UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

The effects of an eccentric-type exercise versus a concentric-type exercise in the management of chronic… Cannell, Lynda Jane 1982

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1982_A7_5 C36.pdf [ 3.42MB ]
Metadata
JSON: 831-1.0077278.json
JSON-LD: 831-1.0077278-ld.json
RDF/XML (Pretty): 831-1.0077278-rdf.xml
RDF/JSON: 831-1.0077278-rdf.json
Turtle: 831-1.0077278-turtle.txt
N-Triples: 831-1.0077278-rdf-ntriples.txt
Original Record: 831-1.0077278-source.json
Full Text
831-1.0077278-fulltext.txt
Citation
831-1.0077278.ris

Full Text

THE EFFECTS OF AN ECCENTRIC-TYPE EXERCISE VERSUS A CONCENTRIC-TYPE EXERCISE IN THE MANAGEMENT OF CHRONIC PATELLAR TENDONITIS by LYNDA JANE CANNELL B.P.E., The University of British Columbia, 1978 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTERS OF PHYSICAL EDUCATION in THE FACULTY OF GRADUATE STUDIES (PHYSICAL EDUCATION) We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA APRIL 1982 (c) Lynda Jane Cannell, 1982 In presenting t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available for reference and study. I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. I t i s understood that copying or publication of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of Physical Education The University of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date April 27, 1982 DE-6 (.3/81) i i ABSTRACT The main purpose of t h i s study was to determine which method of tendon r e h a b i l i t a t i o n - the "eccentric squat" exercise or the universal gym "leg extension/leg c u r l " exercise produces a more s i g n i f i c a n t r e s u l t i n terms of recovery i n the treatment of chronic p a t e l l a r tendonitis. A second objective was to determine i f a relationship existed between patients who presented with p a t e l l a r tendonitis and c e r t a i n biomechanical malalignments and/or muscle imbalances that those patients might have possessed. Nineteen patients with chronic p a t e l l a r tendonitis were studied. They were selected on the basis that they had a h i s t o r y of a t h l e t i c p a r t i c i -pation, wore no orthotics and had had the symptoms of p a t e l l a r tendonitis greater than four weeks. Subjects were randomly placed i n either of two groups: t r a i n i n g using the "eccentric squat" exercise or t r a i n i n g using the "leg extension/ leg c u r l " exercise. Subjects were c l i n i c a l l y and biomechanically examined by a physician and placed on the twelve week exercise program. They were examined and tested at 0, 6 and 12 weeks. Testing included the following variables: thigh circumference measured 4.4 and 10 centimeters above the medial knee j o i n t l i n e , quadricep and hamstring moment of force as measured on the Cybex at 30 degrees per second and a subjective evaluation of pain rated on a scale from 1 to 10. There was no s i g n i f i c a n t difference between the groups i n either quadricep or hamstring moment of force, however hamstring moment of force s i g n i f i c a n t l y increased i n both groups. There was a s i g n i f i c a n t difference i n pain ratings between the groups averaged over the three testing sessions (p <0.01). The group t r a i n i n g with the "eccentric squat" exercise decreased i n pain more than the group performing the "leg extension/leg c u r l " exercise. Also, the "eccentric squat" group produced twice as many "pain free" subjects at the end of the program than the other group. With the retrospective c l i n i -c a l data on the 129 p a t e l l a r tendonitis patients seen at the B.C. Sports i i i Medicine C l i n i c over a three year period, i t appears that the average str u c t u r a l malalignment of the p a t e l l a r tendonitis patient i s no d i f f -erent from the average biomechanical problems any athlete may present with who has any number of difference overuse problems. I t appears indicated to recommend the use of the "eccentric squat" exercise as an approach towards the conservative management of chronic p a t e l l a r tendonitis. CONTENTS Page LIST OF TABLES v i LIST OF FIGURES v i i Chapter 1. INTRODUCTION 1 Statement of the Problem 02 Hypotheses 2 Limitations 3 Delimitations 3 De f i n i t i o n of Terms 3 Rationale 4 2. REVIEW OF LITERATURE 6 Structure and Function of Tendon 6 Pathogenesis of Tendonitis 9 Response of the P a t e l l a r Tendon to Force . . 11 Symptoms of Pa t e l l a r Tendonitis 13 Signs of Pate l l a r Tendonitis 14 Treatment 15 3. PROCEDURES 20 Subjects 20 Treatment Protocol 20 Testing Procedures 20 Analysis of Data 21 V Page 4. RESULTS AND DISCUSSION 23 Results: 23 Quadricep Moment of Force . 23 Hamstring Moment of Force 29 Thigh Girths 29 Pain 32 Clinical Data 32 Discussion 34 5. SUMMARY AND CONCLUSIONS 46 Summary 46 Conclusions . 