated a bigger value for the left variable and a positive value designated a larger value for the right variable. Symmetry-Asymmetry lndices (SAL’s) calculated from variables of the left and right legs are presented in Appendices F, G, and H. Out of the 49 variables calculated: nine were temporal variables, 17 were linear variables and their temporal elements (Appendix F), 18 were sagittal plane variables and their temporal elements (Appendix G), and 5 were frontal plane variables and their temporal elements (Appendix H). 47 48 Between subjects comparison were done by ranking the SAL’s. To facilitate comparisons between the subjects, the absolute values of the SAL’s were placed in ranked order. In this manner, the subject with the lowest level of bilateral asymmetry (most symmetrical) was ranked first, while the subject with highest level of asymmetry was ranked last, and represented by the largest rank number. If two or more values were the same, the rank designated for these values were summed and then averaged, resulting in all of these same values having the same rank value. For the ease of making comparisons between the injured and noninjured groups, figures were used to display the ranking distribution. In these figures, positions of injured subjects were boxed to depict differences in ranking distribution between the two groups. Further, SAL's of fast and preferred speed walking trials within each subject were also compared to determine which walking speed displayed greater bilateral asymmetries. The differences in the distribution of SAL rankings between the injured and the noninjured groups was also determined using the Chi-square statistical technique. Based on the theoretical construct of the study, the SAL’s of the injured subjects were expected to rank 5‘" or greater. For this reason, the frequency of variables ranked 5th or greater were compared with variables ranked smaller than five between the injured and the noninjured groups. Walking Velgm Velocities of walking for each subject for both preferred and fast trials is presented in Table 4. Except for N1, the noninjured subjects exhibited higher velocities than injured subjects for both preferred and fast trials. When compared to data by Finley et al. (1970), normal velocities of walking for the injured subjects were classified as moderate, while the noninjured subjects were classified as moderate (N1), moderate fast 49 (N3), and fast (N2 & N4). For the fast trials, all subjects were classified as very fast for their walking velocities. For fast walking trial, the differences in velocities of walking between the injured and noninjured subjects were more distinct than preferred walking, where the injured subjects displayed a smaller velocity than noninjured subjects. Similar findings were also cited by Tibone et al. (1988) in their functional analysis of untreated and reconstructed PCL injuries. Table 4 Velocities of Walking for Preferred and East Tria_ls_ Group Subject Walking Velocity (cm/s) Preferred Fast Noninjured N1 113.06 349.95 N2 177.73 338.14 N3 141.11 283.06 N4 188.85 291.89 Injured P1 117.67 206.02 P2 122.91 209.06 Limb Segment Length Segment length measurements of the lower limbs were calculated for SAL’s and compared between the subjects and groups (Table 5). No subject exhibited an exact symmetry in any of the three measurements. Between the three measurements, the thigh length showed the highest level of asymmetry, followed by the shank and the standing leg lengths. The levels of asymmetry for the limb length measurements were compared between the subjects by ranking the value of the SAL’s (Figure 12). In this figure, the positions of injured subjects in the ranking distribution is boxed to facilitate Table 5 Symmetry-Asymmetry lndices (SAL’s) for Limb Lengt_h§ 50 Group Subject Standing Leg Thigh Length Shank Length .. -. __ _ .- “Lengthw, Wm .. Noninjured N1 0.0034 0.0100 0.0073 N2 -0.0085 -0.0150 0.0026 N3 -0.0025 -0.0192 0.0106 N4 0.0022 0.0162 0.0091 Injured P1 -0.0011 -0.0124 -0.0098 P2 0.0011 0.0166 -0.0171 Notes: negative sign (-) indicates a bigger value for the left side variable and positive sign (+) indicates a bigger value for the right side variable. 6 ~ A o x 5 1 O X 0 é3 o A o “2 t [Z] 0 1 r O A 0 r a a Standing Leg Length Thigh Length srmk Length Syn'bols and Subjects; 0 N1 A N2 0 N3 a N4 + P1 at P2 Notes: Lower rank indicates higher level of symmetry. Ranks based on absolute values. El Contains at least one injured subject. Figure 12. Ranking of SAL’s for limb length measurements. comparisons between the injured and the noninjured groups. The standing leg length of the injured subjects was found to be more symmetrical than noninjured subjects. However, there was no specific pattern of differences in the thigh and shank lengths between the injured and noninjured subjects. For these lengths, subjects N3 and P2 51 had a higher level of asymmetry than other subjects, with N3 having the greatest in thigh length and P2 for the shank length. _P_e_a_k Torgug for Knee Flexion and Extension Peak torque for knee flexion and extension were determined at three angular velocities: 60 deg/sec, 180 deg/sec, and 300 deg/sec. The peak torque at each angular velocity was calculated for SAL’s and presented in Table 6. At 60 deg/sec, subject N1 showed the highest level of asymmetry in the peak torque for flexion, while subjects N3 and P2 showed a higher level of asymmetry in the peak torque for extension. At 180 deg/sec, subjects N1 and P2 demonstrated a higher level of asymmetry in peak torque for knee flexion. In the peak torque for extension, injured subjects P1 and P2 displayed a higher level of asymmetry than other subjects. In knee flexion at 300 deg/sec, subjects N1 , N3, and P2 displayed a higher level of asymmetry; while in extension, both injured subjects displayed higher asymmetries than noninjured subjects. It was also noted that the torques of the right legs for the injured subjects were greater than their left legs for all velocities. The ranking of SAL's plotted in Figure 13 showed no specific pattern of differences in the level of symmetry between the injured and the noninjured subjects for peak torque for knee flexion at all three angular velocities. However, in all but one of the angular velocities for extension, the injured subjects had the two highest asymmetries. For extension at 180 deg/sec and 300 deg/sec, a pattern of differences between the injured and the noninjured groups showed the injured group to exhibit a greater level of asymmetry. Table 6 52 Symmetry-Asymmetry Injdices (SA_L’s) for Peak Torgge for Selected Angular Velocities for Right and Left Knee Flexion and Extension Group Subject Flexion (deg/sec) Extension (deg/sec) 60 180 300 60 180 300 Noninjured N1 0.5098 0.5085 0.4000 -0.0418 -0.2857 0.0444 N2 -0.0613 0.1314 -0.0667 -0.0405 0.0000 -0.1069 N3 -0.2500 0.0571 -0.3158 -0.2979 -0.1022 -0.0619 N4 -0.0359 0.0000 -0.0144 0.0287 -0.0397 -0.0377 Injured P1 0.1704 0.0343 0.0403 0.1046 0.3041 0.1692 P2 0.0000 0.3467 0.3030 0.2822 0.3736 0.4186 Notes: negative sign (-) indicates a bigger value for the left side variable and positive sign (+) indicates a bigger value for the right side variable. _W WW 6 — o o o o E] E] 51 ° El ° El , 4~ . El 0 . g 3 1 A o A o o o o: 2 J n A u o 1 j E} El El El A El 0 ‘ T l r r fi 60 degsls 180 degsls 300 degsls 60 degsls 180 degsls 300 degsls F Iexion Extension Symbols and Subjects: 0 N1 A N2 0 N3 El N4 + P1 a: P2 Notes: Lower rank indicates higher level of symmetry. *Ranks based on absolute values. [:1 Contains injured subject/s. Figure 13. Rankings of SAL’s for peak torque for knee flexion and extension. 53 Temmral and Linear Variables In the horizontal position for the ankle, knee, and hip for preferred walking speed, all injured and noninjured subjects displayed a similar displacement pattern for both lower extremities (Figure 14). In this figure, the time for first heel strike for each foot in the calibration frame was set at zero. In addition, the position of the foot that first entered the calibration frame was also set at zero. In this manner, the distant between the right and left heel strikes, as depicted in the vertical axis of the figure was the step length. The hips showed a more constant increase in displacement overtime compared to the knees and ankles. The slopes of the lines representing the hips were more constant, demonstrating less variation in horizontal linear velocity in comparison to the ankles and knees. The knees displayed a small increase in displacement during the early period of the stance phase, reached a plateau at weight acceptance time (WAT), and started to increase again after midstance (MS). The displacement patterns of the ankles exhibited a plateau between heel contact (HC) and just before toe off (T D), then increase rapidly until the midswing (MSW). The right and left limbs of each subject demonstrated slight temporal differences in the occurrences of various phases of walking, except for subject N4. Among these subjects, P1 displayed more distinct differences in gait cycle time (GCT), midstance time (MST), toe off time (TOT), and midswing time (MSWI'), (Figure 14 (e)). These differences were further revealed through the comparisons of the SAL’s for temporal variables among the subjects (Figure 15). In this figure, subject P1 had the most occurrence of SAL’s that were ranked 6‘“, indicating that this subject had the most variables with the largest bilateral asymmetries. These results suggested a greater bilateral asymmetry in the occurrences of various events of walking for this subject. Furthermore, seven of the variables had either subject P1 or P2 in 5th or 6”1 rank. _W W W, W. WWW W W. W.WT (a) Subject N1 1 (b) Subject N2 HC l HC I 300 I HC 1 right E 200 ° left 100 0 e i . + 5 ea 0 0.2 0.4 0.6 0.8 1.2 time (a) GCT WAT MST TOT MSWT GCT WAT MST TOT MSWT Left 0.967 0.1 0.23 0.57 0.83 Left 0.884 0.1 0.217 0.5 0734 Right 0.967 0.15 0.23 0.58 0.83 Right 0.867 0.134 0.25 0.517 0734 HI“ (6) Subject N3 H (d) Subject N4 300 Jr HC F eft E 200 « ° 'ght 100 — r O l i 1 cf 41 t 0.0 0.2 0.4 0.6 0.8 1.0 1.2 time (a) GCT WAT MST TOT MSWT GCT WAT MST TOT MSWT Left 1.05 0.183 0.283 0.85 0.85 Left 0.983 0.15 0.25 0.583 0.8 Right 1.05 0.2 0.267 0.65 0.83 Right 0.983 0.15 0.25 0.583 08 HC (0) Subject P1 HC (f) Subject P2 GCT WAT MST TOT MSWT GCT WAT MST TOT Mswr Lert 1.134 0.25 0.367 0.7 0.9 Left 1.101 0.217 0.317 0.7 0.9 Right 1.083 0.183 0.25 0.667 0.883 Right 1.067 0.2 0.33 0.7 0.883 I ——-- Ankle Knee Hip J Figure 14. Temporal elements of various phases of the preferred walking cycle and horizontal position of the ankle, knee, and hip for the injumd (P) and noninjured (N) subjects. 