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Eccentric drop squats as a means of conservative treatment for patellofemoral pain syndrome Pearce, Teri Lynn 2003

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ECCENTRIC DROP SQUATS AS A MEANS OF CONSERVATIVE TREATMENT FOR PATELLOFEMORAL PAIN SYNDROME by TERI LYNN PEARCE B.Phe., The University of Toronto, 2000 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES School of Human Kinetics We accept this thesis as conforming To the required standard THE UNIVERSITY OF BRITISH COLUMBIA June 2003 © Teh Lynn Pearce, 2003 In p resen t ing this thesis in part ial fu l f i lment o f t h e requ i remen ts f o r an advanced d e g r e e at the Univers i ty o f Brit ish C o l u m b i a , I agree that t h e Library shall m a k e it f reely available f o r re fe rence a n d s tudy. I f u r the r agree that pe rmiss ion f o r ex tens ive c o p y i n g of this thesis fo r scholar ly pu rposes may be g ran ted by the head o f m y d e p a r t m e n t o r by his o r her representat ives. It is u n d e r s t o o d that c o p y i n g o r p u b l i c a t i o n o f this thesis f o r f inancial gain shall n o t b e a l l o w e d w i t h o u t m y w r i t t e n permiss ion . D e p a r t m e n t The Univers i ty o f Brit ish C o l u m b i a Vancouver , Canada Date DE-6 (2/88) 11 Abstract Patellofemoral pain syndrome (PFPS) is one of the most common causes of anterior knee pain seen in the field of sport medicine. The multiple variations in the pathophysiology of patellofemoral syndrome provide clinicians with numerous chal lenges when formulating appropriate treatment plans, with treatment often providing transient relief. The purpose of the present study was to determine if individuals suffering f rom PFPS are weak eccentrically in comparison to healthy controls, and if a closed kinetic chain (CKC) eccentric drop squat program can improve muscular strength and functional capacity in this group. Seventeen individuals suffering f rom PFPS between the ages of 19 to 35 years, and 18 healthy controls between the ages of 20 to 36 years participated in the study. Both groups were put on a 12 week CKC home eccentric drop squat program, and tested at 0, 4,8, and 12 weeks using the kinetic communicator (KINCOM®) to measure isokinetic eccentric and concentric strength and using the Victorian Institute of Sport Assessment (VISA) Score as a subjective measure of pain and function. Results indicated that there were no statistically significant improvements in eccentric and concentric strength of the quadriceps and hamstrings of the injured and noninjured legs in both the PFPS group and the control group at 60 and 120 degrees per second. Analysis of the graphs show that the healthy controls were in fact stronger eccentrically, but not to a degree of statistical significance. The VISA score was significantly higher for the control group in comparison to the PFPS group. The results do not statistically support the hypotheses of this study. Al though the graphs suggest that the PFPS group is weaker then the control group, and feedback f rom the PFPS group suggests that the eccentric drop squat program has improved their perceived pain and function, which is of clinical relevance to practit ioners. Ill Table of Contents Title of Chapter/Section Subtitle Page Number Abstract Table of Contents List of Tables List of Figures Acknowledgement Chapter 1 Introduction Purpose of Investigation Statement of the Problem Delimitations Limitations Definition of Terms Hypotheses Chapter 2 (Review of Literature) Anatomy, Function and Biomechanics Patellofemoral Pain Treatment Patellar Taping Closed Kinetic Chain Exercises versus Open Kinetic Chain Exercises Quadriceps Strengthening v vi viii 1 2 3 3 3 4 5 6 10 15 16 17 17 Chapter 3 (Methodology) Sample Parameters Measured and Rationale for their Selection Measurement Techniques and Protocol Treatment Program Exercise Protocol Description of Exercise Execution Analysis of Data 19 20 20 22 23 23 25 Chapter 4 Results 26 Chapter 5 Discussion 49 Chapter 6 Conclusions 63 Appendices i v Appendix A - Pilot Study 64 Appendix B - Patient Log Book Summaries 70 Appendix C - Patient KINCOM® Set-up 73 Appendix D - VISA Score 74 Appendix E - PFPS Informed Consent Form 76 Appendix F - Control Informed Consent Form 79 Appendix G - Participant Log Book 82 Appendix H - Participant KINCOM® 93 Set-up Form References 94 Table of Tables Title of Table Subtitle Page Number Table 1 Manifestations, Etiological Factors and Pathology 11 of PFPS Table 2 Patella Classification Types 15 Table 3a Home Exercise Program - Daily Progressions 23 Table 3b Home Exercise Program - Weekly Progressions 23 Table A1 Participant Descriptive Data Summary 26 Table B1 Participant Home Exercise Program Compliance 27 Table C1 VISA Aggregate Scores 27 Table D1 Patellofemoral Pain Syndrome vs. Treatment 29 - Quadriceps Table D2 Patellofemoral Pain Syndrome vs. Treatment 30 - Hamstrings Table D3 Patellofemoral Pain Syndrome vs. Treatment 35 - Eccentric/concentric Strength Ratios Table D4 Patellofemoral Pain Syndrome vs. Treatment 38 - Hamstrings/quadriceps Ratios Table E1 Controls versus Treatment: Quadriceps 41 Table E2 Controls vs. Treatment: Hamstrings 42 Table E3 Controls vs. Treatment: Eccentric/Concentric 43 Strength Ratio Table E4 Controls vs. Treatment: Hamstrings/Quadriceps Ratio 44 vi Table of Figures and Graphs Title of Figure/Graph Subtitle Page Number Figure 1 Patella Anatomy 6 Figure 2 Soft Tissue Structures Surrounding the Patella 8 Figure 3 Patellar Contact Areas 10 Figure 4 Patellar Nutrition 12 Figure 5 Q-Angle 13 Figure 6 Variations in Patella and Femoral Condyles 15 Figure 7a Front View of Drop Squat 24 Figure 7b Side View of Drop Squat 24 F i g u r e d VISA Aggregate Scores Comparison 28 Figure D1 Quadriceps Eccentric at 60 degrees per second 30 Figure D2 Quadriceps Eccentric at 120 degrees per second 31 Figure D3 Quadriceps Concentric at 60 degrees per second 31 Figure D4 Quadriceps Concentric at 120 degrees per second 32 Figure D5 Hamstrings Eccentric at 60 degrees per second 32 Figure D6 Hamstrings Eccentric at 120 degrees per second 33 Figure D7 Hamstrings Concentric 60 degrees per second 33 Figure D8 Hamstrings Concentric degrees per second 34 Figure D9 Quadriceps Eccentric/concentric Strength Ratios 36 at 60 degrees per second Figure D10 Quadriceps Eccentric/concentric Strength Ratios 36 at 120 degrees per second Figure D11 Hamstrings Eccentric/concentric Strength Ratios 37 at 60 degrees per second Figure D12 Hamstrings Eccentric/concentric Strength Ratios 37 at 120 degrees per second Figure D13 Hamstrings/Quadriceps Ratio Eccentric 39 at 60 degrees per second Figure D14 Hamstrings/Quadriceps Ratio Eccentric 39 at 120 degrees per second Figure D15 Hamstrings/Quadriceps Ratio Concentric 40 at 60 degrees per second Figure D16 Hamstrings/Quadriceps Ratio 40 at 120 degrees per second Figure F1 PFPS vs. Control Quadriceps Eccentric Torque 45 at 60 degrees per second Injured Leg Figure F2 PFPS vs. Control Quadriceps Eccentric Torque 45 at 60 degrees per second Noninjured Leg Figure F3 PFPS vs. Control Quadriceps Eccentric Torque 46 at 120 degrees per second Injured Leg Figure F4 PFPS vs. Control Quadriceps Eccentric Torque 46 at 120 degrees per second Noninjured Leg Figure F5 PFPS vs. Control Hamstrings Eccentric Torque 47 at 60 degrees per second Injured Leg Vll Figure F6 PFPS vs. Control Hamstrings Eccentric Torque 47 at 60 degrees per second Noninjured Leg Figure F7 PFPS vs. Control Hamstrings Eccentric Torque 48 at 120 degrees per second Injured Leg Figure F8 PFPS vs. Control Hamstrings Eccentric Torque 48 at 120 degrees per second Noninjured Leg Vlll Acknowledgement I would like to thank the following people for their support and encouragement throughout my graduate school endeavour; Dave and Carrie Pearce, Ryan Pearce, and Christopher Padgett for their unfailing love and support. My supervisor Dr. Jack Taunton for his confidence in me on this journey and his enthusiasm. My committee members Dr. Don McKenzie and Dr. Rob Lloyd Smith. Elizabeth Vitullo and Sam Zizzi for their friendship and assistance with the statistical analysis. Julie Morin, Tyler Dumont, and Dr. Darren Warburton. Special thanks goes to all the participants who partook in this study for their time and effort. 1 Chapter 1 Introduction Patellofemoral pain syndrome (PFPS) is one of the most common causes of anterior knee pain observed in the orthopedic and sports medicine setting. Although there are a vast number of individuals who are clinically diagnosed with patellofemoral pain syndrome, there seems to be a lack of consensus on how to manage this condition. The multiple variations in the pathophysiology of patellofemoral syndrome provide clinicians with numerous challenges when formulating appropriate treatment plans, with treatment often providing transient relief (7,8,9,11,18,28,40). The etiology of PFPS is multifactorial. Trauma or previous injury to the knee can cause damage to the structures of the knee resulting in PFPS. Increases in knee flexion result in additional pressure between the patella and its various femoral contact points, which increase patellofemoral joint reaction forces (PFJRF). Constant repetitions of activities that increase PFJRF cause a stress overload on the patellofemoral joint (5,14,17,33). Biomechanical problems such as increased Q-angle and excessive pronation have a role in the manifestation of abnormal tracking which plays a key role in PFPS. Muscular dysfunctions primarily tightness of the rectus femoris, illiotibial band (IT band), hamstrings and/or gastrocnemius, weakness of the hip abductors, vastus medialis insufficiency and/or weakness, vastus medialis and vastus lateralis neural imbalances plays a major role in the malalignment of the patella and increases in PFJRF (19,33,40). This complex interplay of factors that affect the mechanics and stability of the patellofemoral joint make rehabilitation of PFPS a complex and challenging problem for clinicians. 2 Treatment of PFPS involves the identification and treatment of all factors that are contributing to the individual's pain. Closed Kinetic Chain exercises (CKC) are becoming increasingly more popular in the rehabilitation of different knee injuries (13,16,36,44). Closed kinetic chain eccentric exercises have successfully been used to treat various injuries. Muscular imbalance between the hamstrings and quadriceps and within the quadriceps (primarily between the vastus lateralis and vastus medialis) plays a major role in abnormal patellar tracking (7,8,9,10). Closed kinetic chain exercises have been extensively shown as an effective way of strengthening the vastus lateralis and vastus medialis, whereas, eccentric exercises have been shown to increase both hamstring and quadriceps strength eccentrically and concentrically (6,15,16,31,36,44). Little is known about the effects of an eccentric squatting program on individuals suffering from PFPS. In fact, an extensive search of the literature (Medline) revealed no investigations using a CKC eccentric squatting exercise program as a means for rehabilitating PFPS. This would be important to evaluate due to the frequency of PFPS, and the need to develop a treatment protocol that is effective long-term. The current study will look at a 12-week eccentric drop squat program as a form of rehabilitation to improve strength, minimize strength imbalances and improve overall function in individuals with PFPS in comparison with healthy controls. Purpose of the Investigation Based on information provided in the literature on the lack of long-term rehabilitative success of PFPS, the purpose of this study is to develop a home closed kinetic chain (CKC) exercise program to improve eccentric and concentric quadriceps muscle strength. 3 A secondary objective of the study is to test CKC exercises as a means of improving knee function and isokinetic strength, with the overall goal of correcting strength imbalances. Statement of the Problem To determine if individuals suffering from PFPS are weak eccentrically in comparison to healthy controls, and if a CKC eccentric drop squat program can improve muscular strength and functional capacity in this group. Delimitations 1) The prescribed home exercise program is simple and requires little equipment. 2) The use of the Victorian Institute of Sport Assessment (VISA) Score records participants perceived pain and knee function. 3) The use of the Kinetic Communicator (KINCOM) to test eccentric and concentric muscle strength through certain motion ranges, and velocities, while performing isolated knee extension and flexion. Limitations 1) In order to maintain homogeneity throughout the sample population specific inclusion criteria was designed and implemented. However this restricts inference to other individuals suffering from PFPS. 2) Testing was performed within set ranges of flexion and extension, and set velocities, therefore, limiting an evaluation to specific components of the range of motion of the knee joint. 4 3) Despite 4 weeks between each testing sessions there is the possibility of a learning effect taking place with the kinetic communicator (KINCOM) test. 4) Subject compliance to the home eccentric drop squat program. Definition of Terms Closed Kinetic Chain (CKC) Exercise When the distal segment of the body is being opposed by a considerable resistance that is substantial enough that the distal end does not move (an example being a squat). 7 Concentric Contraction A muscle contraction in which the muscle tendon units shorten while producing tension and positive work. Conservative Treatment Treatment that is not surgical Eccentric Contraction A muscle contraction in which the muscle tendon units lengthen in response to force, producing negative work. Isokinetic Exercise A muscular contraction in which the velocity of the joint segment is held constant throughout the range of motion by an external mechanism. Patellofemoral Pain Syndrome (PFPS) Diffuse knee pain that is often dull and aching; that may be felt behind the patella, or along the medial border, which may radiate in all directions. 5 Hypotheses It is hypothesized that the proposed home closed kinetic chain eccentric drop squat program will lead to the following results; 1) VISA scores will improve significantly. 