47 Recommendations 48 REFERENCES 49 APPENDIX A. TREATMENT PROTOCOL 54 B. PATIENT ASSESSMENT FORM 60 vi TABLES Table 4.1 Subjects Clinical Evaluation and Biomechanical Assessment 24 4.2 Mean and Standard Deviations of Quadricep Moment of Force" (Newtons) Over the 12 Week Period . . . 26 4.3 Mean and Standard Deviations of Hamstring Moment of Force (Newtons) Over the 12 Week Period . . . 26 4.4 Mean and Standard Deviations of Thigh Girth (Centimeters) Over the 12 Week Period 33 4.5 Patellar Tendonitis Patient's Biomechanical Assessment 38 4.6 Quadricep/Hamstring Ratios 39 4.7 Athletic Involvement of Patellar Tendonitis Patients 45 v i i FIGURES Figure _ 6 Page 4.1 Quadricep Moment of Force (Mean Values in Newtons) Non-Injured Leg 27 4.2 Quadricep Moment of Force (Mean Values in Newtons) Injured Leg 27 4.3 Quadricep Moment of Force (Mean Values in Newtons) Concentric Group 28 4.4 Quadricep Moment of Force (Mean Values in Newtons) Eccentric Group 28 4.5 Hamstring Moment of Force (Mean Values in Newtons) Injured Leg 30 4.6 Hamstring Moment of Force (Mean Values in Newtons) Non-Injured Leg 30 4.7 Hamstring Moment of Force (Mean Values in Newtons) Concentric Group 31 4.8 Hamstring Moment of Force (Mean Values in Newtons) Eccentric Group 31 4.9 Pain Ratings 35 4.10 Pain Ratings: Concentric Group 36 4.11 Pain Ratings: Eccentric Group 37 v i i i ACKNOWLEDGEMENT The author would like to thank those who assisted her in completing this thesis: committee chairman Dr. J. Taunton and committee members Dr. D. Clement, Mr. C. Smith and Dr. R. Hindmarch, for their guidance and help. The author would also like to express additional thanks to Dr. D. McKenzie for his assistance and to Mr. B. Filsinger for his patience, support and greatly appreciated assistance throughout this project. 1 Chapter 1 INTRODUCTION Tendonitis i s a painful inflammatory reaction to overuse a c t i v i -t i e s involving tendon. I t s course may be acute and sel f - r e s o l v i n g or i t may become chronic i n nature r e s u l t i n g i n progressive d i s a b i l i t y and weakening of the tendon (Stanish et a l . , 1980). P a t e l l a r tendonitis (also known as Jumper's Knee or quadriceps tendonitis) was f i r s t described by Slnding - Larson (1921) and Johannson (1922) i n adults. P a t e l l a r tendonitis i s being encountered with increasing frequency as a re s u l t of trends aimed at improved a t h l e t i c performance, namely, year-round p a r t i c i p a t i o n i n a s p e c i f i c a c t i v i t y (jumping, running, kicking or climbing) i n which the extensor mechanism of the knee i s subjected to excessive s t r a i n . James et a l . (1978) examined the incidence of running related i n -j u r i e s i n a c l i n i c a l review of 180 patients. Twenty-nine percent of these 180 runners presented with knee problems, and, of these patients, seven per cent were diagnosed as having p a t e l l a r tendonitis. More recently, Taunton and Clement (1980) conducted a survey of overuse running i n j u r i e s incurred over a two year period i n patients seen i n th e i r c l i n i c . Of the 1650 runners examined, p a t e l l a r tendonitis was found to be the f i f t h most common types of overuse running problem (81 patients). They found the most commonj complaint to be patello-femoral pain caused by a variety of conditions. The second most common was t i b i a l stress syndrome followed by a c h i l l e s tendonitis, plantar f a s c i i t i s , then p a t e l l a r tendon-i t i s . While the etiology of p a t e l l a r tendonitis i s s t i l l not f u l l y understood, a myriad of treatment regimens have been advocated with both c o n f l i c t i n g and less than rewarding r e s u l t s . Once the diagnosis has been made, and the athlete's degree of d i s a b i l i t y established, a thorough know-ledge of the natural h i s t o r y and disease progression of p a t e l l a r tendon-i t i s i s c r u c i a l to the r e h a b i l i t a t i v e procedure. Tendonitis i n general (patellar tendonitis being no exception) has long proven to be very r e s i s -tant to conservative treatment. Rest i s no longer an acceptable solution, 2 and while ice, heat and anti-inflammatory medication decrease the associated pain, the chronic and at times somewhat vicious cycle of tendonitis is not arrested. It has become evident that the most likely etiology of patellar tendonitis is forces that are generated very rapidly, as during athletic par-ticipation, that impose forces that may exceed the maximal tensile strength of the actual tendon, and cause microscopic lesions in the tendon tissue. It is a? goal in any therapy program to enhance muscular strength through hyper-trophy and thereby strengthen the tendon sufficiently so that imposed athletic stresses do not exceed its tensile capacity. The fundamental requirement for hypertrophy of any tissue is the maintenance of