55 Elo>fl BBOD 0E0>flo uoElblo S: 53 2 . Ii] - I D D I I“ 0 W , , . , T . . a GCT ST PS WAT WAP MST MSP MSWT MSWP Variables Symbols and Subjects: 0 N1 A N2 0 N3 El N4 + P1 x P2 Notes: Lower rank indicates higher level of symmetry. *Ranks based on absolute values. 1:! Contains injured subject/s. Figure 15. Ranking of SAL’s for temporal variables for preferred waking. However, only GCT had both injured subjects with two greatest bilateral asymmetries. Similar horizontal linear displacement patterns were found for the fast walking trials (Figure 16). In comparing the patterns of the right and the left legs in each subject, noninjured subject N1 and injured subjects P1 and P2 displayed greater temporal differences in the occurrences of various phases of walking. Ranking of SAL’s for temporal variables for fast walking are presented in Figure 17. This figure displayed distinct differences in bilateral asymmetries between the injured and noninjured groups. The injured subjects (P1 & P2), demonstrated the most variables with greater bilateral asymmetries, with subject P2 having the most variables with the greatest level of asymmetries. All variables had either subject P1 or P2 in 5‘h or 6th rank. Out of these variables, there were four in which both injured subjects had the two largest asymmetries. These variables were stance time (ST), percentage gait cycle for stance phase (PS), GCT, and MSWT. (a) Subject N1 (b) Subject N2 HC l HC HC 300 11 Left 300 Right ‘ Left a 200 Right 5 200 o o 100 10° 0 a R A? +— ———I 0 i is t 4 l 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 time (a) time (s) GCT WAT MST TOT MSWT GCT WAT MST TOT MSWT Left 0.7551 0.067 0.134 0.317 0.434 Left 0.584 0.101 0.133 0.334 0.45 Right 0.551 0.117 0.167 0.334 0.45 Right 0.584 0.101 0.133 0.334 0.45 (c) Subject N3 HC ((1) Subject N4 HC Left HC HC 300 Left 300 Right _ E 200 g 200 Right 0 100 100 O + + i i % o f 1 1c 1 i —1 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 time (s) time (s) GCT WAT MST TOT MSWT GCT WAT MST TOT MSWT Left 0.717 0.117 0.184 0.438 0.551 Left 0.717 0.117 0.167 0.417 0.567 Right 0.717 0.133 0.184 0.438 0.551 Right 0.717 0.117 0.167 0.417 0.567 ((1) Subject P1 (1') Subject P2 HC HO HO HC Left 300 1 Right - 200 g Right 5 Left 100 i . i 0 r 1 i 1 i 1 0.0 0.2 0.4 0.6 0.8 1.0 00 02 Q4 0.5 0.8 1.0 time (s) time (a) GCT WAT MST TOT MSWT GCT WAT MST TOT MSWT Left 0.9 0.167 0.25 0.567 0.733 Left 0.817 0.15 0.2 0.467 0.633 Right 0.883 0.133 0.217 0.533 0.7 Right 0.834 0.133 0.217 0.501 0.667 [ Ankle Knee Hip Figure 16. Temporal elements of various phases of the fast walking cycle and horizontal position of the ankle, knee, and hip for injured (P) and noninjured (N) subjects. 57 4 1 :1. E] c 3 - é a 2 n n u I a a j I I 1 1 o L_____.L_ _uflcfl ..— fi - _n . . s L GCT ST PS WAT WAP MST MSP MSWT MSWP Variables Symbols andSubiects; 0 N1 A N2 0 N3 0 N4 '1' P1 X P2 Notes: Lower rank indicates higher level of symmetry. *Ranks based on absolute values. [:3 Contains injured subject/s. Figure 17. Ranking of SAL’s for temporal variables for fast waking. For stride length, all subjects displayed unequal length between the left and the right legs in preferred walking speed (Table 7). Between the subjects, P2 displayed the highest level of asymmetry. All subjects also displayed a slight difference in stride length between the right and the left legs in the fast walking speed (Table 8). Again, the biggest asymmetry was displayed by P2. In the vertical linear displacement patterns for both preferred and fast walking trials, the ankles displayed the greatest vertical displacement in all subjects (Figure 18 & Figure 19). Maximum vertical displacement occurred between the TO and MSW. When these patterns were examined for bilateral symmetry, subject P1 showed a more distinct difference in the vertical displacement of the ankle during preferred walking speed (Figure 18(8)). This figure showed that the noninjured right ankle of this subject was higher that the left ankle during most of the swing period. Additionally, the right ankle did not return to the same starting height at the end of the stride. The explanation for such Table 7 StWrige Lengths for Preferred Walking SM Group Subject Stride Length (cm) SAL Right Left Noninjured N1 108.81 111.48 -0.0286 N2 150.89 154.01 -0.0205 N3 143.71 146.07 -0.0162 N4 178.82 179.37 -0.0061 Injured P1 131.97 137.86 0.0175 P2 137.41 126.92 0.0794 Notes: negative sign (-) indicates a bigger value for the left side variable and positive Sign (+) indicates a bigger value for the right side variable. Table 8 Stride Lengths for Fast Walking 8% Group Subject Stride Length (cm) SAL Right Left Noninjured N1 185.71 192.70 -0.0369 N2 194.90 199.67 00242 N3 193.79 187.34 0.0338 N4 205.41 204.31 0.0054 lnjured P1 173.76 180.86 -0.0400 P2 151.25 174.20 -0.1410 Notes: negative sign (-) indicates a bigger value for the left side variable and positive sign (+) indicates a bigger value for the right side variable. 59 (a) Subject N1 (b) Subject N2 100 100 T Hip T Hip 80 T 80 E 60 T Knee E 60 ‘" Knee 0 a ° 40 -- 40 20 -L 20 1L Ankle kle A 0 f e i i 1 0 1 1L 1 1r . 0 20 40 60 80 100 0 20 40 60 80 100 96 Galt Cycle 96 Salt Cycle HC WA MS TO MSW HC WA Ms TO MSW Left 0/100 10 24 59 85 Left 0 12 25 57 83 Right 0/100 15 24 60 85 Right 0 15 28 60 85 (c) Subject N3 (d) Subject N4 100 .- _ 100 T __ _fig’ 80 H") ~ 80 J 60 -~ 60 1 Knee E Knee , W 40 40 1: 2°“ /-% 201 N 0 4 i 1r i #1 0 i i i i A. 0 20 40 60 80 100 0 20 40 60 80 100 $6 Gait Cycle 91. Gait Cycle HC WA MS TO MSW HC WA MS To MSW Left 0/100 17 27 62 81 Left 0/100 15 25 59 81 Right 0/100 19 25 62 79 Right 0/100 15 25 59 81 (a) Subject P1 (1') Subject P2 100 L Hip 100 1— Hip 80 1» so 4. ‘— c I 60 1. E 60 F Knee E Knee o 40 = 0 40 a 20+ t... “N A O ‘r § N 0 Jr TL 4? § fl] 0 20 40 60 80 100 0 20 40 60 80 100 $6 Gait Cycle 95 Gait Cycle HC WA Ms TO MSW HC WA MS To MSW Left 0/100 22 32 62 81 Left 01100 20 29 63 82 Right 0/100 17 23 61 81 Right 0/100 19 31 64 82 Figure 18. Percentages gait cycle of various phases of preferred walking and vertical position of the ankle, knee, and hip for injured (P) and noninjured (N) subjects. 60 [ (a) Subject N1 (b) Subject N2 100 4 100 4 - iLfi HL—i Hlp 80 T 80 4; W Knee 60 4 E 60 E T Knee 1w 0 4o .. u 40 4M 20 -.- N 20 d we 0 fix 4 If i I 0 ‘ 4 4 4 fie 4 0 20 40 60 80 100 20 40 60 80 100 96 Galt Cycle '16 Gait Cycle HC WA MS TO MSW HC WA MS TO MSW Left 0/100 12 24 58 79 Left 01100 17 23 57 77 Right 0/100 21 30 60 82 Right 0/100 17 23 57 77 (cl Subject N3 (8) Subject N4 H, '9 80 )..—M 80 + — _— E 60 «l- Knee E 60 "L Knee a o 40 W F 2 0 40 w 20 4 N 20 4 Ankle 0 i 4r 4P *r i 0 i 4 j i ‘1 0 20 40 60 80 100 0 20 40 60 80 100 'll. Gait Cycle SI. Gait Cycle HC WA MS TO MSW HC WA MS TO MSW Left 0/100 16 26 61 77 Left 0/100 16 23 58 79 Right 0/100 18 26 61 77 Right 07100 16 23 58 79 (d) Subject P1 (1') Subject P2 100 4 Hip 100 4 Hip 80 .- 80 » 4' 60 4- 50 .l. 5 Knee § Knee 40 A» 40 I 20 ‘0- N 20 “L Nb 0 4 44 4 4 4 0 « 4e i 4 4 4 0 20 40 60 80 100 0 20 40 60 80 100 $6 Gait Cycle 16 Gait Cycle HC WA MS TO MSW HC WA MS TO MSW Left 07100 19 27 63 81 Left 0/100 18 24 57 77 Right 0/100 15 25 80 79 Right 0/100 16 27 60 80 [ —— Right Leg —— Left Leg ] Figure 19. Percentages gait cycle of various phases of fast walking and vertical position of the ankle, knee, and hip for injured (P) and noninjured (N) subjects. 