2) Following the 12-week eccentric drop squat home program isokinetic eccentric peak torque will increase significantly in the quadriceps and hamstrings of both extremities. 3) Eccentric/concentric ratio (average peak torque) will increase significantly. 4) Hamstring/quadriceps ratio will improve significantly eccentrically and concentrically. 6 Chapter 2 Review of the Literature Anatomy, Function and Biomechanics The patellofemoral joint is classified, as an arthroradial joint (hinge joint) that is comprised of two bones, the patella and the femur. The sliding articulation of the patella with the trochlear groove between the femoral condyles allows for a large range of flexion within the joint (5,13). The patella is a sesamoid bone that is triangular in shape and slightly wider than high, with the base uppermost that rests between the femoral condyles (5). The anterior surface of the patella is slightly convex. The posterior surface has three distinct facets, each covered with articular cartilage. The central vertical ridge separates the medial and lateral regions, each having superior, middle, and inferior articular surfaces. The odd facet, lying medial to the medial facet, has no articular cartilage subdivisions (Figure 1) (5,17,19,20). Figure 1: Patella Anatomy The distal region of the femur is divided into medial and lateral facets that closely match the facets of the patella (5,20,33). The lateral facet is higher and broader then 7 the medial facet and extends more proximally. Proximally the trochlear facets become the supratrochlear fossa. This fossa is filled by the prefemoral fat pad; the fat pad is what the patella articulates with in full extension (19,20). The patella serves as the central structure in the knee extensor mechanism. It acts as a fulcrum to enhance the mechanical advantage of the quadriceps during knee flexion and extension. The integrity and balance of the soft tissue structures surrounding the patellofemoral joint are critical to the position and tracking of the patella (Figure 2) (17,19,20,38). The patellar tendon and the medial and lateral retinacula comprise the passive elements of this soft tissue stabilization system, whereas, the four portions of the quadriceps provide the active elements of the system. Patellar positioning is maintained by the retinacula. The medial retinaculum originates from the distal portion of the vastus medialis and adductor magnus, and inserts into the medial border of the patella. The lateral retinaculum originates from the vastus lateralis and the iliotibial band (IT Band), and inserts on the patella's lateral border. The superior portion of the knee joint capsule thickens and inserts on the patella's superior border, forming the medial and lateral patella ligaments (5,17,19,20,28). The quadriceps provides the majority of the active stabilization of the patella. The attachments of the individual quadriceps heads into the patella are considered structurally in three different components; superficial, intermediate and deep layers. The superficial layer contains the rectus femoris, which inserts into the superior pole of the patella and anteriorly on the superior third of the patella. The intermediate layers consist of the vastus medialis and the vastus lateralis. The vastus medialis and vastus lateralis join together to form a solid aponeurosis that inserts posteriorly to the rectus femoris insertion on the base of the patella. The insertion of the vastus medialis descends further distally than the vastus lateralis. The deep layer contains the vastus intermedius, which inserts on the 8 base of the patella anterior to the capsule but posterior to the other quadriceps muscles. The bony confines of the trochlea help define the normal limits of patella excrusion. Anteriorally the capsule is thin and loose to accommodate the large range of normal knee flexion (5,19,23,38). Figure 2: Soft Tissue Structures Surrounding the Patella In the sagittal plane, the patella serves to increase the angle of pull of the patella tendon on the tibia, thereby improving the mechanical advantage of the quadriceps muscles to produce knee extension. The patella effectively moves the tendon line of 9 action away from the axis, thus increasing the moment arm (19,20,26,29,32,33). As knee flexion increases the patellofemoral contact areas move from proximal to distal on the patella surface (Figure 3). The change in contact areas increases patellofemoral joint reaction forces (PFJRF) and the mechanical advantage provided by the patella to the quadriceps (5,32,38). At full extension the patella is not in contact with the femur. It rests on the supratrochlear fat pad, so there is little compressive load (19,32). In the initial 0 to 10 degrees of flexion, the inferior third of the patella comes into contact with the trochlea. As flexion increases to between 10 to 30 degrees the articular surface of the patella contacts the lateral femur on the inferior patella surface. Compressive forces that are exerted on the patella are greatest at 30 degrees flexion (32,38). During 30 to 60 degrees of flexion the stability of the knee increases and the lateral border of the trochlea is prominent forming a barrier against lateral displacment of the patella. The middle surface of the patella is in contact with the femoral groove. The greatest amount of patella contact area is reached between 60 to 90 degrees of flexion where the upper third of the patella is deep within the trochlea and is firmly in position by the trochlear facets (19,20). Beyond 90 degrees the contact areas split into smaller areas medially and laterally on the upper patella surface to correspond with the areas of contact on the medial and lateral condyles of the femur. It is not until 135 degrees of flexion that the odd facet of the patella makes contact with the femoral condyles (19,20,32,33,28). Effective patellar tracking depends on congruence between the patella and the femur during flexion. Maintaining optimal tracking is critical to optimize patellar surface area contact in order to effectively distribute PFJRF's (19,20,26,37,39). 10 Figure 3: Patellar Contact Areas Patellar Contact Area - Normal Tracking Distal Area of Femur I • Degrees } Knee. Flexion Patella Contact Area 135 Degrees Flexion Degrees Knee Flexion Posterior Surface of Patella (reflected interiorly) Patellofemoral Pain Patellofemoral Pain Syndrome (PFPS) is generally characterized as an overuse condition and is very common especially in females, adolescents, elderly and the athletic population. PFPS has also been commonly referred to as chondromalacia patellae though this term clinically implies lesions of the retropatellar cartilage upon arthroscopic investigation (20,29,32,33). Symptoms experienced by individuals with PFPS generally increase with increasing intensity of different activities, and decreases with rest or decreases in activity intensity. Symptoms may be aggravated by sitting with knees bent for long periods of time (theater sign), ascending or descending stairs, and activities that increase the PFJRF (such as squatting) (2,19,25,32,33,35,42,43). There 11 are multiple factors that have been suggested in the classification of PFPS. Table 1 summarizes the numerous manifestations, etiological factors and pathology that are characteristic of PFPS (5,19,23,25,32,34,35,42). Table 1: Manifestations, Etiological Factors and Pathology of PFPS MANIFESTATIONS ETIOLOGIC FACTORS PATHOLOGY • Diffuse pain arising from the anterior, medial, and/or lateral aspect of the knee • Tightness of the rectus femoris, illiotibial band, hamstrings and/or gastrocnemius • Cartilage degeneration • Pain induced by exercise due to increased patellar compressive forces • Vastus medialis obliquus insufficiency/weakness • Torn retinaculum • Swelling • Increased Q-angle • Synovitis • Loss of motion • Excessive pronation • Sensation of giving away • VLA/MO neural/strength imbalances • Abnormal patellar tracking • Catching/pseudolocking • Weakness of hip abductor and external rotators The diffuse pain is often dull and aching; it may be felt behind the patella, or along the medial border, which may radiate in all directions (32,33). This pain is believed to arise from the subchondral bone, synovium, lateral and medial retinaculum (7,8,9,33). The pain felt by individuals with PFPS is commonly due to the lateral tracking and changes in compressive forces of the patella over the femoral condyles (13). Abnormal tracking affects the nutrition of the articular cartilage and causes swelling of the knee. Articular cartilage nutrition is dependent upon diffusion of the nutrients from superficial to deep layers of the cartilage especially during periods of non-compression (19,32,33). Under compression, the deep layers are less permeable and resist the interstitial flow of fluid (Figure 4) (5). Therefore, fluid escapes and causes swelling. Poor nutrition may cause 12 the articular cartilage to become softened and weakened, which decreases the amount of force that the patellofemoral joint can tolerate (19,23,32). Figure 4: Patellar Nutrition Normal Compressed Released Imbibition IN IN Stability of the patellofemoral joint is highly dependent on the mechanical alignment of the entire lower limb, passive restraints and to a large degree the active restraints primarily the quadriceps. The Q-angle is the angle formed by the vectors representing the pull of the quadriceps and patellar tendon (the lines are formed from the anterior superior iliac spine (ASIS) to the center of the patella and from the center of the patella to the tibial tubercle) (Figure 5) (5). A Q-angle in females of above 15 degrees may be indicative of lateral patellar tracking, which is common in individuals suffering from PFPS (2,19,25,26,30,32,33,38). 13 Figure 5: Q-Angle a ll Underlying anatomical causes of excessive Q-angle include excessive femoral anterversion, external tibial torsion, genu valgum and hyperpronation of the foot (19,32,33). Individuals with increased Q-angle tend to demonstrate patellar squinting usually from femoral neck antiversion. Although an increased Q-angle may result in malalignment of the patella and increased PFJRF, it cannot solely be a measure of PFPS (32,37). Excessive pronation of the foot alters tibial rotations and causes tibial variations (external tibial torsion, or a lateral displacement of the tibial tubercle) (5,39). These variations in foot biomechanics can affect Q-angle, which in turn causes patellar malalignment (25,32,39). The lateral retinaculum can become tight when the vastus lateralis and/or IT band which make up the lateral retinaculum are tight. A tight lateral retinaculum limits medial patellar glide causing malalignment, and excessive pressure on the lateral patellar facet. Inadequate flexibility of the hamstrings and gastrocnemius can also affect the pull of the patella (2,7,19,22,25,32,38). Deficiencies in the vastus medialis can cause abnormal patellar tracking and pain. The vastus medialis obliquus 14 (VMO) is crucial to the stabilization of the patella and to maintaining patellar alignment. If there is not an equal balance between the lateral and medial active stabilizers, then malalignment will occur causing PFPS (19,25,32). Current research suggests that an imbalance in the neural activity between the VMO and the vastus lateralis (VL) can contribute to abnormal tracking (2,7,8,9,10). Although this theory is debated throughout the literature many studies have now shown that there is a deficit in the neural control of VMO and VL in individuals suffering from PFPS (2,7,8,9,10,12,22). Studies done to test this theory have shown that the onset of VL activation in individuals suffering from PFPS occurs significantly sooner then the VMO, whereas, in the asymptomatic population the onset VL and VMO activation occurs simultaneously. Thus this shows a deficit within the neural subsystems controlling the active subsystems of the knee stabilizers. The variations in the literature in regards to neural deficits continue to show the multifactorial nature of PFPS (2,10,12,22,32,33). Anatomical variations within the patellofemoral joint such as patella alta, patella baja, different shaped patellas, and different shaped femoral condyles can effect the tracking of the patella. If the patella sits in an abnormal position in the femoral groove, then its articulations with the articular surfaces of the femur will be abnormal and cause; malalignment of the patella and irregular wearing on the underside of the patella(5,11,33). In patella alta the patella sits in an abnormally high position relative to the joint line of the knee. Therefore, the femoral groove in which the patella sits is much more shallow, allowing the patella more mobility. In patella baja the patella sits in an abnormally low position relative to the joint line of the knee (33). Variations in shapes of the patella and the femoral condyles effects the tracking of the patella within the femoral condyles. There are five main classifications of patellar types (See table 2 and figure 6) (5,33). 