physiological overload on the structure. Muscle can work in three manners: concentrically (when the muscle shortens while i t contracts), isometrically (when the muscle length remains constant while i t contracts), and eccentrically (when the muscle lengthens as i t contracts). While i t is clear that some form of muscle retraining to stimulate hypertrophy is essen-t i a l in attempting to resolve patellar tendonitis, i t is unclear as to which method will optimize the recovery period. Statement of the Problem The purpose of this study is to determine which method of tendon rehabilitation - the "eccentric squat" exercise or the universal gym "leg ex-tension/leg curl" exercise -- produces a more significant result in terms of recovery in the treatment of chronic patellar tendonitis. Subproblem 1. To determine i f a relationship exists between patients who present with .patellar tendonitis, and certain biomechanical malalignments and/or muscle imbalances that those patients may possess. Hypotheses In this study i t is hypothesized that: 1. The "eccentric squat" exercise provides a more significant result than the "leg extension/leg curl" exercise in terms of ultimate recovery time in the treatment of chronic patellar tendonitis. 2. The "leg extension/leg curl" exercise group is able to produce a signifi-cant increase in moment of force as evaluated on the Cybex II isokinetic dynomometer (especially for hamstrings). 3 3. A relationship exists between those who suffer from patellar tendonitis and those, who upon examination, demonstrate biomechanical malalignments of the leg and foot. Limitations The results of this study are limited by: 1. The errors of data collection by the Lummex Cybex II isokinetic dynomo-meter. Gravitational forces are not taken into account by this machine, as well, errors can occur in the accuracy of reading values off the re-cording chart. 2. The errors that could occur in taking thigh girth measurements. 3. The method of subjectively evaluating the patient's improvement as one criteria in determining the success of the programs. 4. The subject's own motivation to work at their exercises. A l l , however, are athletes and it is assumed that their motivational level to improve is exceptionally high. Delimitations The study is delimited by: 1. The sample size. 2. The extent to which subjects are afflicted with patellar tendonitis. Definition of Terms For the purpose of clarification, the following definitions are considered applicable throughout the study: 1. Patellar tendonitis is a painful inflammatory reaction involving the patellar tendon. This reaction is an attempt by the tendon to repair damaged elastin and collagen ultrastrueture with scar tissue. The cause of this damage is forces which act upon the tendon and exceed its tensile strength. Clinically, patellar tendonitis will be diagnosed when exquisite pain is elicited upon palpation at either the inferior of superior poles of the patella, or through the patellar tendon to its insertion at the tibial tubercle, in the absence of any other knee dis-order (Blazina 1973). 2. Chronic patellar tendonitis includes a l l patients who have had the pre-senting symptoms of patellar tendonitis greater than four weeks. 4 3. The "Eccentric Squat" exercise is performed according to that described by Lamb and Stanish (1980) as described in Appendix A. The subject will stand with feet comfortably apart, lower the body to a semi-crouch posi-tion (thighs parallel to the floor) at first slowly, then progressing to very rapidly, then returning quickly to upright. 4. The "Leg extension/leg curl" exercise will be performed on the conven-tional universal gym apparatus initially sitting up and performing leg extensions, then on the stomach performing leg curls (Appendix A). 5. Recovery time involves the following factors which are important in the determination of how successfully the symptoms of patellar tendonitis are controlled by either program: an increase in muscle strength, a de-crease in muscle imbalance, and a decrease in pain. 6. Concentric muscle contraction occurs when the involved muscle contracts while shortening. 7. Eccentric muscle contraction occurs when the involved muscle lengthens while contracting. 8. Isometric muscle contraction occurs when the involved muscle contracts while no change in length occurs. 