61 occurrence might be attributed to the manner of how subject P1 walked for this trial. This subject had first contacted the floor with the ball of his foot, instead of his heel. In the fast walking trials, greater bilateral symmetries were found for the hips in subjects N3 and N2, the knees in subject N2, and the ankles in subjects N3 and P2. However, these asymmetries were not as large compared to the asymmetries exhibited by the ankle of P1 during preferred walking. For the linear horizontal velocity patterns in preferred walking, subject P1 displayed the greatest bilateral asymmetry for the ankle (Figure 20). This asymmetry occurred during the swing phase, with the left ankle showing a higher velocity during most of the swing phase. In fast walking, both injured subjects (P1 8. P2) showed a greater bilateral asymmetry in the knee and ankle velocities (Figure 21). These subjects exhibited a greater bilateral asymmetry during the swing phase compared to the stance phase. For subject P1, the left ankle and knee had higher velocity during the swing phase, while in subject P2, the opposite situation occurred. Greater bilateral asymmetries in the horizontal velocities of the knee and the ankle in the injured subjects could be the result of bilateral asymmetries in gait cycle time and the stride length. For subject P1, due to relatively larger stride length and shorter stride time of the left leg, the velocity of this leg was much greater than the right leg, and vice versa for subject P2. Greater stride length of the left leg in subject P1 during the swing phase could be due to stronger propulsion of the right leg, or the noninjured leg, during the toe-off period. Ranking of SAL’s for linear variables and their temporal elements for preferred walking was presented in Figure 22. With the exception of minimum ankle horizontal velocity (min. AHV), other variables had either subject P1 or P2, or both ranked 5‘” and 6‘“. There were five variables in which both the injured subjects had the two greatest bilateral asymmetries. These variables were stride length (SL), stride velocity (SV), b S b ct N2 1000 (a) Subject N1 1 1000 ( ) u j. I tool a a 600 u | o 11. Gait Cycle ts Gait Cycle HC WA Ms TO MSW HC WA M'S TO MSW Lott 07100 10 24 59 85 Left 07100 12 25 57 83 Right 07100 15 24 80 85 Right 07100 15 28 80 85 (c) Subject N3 (6) Subject N4 1000 4 e 3 E 5 St Gait Cycle MS TO HC WA Ms To Msw Left 07100 17 27 82 81 Leit 07100 15 25 59 81 Right 07100 19 25 82 79 Right 07100 15 25 59 81 (a) Subject P1 in Subject 172 I O E E tieait Cycle StGalt Cycle l-lC WA Ms TO MSW HC WA 1116 TO Marv Left 07100 22 32 62 81 Left 07100 20 29 83 82 Right 07100 17 23 81 81 Right 07100 19 31 64 82 Right Leg Left Leg ] Figure 20. Horizontal velocities for preferred walking for injured (P) and noninjured (N) subjects. 63 (a) Subject N1 (b) Subject N2 . Q E E 0 20 40 100 as Gait Cycle ti Gait Cycle HC WA MS TO MSW HC WA MS TO MSN Left 07100 12 24 58 79 Left 07100 17 23 57 77 Right 07100 21 30 80 82 Right 07100 17 23 57 77 (c) Subject N3 (d) Subject N4 I O E E as Gait cycle HC WA MS TO Msw Left 07100 18 26 61 77 Left Right 07100 18 26 81 77 Right (d) Subject P1 (f) Subject P2 1 000 800 e 600 E 400 200 - 0 96 Gait Cycle HC WA MS TO MSW Left 07100 19 27 83 81 Left Right 07100 15 25 80 79 Right L " RiQh‘ L99 Left Leg 1 Figure 21. Horizontal velocities for fast walking for injured (P) and noninjured (N) subjects. 64 maximum knee horizontal velocity (max. KHV), maximum ankle horizontal velocity (% max. AHV), and the percentage gait cycle for minimum ankle horizontal velocity (% min. AHV). eElEIlIIIIIIIIAAOIZIoE 54.-O-.0EIOED[EDDOEIOO 4~OO<>OUOAAAAOIDOOE1A I: 534A0A0A- OOOAOOOA-O LounuEuEtjooEIAEtjel—iflen tiuAEEoe .[EDOOADCICIO J - 4 4 —---4 4—4-4 --———.——--— 4- ——e——4—r--- 4 -———4-————4—~— 4— —v—4——A-——4— —— .r-—-——4 (Wet-55295255 Egaégééiéééfi. _\. \ x .\ _\- .\ Variables SymbolsandSubjects: ON1AN20N3C1N4+P1xP2 Notes: Lower rank indicates higher level of symmetry. ‘Ranks based on absolute values. 1:! Contains injured subject/s. Figure 22. Ranking of SAL’s for linear variables and their temporal elements for preferred walking. Ranking of SAL’s for linear variables and their temporal elements for fast walking was presented in Figure 23. Except for hip vertical displacement (HVD) and percentage gait cycle for minimum ankle horizontal velocity (% min. AHV), other variables had either subject P1 or P2 in 5th or 6th rank. Out of these variables, there were eight variables in which both subjects P1 and P2 had the two greatest asymmetries. The variables with the greatest asymmetries were stride length (SL), maximum hip horizontal velocity (max. HHV), maximum knee horizontal velocity (max. KHV), percentage gait cycle for minimum hip horizontal velocity (% min. HHV), maximum knee horizontal velocity (max. KHV), percentage gait cycle for maximum knee horizontal velocity (% max. KHV) maximum 65 ankle horizontal velocity (max. AHV), and percentage gait cycle for maximum ankle horizontal velocity (% max. AHV). 612131: 0 o-II-EIEIEIEIEIEJD 0 5--0 OIZIIEIZIU ABE-"EOEA 23440 o E] once 0 O O 8.0 A. £34A A-A [:1 A o O :1 1:1 1:1 0 1:1 A n O :1 240-[30 A :1 CIA A o A a :1 IE 141:1 CI 0.0 O A Cl 0 o A :1 O o O L— -_.._ e... _ 4 _._._ _.+ . L . . . e 4 . e e (’46289555555552585 l 222%; g i E t i E i, x * .\' \ .\' .\ Variables Symbols and Subjects: 0 N1 A N2 0 N3 1:1 N4 + P1 :1: P2 Notes: Lower rank indicates higher level of symmetry *Ranks based on absolute values. CI Contains injured subject/s Figure 23. Ranking of SAL’S for linear variables and their temporal elements for fast waking. Number of variables ranked 5th or 6‘h for SAL’s for temporal and linear variables, and their elements are summarized in Table 9. From this table, it is evident that the injured subjects had a greater proportion of higher ranked asymmetries. Although only one third of the subjects were injured, 56% of the 5th or 6“h place rankings for preferred walking, and 69% for fast walking are associated with the injured subjects. Further investigation of the differences between the injured and noninjured groups for two categories (5 or greater and smaller than 5) of SAL ranking was performed using the Chi-square statistical technique. For both walking Speeds, there were Significant differences in SAL ranking between the injured and noninjured groups (Table 10). The values for the chi-square were 18.79 and 47.09 for preferred walking and fast walking respectively. 66 Table 9 Number of Variables Ranked 5th or 6th for SAL’s for Temmral and Linear Variables and Their Tempgral Elements Group Subject Number of variables ranked 5'h or 6'" for SAL Preferred Walking Fast Walking N1 8 7 Noninjured N2 7 3 N3 5 4 N4 3 2 Injured P1 20 15 P2 9 21 Table 10 phi-Wire Tests for Two Categories of SAL Ranking (5 or Greater and Smgfler than 5) for Temmral and Linear Variables Preferred Walking Fast Walking df 1 1 Chi-square (x2) 18.79‘ 47.09- * significant at 0.05 level Sagittal Plane Variables In the angular displacement patterns for the ankle in the sagittal plane, all subjects displayed a similar pattern of movement (Figure 24 & Figure 25). The ankles plantar flexed during the early stance phase and started to dorsiflex after the midstance, reaching maximum dorsiflexion around toe off. However, bilateral asymmetries were 67 (a) Subject N1 (b) Subject N2 5 4° ’ s x 'i o l 5 E 20 n g _ 3 8 2 ii“ 5% 5:20 ' .3; 0. , E _40 . ‘3661!“ Cycle HC WA MS TO Msw HC WA 1171's TO MSN Left 01100 10 24 59 85 Left 01100 12 25 57 83 Right 01100 15 24 60 85 Right 01100 15 28 60 as (0) Subject N3 (d) Subject N4 1: 40 ' 40 _o ‘ t: g ‘ 2 § E 20 - E 20 . § = 0- Q £5 ° ‘ 53 ° 8 0 100 1, .. 20 40 so so 100 5-20 . g—ZO n. 3 J 40 - “40 9‘ Salt Cycle 96 Galt Cycle HC WA MS TO MSW HC WA MS TO Msw Left 01100 17 27 62 81 Left 01100 15 25 59 81 Right 01100 19 25 62 79 Right 01100 15 25 59 81 (e) Subject P1 (1') Subject P2 40 40 I C C 2 2 3 20 g 20 is is l E 2 38 ° 593 ° 5 20 60 80 100 “U 5 60 100 g -20 g -20 2 2 n. i n. J 40 -40 11. Gait Cycle 11. Salt Cycle HC WA Ms TO MSW HC WA MS TO MSN Left 01100 22 32 62 81 Left 01100 20 29 03 82 Right 01100 17 23 61 81 Right 01100 19 31 64 82 | —— Right Leg — Left Leg ] Figure 24. Ankle plantar-dorsiflexion angles for preferred walking for injured (P) and noninjured (N) subjects. Gnomes—960 A Ewimu 0065063 O 9.00.0 Km& E Flgu nonir 68 Ant—i7 #, i2, 77 77 AV) 7.H-/_7__i_ (a) Subject N1 (b) Subject N2 8 8 8 8 degrees Plantar-Donlflexlon 0 degrees Plantar-Dorelflexlon O .20 .20 ; 4o 40 ‘ ti Gait oycie 56 Gait Cycle 4 HC WA MS T0 MS\N HC WA MS TO MSN Len 01100 12 24 58 79 Le“ 01100 17 23 57 77 R1911 01100 21 30 so 82 Right 0”“) 17 23 57 77 (c) Subject N3 (d) Subject N4 5 5 4° x 2 0 § E a g 20 _ 2 8 2 33% §§ o. s 8 s s f E a ‘20 ’ to i 96 Gait Cycle HC WA MS TO MSW HC WA MS TO MSW Left OHM 16 26 61 77 L311 01100 16 23 56 79 Right 01100 18 26 61 77 Right 01100 16 23 58 79 (d) Subject P1 (1) Subject P2 8 8 B O = 1 a g 20T 1 20 a 3: i 3 g a g u 0‘ V 9§ 0 8 40 60 0 '° 5 E -20 c e. a -20 40 4o 11 Gait Cycie HC WA MS TO MSW Left 01100 19 27 63 81 L21! Right 01100 15 25 so 79 Right I — Right Leg Left Leg ] Figure 25. Ankle plantar-dorsiflexion angles for fast walking for injured (P) and noninjured (N) subjects. mun dhp SUMi squ wan sum sum dom‘ sum agm suhe emwn enen “6% West mehi WI MES] 1ng Smack WMEil I Side. - 69 found in all subjects, for both preferred and fast trials of walking. Subjects N3 and N4 displayed a greater asymmetry in the ankle displacement when compared to other subjects. When examined for the occurrence of maximum dorsiflexion of the ankle, subject P1 displayed a greater bilateral asymmetry both in preferred and fast walking. Angular velocity patterns for the ankles in the sagittal plane during preferred walking Showed greater bilateral asymmetry for subjects N2, N3, N4, and P2 (Figure 26). A more symmetrical pattern was found in subject N1, followed by subject P1. In these subjects, N1 displayed a greater bilateral symmetry throughout the gait cycle, while in subject P1, bilateral symmetry was