15 Table 2: Patella Classification Types Classification of Patella Types Type Facet Size Facet Shape 1 Equal Concave II Medial < Lateral Convex III Medial < Lateral Medial convex, lateral concave Il/lll Medial < Lateral Medial flat IV Medial < Lateral Medial flat or narrow Figure 6: Variations in Patella and Femoral Condyles Type I Type II Type III Type Il/lll Type IV Type II is the most common patella shape, and types III and IV tend to be the most unstable, increasing the chances of patella subluxation. The lateral femoral condyle is normally higher then the medial condyle to help prevent patellat subluxation. Variations in the depth of the femoral groove and the height of the femoral condyles changes the amount of patellar lateral glide. Therefore, abnormal patellar tracking is commonly due to a wide variety of causes, which makes treatment difficult (17,19,33). Treatment Rehabilitation of this condition over the years has proved to be unsuccessful. Long-term follow up has shown that the outcomes of most treatments have provided the patient with only temporary relief of pain (28,32,35). This shows us that the 16 management of PFPS and the identification of biomechanical problems that may cause this condition are inadequately dealt with (19,32,33). Conservative treatment consists of components designed to improve patellar tracking. Different treatment plans consist of quadriceps retraining especially the VMO, stretching lower limb muscles, correcting foot biomechanics, patella mobilization, and patellar taping and bracing (2,10,12,22,40). The patient is assessed and the most appropriate combinations of treatment components are used to combat the PFPS. Although as stated earlier in most cases treatment provides temporary relief at best. Patellar Taping Patellar taping in combination with other treatment components such as quadriceps retraining has become increasingly more common in the rehabilitation of PFPS, if a decrease in knee pain is felt while the patient is taped (2,7,8,9,10,11,12,22). Originally designed by Jenny McConnell patellar taping was designed to realign the patella within the femoral trochlea (2,32,33). This taping technique temporarily reduces pain by improving patella alignment, quadriceps function and patellofemoral joint function (7,8,9,10,12). Current research also shows that patellar taping may enhance the activation and/or timing of the VMO relative to the VL, or decrease the activation and/or timing of the VL relative to the VMO resulting in a more harmonious balance in the neural subsystem of the patellofemoral joint (2,7,8,9,10,12,22). The pitfall to patellar taping is that it provides temporary relief, and the patient must continually reapply the tape job in order for decreases in pain to be felt. This temporary relief can be beneficial when the patient is completing other components of the rehabilitation program (5,12,22). 17 Closed Kinetic Chain Exercises Versus Open Kinetic Chain Exercises There have been many studies that compare the use of closed kinetic chain exercises (CKC) with open kinetic chain exercises (OKC). CKC exercises are achieved when the distal segment of the body is being opposed by a considerable resistance, that is substantial enough that the distal end does not move (an example being a squat). OKC exercises are achieved when the distal end is free to move and the resistance is applied to another point in the chain (an example being a seated leg extension) (3,13,16). CKC exercises are considered to be more functional because they provide a normal physiological load through the skeletal system, the muscle contractions are synergistic and normal propioceptive feedback mechanisms are used (16). CKC exercises have recently become more popular in the rehabilitation of different knee disorders (3,13,16,44,48). Studies have shown that these types of exercises are effective in the development of the vastus medialis and the vastus lateralis, which clinicians believe to be important in treating PFPS (13,16,48). Quadriceps Strengthening Long-term studies on PFPS and quadriceps strengthening have shown that functional gains can be made when the rehabilitation program is progressive in nature, and progresses from simple to complex (2,11,18,27,41,48). Since PFPS is typically reproduced with activities that are associated with increases in PFJRF, the quadriceps strengthening program should be designed to enhance quadriceps strength. However, PFJRF should be kept to a minimum so that symptoms are not exacerbated while completing a rehabilitation program (1,4,28,32). Functional gains will not occur when the patient is faced with pain and swelling. In order to functionally restore lower 18 extremity kinematics, improve patellar tracking and minimize PFJRF, diligent hamstring conditioning must also be included in the strength program (1,4,16,28,32,33). The use of CKC eccentric training as a rehabilitation tool for patients with PFPS has not been well studied. McConnell (32) suggests using eccentric training as part of a treatment regime to improve ascending and descending stairs, and suggests using stepping down from a stair to stimulate eccentric quadriceps action. Stanish and Curwin have extensively studied eccentric drop exercises for the treatment of different tendinopathies (Achilles and patellar), and have had great success with the program (15,31). Eccentric strength is pertinent to movement patterns, and many complaints such as descending stairs involve a large eccentric component (32,33). Therefore, this study proposes to look at the effects of a home CKC eccentric drop squat program on patients suffering PFPS. 19 Chapter 3 Methodology Sample The current study included a Patellofemoral Pain Syndrome (PFPS) group (n = 17) and a control group (n = 18). The participants were all female between the ages of 18 to 40. The PFPS group included individuals who had no prior history of knee surgery, patellar dislocation and/or present with effusion suffering from patellofemoral syndrome, and the control group consisted of healthy females, matched for height, weight and activity level. This sample size was determined from past studies done on, PFPS and a study done by MacLean, and co-investigators (31). Participant inclusion was based on diagnoses of patellofemoral syndrome by a physician from the Allan McGavin Sports Medicine Clinic, University of British Columbia Student Health, and other participating physicians. Participants who were wearing orthotics prior to starting the study were able to use their orthotics during the exercise sessions. Participants who were not wearing orthotics prior to the start of the study were not permitted to use orthotics during the study. The participants were not allowed to use braces or tape their knee for the exercise sessions. Both the PFPS and control groups underwent a 12 week closed kinetic chain eccentric drop squat home program and were tested for strength and function at 0, 4, 8 and 12 weeks. 20 Parameters Measured and Rationale for their Selection • The Victorian Institute of Sport Assessment Score (VISA) was used to monitor participant information regarding the participants perceived knee function and symptomatology before, during and after the exercise program, • The Kinetic Communicator (KINCOM®) 125E Plus a hydraulically powered, computer controlled exercise testing device was used to measure the concentric and eccentric torque of the quadriceps and hamstring muscles groups. This allowed for the evaluation of eccentric and concentric strength gains and relationships. Measurement Techniques and Protocol During the beginning of the initial testing session (week 0) each participant was asked to provide written informed consent (Appendix E and F). The participant was then weighed, measured for height, and asked about approximate level of activity on a weekly basis. A leg measurement was then taken to determine the  3A mark of the fibula. Measurement was taken from the head of the fibula to the centre of the medial mallioli and a mark was made on the leg. The participant was then asked to sit on the KINCOM® to obtain their correct alignment measurements. These measurements were recorded so that the same testing set-up was used for every testing session. During all 4 testing sessions both the PFPS group and the control group performed the VISA and KINCOM® testing. The participants were asked to complete the VISA questionnaire prior to warm up and the KINCOM® testing. This VISA score has been validated as an effective measure of participants perspectives towards their knee function and symptoms related to the patella. After completing the VISA questionnaire each participant received a five-minute warm-up that consisted of light cycling and stretching of the tested muscle groups. 21 Following the warm-up the participants received instruction and performed a series of practice trials to familiarize themselves with the KINCOM® and the applied resistance. During the week 0 testing session each participant performed two submaximal repetitions of each exercise prior to each maximal test. During weeks 4,8 and 12 testing sessions each participant performed two submaximal repetitions of each exercise (at 60 degree per second) prior to maximal testing. This was done to minimize any learning effect that may occur during the testing sessions. During each testing session, the participant's pelvis and exercising thigh was securely strapped to the chair. The mechanical axis of rotation was aligned with the lateral femoral condyle and the load cell was placed, distally, % the length of the fibula. Once the participant was familiar with the KINCOM® they were asked to perform four maximal tests. Four maximal repetitions at a constant velocity of 60 and 120 degrees per second were performed on the injured quadriceps and the noninjured extremity and the injured hamstring and noninjured extremity. Average peak torque was recorded between zero and 90 degrees of knee flexion. Fifteen seconds were given between each trial. Each subject was given the same verbal start commands "Ready and up" for quadriceps testing and "Ready and down" for the hamstrings. Each participant was also given standardized encouragement during the trial to motivate them to push as hard as they could. At the end of the baseline KINCOM® testing, the 12-week CKC eccentric drop squat home exercise program and the logbook (where participants recorded any modifications in the exercises or if they did not do the exercises that day) were explained to the participants. The squatting exercises were demonstrated, and the participant was then asked to practice the squats in front of the investigator for evaluation. All participants were tested at time 0, 4, 8 and 12 weeks. After the week 4 22 and 8 testing sessions, any individual participant modifications due to pain or discomfort were discussed. Treatment Program Both the PFPS and control group performed a 12-week CKC eccentric drop squat home exercise program. In order to evaluate program compliance and participant motivation, the participants were asked to keep a logbook. The exercise program required very little equipment, was to simple to do, and is both progressive and challenging. The prescribed exercise protocol focused on: • Correcting strength imbalances in the quadriceps and hamstrings and, • Improving strength and endurance of the quadriceps and hamstrings. The exercise protocol was modeled after the program currently used at the Allan McGavin Sports Medicine Clinic and a study done by MacLean and co-investigators (31) and Cannell and co-investigators (6). The exercise protocol consisted of modified eccentric drop squats with the participants executing two-legged squats for the first six weeks with a gradual increase in weights, and then starting at week 7 single-legged squats on both legs are introduced. The exercises were executed seven days a week for 12 weeks with daily repetition and weekly resistance progressions. The participants were advised to stretch the muscle groups involved in the squatting exercises before and after performing the squatting exercises, and ice each knee for 15 to 20 minutes after the exercise session. 23 Exercise Protocol Table 3a and 3b shows the home exercise program that the participants completed. Table 3a: Home Exercise Program - Daily Progressions Daily Progressions Day Progression 1 3X8 Repetitions 2 3X10 Repetitions 3 3X12 Repetitions 4 3X14 Repetitions 5 3X16 Repetitions 6 3X18 Repetitions 7 3X20 Repetitions Table 3b: Home Exercise Program - Weekly Progressions Weekly Progressions Two-leaaed Single Legged Week Sets Drop Speed Resistance Sets Drop Speed Resistance 1 3 Slow None 0 - -2 3 Fast None 0 - -3 3 Fast 2kg/hand 0 - -4 3 Fast 4kg/hand 0 - -5 3 Fast 6kg/hand 0 - -6 3 Fast 8kg/hand 0 - -7 2 Fast 8kg/hand 1 Fast None 8 2 Fast 8kg/hand 1 Fast 2kg 9 2 Fast 8kg/hand 1 Fast 4kg 10 1 Fast 8kg/hand 2 Fast 4kg 11 1 Fast 8kg/hand 2 Fast 6kg 12 1 Fast 8kg/hand 2 Fast 8kg Description of Exercise Execution For weeks one to six the participants performed two-legged eccentric squats with weekly progressions in resistance. The participants started in a standing position 24 hands by their side, and feet positioned shoulder width apart. The squat was initiated by unlocking the knees. Flexion continues at the knee and hip to a depth of no more than 45 degrees. The participant was instructed to look down at their "knee caps" and make sure that they were aligned over the second digit. They were also instructed to keep their feet flat on the floor at all times. Figure 7a and 7b: Front v i e w of d r o p squat S ide v i e w of d r o p squat Alignment of knees B B e n d k" e e & n o m o r e t h a n 45" Flexion was performed at the prescribed speed (slow or fast). From the position of flexion, the participant slowly returned to the standing upright position by actively extending the knee and hip. The squat was then repeated for the prescribed amount of repetitions. Resistance from handheld weights was introduced incrementally each week. During weeks seven to 12 the number of two-legged squats was slowly reduced and single-legged squats performed on each leg were introduced. The one-legged squat involved performing the squat with one extremity at a time. The starting position for the single-legged squat involves standing on one leg and flexing the other leg to 90 degrees of flexion off the ground. To maintain balance the participant lightly touched a nearby counter or railing. From the starting position, the participant unlocked their knee and continued flexion of the knee and hip to a depth of no more than 45 degrees. The 25 participant then actively extended their knee (avoiding full extension) and hip slowly to return to standing. The squat was then continued for the prescribed amount of repetitions. Resistance was progressively increased weekly. Analysis of Data The use of SPSS version 10.0 for Windows was used for all statistical analysis. Significance was accepted at the p<0.05 level for all statistical analysis. The use of descriptive statistics were used to describe participant characteristics (height, weight and activity level). A T-test was used to compare participant compliance to the home exercise program in both the PFPS Group and the control group. Average peak isokinetic torque values collected by the KINCOM® and VISA values were statistically analyzed using 1X4 and 2X4 repeated measures analysis of variance (RMANOVA). Tukey's HSD (honestly significant difference) testing was used for all post hoc comparisons. 