9. Isokinetic exercise as performed on the Cybex II dynomometer during the testing procedure is a dynamic type of resistive exercise with two unique features: (i) the angular velocity of the Cybex can be specified (in this study at 30° per second). (ii) when the specified velocity is reached, the device automatically accommodates to give maximal resistance at each point in the range of motion while allowing the specified velocity to be maintained. Therefore, muscular force can be maximal at a l l points in the range of motion. Rationale According to Lamb and Stanish (1980), there are two basic avenues of treatment of patellar tendonitis. One is to remove the stresses which are responsible for the init i a l lesion, the other is to enhance the strength of the actual tendon so that imposed stresses do not result in injury. Removing the stresses involves extended periods of rest. To an athlete, this means stopping or greatly decreasing his or her training pro-gram. Poor patient compliance and a further decrease in the tensile strength of the tendon ensues. 5 The most sensible approach would be to increase the tensile strength of the tendon. Tendon is a viable substance that will respond to a training protocol. Lamb and Stanish (1980) believe that tendonitis develops secondary to an eccentrically applied load, as occurs when anta-gonist muscles contract eccentrically as the movement of a body segment is decelerated and its direction changed. Three methods of enhancing strength are via concentric, eccentric, or isometric contractions. There-fore, this study was designed to examine the difference between the "eccentric squat" exercise which is largely an eccentric type of movement, and the "leg extension/leg curl" exercise which is largely a concentric exercise, in the management of chronic patellar tendonitis. 6 Chapter 2 REVIEW OF LITERATURE This chapter presents a general view of the literature. The con-tent of this chapter is divided into six main categories: the structure and function of tendon, pathogenesis of tendonitis, response of the patellar ten-don to force, symptoms of patellar tendonitis and treatment. Structure and Function of Tendon Tendon Is composed of collagen and elastin embedded in a matrix of mucopolysaccharides. Viewed cross-sectionally, tendon represents an organized grouping of regular parallel fibers. The collagen is arranged in a hierarchy of progressively smaller subunits in diameter from the tendon fascicle through f i b r i l or fiber, subfibril, microfibril to the smallest component tropocollagen. In a relaxed or unstretched state, tendon has a wavy appearance. It is not clear whether this wave is an inherent property of the constituent fibrils de-termined by the amino acid sequences of their component tropocollagen mole-cules, or the result of the interaction of collagen fibrils with non colla-genous components of the tissue. This wavy configuration disappears when the tendon is stretched (due to the elastin content of the tendon), and functions to damp the sudden strain imposed on the tendon when the muscle contracts. When the tissue is stretched, initial extension is associated with a flatten-ing of the wave pattern (Booth 1975, Harkness 1968, Vidiik 1978). The main function of tendon is the transmission of the tension de-veloped by a muscle, and the mechanical properties of the structure (great tensile strength, flexibility, low extensibility and almost perfect elastici-ty) reflect these functional demands. Like other connective tissue, tendon is viscoelastic and composed of materials of varying tensile strength. The maximum values for the tensile strength of human tendon is 5-10 kg/mm^  and for collagen 15-30 kg/tnm^  (Harkness 1968). It has been estimated that during a muscle contraction of maximum isometric tension, the tendon is stressed no more than one quarter of its ultimate tensile strength (Vidiik 1969). At these physiological tensions which lie at the bottom of the stress-strain curve, the tendon is relatively easily extensible, and perfectly elastic 7 since greater stresses affect the collagen network itself (Booth 1978). Production of muscle tension has been found to be higher in eccentric contrac-tion than concentric contraction, and the difference between the two types of work loads increases with the increase in contraction velocity (Komi 1977). There is a heterogenity of fibers in!the mechanical and physico-chemical structural stability of tendon (Chvapil 1967). It seems that tendon collagen is stronger than its surrounding matrix. Within the collagen compo-nent, smaller bundles are stronger than the larger bundles, which are not ideally arranged along the line of force (Lamb 1980). Harkness (1968) found that as load is applied, weaker fibers should not depend so mutjh on the dia-meter of their fibers, but more on their location in the tendon (Chvapil 1967). Also, the bone-tendon interface is inherently weaker than the tendon proper, and is therefore usually the site of initial tendon injury (Vidiik 1969). The heterogeneous nature of tendon is also evident when examining the stress-strain curve for tendons. There is not a linear relationship be-tween applied stress (tension per cross-sectional area) and resultant strain (percent increase in length over resting length). Rather, the curve is charac-teristically sigmoid in shape indicative of the viscoelastic