displayed between WA and TO. For ankle plantar- dorsiflexion velocity patterns in fast walking, bilateral asymmetry was exhibited by all subjects (Figure 27). However, N2 and P1 displayed a higher level of asymmetry due to a greater difference in the magnitude of the velocity at various walking phases. For other subjects, there was a smaller asymmetry in the patterns of the movement, but greater asymmetry in the magnitude of the velocities. Knee angular displacement patterns Showed a flexion-extension-flexion- extension pattern for all subjects. in preferred walking, the most symmetrical patterns were found in subjects N1, N3, and N4 (Figure 28). The greatest bilateral asymmetry was found in subject P1 in which the right knee Showed a smaller range of motion than the left knee. This asymmetry was caused by the differences in the temporal elements between the limbs during the early part of the walking cycle. When fast walking, greater bilateral asymmetries were found in subjects N1, P1, and P2, with subject P1 showing the greatest amount of symmetry (Figure 29). The asymmetry in subject N1 was due to smaller flexion-extension range of motion in the left knee during early stance period; while in subject P1, it was due to smaller knee angular displacement in the noninjured Side. This knee exhibited smaller angular displacement during the early period of the 70 (a) Subject N1 7' (b) Subject N2 600 T 600 T 400 j 400 § 200 «- § 200 5 ° 1W 9 ° 400 1 400 T 600 t -600 ‘56 Gait Cycle 96 Gait Cycle HC WA MS TO MSW HC WA MS TO MSW Left 0/100 10 24 59 85 Lelt 0/100 12 25 57 83 Right 01100 15 24 so 85 Right 01100 15 28 60 85 600 (c) Subject N3 600 (d) Subject N4 400 ~ 200 it E. 0 ° -200 2° 100 -400 -600 i 96 Gait Cycle '16 Gait Cycle HC WA MS TO MSW HC WA MS TO MSW Left 0/100 17 27 62 81 Left 01100 15 25 59 81 Right 0/100 19 25 62 79 Right 0/100 15 25 59 81 600 (e) Subject P1 600 (1) Subject P2 400 g 200 E, 0 'o _200 20 40 100 -400 . 4500 l 96 Gait Cycle 96 Gait Cycle HC WA MS TO MSW HC WA MS TO MSW Leit 0/100 22 32 62 81 Left 0/100 20 29 63 82 Right 0/100 17 23 61 81 Right 01100 19 31 64 82 Figure 26. Ankle plantar-dorsiflexion angular velocities for preferred walking for injured (P) and noninjured (N) subjects. 000x009 0..er 71 (b) Subject N2 3 1i Gait Cycle HC WA MS TO MSW Lelt 01100 12 24 58 79 Left Right 01100 21 30 60 82 Right l (c) Subject N3 95 Gait Cycle 95 Gait Qjcle HC WA Ms TO Msw l-lC wA Ms TO MSW Left 01100 16 23 61 77 Left 01100 16 29 ST 79 Right 01100 19 26 61 77 Right 01100 16 23 59 79 (d) Subioct P1 (r) Subject P2 95 Gait Cycle _J Ms TO WA Ms TO Msw Leit 01100 19 27 93 e1 Leit 01100 19 24 57 77 Right 01100 15 25 so 79 Right 01100 10 27 90 90 [ —— Right Leg Left Leg ] Figure 27. Ankle plantar-dorsiflexion angular velocities for fast walking for injured (P) and noninjured (N) subjects. Ph<42lidlm l-Iiuuluce’u I90» GOD (a) Subject N1 (b) Subject N2 80 v 80 9 60 4» 5 60 3 3 g * 40 “" g E 40 g g 20 t. g g 20 to: i0 0 20 40 60 80 100 96 Gait Cycle HC WA Ms TO MSW Leit 01100 10 24 59 85 Leit Right 01100 15 24 60 85 Right 60 T (c) Subject N3 80 i (d) Subject N4 50 _. c 5 9 it 3 it“ " i it 5 a 8 g; 20 «r- I: "2' i O 0 + + i i 1 3'5 in 0 20 40 60 80 100 96 Gait Cycle steeit Cycle HC WA MS TO M‘SW HC WA MS TO MSW Left 01100 17 27 62 61 tall 01100 15 25 59 81 Right 01100 19 25 62 79 Right 01100 15 25 59 81 (a) Subject P1 (r) Subject P2 30 _- 80 g 60 .2 3 3 4o 9’ - 20 g 0 r i i t i fi' 0 20 40 60 80 100 iteait Cycle steelt Cycle HC WA Ms TO MSW HC WA MS 70 MSW Leri 01100 22 32 62 61 Lett 01100 20 29 63 82 Right 01100 17 23 61 61 Right 01100 19 31 64 82 [ Right Leg Left Leg I Figure 28. Knee flexion-extension angles for preferred walking for injured (P) and noninjured (N) subjects. 73 (a) Subject N1 (b)Subject N2 80 80 5 60 73‘ 60 x .9 5&6 3:6 h .2 E .2 §2m 3” 3 0 47 7* ‘ ‘ 5 0 + a i 0 20 4o 60 80 100 ° 8 8 8 8 § 15 Gait Cycle 19 Gait Cycle HC WA Ms T0 MSW HC WA Ms TO MSW Lett 01100 12 24 56 79 um 01100 17 23 57 77 Right 01100 21 30 60 62 Right 01100 17 23 57 77 (c) Subject N3 (d) Subject N4 80 T 80 ”1’ ém- 3w» .9 6 h s h. 5 3: 20 g 0 20 1’- iii 0 g o i t t i l 0 20 40 60 80 100 it Gait Cycle 1t Gait Cycle HC WA MS TO Msw l-lC WA MS TO MSW Left 01100 16 26 61 77 Lelt 01100 16 26 5'6 79 _R‘ight 01100 18 26 61 77 Right 01100 16 23 456 79 (d) Subject P1 (0 Subject P2 80 g 60 X t i 4° 6' '6 20 E m 0 5 100 at Gait Cycle 96 Gait Cycle HC WA MS TO MSW HC WA Ms TO MSW Lett 01100 19 27 63 61 tall 01100 16 24 57 77 ”Right 01100 15 25 60 7'9 Right 01100 16 27 60 60 [ —- Right Leg Left Leg ] Figure 29. Knee flexion-extension angles for fast walking for injured (P) and noninjured 009666. 74 stance phase and during the swing phase. Subject P2 displayed a lower angular displacement for the noninjumd side, the left leg, from heel contact until the midswing phase. This greater angular displacement of the injured leg could be due weaker muscles, especially the quadriceps, of the injured leg, which failed to support the body weight effectively during WA period compared to the noninjured leg. In the knee angular velocity for preferred walking, the greatest bilateral asymmetry was found in subject P1 (Figure 30). This asymmetry was greatly due to the difference in the magnitude of the velocity, in which the right leg Showed a smaller velocity. In fast walking, subjects N1, N2, and P2 Showed a greater bilateral asymmetry (Figure 31). Most of the differences in these three subjects were due to the differences in temporal factors for velocity changes. Hip angular displacement patterns displayed an extension-flexion movement for all subjects. In preferred walking, a greater bilateral asymmetry was found in the injured subjects, P1 and P2 (Figure 32). The asymmetry in subject P1 was largely due to the difference in the magnitude of the flexion-extension, while in subject P2, it was due to the displacement pattern. The extension of the right hip in this subject was prolonged until the toe off period, which is at approximately 64 percent of the gait cycle period, while other subjects Showed that hip extension occurred only until 50 percent of the gait cycle. For fast walking, a greater bilateral asymmetry of the hip angular displacements was found in subjects N1, N2, P1 and P2 (Figure 33). However, the pattern of the asymmetries were different between two injured subjects (P1 & P2) and noninjured (N1 & N2). In the injured subjects, asymmetries were observed in flexion and extension, while in the noninjured subjects, these asymmetries were only displayed during flexion. Subjects P1 and P2 also exhibited a smaller magnitude for flexion- extension in the noninjured Side, the right hip. 75 (a) Subject N1 (b) Subject N2 16 Gait Cycle 15 Gait Cycle HC WA MS TO MSW l-lC WA MS TO MSN Left 0/100 10 24 59 85 Left 0/100 12 25 57 83 Right 01100 15 24 60 85 Right 0/100 15 28 80 85 (c) Subject N3 ((1) Subject N4 96 Gait Cycle 16 Gait Cycle HC WA Ms TO MSW HC WA Ms TO M_SW Lelt 01100 17 27 62 61 Lelt 01100 15 25 5—9 61 i'light 01100 19 25 62 7'9 Right 01100 15 25 59 61 (9) Subject P1 (0 Subject P2 -fl-JI "' . 'lt Gait Cycle 95 Gait Cycle HC WA MS TO MSW HC WA MS TO MSN Left 01100 22 32 82 81 Left 0/100 20 29 63 82 RV! 0/100 17 23 61 81 let 01100 19 31 64 82 L —— Right Leg Left Leg | Figure 30. Knee flexion-extension angular velocities for preferred walking for injured (P) and noninjured (N) subjects. 76 (a) Subject N1 (b) Subject N2 600 j 400 j t 3 2": A 3 5' _200 o a —400 I -600 1 % Gait Cycle ‘16 Gait Cycle HC WA MS TO MSN HC WA MS TO MSW Left 0/100 12 24 56 79 Left 0/100 17 23 57 77 Right 0/100 21 30 60 62 Right 0/100 17 23 57 77 (6) Subject N3 (d) Subject N4 20 80 1t. Gait Cycle '16 Gait Cycle HC WA MS TO MSN HC WA Ms TO MSW Left 01100 16 26 61 77 Left 0/100 16 23 58 79 Right 0/100 16 26 61 77 Right 0/100 16 23 58 79 (d) Subject P1 (f) Subject P2 0 0 If e '4 3 a a O 0 '5 ‘6 HC WA MS TO MSW Left Left 01100 18 24 57 77 Right Right 01100 16 27 60 60 Right Leg —— Left Leg | Figure 31. Knee flexion-extension angular velocities for fast walking for injured (P) and noninjured (N) subjects. 77 ' b Sub'ect N2 40 i (a) Subject N1 40 ( ) j I 5 2° .3. 5 2° 5 g F g lg o t g “f 0 I t ‘ I 8' g , 8’ 5 20W 100 'U U §-2o : g -20 it} i W -40 ‘ -40 % Gait Cycle '16 Gait Cycle HC WA Ms TO MSW HC WA MS TO Ms1v Left 01100 10 24 59 65 Left 01100 12 25 57 63 Right 01100 15 24 60 65 Right 01100 15 26 60 85 40 40 (6) Subject N4 5 2o 5 20 6 ’6 It — _ 8 ‘g 0 3‘2 0 h 2 8’ 2 20 80 100 gem ”gm 1 j t -40 -40 1‘ Gait Cycle % Gait Cycle HC WA MS To WSW HC WA M—S TO Msw Left 01100 17 27 62 61 Left 01100 15 25 59 81 Right 01100 19 25 62 79 Right 01100 15 25 59 61 40 . (e) Subject P1 40 (1*) Subject P2 5 20 L 5 20 i x 2 a 2 3 t o .7 . , t t o g a o 20 100 g g 20 80 100 E 20 ,. g -20 ii at 40 40 15 Gait Cycle 16 Gait Cycle HC WA Ms T0 Msw HC WA Ms T0 Msw Left 01100 22 32 62 61 Left 01100 20 29 63 62 Right 01100 17 23 61 81 Right 01100 19 31 64 62 [ Right Leg Left Leg 1 Figure 32. Hip flexion-extension angles for preferred walking for injured (P) and noninjured (N) subjects. (a) Subject N1 (b) Subject N2 40 . 40 § 20 ‘. g 20 § 2 I a 2 L /& . l: O T 3 I: 0 . i I *1 g a o g 3°; 20 4o 60 60 100 5 -20 l .5 -20 X I in ‘ in 40 I -40 % Gait Cycle 56 Gait Cycle HC WA Ms TO MSW HC WA M5 TO MSW Left 01100 12 24 56 79 Left 01100 17 23 57 77 Right 01100 21 30 60 62 Right 01100 17 23 57 77 (c) Subject N3 (6) Subject N4 40 f.» 5 20 I I It 2 a 2 /\ E I: § ‘2 0 l i 51—1 g” i g” 72 20M 60 100 it it “2° in ui .40 56 Gait Cycle 1‘ Gait Cycle HC WA MS TO MSW Hc WA MS To MSW L611 01100 16 26 61 77 Left 01100 16 23 56 79 Right 01100 16 26 61 77 Right 01100 16 23 58 79 (d) Subject P1 40 (f) Subject P2 40 ~ 5 s T: 20 I : 2° 69 2 in 2 0 lg o n.. g g 0 I . 