1X4 RMANOVA was used to determine significant differences throughout the 12-week exercise program on each of the dependent variables (VISA results, average peak torque values, eccentric/concentric ratios and hamstrings/quadriceps ratios). Tukey's HSD testing was used for all post hoc comparisons. 2X4 RMANOVA was used to compare the injured extremity to the noninjured extremity for the following dependent variables; average peak torque values, eccentric/concentric ratios and hamstrings/quadriceps ratios. A 2X4 RMANOVA was also used to compare the PFPS group to the control group in the following dependent variables; VISA score, and average eccentric peak torque values for the quadriceps and hamstrings. 26 Chapter 4 Results A. Participant Descriptive Results Participants were matched for height, weight and activity level in order to maintain homogeneity throughout the Patellofemoral Pain Syndrome (PFPS) Group and the Control Group. All participants in the PFPS group presented with only one leg suffering from PFPS. Table A1 summarizes the descriptive data of the two groups. There were no significant differences between the two groups. Table A1: Participant Descriptive Data Summary Mean ± Standard Deviation Group Age (years) Weight (kg) Height (cm) Activity Level (hr/wk) PFPF 27.53 ± 5.56 66.88 ± 14.41 167.23 ±4.13 9.88 ± 10.68 NORM 23.39 ± 3.87 65.44 ± 10.99 167.19 ±5.84 9.53 ±3.98 PFPS = Patellofemoral Pain Syndrome NORM = Controls kg = kilograms cm = centimetres hr/wk = hours per week B. Participant Compliance Participants in both the PFPS group and the control group were asked to record their compliance to the home exercise program in a log book. Statistical analysis indicated that there was not a significant difference between the two groups compliance (Table B1). Although descriptive statistics on this group showed that the control group ranged from being 25% compliant to 100% compliant, where as the PFPS group had a range of 63% compliant to 100% compliant. 27 Table B1: Participant Home Exercise Program Compliance (%) Mean ± Standard Deviation PFPS NORM 90.47 ± 9.51 83.39 ± 17.83 NS PFPS = Patellofemoral Pain Syndrome NORM = Control Group NS = not significant p<0.05 C. Victorian Institute of Sport Assessment (VISA) Scale 12-week Comparison The controls exhibited significantly higher VISA aggregate scores than the PFPS group (Table C1; Figure C1). However, neither group experienced a significant change over the 12 weeks. Although a small non-significant increase occurred in the PFPS group from week 4 to 12. The analysis of the individual VISA score questions revealed that there were no significant changes in any of the questions. Table C1: VISA Aggregate Scores Mean ± Standard Deviation Time PFPS NORM 0 wks 65.41 ± 14.52 97.39 ±5.16 4 wks 64.29 ± 18.69 97.22 ± 5.93 8 wks 68.53 ±17.02 97.06 ± 6.52 12 wks 70.41 ±20.32 98.33 ± 3.38 PFPS = Patellofemoral Pain Syndrome NORM = Control Group wks = weeks 28 Figure C1: VISA Aggregate Scores Comparison 110T 100 2 90 o o CO CO o 80-^  70 60 Time (Weeks) Participant Group PFPS Control 12 D. Patellofemoral Pain Syndrome Group Versus Treatment It was hypothesized that the isokinetic eccentric peak torque of the quadriceps and the hamstrings would increase significantly. Statistical analysis at both velocities (60 and 120 degrees per second) indicated that there were no significant increases in quadriceps and hamstrings eccentric torque for both the injured and noninjured extremity during the 12-week program (Table D1 and Table D2). Statistical analysis at both velocities (60 and 120 degrees per second) also revealed that concentric peak torque of both the quadriceps and hamstrings injured and noninjured extremity did not increase significantly (Table D1 and Table D2). When comparing the quadriceps and hamstrings eccentric torque on the injured leg and noninjured leg at 60 and 120 degrees per second there were no significant time by group differences between the two legs. There was a significant (p<0.05) time effect 29 for both velocities (60 and 120 degrees per second). Figures D1 and D2 illustrate the strength patterns of the quadriceps and Figures D5 and D6 illustrate the strength patterns of the hamstrings. When comparing the quadriceps and hamstrings concentric torque on the injured leg and noninjured leg at 60 and 120 degrees per second there were no significant time by group differences between the two legs. There was a significant time effect (p<0.05). Figures D3 and D4 illustrate the quadriceps and D7 and D8 illustrates the hamstrings concentric strength patterns. Table D1: Patellofemoral Pain Syndrome Versus Treatment - Quadriceps Time Average Peak Torque ± S.D. INJQUADECC 0 wks 151.94 ±59.37 @ 60 deg/sec 4 wks 148.94 ± 52.08 NS 8 wks 143.47 ± 54.57 NS 12 wks 155.65 ±44.64 NS NONQUADECC 0 wks 148.35 ±49.27 @ 60 deg/sec 4 wks 139.29 ±53.82 NS 8 wks 141.29 ±51.35 NS 12 wks 159.24 ±49.08 NS INJQUADECC 0 wks 143.29 ±46.95 @ 120 deg/sec 4 wks 153.88 ±47.92 NS 8 wks 145.88 ±41.23 NS 12 wks 157.12 ±41.64 NS NONQUADECC 0 wks 146.76 ± 44.63 @ 120 deg/sec 4 wks 149.12 ±42.81 NS 8 wks 145.71 ±41.96 NS 12 wks 158.88 ±42.66 NS Time Average Peak Torque ± S.D. INJQUADCON 0 wks 103.00 ±23.35 @ 60 deg/sec 4 wks 108.65 ±22.10 NS 8 wks 109.94 ±24.15 NS 12 wks 111.59 ± 21.88 NS NONQUADCON 0 wks 103.00 ±27.50 @ 60 deg/sec 4 wks 105.06 ±20.82 NS 8 wks 109.82 ±27.26 NS 12 wks 115.47 ±31.07 NS INJQUADCON 0 wks 83.12 ± 18.70 @ 120 deg/sec 4 wks 89.47 ± 20.92 NS 8 wks 88.88 ± 17.42 NS 12 wks 91.88 ±20.14 NS NONQUADCON 0 wks 79.47 ±21.76 @ 120 deg/sec 4 wks 89.06 ± 19.10 NS 8 wks 90.88 ± 18.15 NS 12 wks 96.47 ± 16.90 NS INJ = injured ECC = eccentric wks = weeks NON = noninjured CON = concentric NS = not significant p<0.05 QUAD = quadriceps deg/sec = degrees per second 30 Table D2: Patellofemoral Pain Syndrome Versus Treatment - Hamstrings Time Average Peak Torque ± S.D. INJHAMSECC 0 w k s 90.71 ± 27.44 @ 60 deg/sec 4 w k s 85.88 ± 23 .52 NS 8 w k s 94.41 ± 22.25 NS 12 w k s 96.88 ± 23.90 NS NONHAMSECC 0 w k s 97.06 ± 24.48 @ 60 deg/sec 4 w k s 98.88 ± 22.52 NS 8 w k s 101.88 ± 2 2 . 6 7 NS 12 w k s 105.00 ± 2 4 . 9 2 NS INJHAMSECC 0 w k s 97.06 ± 2 2 . 3 1 @ 120 deg/sec 4 w k s 96.06 ± 25.06 NS 8 w k s 102.53 ± 19.29 NS 12 w k s 101.76 ± 2 0 . 9 1 NS NONHAMSECC 0 w k s 100.12 ± 2 5 . 7 2 @ 120 deg/sec 4 w k s 105.06 ± 2 1 . 2 0 NS 8 w k s 111.18 ± 15.00 NS 12 w k s 112.88 ± 2 0 . 3 9 NS INJ = injured ECC = eccentric wks = weeks Time Average Peak Torque ± S.D. INJHAMSCON 0 w k s 70.71 ± 14.65 @ 60 deg/sec 4 w k s 72.29 ± 14.79 NS 8 w k s 72.35 ± 12.32 NS 12 w k s 73.94 ± 13.36 NS NONHAMSCON 0 w k s 72.53 ± 14.53 @ 60 deg/sec 4 w k s 76.00 ± 12.43 NS 8 w k s 74.65 ± 9.80 NS 12 w k s 79.06 ± 12.49 NS INJHAMSCON 0 w k s 67.71 ± 12.37 @ 120 deg/sec 4 w k s 70.41 ± 12.50 NS 8 w k s 71.88 ± 16.01 NS 12 w k s 66.82 ± 1 1 . 8 5 NS NONHAMSCON 0 w k s 69.71 ± 14.51 @ 120 deg/sec 4 w k s 72.59 ± 9.79 NS 8 w k s 69.41 ± 12.12 NS 12 w k s 71.59 ± 1 1 . 3 3 NS NON = noninjured CON = concentric NS = not significant p<0.05 HAMS = hamstrings deg/sec = degrees per second Figure D1: Quadriceps Eccentric at 60 degrees per second 170n 16CH O 150-1 cr i o » 140-^ 130 I 4 8 TIME (Weeks) PFPS Group * Injured Noninjured 12 31 Figure D2: Quadriceps Eccentric at 120 degrees per second 160 PFPS Group • . . . Injured Noninjured TIME (Weeks) Figure D3: Quadriceps Concentric at 60 degrees per second 118 4 8 TIME (Weeks) PFPS Group * Injured Noninjured 3 2 Figure D4: Quadriceps Concentric at 120 degrees per second 100n 1 90-ZJ cr 80 7 70 PFPS Group * In jured Non in ju red 12 TIME (Weeks) Figure D5: Hamstrings Eccentric at 60 degrees per second 110 100 cr 4 8 TIME (Weeks) 33 Figure D6: Hamstrings Eccentric at 120 degrees per second 120 110 CD 3 F o 100-90 PFPS Group * Injured B Noninjured 4 8 TIME (Weeks) 12 Figure D7: Hamstrings Concentric 60 degrees per second PFPS Group ® I n j u r e d N o n i n j u r e d 4 3 TIME (Weeks) 12 34 Figure D8: Hamstrings Concentric 120 degrees per second PFPS Group Injured " Noninjured 6 4 8 1 2 \ TIME (Weeks) It was hypothesized that the eccentric/concentric strength ratios of the quadriceps and hamstrings of both the injured and noninjured extremities would increase significantly at both velocities (60 and 120 degrees per second). However, statistical analysis revealed that eccentric/concentric strength ratios did not increase significantly (Table D3). Comparisons on the injured and noninjured quadriceps and hamstrings eccentric/concentric strength ratio at both velocities (60 and 120 degrees per second) leg did not significantly change. Figures D9 to D12 illustrate the eccentric/concentric strength patterns. ZZ cr 35 Table D3: Patellofemoral Pain Syndrome Versus Treatment - Eccentric/concentric Strength Ratios Time Average Peak Torque ± S.D. Time Average Peak Torque ± S.D. QUADINJ E/C 0 w k s 1.46 ± 48 @ 60 deg/sec 4 w k s 1.34 ± 32 NS 8 w k s 1.28 ± 29 NS 12 w k s 1.38 ± .24 NS QUADNON E/C 0 w k s 1.45 + .32 @ 60 deg/sec 4 w k s 1.29 ± .32 NS 8 w k s 1.27 ± .29 NS 12 w k s 1.39 + .30 NS QUADINJ E/C 0 w k s 1.73 + .49 @ 120 deg/sec 4 w k s 1.74 + .52 NS 8 w k s 1.63 + .29 NS 12 w k s 1.72 ± .32 NS QUADNON E/C 0 w k s 1.85 ± .35 @ 120 deg/sec 4 w k s 1.67 + .38 NS 8 w k s 1.59 ± .33 NS 12 w k s 1.64 ± .28 NS HAMSINJ E/C 0 w k s 1.28 + 27 @ 60 deg/sec 4 w k s 1.21 + .30 NS 8 w k s 1.31 + .25 NS 12 w k s 1.31 + .20 NS HAMSNON E/C 0 w k s 1.35 + .28 @ 60 deg/sec 4 w k s 1.31 ± .27 NS 8 w k s 1.36 + .23 NS 12 w k s 1.33 + .22 NS HAMSINJ E/C 0 w k s 1.45 + .33 @ 120 deg/sec 4 w k s 1.37 + .36 NS 8 w k s 1.45 + .26 NS 12 w k s 1.54 + .29 NS HAMSNON E/C 0 w k s 1.44 + .28 @ 120 deg/sec 4 w k s 1.47 + .31 NS 8 w k s 1.63 + .27 NS 12 w k s 1.58 ± .19 NS INJ = injured NON = noninjured QUAD = quadriceps HAMS = hamstrings E/C = Eccentric/concentric strength ratio deg/sec = degrees per second wks = weeks NS = not significant p<0.05 36 Figure D9: Quadriceps Eccentric/concentric Strength Ratios at 60 degrees per second 4 8 TIME (Weeks) Figure D10: Quadriceps Eccentric/concentric Strength Ratios at 120 degrees per second c cu o c o o 15 LU 1.9 *= 1.8 CO 1.7 c 0) o ?, 1.6 1.5 4 8 TIME (Weeks) PFPS Group # Injured * Noninjured 12 37 Figure D11: Hamstrings Eccentric/concentric Strength Ratios at 60 degrees per second 4 8 TIME (Weeks) Injured Noninjured Figure D12: Hamstrings Eccentric/concentric Strength Ratios At 120 degrees per second 1.7-'•5 CC o c 0 o c o O o c 0 o o LU 1-5H 1.4-1.3 PFPS Group Injured Noninjured 12 TIME (Weeks) 38 It was hypothesized that the hamstrings/quadriceps ratio would improve significantly. There were no significant differences in the hamstrings/quadriceps ratio both in the injured and noninjured extremity at 60 and 120 degrees per second (Table D4). Tukey's honestly significant difference (HSD) post hoc analysis revealed a significant decrease (p<.05) on the hamstring/quadriceps concentric ratio noninjured extremity at 120 degrees per second (Table D4). Comparisons on the injured and noninjured legs hamstring/quadriceps ratio eccentrically and concentrically at both velocities (60 and 120 degrees per second) leg did not increase significantly. Figures D13 to D16 illustrate the hamstrings/quadriceps patterns. Table D4: Patellofemoral Pain Syndrome Versus Treatment -Hamstrings/quadriceps Ratios Time Average Peak Torque ± S.D. Time Average Peak Torque ± S.D. ECCINJ H/Q 0 w k s .65 ± 21 @ 60 deg/sec 4 w k s .63 ± 22 NS 8 w k s .72 ± 24 NS 12 w k s .65 ± 15 NS ECCNON H/Q 0 w k s .69 ± 16 @ 60 deg/sec 4 w k s .77 ± 21 NS 8 w k s .78 ± .22 NS 12 w k s .69 ± .15 NS ECCINJ H/Q 0 w k s .73 ± .22 @ 120 deg/sec 4 w k s .67 ± .22 NS 8 w k s .75 ± .23 NS 12 w k s .68 ± .18 NS ECCNON H/Q 0 w k s .71 ± .16 @ 120 deg/sec 4 w k s .74 ± .17 NS 8 w k s .84 ± .33 NS 12 w k s .75 ± .19 NS CONINJ H/Q 0 w k s .70 + 12 @ 60 deg/sec 4 w k s .68 + 15 NS 8 w k s .67 ± 12 NS 12 w k s .67 + 11 NS CONNON H/Q 0 w k s .75 + 2 8 @ 60 deg/sec 4 w k s .73 + 14 NS 8 w k s .70 + .13 NS 12 w k s .71 + .13 NS CONINJ H/Q 0 w k s .92 + .22 @ 120 deg/sec 4 w k s .83 + .26 NS 8 w k s .82 + .13 NS 12 w k s .74 + .13 NS CONNON H/Q 0 w k s .92 + .22 @ 120 deg/sec 4 w k s .84 + .20 NS 8 w k s .78 + .13 NS 12 w k s .75 + .13 S* INJ = injured NON = noninjured ECC = eccentric CON = concentric H/Q = Hamstrings/quadriceps strength ratio deg/sec = degrees per second wks = weeks NS = not significant p<0.05 S* = significant week 0 - 1 2 39 Figure D13: Hamstrings/Quadriceps Ratio Eccentric at 60 degrees per second CO a: eo Q . CD O ' i— T J CO 3 g "35 O) c co E co X 4PFPS Group * Injured Noninjured TIME (Weeks) Figure D14: Hamstrings/Quadriceps Ratio Eccentric at 120 degrees per second CO CH co Q . CD O *i "O CO 3 g "35 cn _c '\— (O E CO X 4 8 TIME (Weeks) 40 Figure D15: Hamstrings/Quadriceps Ratio Concentric at 60 degrees per second PFPS Group • * Injured B Noninjured 12 TIME (Weeks) Figure D16: Hamstrings/Quadriceps Ratio at 120 degrees per second CO or (/> Q. CJJ O ' i T3 CO ZZi q 'k_ —^< CA E CO X PFPS Group ® Injured Noninjured 4 8 TIME (Weeks) 41 E. Control Group versus Treatment Healthy controls were analyzed for comparison with the PFPS group. In the control group, there was no significant difference from week 0 to week 12 in quadriceps and hamstrings eccentric and concentric peak torque values at both velocities (60 and 120 degrees per second) (Table E1 and E2). Table E1: Controls versus Treatment: Quadriceps Time Average Peak Torque ± S.D. INJQUADECC 0 w k s 186.89 ± 5 7 . 3 7 @ 60 deg/sec 4 w k s 183.11 ± 6 6 . 1 5 NS 8 w k s 171.11 ± 6 9 . 3 2 NS 12 w k s 181.83 ± 6 8 . 6 8 NS NONQUADECC 0 w k s 168.50 ± 6 6 . 0 1 @ 60 deg/sec 4 w k s 170.39 ± 5 0 . 6 7 NS 8 w k s 171.33 ± 5 6 . 4 3 NS 12 w k s 180.94 ± 5 4 . 5 2 NS INJQUADECC 0 w k s 184.34 ± 6 6 . 8 2 @ 120 deg/sec 4 w k s 176.67 ± 6 1 . 3 1 NS 8 w k s 169.56 ± 6 6 . 7 9 NS 12 w k s 184.44 ± 6 8 . 6 5 NS NONQUADECC 0 w k s 166.56 ± 6 1 . 6 2 @ 120 deg/sec 4 w k s 170.50 ± 4 7 . 0 9 NS 8 w k s 174.28 ± 5 5 . 6 9 NS 12 w k s 173.22 44.79 NS Time Average Peak Torque ± S.D. INJQUADCON 0 w k s 127.44 ± 39.22 @ 60 deg/sec 4 w k s 126.56 ± 3 5 . 1 6 NS 8 w k s 124.22 ± 36.46 NS 12 w k s 124.89 ± 36.47 NS NONQUADCON 0 w k s 124.72 ± 3 4 . 4 5 @ 60 deg/sec 4 w k s 126.72 ± 35.57 NS 8 w k s 126.00 ± 33.94 NS 12 w k s 130.00 ± 34.49 NS INJQUADCON 0 w k s 103.17 ± 3 1 . 8 8 @ 120 deg/sec 4 w k s 104.39 ± 2 8 . 8 7 NS 8 w k s 101.11 ± 2 6 . 3 5 NS 12 w k s 105.57 ± 3 1 . 