nature of tendon tissue. Tendons display both elastic and plastic properties. It displays elasticity i f i t returns to its original geometric shape after the stress is removed, and i f i t does not return to its original shape, i t displays plastic properties. When stressed, the tendon's gradual return to the original shape is termed the elastic after-effect. Vidiik (1967) found that tendons display plastic tendencies when submaximal loads are applied for longer periods of time. In a region of low strain (0-2 percent greater than o r i g i n a l y r e s t T ing length), considerable extension occurs with minimal increases in intra-tendon tension. Histological studies demonstrated that the wavy structure of the tendon that the collagenous bundles display in a relaxed state are re-sponsible for this phenomenon (Kastelic 1978). Abrahams (1967) showed that the amount of tension in this lower region of the curve is dependent on the rate as well as the magnitude of strain, with rapid straining resulting in considerably higher tensions. Oakes and Bialkower (1977) found that exposure to heat and the enzyme elastase also have detrimental effects on the tendon, destroying this portion of the curve, and decreasing the tensile strength of the tendon. 8 In the mid portion of the curve in an area of strain equal to 3-5 percent greater than resting length, there is a linear rise in tension with increasing strain. In this portion of the curve, the amount of exten-sion is controlled entirely by the behavior of the collagen fibers which are now fully extended and orientated in the direction of the load (Abraham 1967). With strain greater than 5-6 percent of the tendon's resting length, there is no further rise in tension, and further strain results in increasing gross disruption. Physical rupture, or compete failure of the tendon, have been demonstrated at strains of 10 percent (Harkness 1968) and 30 percent (Abraham 1967) of the resting length. Damage to the tendon ultra-structure, therefore, can occur at tensions well below those measured as being maximal tensile strength. This damage does not become apparent as a gross rupture. Smaller stresses and strains through the tendon itself during intense exercise can cause the tendon to rupture i f there is an alteration of the normal angle between bone and muscle belly that leads to an unequal distri-bution of stresses at those sites where a rupture would be most likely. , Chvapil (1967) studied the anatomy, physiology and mechanics of bone-tendon muscle groups and showed that the tendon is at its most vulnerable under the following circumstances: (i) When tension is applied obliquely. (ii) When tension is applied quickly. ( i i i ) When the tendon is tense before the trauma. (iv) When the attached muscle group is stretched in an eccentric manner by external forces such as gravity or the muscular strength of the thigh, for example, in an unexpected manner. (v) When the tendon is weak in comparison with the muscle. He demonstrated that, mechanically, even healthy tendons can be ruptured. It has yet to be proven whether the observed changes in the load-elongation (stress-strain) curve after a previous elongation of the tendon are responsible for a weaker tendon that is more susceptible to injury. Tendon is a viable and metabolically active tissue that is capable of altering its structure in response to external stresses. Significant oxy-gen consumption, concentration of metabolic enzymes, collagen synthesis and blood flow hawe been measured. Because of their living and adapting nature, these and other structural characteristics of tendon are influenced by both physical activity and disuse. 9 In experiments carried out on animals, physical exercise has been shown to increase the tensile strength in tendon (Booth and Gould 1975, Kiiskiner 1977, Vidiik 1967, Tipton 1975). Structural changes that seem to account for this increase of isolated tendon tensile strength seem to be re-lated to the thickness of the tendon tissue and its collagen content. The exercise has been shown to increase collagen synthesis (Heikkinen 1970, Vidiik 1978, Byrd 1973, Kiiskinen 1977), to increase the content of glyco-saminoglycan ground substance (Kiiskinen and Heikkinen 1972) and to increase the fiber size and number of cellular nuclei (Booth and Gould 1975). In addi-tion, the oxygen consumption and blood flow in the tendon increases as a re-sult of physical activity (Vailas 1978). Vailas (1978) also demonstrated that the concentration of metabolic enzymes increases as well as the rate of enzyme activity due to the exercise. Increases in nitrogen content have also been recorded (Heikkinen and Vuori 1970). Physical inactivity causes a reversal on many of the trends assoc-iated with physical training. The collagenous network of the tendon is dis-rupted as a result of a decrease in oxygen