4 ii 7 j a g o #1 .3 7. (i 20 60 100 ‘9 ; 2° 8° 10° 5 -2o 1 5 -2o 9 i 9' I in in 40 —‘ -40 % Gait Cycle ‘11. Gait Cycle Hc WA MS TO MSW HC WA MS T0 MSW Left 01100 19 27 63 61 Left 01100 18 24 57 77 Right 01100 15 25 60 79 Right 01100 16 27 60 so I —— Right Leg — Left Leg I Figure 33. Hip flexion-extension angles for fast walking for injured (P) and noninjured (N) subjects. 79 In hip angular velocity pattems for preferred walking, greater asymmetries were exhibited by the injured subjects, P1 and P2 (Figure 34). In subject P1, there was a difference in the velocity pattern shortly after the midstance period, while in subject P2, asymmetry occurred throughout the gait cycle. In fast walking, the greatest bilateral asymmetries were found in subjects N1 and N2 (Figure 35). The asymmetries displayed were largely due to the difference between the right and the left hips in the magnitude of the velocity, and the time at which maximum hip angular velocity occurred. Ranking of SAL’s for sagittal plane variables for the preferred walking trial are presented in Figure 36. From this figure, subject N4 was found to have the most variables ranked 5th or 6‘“, followed by subjects P1 and P2. There was only one variable in which both injured subjects had the greatest bilateral asymmetries; the percentage gait cycle for maximum hip flexion (% max. HF). Ranking of SAL’s for sagittal plane variables for the fast walking trial showed a slightly different pattern compared to preferred walking (Figure 37). Injured subject P1 was found to have the most variables with the greatest SAL’s, followed by subjects N1, P2 and N3. For subject P1, most of these indices were associated with the movement of the hip and the knee. There were two variables in which both injured subjects had the two greatest asymmetries; maximum knee extension (max. KE) and percentage gait cycle for maximum ankle dorsiflexion (% max. AD). Comparisons of SAL’s that were ranked 5th and 6‘” for sagittal plane variables are summarized in Table 11. For preferred walking, 39% of higher ranked asymmetries were associated with the injured subjects, while for fast walking, the percentage was Slightly lower (33%). Noting that one third of the subjects were injured, these diStributions indicated no differences in the two categories (5 or greater and smaller than 5) for SAL ranking between the injured and noninjured groups. Results of the Chi- 80 600 (a) Subject N1 (b) Subject N2 400 4 200 —I § 0 i A 3 .200 g) 20 4o 60 so 100 400 i 600 -L 96 Gait Cycle 96 Gait Cycle HC WA Ms T0 MSW HC WA Ms TO MSW Lelt 01100 10 24 59 85 Let! 01100 12 25 57 as Right 07100 15 24 so 65 Right 01100 15 28 so 85 600 (c) Subject N3 600 (d) Subject N4 400 200 i o 3 _200 40 60 100 400 600 96 Gait Cycle 96 Ga lt Cycle HC WA Ms TO MEN HC WA Ms TO M'STN Lell 07100 17 27 62 81 Lott 07100 15 25 so 61 Right 01100 19 25 62 7'9 Right 07100 15 25 so 81 (e) Subject P1 600 T (0 Subject P2 0 60 100 96 Gait Cycle SI. Gait Cycle HC WA Ms TO Msw HC WA Ms TO Msw Let't 07100 22 32 e2 81 Left 07100 20 29 as 82 Right 01100 17 23 61 81 Right 07100 19 31 64 82 [ Right Leg Lefl L09 Figure 34. Hip flexion-extension angular velocities for preferred walking for injured (P) and noninjured (N) subjects. 81 (a) Subject N1 (b) Subject N2 $6 Gait Cycle 96 Gait Cycle l-lC WA Ms TO Msw l-lC WA Ms TO Msw Left 07100 12 24 56 79 Left 07100 17 23 57 77 Right 07100 21 30 60 62 Right 07100 17 23 57 77 (c) Subject N3 (d) Subject N4 600 600 400 400 3 0 L + l i 3 0 f [\q _200 60 100 _200 40 60 so 100 400 -400 -600 -600 16 Gait Cycle 11. Gait Cycle HC WA Ms TO M§N HC WA Ms TO MSN Lelt 07100 16 26 61 77 um 07100 16 23 F6 79 Right 07100 18 26 61 77 Right 07100 16 23 5—6 79 (d) Subject P1 (0 Subject P2 g 200 g 200 3 ° ° 400 400 -600 -600 96 Gait Cycle 96 Gait Cycle HC WA Ms TO Msw HC WA Ms TO MSW Lel't 97100 19 27 63 61 Let! 0/100 16 24 57 77 Tight 07100 15 25 60 179 mg: 07100 16 27 60 60 [ —— Right Leg Left Leg J Figure 35. Hip flexion-extension angular velocities for fast walking for injured (P) and noninjured (N) subjects. 82 G—EUIIIIIEEJDAEI D 0 ° I°IZI 5~OAOIIAEIOODODDODDDD 4-+oooo<>AAA+Ao A+A+o t .93"... §3eruuuoEEloEo E) E] 2—0-IEOOAODODOAE00A- 141:1ng AC] 0E .EAOAEOA ogeéfi &.£.¥.§.g9§s§.§.§.§.§.9.9.&.&. dééégxdéééé .2222 3 \ -\ 3 x .\' 3 N x Variables [ Symbols and Subjects: 0 N1 A N2 0 N3 1:1 N4 + P1 x P2 Notes: Lower rank indicates higher level of symmetry. ‘Ranks based on absolute values. :1 Contains injured subject/s. Figure 36. Ranking of SAL’s for sagittal variables and their temporal elements for preferred walking. I 61IE°EII0 IIII ° 0 DEIO A soA-oo ooo OE-EAOEOO 4EII°E° IEEA°DIIEl AE Sé :1 A00 D g3°°Eu° °E E “E 2 0 EliAAOO oo- :1- u u a e 1 [:1 o ADDDA oEij .0 0L. .. .2. . . e Et“¥% §“""§ 999:3 iiziééégéé’ééégétéz g N \ g \ \ 5: .\° { Variables SymbolsandSubjects:oNlAN20N3|jN4+P1xP2 Notes: Lower rank indicates higher level of symmetry. *Ranks based on absolute values. D Contains injured subject/s. Figure 37. Ranking of SAL’s for sagittal variables and their temporal elements for fast walking. 83 square tests also found no significant differences in SAL rankings between the groups for both walking speeds (Table 12). Table 11 Number of Variables @lgd 5th or 6th for SAL’s for Sagittal Plane Variables Group Subject Number of variables ranked 5"I or 6" for SAL Preferred Walking Fast Walking N1 5 8 Noninjured N2 3 4 N3 4 6 N4 10 2 injured P1 6 10 P2 6 6 Table 12 Chi-sguare Tests for Two Categories of SAL Ranking (5 or Greater and Smalller than 5) for Sagittal Plane Variables Preferred Walking Fast Walking df 1 1 Chi-square (f) 0.75 3.00 * Significant at 0.05 level. Frontal Plane Variables The hip abduction-adduction angular displacement patterns for preferred walking are presented in Figure 38. All subjects exhibited their own specific pattern and high level of bilateral asymmetries. Among the subjects, N4 demonstrated smaller bilateral asymmetry in the occurrences of abduction and adduction, while subject P1 showed the smallest range of motion. Abduction-adduction angular displacement 84 patterns for fast walking showed a more symmetrical pattern when compared to preferred walking (Figure 39). However, the level of bilateral asymmetries remained large, and no distinct difference could be found between the subjects. The range of motion for all subjects was smaller than those demonstrated in preferred walking. Hip abduction-adduction velocity patterns demonstrated large bilateral asymmetries between the hips in all subjects for both preferred and fast walking (Figure 40 & Figure 41). In fast walking, there were more variations in the velocity throughout the gait cycle in all subjects. The magnitude of the velocity increased and decreased more rapidly when compared to preferred walking. There were no distinct differences in the gait pattern for this variable between the injured and noninjured subjects. However, a difference could be seen in the pattern of the injured subjects for preferred walking as they demonstrated a more constant velocity in the injured side, the left leg. Figure 42 displays the ranking of SAL’s for frontal plane variables for preferred walking. Injured subject P2 showed had most variables ranked 5th or 6‘“, indicating that this subject had the most variables with the greatest asymmetries. There were two variables in which the injured subjects had the two greatest asymmetries; maximum hip adduction (max. HAD) and percentage gait cycle for maximum hip adduction (% max. HAD). When frontal plane variables for fast walking were examined, injured subject P2 had the most variables of SAL ranked 5‘“ or 6"1 (Figure 43). There was no single variable, in which both injured subjects had the two greatest asymmetries, although all Variables had either subject P1 or P2 in the 5th or the 6th rank. 85 40 T (a) Subject N1 40 ‘ (bl Subiect N2 8 5 . 3 20 1 3 2o , i i 3 ‘1'- o . . . g‘? o . . - , . 8' c g» g I 1, § 0 20 40 60 0 u -.= 0 20 60 100 0 g -20 ~ g -20 - 3 2 -40 I 40 96 Gait Cycle % Gait Cycle _—I HC WA MS TO MSW HC WA Ms TO MSW Left 0/100 10 24 59 85 Left 07100 12 25 57 63 Right 07100 15 24 60 65 Rigtt 07100 15 26 60 65 40 T (c) Subject N3 40 (d) Subject N4 6 s I E 20 g 20 . i i g g 0 —4——i g 4 0 NA . § 3 20 4o 60 80 100 g g 0 20 4o 60 100 0 3 -20 it -20 2 2 -40 -40 5t Gait Cycle 9‘ Gait Cycle HC WA MS T0 Msw HC WA MS TO MSN Left 07100 17 27 62 61 L611 07100 15 25 59 61 Right 07100 19 25 62 79 Right 01100 15 25 59 61 (6) Subject P1 40 (f) Subject P2 40 E E O O E 20 1 i a 3 § 3 g g o - f5. 3; § 20 4o 60 0 g 3 20 E ° 8 3 j < 40 '16 Gait Cycle 56 Gait Cycle 176 WA MS T0 MSW HC WA Ms T0 Marv Left 07100 22 32 62 81 Left 07100 20 29 63 62 Right 07100 17 23 61 81 Right 07100 19 :11 64 82 F Right Leg Left Leg ] Figure 38. Hip abduction-adduction angles for preferred walking for injured (P) and noninjured (N) subjects for injured (P) and noninjured (N) subjects. 