3 4 NS NONQUADCON 0 w k s 101.33 ± 31.19 @ 120 deg/sec 4 w k s 108.89 ± 28.38 NS 8 w k s 104.00 ± 3 0 . 5 9 NS 12 w k s 106.72 ± 2 8 . 8 5 NS INJ = injured matched NON = noninjured matched QUAD = quadriceps ECC = eccentric CON = concentric deg/sec = degrees per second wks = weeks NS = not significant p<0.05 42 Table E2: Controls vs. Treatment: Hamstrings Time Average Peak Torque ± S.D. Time Average Peak Torque ± S.D. INJHAMSECC 0 w k s 114.17 ± 3 6 . 6 2 @ 60 deg/sec 4 w k s 107.28 ± 2 8 . 2 7 NS 8 w k s 103.72 ± 2 6 . 3 9 NS 12 w k s 107.22 ± 2 7 . 8 3 NS NONHAMSECC 0 w k s 100.00 ± 3 7 . 2 7 @ 60 deg/sec 4 w k s 99.17 ± 3 0 . 8 2 NS 8 w k s 97.89 ± 30.41 NS 12 w k s 89.89 ± 20.64 NS INJHAMSECC 0 w k s 118.94 ± 41 .18 @ 120 deg/sec 4 w k s 114.78 ± 2 8 . 9 7 NS 8 w k s 110.83 ± 2 8 . 9 1 NS 12 w k s 112.89 ± 2 8 . 6 1 NS NONHAMSECC 0 w k s 103.39 ± 3 5 . 1 2 @ 120 deg/sec 4 w k s 107.83 ± 2 9 . 1 2 NS 8 w k s 104.22 ± 3 4 . 7 9 NS 12 w k s 98.33 ± 25.37 NS INJHAMSCON 0 w k s 87.50 ± 22.35 @ 60 deg/sec 4 w k s 88.44 + 23.02 NS 8 w k s 85.33 + 18.22 NS 12 w k s 85.22 + 23.14 NS NONHAMSCON 0 w k s 74.67 + 22.10 @ 60 deg/sec 4 w k s 79.33 ± 18.68 NS 8 w k s 81.44 + 19.76 NS 12 w k s 77.56 + 19.87 NS INJHAMSCON 0 w k s 83.33 + 26.43 @ 120 deg/sec 4 w k s 85.78 + 25.61 NS 8 w k s 79.78 + 21.47 NS 12 w k s 81.72 + 22.30 NS NONHAMSCON 0 w k s 68.67 + 22..91 @ 120 deg/sec 4 w k s 72.61 + 21.27 NS 8 w k s 75.33 + 18.96 NS 12 w k s 73.50 + 23.33 NS INJ = injured matched NON = noninjured matched HAMS = hamstrings ECC = eccentric CON = concentric deg/sec = degrees per second wks = weeks NS = not significant p<0.05 There were no significant differences in eccentric/concentric strength ratios at 60 and 120 degrees per second in the quadriceps and hamstrings (Table E3). 43 Table E3: Controls vs Treatment: Eccentric/Concentric Strength Ratio Time Average Peak Torque ± S.D. QUADINJ E/C 0 w k s 1.49 ± .24 @ 60 deg/sec 4 w k s 1.45 ± 32 NS 8 w k s 1.37 ± 34 NS 12 w k s 1.44 ± 31 NS QUADNON E/C 0 w k s 1.32 ± .27 @ 60 deg/sec 4 w k s 1.35 ± .26 NS 8 w k s 1.36 ± .26 NS 12 w k s 1.40 ± .26 NS QUADINJ E/C 0 w k s 1.79 ± .34 @ 120 deg/sec 4 w k s 1.69 ± .35 NS 8 w k s 1.64 ± .32 NS 12 w k s 1.73 ± .30 NS QUADNON E/C 0 w k s 1.63 ± .29 @ 120 deg/sec 4 w k s 1.58 ± .25 NS 8 w k s 1.70 ± .38 NS 12 w k s 1.64 ± .20 NS Time Average Peak Torque ± S.D. HAMSINJ E/C 0 w k s 1.30 ± .22 @ 60 deg/sec 4 w k s 1.24 ± .25 NS 8 w k s 1.22 ± .18 NS 12 w k s 1.27 ± .18 NS HAMSNON E/C 0 w k s 1.32 ± .20 @ 60 deg/sec 4 w k s 1.24 ± .22 NS 8 w k s 1.19 ± .20 NS 12 w k s 1.18 ± .15 NS HAMSINJ E/C 0 w k s 1.43 + .25 @ 120 deg/sec 4 w k s 1.40 ± .37 NS 8 w k s 1.43 ± .30 NS 12 w k s 1.40 ± .20 NS HAMSNON E/C 0 w k s 1.52 ± .30 @ 120 deg/sec 4 w k s 1.51 ± .29 NS 8 w k s 1.37 ± .24 NS 12 w k s 1.37 ± .23 NS INJ = injured matched NON = noninjured matched QUAD = quadriceps HAMS = hamstrings E/C = Eccentric/concentric strength ratio deg/sec = degrees per second wks = weeks NS = not significant p<0.05 Hamstring/quadriceps ratios did not significantly improve in the control group. Although it is interesting to note that except for week 12 on both the noninjured eccentric matched leg for both 60 and 120 degrees per second the controls hamstring/quadriceps ratios are all within a healthy value of 0.60 and above (Table E4) (5,24,33,46). 44 Table E4: Controls vs. Treatment: Hamstrings/Quadriceps Ratio Time Average Peak Torque ± S.D. ECCINJ H/Q 0 w k s .62 ± 13 @ 60 deg/sec 4 w k s .63 ± 18 NS 8 w k s .66 ± 19 NS 12 w k s .64 ± 19 NS ECCNON H/Q 0 w k s .61 ± 12 @ 60 deg/sec 4 w k s .60 ± 13 NS 8 w k s .59 ± .13 NS 12 w k s .52 ± .10 NS ECCINJ H/Q 0 w k s .64 ± .17 @ 120 deg/sec 4 w k s .68 ± .15 NS 8 w k s .70 ± .17 NS 12 w k s .66 ± .19 NS ECCNON H/Q 0 w k s .64 ± .12 @ 120 deg/sec 4 w k s .64 ± .11 NS 8 w k s .60 ± .12 NS 12 w k s .58 ± .12 NS INJ = injured matched NON = noni Time Average Peak Torque ± S.D. CONINJ H/Q 0 w k s .71 + 2 0 @ 60 deg/sec 4 w k s .71 + .13 NS 8 w k s .71 + .11 NS 12 w k s .69 + .12 NS CONNON H/Q 0 w k s .60 + .12 @ 60 deg/sec 4 w k s ^64 + .12 NS 8 w k s .66 + .12 NS 12 w k s .60 + .13 NS CONINJ H/Q 0 w k s .82 + .22 @ 120 deg/sec 4 w k s .83 + .15 NS 8 w k s .79 + .15 NS 12 w k s .79 + .14 NS CONNON H/Q 0 w k s .69 ± .15 @ 120 deg/sec 4 w k s .67 + .12 NS 8 w k s .75 + .17 NS 12 w k s .69 + .10 NS ECC = eccentric CON = concentric H/Q = Hamstrings/quadriceps strength ratio deg/sec = degrees per second wks = weeks NS = not significant p<0.05 F. PFPS Group Versus Control Group: Eccentric Peak Torque There was no significant difference between the PFPS group and the control group in eccentric peak torque in both the quadriceps and hamstrings at both 60 and 120 degrees per second (Figures F1 - F8). 45 Figure F1: PFPS vs. Control Quadriceps Eccentric Torque at 60 degrees per second Injured Leg 190 180 E 170 cu cr O 160 Participant Group * PFPS m Control Figure F2: PFPS vs. Control Quadriceps Eccentric Torque at 60 degrees per second Noninjured Leg 190 Participant Group 46 Figure F3: PFPS vs. Control Quadriceps Eccentric Torque at 120 degrees per second Injured Leg 190 180 E 170 CD 3 cr O 160 150H 140 Participant Group TIME (Weeks) Figure F4: PFPS vs. Control Quadriceps Eccentric Torque at 120 degrees per second Noninjured Leg 180 Participant Group • PFPS Controls TIME (Weeks) 47 Figure F5: PFPS vs. Control Hamstrings Eccentric Torque at 60 degrees per second Injured Leg 120 110 0) 100 Z3 CT 90T 80 Participant Group PFPS Control 4 3 TIME (weeks) 12 Figure F6: PFPS vs. Control Hamstrings Eccentric Torque at 60 degrees per second Noninjured Leg 110 100* E z CD cr Paticipant Group PFPS Control 4 8 Figure F7: PFPS vs. Control Hamstrings Eccentric Torque at 120 degrees per second Injured Leg 1 3 0 n 1 120H CD 11CH E o i o o H 9 0 I Participant Group • PFPS " Controls 4 8 TIME (Weeks) 1 2 Figure F8: PFPS vs. Control Hamstrings Eccentric Torque at 120 degrees per second Noninjured Leg 1 2 0 110H CD c r 1 0 0 f 9 0 I Participant Group • PFPS B Controls 4 8 TIME (Weeks) 1 2 49 Chapter 5 Discussion Patellofemoral pain syndrome (PFPS) is one of the most common causes of anterior knee pain seen in the field of sport medicine. Treatment of PFPS has been studied extensively due to lack of long term success (2,26). The multifactorial etiology of PFPS (trauma, overuse, biomechanical problems (increased Q-angle, excessive pronation) and muscular dysfunctions (muscular weaknesses, tightness and neural imbalances)] leads to complexity in determining the best treatment solutions (2,30,31). Conservative treatment of PFPS aims to optimize patellar positioning and to improve lower limb mechanics. When patellar positioning and lower limb mechanics have been corrected significant decreases in pain are felt by patients (7,8,9,10,33). Stair stepping tasks in conjunction with taping, and closed kinetic chain exercises (CKC) (such as wall squats) are commonly used rehabilitation practices in the treatment of PFPS (2,7,8,9,10,11,30,31). Practitioners at the Allan McGavin Sports Medicine Centre (University of British Columbia, Vancouver, Canada) currently employ the eccentric drop squat program as part of their treatment protocol for PFPS. This investigation examined individuals with PFPS to determine if they were weak eccentrically in comparison to healthy controls. It also evaluated the effects of the 12-week home eccentric drop squat program commonly used by the Allan McGavin Sports Medicine Centre as a form of conservative treatment to improve function and strength in PFPS and healthy controls. The study included two groups of females; a PFPS group (n=17) and a control group that was matched for height, weight and activity level (n=18). Both groups under took a 12-week home eccentric drop squat program that consisted of gradual progressions (both daily and weekly), and 4 testing sessions. 50 Testing sessions were done at 0, 4, 8 and 12 weeks and consisted of isokinetic strength testing and subjective testing for pain and function. All participants with PFPS were diagnosed by a physician using specific inclusion criteria (see methods) and their only treatment was the eccentric drop squat program. Participants were not permitted to use braces, taping, physiotherapy or other rehabilitation techniques in conjunction with this program. Participant Compliance Since this program was designed as a home rehabilitation program participants were asked to log their program compliance. Even though there was no statistical difference between the PFPS and control group in program adherence it is interesting to compare the range in compliance between the two groups. Compliance ranged from 63% to 100% in the PFPS group with 11 out of the 17 above 90% and 25% to 100% in the control group. When asked about the days that were missed the controls commonly said that they "forgot", where the PFPS participants commonly missed due to pain. The control group also commented that they found the program easy and that they did not feel that they were gaining anything from the gradual progressions of the rehabilitation program. The ease of the progressional steps of the program design could be a reason for the range in compliance that was seen by the control group. Unfortunately, when using a home program exercise design it is difficult to definitively monitor program adherence. Also, it was unrealistic to ask participants to come to the clinic everyday for approximately ten minutes of rehabilitation exercise. 51 Victorian Institute of Sport Assessment (VISA) Score The VISA score was used as a subjective measure for pain and function at each testing session. Significant differences (p<0.05) were observed between the control group and the PFPS group. This finding is consistent with the pilot research (Appendix A) done to validate the VISA score as a measure of pain and function for individuals with PFPS. There were no significant improvements in both the PFPS group and the control group. This finding was expected for the control group as they have normal functioning knees and should report a score of close to 100. However, we did hypothesize a significant improvement from week 0 to week 12 in the PFPS group. Due to the make up of the VISA score, in order to score high on questions 7 and 8 the participant needs to be back to full activity at the same level or higher without pain, and needs to be able to continue at this level for a substantial period of time before the onset of pain in the knees stops them from participating. Questions 7 and 8 are worth a total of 40 points out of a possible 100. Scoring low on these two questions substantially lowers the final score. The PFPS participants gradually increased their work load/activity level as the 12 weeks progressed, but not to levels that they were prior to injury. Gradual increases in activity level are common during rehabilitation programs in order to decrease further injury and to maximize the treatment program that the individual receives. Therefore, it is speculated that one possible reason for the lack of significance seen is due to gradual return to activity exhibited by the PFPS group. It is possible that if this group were^to be monitored for a longer period of time that their VISA aggregate scores may show significant improvements. The VISA scores did not follow the same pattern as the strength measures (drop in week 8) which you would expect if the participants were suffering from increased pain during week 8. This leads investigators to speculate that the VISA may not be a reliable tool for individuals 52 suffering from PFPS, and that the use of the visual analogue scale (VAS) for pain and function may be a better quantitative measure. Quadriceps and Hamstrings Eccentric Peak Torque There were no significant changes from week 0 to week 12 in quadriceps eccentric average peak torque values. Participants did however produce higher eccentric peak torque values, than concentric peak torque values. The production of higher eccentric peak torque values than concentric peak torque values is consistent with literature on eccentric and concentric torque characteristics in extension (quadriceps) and flexion (hamstrings) (21, 24). It is interesting to note that the injured leg by week 4 was producing eccentric torque values higher then those of the noninjured leg. During week 8 testing the injured leg at both velocities (60 and 120 degrees per second) dropped dramatically, and started to gradually increase again by week 12 (Figure D1 and D2). The noninjured leg also dropped during week 8, and improved by week 12. Although the graph shows a steeper slope in the positive direction after week 8 for the noninjured leg which may indicate a faster rate of recovery. We believe this drop in the eccentric peak torque values is possibly due to the onset of single legged squats during week 7. As there was an increase in load applied to the leg, and alignment of the leg and knee joint is crucial to proper execution of the squat. The increased load and potential for valgus strain due to misalignment during the drop phase of the squat, increases the chance of pain during the exercise. The gradual increase in peak torque values present in the raw data and by observation of the graphs as the weeks went on indicates that that there may be an improvement in the single legged squatting technique, which in turn will improve alignment issues that occur during the drop phase. 53 Eccentric hamstrings strength on the injured and noninjured leg did not produce significant improvements during the 12 weeks. Similar to the quadriceps the hamstrings also produced higher eccentric peak torque values than concentric peak torque values, which is consistent with previous studies (21,24). Unlike the quadriceps, the hamstrings eccentric peak torque dropped during week 4 and gradually increased for the last 8 weeks (Figure D5 and D6). The decrease in eccentric peak torque values during week 4 could possibly be due to the increases in resistance. The eccentric strength of the hamstrings noninjured leg however remained fairly linear in comparison to the injured leg. Eccentric/Concentric Strength Ratios Eccentric/concentric strength ratios for both the quadriceps and hamstrings injured and noninjured leg did not yield any significant improvements. Both legs produced ratios that were well over 1.0, which were consistent with the eccentric and concentric peak torque values (eccentric producing higher values). The quadriceps and hamstrings eccentric/concentric strength ratios produced graphs similar to the eccentric graphs (where the peak torque values dropped in week 8 for the quadriceps and week 4 \ for the hamstrings). It is interesting to note that the injured quadriceps eccentric/concentric ratios tend to be higher or close to the values of the noninjured leg, where as the noninjured hamstrings ratios for 60 and 120 degrees per second were stronger then the injured hamstring. Research in the area of posterior cruciate ligament (PCL) insufficiency that formed the basis of some components of the exercise protocol used for this study also did not yield significant improvements in the eccentric/concentric strength ratios (31). 