consumption and concentration of metabolic enzymes (Vailas 1978), and a decrease in collagen synthesis (Heikkinen and Vuori 1970). Physical disuse also causes a decrease in the capillary volume of the tendons and hence, greater extensibility per unit of load (Booth and Gould 1975). The constituents of the tendon, therefore, vary in a number of ways with the changes in the level of chronic physical activity. In the re-habilitative phase after an injury, the strength of the tendon is quite sensi-tive to the quantity of physical activity (Booth and Gould 1975). Pathogenesis of Tendonitis The biomechanical aspects of the development of patellar tendon-iti s rest on the concept that certain activities place enough stress on the knee extensor mechanism to cause microtearing of the attachments of the ten-don to bone (Blazina 1973). Tendonitis results in an inflammation of a ten-don and of the musculotendinous attachment while tenosynovitis is an inflam-mation of the tendon in the tendon sheath (most common) (Magee 1980). The inflammation of the tendon results in a loss of the smooth gliding action of the tendon as dense fibrous adhesions may form, and these adhesions may lead to stenosis of the sheath (Magee 1980). Blazina (1973) 10 felt that the formation of calcium or scar tissue depended upon which com-ponent of the tendon overresponded. Degeneration of the involved tendon would ensue and cause the tendon to become thicker, softer and lose its normal lustre. Smillie (1978) stated that the exact pathology of tendonitis to his knowledge was unknown, but that there was a possibility that a deficient blood supply at the osseus-tendonous junction could cause circulatory impair-ment to healing. This has been well described in cases of supraspinatus ten-donitis or in tennis elbow. Rathburn and McNabb (1970) have reported the ex-istence of a constant zone of relative avascularity near the insertion of the supraspinatus tendon which corresponds to the most common site of degeneration and rupture of the rotator cuff. These authors suggest that the constant pres-sure of the head of the humerus on the supraspinatus tendon might wring out the vessels in this area and accentuate the observed avascularity. The patel-la has been observed to have a somewhat deficient blood supply, particularly at the inferior pole. The blood supply to a tendon is tenuous. Small nutri-ent arteries enter the paratenon (sheath) of the patellar tendon at the musculotendinous junction and from the periosteum. Branches extend into the deepest fibers to isupply blood. It is at the midpoint of the tendon which is at the end of the supply lines that is most likely to suffer the effects of any interference with blood flow. Increases in tension within a tendon has been shown to decrease and to finally stop the blood flow in veins and capillaries (Schatzker 1969). The capillary bed decreases with age and in-activity (Schatzker 1969). Anatomical pathologic examination of excised tendon tissue perform-ed by Roels (1978), revealed evidence of a local mucoid degeneration and fibrinoid necrosis of the tendon. Also, he observed clefts in the tissue with a cellular border due to microtearing within a tendon. There were also areas of regeneration with proliferation of fibroblasts and thin walled vessels. Kerlan! (Blazina and Kerlan 1973) felt that there was some "factor" of an immunologic or metabolic nature present that dictates why the body re-sponds to injury in such a destructive manner that often accompanies chronic tendonitis. Stanish and Lamb (1980) stated that the painful inflammatory re-action of the tendonitis is initiated by microscopic disruption of the ten-11 don's collagenous elastic ultrastrueture, and represents an attempt to re-pair the damaged tissue with scar. As forces exceed the tensile strenths of the weaker tendon fibers, these fibers rupture and place a greater proportion of the tensile load on the remaining fibers. With such repetitive loading, which is at times unexpected, these fibers then have an increasingly stronger likelihood of rupturing also. Clancy (1976) felt that the ensuing inflamma-tory response also weakens the tendon Ultrastructure causing i t to become thicker and softer and further perpetrating the vicious tendonitis cycle. Subotnick (1978) feels runner's knee problems (being a combination of factors such as chondromalacia, patellar compression/subluxation and/or patellar tendonitis) are related to improper foot function. Torsional and angular malalignments of the lower extremity have a significant influence on knee mechanics. Foot function and its influence upon knee mechanics has in the past been ignored. As the foot abnormally pronates, due in part to a varus leg/foot alignment, the medial longitudinal arch tends to flatten, and an obligatory internal tibial rotation occurs. Hence, excessive and