86 (a) Subject N1 (b) Subject N2 40 40 . I: c i O 0 E 20 4 g 20 1 g g 0 g 0 ’ .A‘ § ,9 g 0 20 40 60 80 100 § -20 1 g ‘20 i 'U 3 40 . < 40 at Gait Cycle ttcait Cycle HC WA MS T0 MSW HC WA MS TO MSW L911 OHM 12 24 53 79 Left 0/100 17 23 57 77 Right 0I100 21 30 60 82 RM 07100 17 23 57 77 (c) Subject N3 (d) Subject N4 40 40 I 20 ‘ 20 . degrees Adduction-Abduction 0 degrees Add uctlon-Abduction 0 20 4o 60 80 100 .20 40 ‘ 4o 96 Gait Cycle lit Gait Cycle HC WA MS T0 MSN HC WA M—S TO MSW Left 07100 16 26 61 77 Letl 07100 16 23 56 79 Right 07100 16 26 61 77 Right 07100 16 23 56 79 (d) Subject P1 (f) Subject P2 40 v c 40 5 ‘ 0 § 20 § 2° ' 33 it a ‘f o §1 : 0 , , 7 * g 5 20 so so 100 1:: § 0 20 40 60 80 100 § -20 5 -2° 1 '0 2 I 3 .40 L 40 %Galt0/cle etcait Cycle j_ _ _J HC wA MS T0 MSW HC WA Ms TO MSW Left 07100 19 27 63 61 Left 07100 16 24 57 77 Right 07100 15 25 60 79 Right 07100 16 27 60 L —— Right Leg Left Leg 7 Figure 39. Hip abduction-adduction angles for fast walking for injured (P) and noninjured (N) subjects. 87 ___._____fi_(i _____.___.fl_ F—T‘”~ 600 T (a) Subject N1 600 T (b) Subloct N2 400 I 200 3 0 _200 60 80 100 400 - -600 $6 Gait Cycle St Gait Cycle HC WA Ms T0 MSW l-ic WA Ms TO MSW Left 07100 10 24 59 65 Lelt 07100 12 35 57 63 Right 07100 15 24 60 65 Right 07100 15 26 60 66 ' 600 (6) Subject N3 (1!) Subject N4 I 400 I ‘ § 200 1 0 _ I 1 2 _200 (g 20 60 100 400 T -600 I at Gait Cycle at Salt Cycle HC WA 1116 TO W HC WA Ms TO TSN Lelt 07100 17 27 62 61 Left 07100 15 25L ES? 61 Right 07100 19 25 62 79 Right 07100 15 25 E 61 (e) Subject P1 600 (f) Subject P2 600 I 400 400 I- § 200 g 20° I 0 0 7 3 3 R S 8 8 .200 20 80 -200 II 1- 4m T -400 1*- -600 + .500 _L 96 Gait Cycle 96 Gait Cycle HC WA Ms TO MSN HC WA Ms T0 MSW Lelt 07100 22 32 62 61 Lelt 07100 20 29 63 62 Right 07100 17 23 61 61 Right 07100 19 31 64 62 [ —— Right Leg Lefi L09 Figure 40. Hip abduction-adduction angular velocities for preferred walking for injured (P) and noninjured (N) subjects. 88 (a) Subject N1 (b) Subject N2 600 T 400 g 200 § 0 13 .200 60 80 100 -400 -600 96 Gait Cycle 16 Gait Cycle HC WA MS T0 Msw Hc WA MS To Msw Left 0/100 12 24 58 79 Left 01100 17 23 57 77 Right 01100 21 30 60 82 Right 01100 17 23 57 77 (c) Subject N3 (d) Subject N4 'lii Gait Cycle 96 Gait Cycle HC WA MS TO MSW HC WA Nis TO MSW Leit 01100 16 26 61 77 Left 6/100 16 23 56 79 Right 01100 16 26 61 77 Right 01100 16 23 E 79 (e) Subject P1 (1') Subject 92 3' 96 Gait Cycle 96 Gait Cycle HC WA MS TO MS\N HC WA MS TO M90! L011 01100 19 27 63 81 Lelt 01100 18 24 57 77 Right 01100 15 25 60 79 Rm 01100 16 27 60 80 [ —— Right Leg Left L99 I Figure 41. Hip abduction-adduction angular velocities for fast walking for injured (P) and noninjured (N) subjects. 89 6 — 0 [El [3:] o 0 5~ 0 (:1 El 4 « A o o o A E3. E] A A 2 1 o n n i: 1 4 u n o A o o L _ . . fl f HROM mum it max. HAD max. HAB 96 mm Variables Symbols and Subjects: 0 N1 A N2 0 N3 El N4 + P1 X P2 Notes: Lower rank indicates higher level of symmetry. 'Ranks based on absolute values. :3 Contains injured subject/s. Figure 42. Ranking of SAL’s for frontal plane variables and their temporal elements for preferred walking. 61 El A El 5 - o e [Z] 0 A 4 ,, n n o o o E 3 1 IX] 0 A u 2 « o o n i: o ‘ 1 1 A A 123 ! ° i"- 7R3?” ““ mm * ... mm ‘ mm ‘ ......” Variables L Symbols and Subiects: 0 N1 A N2 0 N3 El N4 + P1 X P2 Notes: Lower rank indicates higher level of symmetry. ‘Ranks based on absolute values. :1 Contains injured subject/s. Figure 43. Ranking of SAL’s for frontal plane variables and their temporal elements for ’ fast walking. 90 Comparisons of SAL’s ranked 5th or 6th for frontal plane variables are summarized in Table 13. For preferred walking, 60 percent of the variables in this wtegory were associated with injured subjects. However, percentage of variables associated with injured subjects for fast walking was slightly lower (50 percent). Using the chi-square tests, significant differences were found in SAL ranking categories for preferred walking, but not for fast walking (Table 14). Table 13 Number of Variables Ranked 5th or 6th for SAL’s for Frontal Plane Variables Group Subject Number of variables ranked 5”I or 6th for bilateral symmetry Preferred Walking Fast Walking Noninjured N1 2 1 N2 0 2 N3 2 2 N4 0 0 Injured P1 2 2 P2 4 3 Table 14. Chi-gguare Tests for Two Categories of SAL Ranking (5 or Greater and Smgjfir thin 5) for Frontal Plane Variables. Preferred Walking Fast Walking df 1 1 Chi-square (x2) 6.26‘ 2.76 " Significant at 0.05 level. 91 Symmetry-Amnetrv Inge; Level (SAL) for Fast and Preferred Wamg Comparisons of SAL’s between preferred and fast walking were performed to determine which of the two walking speeds was more appropriate in differentiating injured and noninjured gait (Figure 44 (a) - (e)). These figures display the differences in the absolute values of the SAL’s between the preferred and fast walking trials for each subject. Generally, no Specific pattern of differences in the SAL's was illustrated between the preferred and fast walking trials in all the subjects. Some subjects exhibited greater SAL values in fast walking trials, while others exhibited the opposite situation. Most of the SAL values for temporal and linear variables, and their temporal elements showed small differences between the two walking speeds. However, there were differences in the number of variables, with greater SAL’s between the walking speeds among the subjects (Table 15). However, these differences were more distinct in subject P2, in which the fast walking trial of this subject had more variables with greater SAL's than the preferred walking trial. Such results indicated that gait for P2 was more affected during fast walking than preferred walking. Subject P2 may had higher adaptation during preferred walking, however, profound changes became apparent at higher velocity of walking. Such changes could be due to problems of coordination and stability (Poulis et al., 1994). Differences in the bilateral asymmetries between the walking speeds were also found for sagittal plane variables. Most of these differences were associated with angular displacement variables. Subject P1 exhibited the most variables with greater difference in the SAL values between the two walking speeds. When SAL’s were compared between the walking speeds among the subjects, the fast walking trial had more variables with greater SAL than preferred walking for both injured subjects (P1 & P2) and noninjured subject N1 (Table 16). 92 ._.2 83.35 .2 95.32, ~me ccm 8:935 5923 9.76 Co mcomtmano .5 3 9:9“. .mo:_m> 22033. mcamtg ocma _wEoE (L ’k 3.3:? mama .333 8:33 ecu e 8:32, 85.26 a L 3.3:? .69.: can .33qu... ‘ m OVH’XPUJ WWW, WWW I L. e..... ELL—..- 8 BL_L_ __' . L L L L L iIT|+l+||T| B-I dVWV. dvxeuJ OVMY. mm 3' NDHVVM B may ENWX gym .1le7. ”film WV!“ IE] N38! EWX 3.4m gimz B—I :HXWJ I—Cl WVM .z .835 E LLLL , .Nz 80.33 .63. 92.95 53 ccm 8:935 c3353 w.._ 2239.: main; “we". I 95.33 veep—oi u mofiwtg ccma _Ecoi mofimtg 3:33 .363 833:9 Lace: ecu .8an3... WWW WWW WWW .L. . :W A 7 k l ‘ i .7. Wm% WM AHNWX AH>l 7““ I awmz :1 BVH ‘XPUJ ‘ 0V 'XQUJ y. [—8 GV‘XN’ WDHVVM I 347mm % vaw 7. AHV mu: Amri-1w 7. Bl AH)l vim BI 7614wa I] Ai-i-i um N-H mu 7. i3 AH-i'mu Lmsw dSlN 13w awn rm Sd Ls 139 [I GAV 0AM OAH I AS 'IS dMSW {J % dVV‘WJ'V. I—B dvxew B—Ijjmy. «z .835 3. 94 .m2 83.33 .2 main; “map can obey—ea c3923 m.._ 2239‘. E23 mi M 33m, 350““. m ‘ , moEutm> , mama _Ecoi 33%? 253 .353 333...; .52.: new .8253 T? ‘ A V n J! W 7. Z 7. X ‘Lhouvvm 'AHvuwz AHvur-u I‘M-{vmz TAva-I Aquw I) wmx l1 imam [a ’Am'uwx liN-HU!“ I AHNU!“ X B—Idvm I] CNWV. B—I [—51 [I —+:1 me B—l 01w B———~—1IGA>I = . m—u dSW B—I HS” III B. ESd (D N o o o 0 IE] B——IIGVHW I———_EI dvwi-z BI Ffl +—‘r . o_ ._ .1vs E 8033 E 97 .Nn. 8&93 .2 95:95 .98 van 8:965 5923 m.._ 2203.3 33.2.3 053 _mEoE rl 3.3:? 253 _wanw mos—35> 30:: can _Sano 1_. 9.233 so“. x 9:52, 85.2.“. n.. _fi 1 # A “ dV‘XOUJ-y. dV'XOUJ CNMV. V A ‘ mvm T w mm In AHVW 7. IE mm I——E1[ AHNUw °/. Iéi W'wi x m B 3. .1 ET! 9 a a 11 No R 11 3 41 0.0 11 ad I] B—I muwm I—-—-El wow 4:: 4+ Cl El... B~—————I mvuwz 11.2 13 :3 w .13 _ A _ _ .— l-— D 1- ow «a snag S 98 Table 15 Compajson of SAL’s between Preferred and Fast Walking Trials for Tempgral and Linear Variables and Their Temporal Elements Group Subject Number of variables with greater SAL’s‘ Preferred Walking Fast Walking Noninjured N1 11 14 N2 20 5 N3 1 1 12 N4 9 7 Injured P1 15 1 1 P2 3 23 * Absolute values. Table 16 Comgrison of SAL’s between Preferred and Fast Walking Trials for Sagittal Plane .Vfliab—IeS. Group Subject Number of variables with greater SAL’s‘ Preferred Walking Fast Walking Noninjured N1 8 10 N2 12 6 N3 9 9 N4 12 5 Injured P1 7 1 1 P2 7 1 1 *Absolute values. Most of the variables for the frontal plane demonstrated a distinct difference in the values of the SAL’s between the two walking speeds. The preferred walking speed had more variables with greater SAL’s than the fast walking for subjects N1 , N3, P1, and P2, and vice versa for other two subjects (Table 17). 