54 Hamstrings/Quadriceps Ratio Eccentric and Concentric There were no significant differences seen in the hamstrings/quadriceps ratio, except for on the noninjured leg concentrically at 120 degrees per second there was a significant decrease. Both the injured leg and the noninjured leg hamstrings/quadriceps ratio decreased by week 12 (Graphs D13 - D16). The values obtained both eccentrically and concentrically were all 0.60 and above, which is considered in the literature within a healthy hamstrings/quadriceps ratio (5,24,33,46). Individual raw data reveals that some of the participants in both the PFPS group and the control group were below what is considered a healthy ratio value. 5,24,33,46 Controls versus Treatment Healthy controls were used in this study as a baseline for eccentric measures. There were no significant differences in the controls with regards to eccentric and concentric peak torque values, eccentric/concentric strength ratios, and hamstrings/quadriceps ratios. The controls also followed a similar pattern to the PFPS group and were able to produce higher eccentric peak torque values then concentric torque values (i.e. eccentric/concentric strength ratios were all above 1.0). There hamstrings/quadriceps ratios were all within a healthy (0.60), except for the eccentric noninjured leg at both 60 and 120 degrees per second. PFPS Group Compared to Healthy Controls - Eccentric Torque There were no significant differences in eccentric torque between healthy controls and the PFPS group. However, the control group produced higher peak torque values on the quadriceps and the hamstrings, except in the hamstrings noninjured leg at 60 and 120 degrees per second (Figures F1-F8). 55 Kinetic Communicator KINCOM® The KINCOM® was used in this study to measure quadriceps and hamstrings eccentric and concentric strength. The KINCOM is unable to isolate the individual quadriceps and hamstrings muscles. Throughout the literature individuals suffering from PFPS tend to be weak in the vastus medialis obliquus (7,8,9,10,32,33). The testing device used was unable to specifically isolate increases in an individual muscle within a muscle group. The use of the KINCOM® may not have been specific enough for the purposes of this study. The use of EMG and MRI in conjunction with the KINCOM® would allow investigators to measure muscle activation and increases in muscle size, as well as, peak torque in select muscle groups. The use of the EMG would also allow investigators to measure involuntary muscle inhibition that may result due to pain during both the muscle strength testing and during the CKC eccentric drop squats. A large range of flexion (0 to 90 degrees) was chosen for the strength testing in order to reflect the large ranges of flexion exhibited at the knee joint in everyday activities. The strength program used in this study did not go beyond 45 degrees of flexion. Therefore, the testing ranges may not accurately portray any strength gains within the range being exercised. Eccentric Drop Squat Program This study isolated one specific treatment regime for PFPS, in order to investigate whether a closed kinetic chain (CKC) eccentric drop squat program would improve the strength and functional capacity of individuals suffering from PFPS. Although no significance was seen in any of the hypotheses measured, the feedback 56 given by the participants is of importance for clinicians. The overall response by individuals with PFPS to the program was positive. As stated earlier participants were increasing their activity level with minimal to no pain, and were completing everyday tasks (such as ascending and descending stairs) with minimal to low pain. The verbal feedback given to the investigator was not consistent with the results obtained from the VISA score which did not support improvements in strength and function. As stated earlier a more sensitive measure is needed to better analyze participants subjective feedback The eccentric drop squat program was easy for the participants to implement and was gradual in progression. Individual differences in perception of pain, severity of PFPS and in physical characteristics may determine the progressional steps of the eccentric drop squat program. Clinicians may need to modify different stages of the strength program to allow patients to move at a pace that works best for them. The introduction of single legged squats was a challenge point for the participants in this study. Designing a program that consists of two legged squats only with increases in repetitions, sets and resistance would be an ideal way to overcome the alignment problems and pain. If clinicians choose to introduce patients to single legged squats they must ensure that the patient is able to maintain the correct patellar alignment. Due to the multifactoral nature of PFPS an isolated treatment protocol may not be adequate to meet the complete rehabilitation needs of the patient. Where strength is presenting as the primary cause of the PFPS in an individual the use of an isolated strength program may be adequate. However, due to the other possible etiological factors that cause PFPS, strength issues may not be the primary cause of injury therefore, the use of a strength program without correcting the primary factor would not be sufficient. The use of taping may be needed in the initial stages of a strength 57 program to maintain correct patellar alignment, until the muscle has been trained neuromuscularly to maintain proper patellofemoral alignment (7,8,9,12,22). Orthotics may need to be prescribed to correct excessive pronation of the foot in conjunction with the strength program (4,30,39). The use of an external device such as taping/bracing to maintain patellar alignment in conjunction with a strength program such as stair stepping is commonly used in PFPS studies (7,8,9,12,30,39). It is important for patients to be thoroughly examined to find the correct treatment or combination of treatments possible. The results of this investigation lead the investigator to believe that participants in this study might have had more significant gains if the program offered another treatment option in conjunction with the eccentric drop squat strength program. Canned et al and MacLean et al Cannell and co-investigators and MacLean et al investigated CKC eccentric drop squats in individuals suffering from patellar tendonopathy and isolated PCL injuries respectively (6,31). Both studies observed significant improvements in eccentric strength. It is interesting to look at these studies in comparison to the results obtained in this study, due to similarities in study design. This study had the control group that was matched for activity level and participated in the treatment protocol, whereas, Cannell did not use controls and MacLean's study did not have the controls exercise and used sedentary individuals. The treatment protocol had gradual progressions which tended to be easy for the controls. The above two studies were done on a population of individuals that strength was a primary focus for their treatment, where as, this study included all individuals suffering from PFPS as long as they were within the age specifications and had not had history of knee surgery and/or patellar dislocation. This means that the primary etiological factor may not have been strength in 58 participants of this study, which means without correcting other issues contributing to the PFPS significant improvements will not be seen. This study also only included female subjects, which differs from the other two studies. Physiological differences between males and females may also affect test outcomes. Although more sophisticated testing devices would be needed to determine this. All three studies look at the knee joint but the injuries themselves are different. A complication associated with PCL insufficiency is PFPS, although MacLean's study does not state the number of participants that had PFPS, if any. Therefore, even though the two studies obtained significant improvements and the study design and the exercise being examined was the same, the etiological factors of the injuries differ which would lead to the contrast in results. Investigators General Observations throughout the Study Participants in both the PFPS group and the control group who were of heavier weight found the fast drop painful on their knees. The participants in the PFPS group found that the fast drop exacerbated the pain in their injured leg and found they were developing pain during the drop phase of the squat in their noninjured leg. Participants in the control group that were matched with the participants in the PFPS group who were having difficulties with the fast drop commented on the pain they were developing in their knees during the fast drop phase of the squat. This concerned the controls that have no previous knee problems. The speed was modified for these individuals so that they started with slow drops and slowly increased their speed on a weekly basis. This modification provided relief of pain to both groups. Unfortunately studies done by Cannell and co-investigators (6) and MacLean and co-investigators (31) either did not use controls or the controls did not partake in the treatment protocol so there is no data 59 or information on feedback presented by the controls, nor was there comment on how injured participants of heavier weight responded to the speed of the drop phase of the squat. The single legged squats tended to be the most problematic for participants. During the week 8 testing participants in the PFPS group commented on increased pain during the single legged squats. Demonstration of these squats to the investigator showed that the knee alignment during the drop phase of the squat was incorrect. This group tended to have trouble maintaining control on the drop and their knee would "buckle" (Valgus strain) and then straighten out right before they would start the up phase of the squat. Alignment corrections were given to these participants, although this proved to be quite difficult for some to consistently maintain proper alignment. It was suggested to these individuals to perform the single legged squats in a doorway without any weight so that they could lightly touch the walls on both sides; this allowed them assistance for balance and improved the alignment of their knee while squatting. It was also observed that during the week 8 testing sessions many participants decreased in their average peak torque values on various components of the testing. Improvements were seen in the twelfth week on some of the torque measurement. The drop in the average peak torque values could possibly be due to the initiation of single legged squats and the pain felt by participants of the PFPS group. The above two observations indicates that the program may need some modification depending on individual characteristics and strength. Therefore, for some individuals the 12-week program needs to be broken down into smaller progressions to decrease pain during exercise execution and to ensure full program compliance and completion. 60 Investigation also showed that day 6 of a week (where the daily repetitions were 18) tended to be the most commonly missed day. Participants also tended to make any daily modifications the day after a missed day. Although the KINCOM® provides a testing measure for strength that is consistent and reliable, many factors can influence the results produced by participants. The participant's emotional and physical state during the testing session seemed to be the factor that had the most effect on how the participant would do during the test. Participants who came to the testing session tired, in pain, or feeling stressed and upset tended to have more difficulties producing four consistent maximal strength values. In order to collect four good trials the participant had to repeat the test multiple times. This caused for fatiguing of the extremity being tested in both groups and pain in the PFPS group injured leg. Participant Overall Program View There were 17 participants in the PFPS group. Fourteen of the 17 participants said they would continue on doing the squats. They commented that they felt a lot stronger and symptoms of pain and swelling had decreased and the sensation that there knee was going to give away on them or was not tracking properly had decreased. Thirteen of the 14 participants that said that they would continue on with the squats discussed with the investigator ways of altering the program so that they could continue doing the squats long term and use them in conjunction to increasing their activity level back to normal levels. The three participants who said they would not continue doing the squats said it was due to pain during the single legged squats, and they felt that the program did not help improve the state of their knee, as their knee felt the same as it did on week 0. This information provided by the participants is useful for 61 clinicians. Despite the lack of significant increases found during analysis participants felt that they were getting stronger and felt less pain and were starting to go back to activities they could not do previous to starting the program. For Future Research The learning effect of the KINCOM® is also something to take into consideration for future research. Participants, especially in the control group, were able to adjust how they pushed by following the graphs on the computer in order to obtain the same result that they previously produced. Future research should consider turning the computer screen away from the participants. It was decided in this study to use the computer screen as a motivational tool to encourage the participants to push maximally. Future studies may consider using a modified VISA score in combination with a visual analog scale (VAS) for pain and one for function in order to obtain a better indication of improvements felt by the participant. The combination of a modified VISA and the VAS for pain and function may be a possible solution for the weighing placed on questions 7 and 8 in the VISA score, so that improvements can be noted even if the participant is not at a level equal or higher than previous to the injury. Other CKC exercises, such as leg press, could be studied in isolation or in conjunction with the eccentric drop squat exercises to observe the strength and functional gains in individuals suffering from PFPS. Studies on other CKC exercises would increase the variety of exercises that this population could do as part of their treatment protocol and as a maintenance program. The use of magnetic resonance imaging (MRI) to observe muscles activated in the CKC eccentric drop squats program. The use of MRI in future studies would be a good tool for determining if the vastus medialis oblique (VMO) is being activated as well 62 as, what other muscles are being activated. This will lead to a better understanding of what is going on anatomically in the musculature while on the CKC eccentric drop squat program. Observing strength gains and pain and functional improvements using combinations of treatment protocols such as strength, orthotics, bracing/taping and/or stretching would be an ideal next step for future research. 