prolonged pronation is a compensatory motion to accommodate a malalignment of the foot or leg and creates increased forces applied not only to the supporting struc-tures of the foot but also the knee (James 1981). The thigh internally rotates, but the foot, being fixed on the ground, cannot turn in, therefore allowing for an unstable patella (Subot-nick 1978). An increased Q angle from lateral placement of the tibial tubercle, or excessive amount of external tibial rotation predisposes the patella to lateral displacement with vigorous quadriceps contraction (James 1981). The possible relationships between tendon blood supply, blood flow, aging, muscular tension, excessive use and biomechanical malalign-ments on one hand, and degeneration and rupture on the other, have never been adequately explored. Response of the Patellar Tendon to Force The patellar tendon is subjected to both the forces generated by muscular contraction of the quadricep muscle group and to the forces applied externally by the tibia and the femur. A muscle generates force via three mechanisms of contraction: concentric, isometric and eccentric. Whether or 12 not an injury occurs to the tendon depends upon the magnitude of these forces, the speed of applied tension and the initial strength of the tendon in rela-tion to the muscle (Chavpil 1967). The tension produced during concentric contractions is inversely re-lated to the velocity of the muscle shortening, with the maximum concentric tension being generated duringL<the isometric condition (Komi 1973). A muscle contraction of maximum isometric force stresses the tendon no more than one quarter of its ultimate tensile strength (Vidiik 1969). The velocity of lengthening influences the amount of tension that can be developed in the muscle during the eccentric contraction. When the muscle is rapidly stretched while contracting, there is a large increase in intratendon tension directly related to the velocity of elongation (Komi 1973). Peak eccentrically genera-ted forces have consistently been shown to exceed those generated by maximal isometric contraction (Harkness 1968, Komi 1973). In contrast, in a resting state, muscle is very extensible and when passively stretched, the tension is almost entirely absorbed by the compliant muscle tissue with no rise in intra-tendon tension (Cavagna 1977). Eccentric muscle contraction is an integral part of any skilled or forceful movement. When deceleration of a body part or reversal of direction is necessary, eccentric muscle contraction plays a key role. Cavagna (1977) stated that the amount of force generated is directly related to the mass of the segment involved and the rate deceleration. Wahrenberg (1978) monitored unskilled subjects during the eccentric phase of kicking a ball. He recorded forces of up to 5200 Newtons in the patellar tendon, a figure which approaches the measured maximum tensile strength of the patellar tendon. The authors concluded that i f such forces were to be continued on a repetative basis, such forces could indeed result in patellar tendonitis. Some studies involving running and jumping animals have shown that eccentric forces actually can exceed the established values for tendon tensile strength (Alexander 1974, 1977). Komi (1973) employed maximal eccentric contraction as the stimulus for muscle hypertrophy, and found ItWat the eccentrically trained subjects suffered from severe muscle soreness during the preliminary period of training. This could possible indicate damage to muscle connective tissue or the tendon-muscle junction. Johnson (1976) reported that subjects exercising eccentri-cally a l l found this type of training easier to do rather than the concentric 13 type, even though they knew they were handling heavier resistances. More recently, eccentric contraction has been associated with less forceful repetitive activities such as running. Cavagna (1977) demonstrated that the extensor mechanism of the knee and the plantar flexors of the foot contract initially eccentrically upon foot strike and then subsequently con-centrically during the toe-off phase. Lamb and Stanish (1980) discuss how mechanical energy may be stored by the stretching of series elastic elements of muscle or tendon during eccentric contraction (and be re-utilized by the immediately following concentric contraction. Cavagna (1964, 1977) has shown that the re-utilization of this "stored elastic energy" increases the mechani-cal efficiency of running by as much as 40-50 percent and may contribute as much as 50 percent of the total energy requirements of running. Muscles with short fibers and long extensible tendons such as the extensor mechanism of the knee, and the plantar flexors of the foot with their long patellar and achilles tendons, appear to be best adapted for energy storage. It is interesting to note that both these tendons