99 Table 17 Comarison of SAL’s Between Preferred and Fast Walking Trials for Frontal Plane Variables Group Subject Number of variables with greater SAL’s* Preferred Walking Fast Walking N1 4 1 Noninjured N2 2 3 N3 3 2 N4 1 4 Injured P1 3 2 92 4 1 *Absolute values. m Comparison of SAL’s for the limb length measurements found no specific pattern of differences in the bilateral asymmetry between the subjects. Such conditions suggested that all subjects had similar characteristics in terms of limb length bilateral asymmetry. These results might also be attributed to individual characteristics of structural parameters of the subjects. However, this finding might also result from measurement errors. There were some difficulties in determining the bony landmarks that served as the endpoints for the measurement of each segmental length. Peak torque for knee extension showed a pattern of difference in the bilateral asymmetry between the injured and noninjured subjects at angular velocities of 180 and 300 deg/sec. Injured subjects demonstrated a higher level of asymmetries in these measurements. The injured subjects also exhibited a greater peak torque of the right leg (noninjured leg) in all torque measurements. Such results indicated a stronger extensors (quadriceps) and flexors (hamstrings) of the noninjured limb. Since EMG was not performed and ground reaction forces were not measured, the explanation to associate 100 the stronger quadriceps and hamstrings of the noninjured limb with knee flexion- extension was beyond the scope of this study. Perhaps, a stronger right limb of the injured subjects might be due to its compensating action in weight bearing task during walking. Because of the PCL injury of the left limb, the right limb may have played a more dominant role during walking, thus, resulting in stronger flexors and extensors of the limb at the knee joint. In summary, there were differences in bilateral asymmetries between the injured and noninjured groups in several of the gait parameters studied, both in the temporal and kinematic variables. In the temporal variables, the injured subjects were found to have greater bilateral asymmetries for both GCT and in the occurrence of various walking phases percentage. In the linear kinematic patterns, the injured subjects had greater bilateral asymmetries in SL, AHV, and KHV. These asymmetries could be related to the asymmetries of the temporal elements of the walking phases. Because WA composed a greater percentage of the gait cycle, the left leg had to move faster in the subsequent phases of walking, the TO and MSW, to compensate for the longer time taken during this period. Comparisons of SAL’s for linear variables and their temporal elements also demonstrated greater bilateral asymmetries in the injured subjects. Ranking of the SAL’s showed both injured subjects had the most variables with a higher level of bilateral asymmetries in both walking speeds. Significant differences in two categories (5 or greater and smaller than 5) of SAL rankings between the injured and noninjured groups. However, the type and number of variables, which constituted these asymmetries, were not consistent between the two walking speeds. There were five variables in which the injured subjects had consistently greater SAL’s than noninjured subjects for both walking trials: GCT, SL, max. KHV, min. KHV, and max. AHV. These 101 results indicated that subjects with PCL injuries suffered gait abnormalities, which were closely associated with these types of variables. The injured subjects also demonstrated greater bilateral asymmetries than the noninjured subjects in several gait patterns for sagittal plane variables. The patterns in which the injured subjects displayed greater asymmetries were knee flexion-extension angles and velocity, and hip flexion-extension angles and velocity. Between the injured subjects, there was a greater bilateral asymmetry in the flexion-extension displacement for the knee for subject P1 than P2. Subject P1 had a smaller range of motion in the right knee than the injured left knee in both the stance and swing period. This subject also had increased knee flexion angles in the injured limb during the WA phase of the gait cycle when compared to the noninjured limb. This finding was similar to what was found by Tibone et al. (1988). Time taken for this WA period was also prolonged for the injured leg. This longer WA period indicated that there was a longer lasting quadriceps force to support the injured leg and to protect it from further injury. In addition, the injured leg stance time was much longer to that of the uninjured leg. Consequently, the flexion- extension angular velocity displayed a similar result. Comparisons of SAL's for sagittal plane variables summarized in Table 16 showed subject N4 had the most variables with higher levels of asymmetries in preferred walking, while P1 in fast walking. When these results were compared in Figure 38 and Figure 39, it could be observed that most of the variables with greater asymmetries for N4 were associated with the ankle, while for P1 and P2, these asymmetries were mainly associated with the hip and the knee. Such findings supported the difference displayed by the gait pattern. Comparing the results in Tables 11 and 16 indicated that, for sagittal plane variables, most of the subjects had greater SAL’s in fast walking than preferred walking. The largest difference was displayed by P1 indicating that this subject was more affected than other subjects for sagittal plane variables in fast walking. 102 Although several differences in gait pattern were noted for some of the sagittal plane variables between the injured and noninjured groups, comparison of SAL ranking categories using the Chi-square tests did not yield statistically significant results. The proportion of variables ranked 5th or 6th was very similar between the two groups, especially in preferred walking. The injured subjects had only one variable in which the SAL was consistently greater than noninjured subjects in both walking trials; max. HE. This situation was greatly due to the difference in types of variables that were ranked 5'5h or 6“h between P1 and P2. For P1, most of the asymmetries were associated to range of motion and movement of the knee, while for P2, most of the variables were associated to the movement of the hips and ankle. There was no distinct difference in bilateral asymmetry for frontal plane gait patterns between the injured and noninjured groups. However, comparison of SAL’s between the groups showed injured subjects had a greater proportion of variables in the higher ranked category. Injured subject P2 also demonstrated having the most variables with greater asymmetries in both of the walking speeds (Table 13). At the same time, the results in Table 17 indicated that the gaits for both injured subjects were more affected during preferred walking. These results suggested that, for frontal plane variables, gait of injured subjects, especially P2, was more greatly affected in preferred walking than fast walking. The chi-square tests further supported this finding. The test results found significant differences in the ranking categories between the injured and noninjured groups for frontal plane variables for preferred walking. Between the injured subjects, P1 had more variables with greater level of asymmetries when compared to injured subject P2. This condition suggested that P1 was more affected by the injury. The most suitable explanation for this situation might be related to the difference in the age of injury between these two subjects. Subject P1 was only diagnosed for PCL injury two weeks before the test although the injury had 103 occurred for two and a half years. Before being diagnosed for PCL injury, it was believed that the injury was an ACL injury. Thus, the rehabilitation program that subject P1 underwent prior to the PCL diagnosis was tailored for that of ACL injury. For injured subject P2, higher adaptation might have occurred due to greater time interval from the injury compared to P1. Although the WA period was prolonged compared to noninjured subjects, there was greater symmetry in the knee range of motion at this phase than subject P1. The higher level of asymmetry for P2, when compared to the noninjured subjects might be due to inadequacy of the rehabilitation program, or might be an eariy indication for deterioration due to the injury. Such deterioration can be detected less than five years after the injury (Keller et al., 1993). CONCLUSIONS The purpose of this study was to compare bilateral asymmetries between individuals who had PCL injury to those without PCL injury. This study also examined the possibility of using bilateral kinematic analysis of gait as a supplementary and additional method for dynamically evaluating PCL knee injuries. Bilateral asymmetries in g the gait patterns for movement in the sagittal and frontal planes of PCL injured subjects 7 were compared to noninjured subjects. In addition, Symmetry-Asymmetry Index Levels (SAL’s) for linear, temporal, and angular parameters of gait were also compared between the two groups. The results of this study showed no specific pattern of differences in the bilateral asymmetry between the injured and noninjured subjects for the limb length measurements. However, a pattern of difference was observed in the bilateral asymmetry of peak torque for knee extension between the groups at angular velocities of 180 and 300 deg/sec. The injured subjects also exhibited a greater peak torque of the right leg (noninjured leg) in all of the torque measurements. The injured group also demonstrated greater bilateral asymmetries than the noninjured group in the following gait patterns: 1. temporal variables; gait cycle time and percentage gait cycle for the occurrence of various phases of walking; 2. linear variables: stride length (SL), ankle horizontal velocity (AHV), and knee horizontal velocity; and 3. sagittal plane variables: knee and hip flexion-extension angles and velocities. 