63 Chapter 6 Conclusion The purpose of this investigation was to determine if individuals suffering from patellofemoral pain syndrome (PFPS) are weak eccentrically in comparison to healthy controls, and can a closed kinetic chain (CKC) eccentric drop squat program improve muscular strength and functional capacity in these individuals. Statistical analysis does not support any of the hypothesis determined prior to initiation of the study. Analysis of the output graphs suggests that eccentrically the participants with PFPS were weaker eccentrically in comparison to healthy controls on their injured leg. Participant logbook feedback does support improvements in functional capacity and increases in activity level with minimal to no pain, although the VISA scores do not. Therefore, despite a lack of statistical significance this study acts as a stepping stone for further research on eccentric CKC exercises in individuals suffering from PFPS. 6 4 Appendix A Pilot Study Prior to investigation a pilot study to validate the use of the Victorian Institute of Sport Assessment (VISA) Score as a measure of knee pain and function in patients suffering from patellofemoral pain syndrome (PFPS). Introduction Patellofemoral pain syndrome (PFPS) remains one of the most common causes of anterior knee pain encountered in the sport medicine setting. The multifactorial etiology of PFPS makes successful long-term treatment challenging for clinicians 1 , 2. Many studies have been conducted on the subject PFPS and among these studies many different outcome measures have been used to subjectively measure and assess pain and function 1 , 2. There is a lack of consistency within the literature on pain and functional scales for this population; therefore, many different scales are used throughout the PFPS research. The use of the Victorian Institute of Sport Assessment (VISA) scale has proved to be a reliable and valid scale within individuals suffering from Achilles tendinopathy and patellar tendinopathy. Designed by the Victorian Institute of Sport Tendon Study Group in Melbourne, Australia the VISA consists of eight questions that measure the domains of pain and function in daily living and sport. The scale ranges from 0 to 100 -65 where 100 represents a perfect score. This outcome measure is easy to administer and requires minimal time and investigator assistance 3 , 4. Purpose of Investigation The purpose of this pilot study was to validate the use of the Victorian Institute of Sport Assessment (VISA) Score as a subjective method to measure knee pain, and function in daily living and in sport within individuals suffering from patellofemoral pain syndrome. Hypothesises Hi = U-PFPS - uc * 0 Ho = U-PFPS - M-c = 0 The mean scores of the PFPS group will be significantly lower then the mean scores of the control (healthy, no knee pain) group. Methodology Sample This study included two groups (n = 46, f = 32, m = 14) a control group and a PFPS group. The Patellofemoral Pain Syndrome (PFPS) group consisted of n = 23 (f = 17, m = 6) subjects diagnosed with Patellofemoral Pain Syndrome (PFPS) by physicians at the Allan McGavin Sport Medicine Clinic (University of British Columbia), UBC Student Health Centre, and the David L. Macintosh Sport Medicine Clinic 66 (University of Toronto). The control group consisted of n = 23 (f = 15, m = 8) subjects who were randomly selected with no knee pain or history of knee pain who participate in regular physical activity/sport. All subjects were between the ages of 18 to 50 years. Measures Patients diagnosed with PFPS by physicians at the Allan McGavin Sports Medicine Clinic (UBC), the UBC Student Health Centre, and the David L. Macintosh Sport Medicine Clinic (UofT) were asked to complete the Victorian Institute of Sport Assessment (VISA) Score to test it's validity as a subjective measure for knee pain and function. Healthy active individuals with no knee pain or history of knee pain were also asked to complete the VISA score. The completed VISA scores were given to the researcher, where the scores were then totalled. The two groups were then analyzed using SPSS. An independent, two-tailed T-test at alpha 0.05 was preformed and adjustments were made to account for the spread in the variance. 67 Results Table 1 shows the totals of all the questions on all the participants in the study. Table 1: PFPS: Control: Subject # Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Total Subject # Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Total i 1 10 10 10 3 7 10 4 20 74 C1 10 10 10 9 10 10 10 30 99 2 4 2 2 0 2 10 4 10 34 C2 10 10 10 10 10 10 10 30 100 3 8 2 3 6 3 8 10 20 60 C3 10 10 10 10 10 9 4 30 93 4 6 3 6 3 5 3 4 5 35 C4 10 10 10 10 10 10 4 30 94 5 10 10 10 10 7 10 10 30 97 C5 10 10 10 9 10 10 4 30 93 6 10 8 6 8 8 5 10 20 75 C6 10 10 10 10 10 10 10 30 100 7 10 10 10 10 10 10 0 20 80 C7 10 10 10 10 10 10 10 30 100 8 2 5 7 3 3 4 10 20 54 C8 10 10 10 10 10 10 4 30 94 g 10 10 10 10 10 10 10 20 90 C9 10 10 10 10 10 10 10 30 100 10 5 2 10 10 10 7 0 10 54 C10 10 10 10 10 10 10 10 30 100 11 10 10 10 9 10 10 0 20 79 C11 10 10 10 10 10 10 10 30 100 12 1 2 3 0 1 0 4 20 31 C12 9 10 10 10 10 10 10 30 99 13 10 5 10 5 7 9 4 20 70 C13 10 10 10 10 10 10 10 30 100 14 10 10 10 9 9 10 10 30 98 C14 10 10 10 10 10 10 10 30 100 15 3 6 6 4 4 7 7 14 51 C15 10 10 10 10 10 10 10 30 100 16 10 10 7 7 4 2 0 10 50 C16 10 10 10 10 10 5 7 30 92 17 10 9 10 8 5 6 4 14 66 C17 10 10 10 10 10 10 10 30 100 18 10 10 10 9 9 8 10 30 96 C18 10 10 10 10 10 10 10 30 100 19 5 3 10 2 4 10 4 5 43 C19 8 10 10 10 10 10 10 30 98 20 7 3 3 1 2 2 7 20 45 C20 5 10 10 10 10 10 10 30 95 21 5 0 8 5 9 5 4 20 56 C21 10 10 10 10 10 10 10 30 100 22 10 10 9 8 10 7 4 20 78 C22 10 10 10 10 10 10 10 30 100 23 3 10 5 6 8 10 4 10 56 C23 10 10 10 10 10 10 10 30 100 Table 2 summarizes the mean, standard deviation and standard error of the total scores from each group. Table 2: Group n Mean Standard Deviation Standard error PFPS 23 62.7 20.69 4.32 Control 23 98.13 2.89 0.604 68 An independent two-tailed T-Test was preformed at alpha level 0.05. The test was preformed both with equal variances assumed and unequal variances assumed. A t = -8.131 was obtained. The critical region was 2.704, therefore, the null hypothesis is rejected and there is significant difference between the two means. Therefore, we are 95% confident that the differences between the two means fall between the upper and lower confidence intervals (95% confidence interval). Therefore, the VISA score can be used as a valid method of subjectively measuring pain and function in patients suffering from PFPS. Discussion The VISA score displayed validity when tested in a population of patients suffering from PFPS and a healthy, active control group. By validating the VISA score for this population, researchers and clinicians will now have a method of measuring pain and function that is valid and easy to use. In order to maintain randomization and to ensure that the survey was including the differing severities of PFPS all patients diagnosed with this injury were asked to complete the survey. Therefore, the large variation in the standard deviation is believed to be from the varying degrees of severity of the injury and the individual pain thresholds of the patients. Since perceived pain is different for each individual, and the severity of the injury differs from patient to patient it is assumed that each individuals will have varying scores. 69 This study shows that the VISA score is a valid measure to subjectively assess pain and function in daily living and sport. Although the test, re-test reliability for an individual suffering from PFPS was not tested in this study it has been shown to be a valid and reliable measure for Achilles tendinopathy and patellar tendinopathy. Future studies should look at the reliability of the VISA score for re-test purposes. This would allow clinicians to administer the VISA score during follow-up visits as an instrument to assess patient progress. References 1. Bennell, K. (2001). Management of patellofemoral pain syndrome: merging the scientific evidence with clinical practice. New Zealand Journal of Sport Medicine. 29(1), 20-25. 2. Papagelopoulos, P.J., & Sim, F.H. (1997). Patellofemoral pain syndrome diagnosis and management. Orthopaedics. 20(2), 148-157. 3. Robinson, J., Cook, J., Purdam, C , Visentini, P., Ross, J., Maffulli, N., Taunton, J., & Kahn, K. (200.1). The VISA - A questionnaire: a valid and reliable index of the clinical severity of Achilles tendinopathy. British Journal of Sports Medicine, 35, 3 3 5 - 3 4 1 . 4. Visentini, P., Kahn, K., & Cook, J. (1998). The VISA score: an index of the severity of jumper's knee (patellar tendinosis). Science Medicine and Sport. 1, 22-28. 7 0 Appendix B Participant Log Book Summaries PFPS001 Lots of pain during week 11, pain continued into final week (week 12). PFPS002 No comments. PFPS003 Started full time curling training during week 10 and started into competitive season during week 12. PFPS004 Started full time curling training during week 5 and started into competitive season during week 6. During week 9 competed in major bonspiel and curled a total of 6 games in 3 days. Knees were very sore after this point with swelling and stiffness. PFPS005 Skied and snowboarded throughout whole program. Found her knees very sore after being on the mountain, found testing hard PFPS006 Had no problems with the program. PFPS007 Had problems initially with single leg squats. This was corrected after talking to investigator about alignment of knee for single leg squats and the amount of weight to be using and where to hold the weights PFPS008 From week 10 on had 3x per week where she did not use weights, but did the squats. No other comments given to whether this was due to pain in knees. Investigator attempted to contact subject but with no success. 71 PFPS009 Missed almost all of week 11 due to having a bad flu. Never used weights on the weekend due to traveling every weekend. PFPS010 No problems with program. Had questions about single leg squats on week 8 testing, in regards to alignment of knee but was doing the squats correctly. PFPS011 No comments, missed a few days while ill. PFPS012 Lacked exact weight so modified throughout program, used closest weight she could for prescribed exercise. Weeks 6 and 7 knee sore. Week 8-10 did 20 reps per day vs. prescribed daily amount. During weeks 11 and 12 got ill and did not do all the exercises. PFPS013 Was traveling for first 3 weeks of program found it hard to do week 3 with weights. Knees felt sore but commented on having to sit on a bus for hours at a time, followed by a lot of hiking on uneven terrain. Commented on week 4 about pain at end point of squat during the drop phase, this pain was relieved by correcting her alignment and ensuring that she did not go past her second toe during the drop. PFPS014 Had to decrease the amount of weight for the single legged squats. Had to gradually work her to a fast drop as the fast drop initially caused pain, so we modified the program so that she started with slow drops, and increased drop speed each week. PFPS015 Had problems with knee alignment on single leg squats, had to have her do the squats in between a doorway so that she could maintain proper alignment. Had to decrease weight with single leg squats as it was to heavy and she could not do the prescribed squats. Weight was added to the back so she could have her hands free to hold onto doorframe. 72 PFPS016 Had trouble with fast drop, had to start her with a slow drop and increase her speed on the drop weekly. She maintained a slow drop for her single leg squats up until week 12 where she felt she could increase the speed on her single leg. She also used a doorframe for week 7 and 8 to maintain alignment in single leg squats. PFPS018 Started to increase training during week 10, this gave her pain in the knee. Hurt left quad during week 12. Had to approximate on the weights she used during the program, but used weights as close to the prescribed amount as she could. 73 Appendix C Participant KINCOM® Set-up Quadriceps (Extension) Set-up: Hamstrings (Flexion) Set-up: Drawings By Christopher Padgett (2003). 