104 105 Comparisons of SAL’s for linear variables and their temporal elements also demonstrated greater bilateral asymmetries in the injured subjects. However, the type and number of variables, which constituted these asymmetries, were not consistent between the two walking speeds. Three hypotheses were tested in this study. The first hypothesis stated that persons with Grade II PCL injury will demonstrate greater bilateral asymmetries in gait . patterns than persons without PCL injury in the following: horizontal and vertical displacements of the ankle, knee, and hip; horizontal velocities of the ankle, knee, and hip; sagittal plane angular displacements and velocities of the ankle, knee, and hip; and frontal plane angular displacements and velocities of the knee and hip. Results of the study supported this hypothesis. Support for this statement is provided in Table 18. Most of these gait patterns were associated with linear horizontal and sagittal plane variables. These abnormalities seem to be more easily detected since normal gait patterns had high level of bilateral symmetry in the linear and angular sagittal plane motions of the hips and knees, a finding previously supported by Hannah et al. (1984). Injured subject P1 had more variables with greater bilateral asymmetries, especially in preferred walking. Findings of this study also supported the second hypothesis; persons with Grade II PCL injury will demonstrate greater SAL’s, than persons without PCL injury in the following: temporal parameters of gait cycle time, stance time, and weight acceptance time; positional parameters of midstance, and midswing; stride length; vertical displacements of the ankle, knee, and hip; and horizontal velocities of the ankle, knee, and hip. The Chi-square tests demonstrated the differences in ranked categories between the injured and the noninjured groups for both walking speeds. Table 19 presents a list of linear and temporal variables in which injured subjects P1 and P2 were highly ranked in the SAL’s. Table 18 106 Gait Patterns with Greater Bilateral Asvmmetriesjn lniured Sgbiects Walking Speed Gait Patterns P1 P2 Preferred Walking Horizontal position of the ankle, Horizontal position of the ankle, knee, and hip knee, and hip Vertical position of the ankle Horizontal velocities of the ankle Horizontal velocities of the ankle and knee. and knee Knee flexion-extension Knee flexion-extension angular velocity Hip flexion—extension Hip flexion-extension Hip flexion-extension angular Hip flexion-extension angular velocity velocity Fast Walking Horizontal position of the ankle, Vertical position of the ankle knee, and hip Horizontal velocities of the ankle and knee Knee flexion-extension Hip flexion-extension Horizontal velocities of the ankle and knee Knee flexion-extension Hip flexion-extension m...” -le-il~ ..I. mus-...— Table 19 107 Linear and Temmral Variables with Greater SAL's flanked 5th or 6‘“) in lniured Subiects Walking Speed Variables P1 P2 Preferred Temporal GCT, ST, WAT, WAP, GCT Walking MST, MSP, MSWT Linear SL, SV, HVD, KVD, AVD, SL, SV, max. HHV, % max. HHV, % min. HHV, min. HHV, max. KHV, max. KHV, % max. KHV, % min. KHV. max. AHV. min. KHV, max. AHV, % max. "/0 min. AHV AHV, % min. AHV Fast Walking Temporal GCT, ST, PS, WAT, WAP, GCT, ST, PS, MSP, MST, MSWT MSWT, MSWP Linear SL, max. HHV, SL, SV, KVD, AVD, % min. HHV, max. KHV, % max. KHV, min. KHV, max. AHV, % max. AHV max. HHV, % max. HHV, min. HHV, % min. HHV, max. KHV, % max. KHV, min. KHV, % min. KHV, max AHV, % max. AHV, min. AHV The results from this study did not support the third hypothesis; persons with Grade II PCL injury will demonstrate greater SAL’s than persons without PCL injury in the following angular parameters: sagittal plane angular displacements and velocities of the ankle, knee, and hip; and frontal plane displacement and velocity of the hip. Since significant differences in the ranks of categories between the injured and noninjured subjects were found in the frontal plane variables for preferred walking only, this hypothesis was rejected. In summary, within the limitations of the study, the following conclusions were warranted: 108 1. The gait patterns of the PCL injured subjects had greater bilateral asymmetries than noninjured subjects. 2. For the linear and temporal variables, SAL’s of the PCL injured subjects demonstrated greater bilateral asymmetries than noninjured subjects. With such conclusion, this study indicated suitability of using bilateral kinematic analysis of gait as a supplementary alternative to static techniques for diagnosing PCL injuries. Suggestions The generalization of the results of this study is limited due to the small number of subjects. The analyses were also limited to temporal and kinematic analyses which prohibited an explicit explanation for the occurrence of greater bilateral asymmetries in the injured subject. Due to this limitation, explanation for greater bilateral asymmetries in the injured subjects could only be assumed through the history of the injury, other measurements deemed related to the asymmetry, and from related literature. Further study to examine these assumptions should be carried out. Methods that include EMG data and kinetic parameters should be employed to allow better understanding of the asymmetries demonstrated. It was also noted that rejection of the third hypothesis might be due to combining the frontal and sagittal plane variables together into a single hypothesis. It would be appropriate that these variables be analyzed independently so that a more specific information could be gathered. APPENDICES 109 APPENDIX A Informed Consent Form Subject’s Name: The present study will consists of a biomechanical evaluation of gait characteristics of individuals with and without posterior cruciate ligament (PCL) injuries. On the test day, prior to the testing, the length of the lower limb segments, will be measured. Knee joint laxity will be tested utilizing the standard Posterior Drawer Test, and will be performed by a certified athletic trainer or a physician. Leg strength will also be measured through the use of a Cybex dynamometer. You will be asked to complete an information sheet. You will I be asked to walk along a walkway while being video taped. This will be require you to perform three trials at normal walking speed, and three trials where you have to walk as fast as possible. All testing will only require a single day commitment of approximately two hours. In case of equipment failure you may be asked to return another day to complete testing. I understand that video tape records will be taken of my walking gait and that these may be used for instruction and/or presentation. I understand that participation in this study is voluntary, and that I am free to withdraw during any portion of the study without penalty. I understand that all results will be treated with strictest confidence and I will remain anonymous in any report of research findings; on request and within these restrictions results may be made available to me. I understand that if I am injured as a result of my participation in this research project, Michigan State University will provide emergency medical care if necessary. I further understand that if the injury is not caused by the negligence of MSU, I am personally responsible for the expense of this emergency care and any other medical expenses incurred as a result of this injury. Signed: Date: Address: Telephone No: ( ) PRINCIPAL INVESTIGATOR: SAIDON AMRI Telephone: (517) 355-0925 FACULTY ADVISOR : EUGENE BROWN, PhD. Telephone: (517) 353-6491 110 APPENDIX B Subject No : Subject Informgtipp Please complete the follgwinflq items. Name : Height: ft in. Age : years Weight : lbs Date of birth : / I Gender: male/female (circle one) (month/ day / year) Date : Dominant/Kicking Leg: left lright (circle one) Injury History. Date of injury : / (month I year) Type of Rehabilitation : Activity Approximate Length of Describe intensity Beginning rehabilitation (montiiyear For the next three itemsgircle the response that applies best to you. 1. Pain in injured knee : No painl pain with strenuous sportsl pain with light sports 2. Swelling in injured knee : No swelling! swelling with strenuous sportsl swelling with light sports 3. Limitation to activity: No limitation/ limited to less strenuous sportsl limited to light activity V'- ““‘”‘T_~”l IT Ann-5......“ _ 111 APPENDIX C Subject No: Posterior Drawer Test Left Right DESCRIPTION GRADE Comment (if any): Date : / / (month/ day / year) Physician: 112 APPENDIX D Subject No: Ms: Velocity Left Right (deg/sec) (Nm) (Nm) Flexion Extension Flexion Extension 60 180 300 Comment (if any): Date: / / (month/ day / year) Athletic Trainer: 113 APPENDIX E Subject No: Anthrppometric Measures Left Side Right Side (cm) (cm) Standing Leg Length (greater trochanter to floor) Sggmental Lengths: Thigh Length (greater trochanter to upper edge of tibia) Shank Length (upper edge of tibia to lateral malleoleus) Date : / I (month/ day l year) Anthropometrist: 114 89.0 32.0 88.0 800., :89 009.0 08:- 88.9 {:9 88... 0000.0 «08.9 65: EoEoooEflu _3_to> 35. £09 980 08.0 88. 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