74 Appendix D Victorian Institute of Sport Assessment (VISA) Score 1. For how long can you sit pain free? P O I N T S O m i n | | | | | | | | | | | | | | | | | | I | I 1100 min 0 1 2 3 4 5 6 7 8 9 10 2. Do you have pain walking down stairs with a normal gait cycle? Strong P O I N T S Severe I I I I No Pain Pain 0 1 2 3 4 5 6 7 8 9 10 3. Do you have pain at the knee with full active non-weight bearing knee extension? Strong P O I N T S Severe | | | | | | | | | | | | | | | | | | | | | I No Pain Pain 0 1 2 3 4 5 6 7 8 9 10 4. Do you have pain when doing a full weight-bearing lunge? Strong P O I N T S Severe I I I I I I I I I I I I I I I I | I I I I I No Pain Pain 0 1 2 3 4 5 6 7 8 9 10 5. Do you have problems squatting? P O I N T S Unab le | | | | | | | | I | | | | | | | | I I I I |No Prob lem 0 1 2 3 4 5 6 7 8 9 10 6. Do you have pain during or immediately after doing 10 single leg hops? Severe P O I N T S Pain / | | j | | | | | I | I | | | | | I | I I I I No Pain Unable 0 1 2 3 4 5 6 7 8 9 10 75 7. Are you currently undertaking sport or other physical activity? o • Not at ail 4 | | Modified training ± modified competition 7 | 1 Full training ± competition but not at the same level as when symptoms began 10 | ( Competing at same level or higher level as when symptoms began 8. Please complete EITHER A, B OR C in this question. • If you have no pain while undertaking sport please complete Q8A only. • If you have pain while undertaking sport but it does not stop you from completing the activity, please complete Q8B only. • If you have pain that stops you from completing sporting activities, please complete Q8C only. A. If you have no pain while undertaking sport, for how long can you train/practice? NIL 1-5 min 6-10 min 11-15 min >15 min POINTS 0 14 21 30 B. If you have some pain while undertaking sport, but it does not stop you from completing your training/practice, for how long can you train/practice? NIL 0 1-5 min 6-10 min 11-15 min >15 min POINTS 10 14 20 C. If you have pain that stops you from completing your training/practice, for how long can you train/practice? NIL 1-5 min 6-10 min 11-15 min >15 min POINTS 0 10 TOTAL SCORE | 100 77 Purpose: The purpose of this study is to determine if individuals suffering from patellofemoral pain syndrome (PFPS) are weak eccentrically in comparison to healthy volunteers. As well as, can we improve this group functionally and strength wise with a closed kinetic chain (CKC) eccentric drop squat home program? Study Procedures: You will be asked to come into the Allan McGavin Sports Medicine Centre on four different occasions in a time span of 12-weeks. Your first visit will be time 0 and you will be asked to come back on weeks 4, 8 and 12. Week 12 being your final session. During each session you will be asked to fill out the Victorian Institute of Sport Assessment (VISA) Score, which subjectively measures pain and function in daily life and in sport. Following completion of the questionnaire you will be asked to do a five minute warm-up on the bike that will be followed by some stretches of the muscle groups that will be used during the test. After the warm-up and stretch session you will have your hips and shoulders secured with straps into the Kinetic Communicator (KINCOM) chair and then taken through an instruction and practice trials on the KINCOM to familiarize yourself with the testing equipment. Once you are familiar with the testing equipment a total of 16 maximal tests will be done on each leg - 4 tests on the hamstrings at a speed of 60 degrees per second, 4 tests on the quadriceps at a speed of 60 degrees per second, 4 tests on the hamstrings at a speed of 120 degrees per second and 4 tests on the quadriceps at a speed of 120 degrees second. After the tests are completed you will be instructed on how to do the eccentric drop squats. You will be asked to do an eccentric drop squat home program everyday for 12-weeks that will take approximately 10 minutes per day. There will be both daily and weekly progressions in repetition and resistance. You will be asked to keep record of your progress. This record allows the investigators to observe compliance to the exercise program and to note any difficulties or changes that occurred while doing the exercise program. Risks: There is a possibility that you may experience post exercise muscle pain and occasionally will have swelling of the knee during the testing procedures and/or during the drop squat exercise home program. These can be resolved with post testing or exercise icing for 20 minutes. Benefits: Lower body strength gains from the daily squatting exercises and reduction or elimination of knee pain. Alternative Treatments: During participation in the study other treatment options such as physical therapy, new orthotics, braces and other lower body strength programs cannot be used. After 8 0 Purpose: The purpose of this study is to determine if individuals suffering from patellofemoral pain syndrome (PFPS) are weak eccentrically in comparison to healthy volunteers. As well as, can we improve this group functionally and strength wise with a closed kinetic chain (CKC) eccentric drop squat home program? Study Procedures: You will be asked to come into the Allan McGavin Sports Medicine Centre on four different occasions in a time span of 12-weeks. Your first visit will be time 0 and you will be asked to come back on weeks 4, 8 and 12. Week 12 being your final session. During each session you will be asked to fill out the Victorian Institute of Sport Assessment (VISA) Score, which subjectively measures pain and function in daily life and in sport. Following completion of the questionnaire you will be asked to do a five minute warm-up on the bike that will be followed by some stretches of the muscle groups that will be used during the test. After the warm-up and stretch session you will have your hips and shoulders secured with straps into the Kinetic Communicator (KINCOM) chair and then taken through an instruction and practice trials on the KINCOM to familiarize yourself with the testing equipment. Once you are familiar with the testing equipment a total of 16 maximal tests will be done on each leg - 4 tests on the hamstrings at a speed of 60 degrees per second, 4 tests on the quadriceps at a speed of 60 degrees per second, 4 tests on the hamstrings at a speed of 120 degrees per second and 4 tests on the quadriceps at a speed of 120 degrees second. After the tests are completed you will be instructed on how to do the eccentric drop squats. You will be asked to do an eccentric drop squat home program everyday for 12-weeks that will take approximately 10 minutes per day. There will be both daily and weekly progressions in repetition and resistance. You will be asked to keep record of your progress. This record allows the investigators to observe compliance to the exercise program and to note any difficulties or changes that occurred while doing the exercise program. Risks: There is a possibility that you may experience post exercise muscle pain. This can be resolved with some light stretching. Benefits: Lower body strength gains from the daily squatting exercises. Confidentiality: Any information resulting from this research study will be kept strictly confidential. All documents will be identified by code number and kept locked in a filing cabinet. You will not be identified by name in any of the reports of the completed study. Your medical record may, however, be inspected by the Health protection Branch (HPB Canada) in the presence of an investigator or his or her designate. Copies of the 83 Exercise Protocol The exercise protocol that will be used in this study is modeled after the program currently used at the Allan McGavin Sports Medicine Clinic and a study done by MacLean, Taunton et al (2000). The exercise protocol consists of modified eccentric drop squats; you will execute two-legged squats for the first six weeks with a gradual increase in weights, and then starting on week #7 single-legged squats on both legs will be introduced. The exercises will be executed seven days a week for 12 weeks with daily and weekly progressions. The number of repetitions will gradually increase daily, and resistance will increase weekly. Daily Progression: Day #1 3X8 Repetitions , Day #2 3X10 Repetitions Day #3 -> 3X12 Repetitions Day #4 -» 3X14 Repetitions Day #5 -»3X16 Repetitions Day #6 3X18 Repetitions Day #7 3X20 Repetitions Weekly Progression: Testing Week #1 Slow drop two-legged, eccentric squats, Week #2 Fast drop two-legged, eccentric squats, Week #3 Fast drop two-legged with 2kg/hand, eccentric squats, Week #4 Fast drop two-legged with 4kg/hand, eccentric squats, Testing Week #5 Fast drop two-legged with 6kg/hand, eccentric squats, Week #6 -¥ Fast drop two-legged with 8kg/hand, eccentric squats, 84 Week #7 2 sets of fast drop two-legged with 8kg/hand, eccentric squats; 1 set fast drop one-legged squat per leg, Week #8 -> 2 sets of fast drop two-legged with 8kg/hand, eccentric squats; 1 set fast drop one-legged squat per leg with 2kg in hand, Testing Week # 9 - ^ 2 sets of fast drop two-legged with 8kg/hand, eccentric squats; 1 set fast drop one-legged squat per leg with 4kg in hand, Week #10 1 set of fast drop two-legged with 8kg/hand, eccentric squats; 2 sets fast drop one-legged squat per leg with 4kg in hand, Week #11 -> 1 set of fast drop two-legged with 8kg/hand, eccentric squats; 2 sets fast drop one-legged squat per leg with 6kg in hand, and Week #12 1 set of fast drop two-legged with 8kg/hand, eccentric squats; 2 sets fast drop one-legged squat per leg with 8kg in hand. Testing 85 Description of Exercise Execution: For weeks one to six you will be performing two-legged eccentric squats, with weekly progressions in resistance. You will start in a standing position, with your hands by your side, and feet positioned shoulder width apart. The squat will be initiated by unlocking the knees. Flexion (bending the knees) continues at the knee and hip to a depth of a %, or less the 45 degrees. You should be able to look down at your "knee caps" and see them aligned over the second digit (toe). Also, the feet should remain flat on the floor at all t imes. Flexion (bending the knees) is done at the prescribed speed (slow or fast). From the position of f lexion you will slowly return to standing upright by actively extending (straightening) the knee and hip. The squat is then repeated for the prescribed amount of repetitions. Resistance from handheld weights is introduced incrementally each week. During weeks seven to 12 the number of two-legged squats is slowly reduced and single-legged squats performed on each leg are introduced. The one-legged squat involves performing the squat with one extremity at a t ime. The starting position for the single-legged squat involves standing on one leg and flexing (bending) the other leg to 90 degrees of flexion off the ground. To maintain balance you lightly touch a nearby counter or railing. From the starting position you unlock your knee and continue flexion of the knee and hip to a depth of % or less then 45 degrees. You then actively extend (straighten) your knee (avoiding full extension) and hip slowly to return to standing. The squat is then continued for the prescribed amount of repetitions. Resistance is again progressively increased weekly. Please be advised that you should stretch the muscle groups involved in the squatt ing exercises before and after performing the squatting exercises, and ice each knee for 15 to 20 minutes after the exercise session. 86 Stretching Exercises: Listed below are descriptions and diagrams of stretches that will stretch the appropriate muscle groups being used during the eccentric drop squat program. Hold each stretch for 30 seconds and make sure that you do both legs. Please do a gentle stretch... if it hurts you have gone too far. Hamstring Stretches: Groin Stretch: Calf and Achilles Tendon Stretch: Hip Flexor Stretch: Back and Hamstring Stretch: Pictures taken from; . Anderson, B. (2000). Stretching (Revised Edition). California: Shelter Allan McGavin Sports Medicine Centre. Stretching [Brochure]. 89 Weeks 1 - 3: Name: Week 1 Slow Drop, 2 Legged Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. -Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: Week 2 Fast Drop, 2 Legged Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: Week 3 Fast Drop, 2 Legged with 2kg/hand Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: 90 Weeks 4 - 6: Name: Week 4 Fast Drop, 2 Legged wi th 4kg/hand Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: Week 5 Fast Drop, 2 Legged wi th 6kg/hand Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: Week 6 Fast Drop, 2 Legged wi th 8kg/hand Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: 91 Weeks 7-9: Name: Week 7 2 sets Fast Drop, 2 Legged with 8kg/hand; 1 set 1 Legged Squats/Leg Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: Week 8 2 sets Fast Drop, 2 Legged with 8kg/hand; 1 set 1 Legged Squats/Leg with 2 kg Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: Week 9 2 sets Fast Drop, 2 Legged with 8kg/hand; 1 set 1 Legged Squats/Leg with 4kg Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: Weeks 1 0 - 1 2 : 92 Name: Week 10 1 set Fast Drop, 2 Legged with 8kg/hand; 2 sets 1 Legged Squats/Leg with 4kg Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: Week 11 1 set Fast Drop, 2 Legged with 8kg/hand; 2 sets 1 Legged Squats/Leg with 6 kg Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: Week 12 1 set Fast Drop, 2 Legged with 8kg/hand; 2 sets 1 Legged Squats/Leg with 8kg Day 1 3X8 reps. Day 2 3X10 reps. Day 3 3X12 reps. Day 4 3X14 reps. Day 5 3X16 reps. Day 6 3X18 reps. Day 7 3X20 reps. • Please note any changes in repetitions, resistance and any other information regarding the exercises for the week: 93 Appendix H Participant KINCOM® Set-up Form Name: Date: PFPS Code: Control Right Leg Seat Chair Facing wall and centre Seat angle at 10 degrees Seat all the way down Movement of chair R to L set at Seat forward or back (G) set at Head Movement of head towards subject set at Head height set at Safety locks set at Leg Measurement at 3/4 Lever arm set at Anatomical zero with goneometer Measure on inclinometer Left Leg Seat Chair Facing wall and centre Seat angle at 10 degrees Seat all the way down Movement of chair R to L set at Seat forward or back (G) set at Head Movement of head towards subject set at Head height set at Safety locks set at Leg Measurement at 3/4 Lever arm set at Anatomical zero with goneometer Measure on inclinometer 94 References 1. Arroll, B., Ellis-Pegler, E., Edwards, A., & Sutcliffe, G. (1997). 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