are the site Vof the chronic tendinitides associated with running and jumping ath-letes (Taunton and Clement 1980} James 1978). As far as Lamb and Stanish (1980) are concerned, the most likely etiology for the microscopic lesions characteristic of tendonitis is excess-ive force generated during repetitive eccentric muscle contractions. Concen-trie and isometric contractions may exacerbate previously established tendon-i t i s , but those forces do not appear to be sufficient to cause the init i a l re-sult. Symptoms of Patellar Tendonitis Clinically, the athlete with patellar tendonitis will present with an aching pain centered over the infrapatellar or suprapatellar region. The pain may be especially localized to the inferior or superior poles of the patella, and may disappear after a period of rest varying from a few hours to several days. Swelling may or may not be present. Deceleration while play-ing a sport may be impossible without a feeling of giving way (Grossman 1977). Invariably, the athlete has been involved in some type of repetitive activity involving jumping, climbing, kicking or running (Blazina 1973, Roels 1978). Blazina (1973), in describing the clinical aspects of patellar ten-14 donitis conveniently classified the symptoms of patellar tendonitis into three stages. In stage one, the patient will experience pain after activity only, and no undue functional impairment will be evident. When the patient experi-ences pain during and after activity, he is exhibiting stage two symptoms. This athlete is s t i l l usually able to perform at a satisfactory level. The end stage symptoms are classified as such when pain during and after activity is more prolonged, and the athlete has progressively increasing difficulties in performing at a satisfactory level. This athlete, i f allowed to continue intense activity, may experience a sudden catastrophic episode, feel a tremen-dous "giving way" and be functionally impaired and unable to extend the knee. In other words, he may completely rupture the tendon. Over a seven year period, Blazina (1974) saw 300 basketball players with patellar tendonitis. Of these, 186 were in phase 1, 92 were in phase 2, 18 were in phase 3, 4 were in phase 4. Three of these players ruptured their extensor mechanism while playing. Patellar tendonitis usually develops over a period of time due to repetitive activity. On rare occasions, the athlete may relate a single epi-sode (a direct blow, a certain landing or take-off) (Blazina 1973). Signs of Patellar Tendonitis The establishment of the diagnosis of patellar tendonitis on the basis of physical examination depends upon the elicitation by the examiner of definite exquisite tenderness upon palpation of the inferior or superior poles of the patella (Blazina 1973). Generalized effusion of the knee is fairly un-common, however cystic fluctuations in the area may be palpated (Blazina 1973). Crepitus is not an uncommon phenomenon. Many of the patients exhibit anatomi-cal, biomechanical problems such as genu recurvatum or genu valgum or varum, patellar hypermobility, increased Q angle, patella alta, musfcle imbalances, quadricep wasting, forefoot and/or rearfoot varum (Blazina 1973, Rubin 1980, Taunton and Clement 1980). X-ray examination may or may not reveal irregularities of the in-volved pole of the patella. Fatigue fractures may eventually be detected i f follow-up films were taken (Blazina 1973). In adolescents, irregular centers of ossification at the involved poles have been noted and preadolescent and adolescent athletes more often develop tendonitis at the distal insertion of 15 the patellar tendon. Osgood-Schlatter's disease represents a traction in-jury at the open apophysis of the tibial tubercle (Rubin 1980). Calcifica-tion of the involved tendon especially near the tibial tubercle has been noted especially in patients who had Osgood-Schlatter's disease as a child (Blazina 1973). Another change commonly seen is an elongation of the in-volved pole (Roels 1978). Sinding-Larson-Johannson disease is also common among adolescents, and can also represent a type of traction apophysitis as seen with Osgood-Schlatter's disease. It is a form of osteochondritis of the ossification center of the lower pole of the patella. Treatment The etiology of patellar tendonitis is s t i l l not fully understood. There have been, however, a myriad of treatment regimens advocated with both conflicting and less than rewarding results. With Blazina's (1973) classifi-cation of symptoms came his outlined approach to treating patellar tendonitis. Athletes who were stage one in Blazina's criteria were treated with ice or ice massage post activity, and again in the day i f indicated. An elastic support wrap was applied to the superior aspect of the knee to ease the pain. If pain increased, anti-inflammatory medication was added for 10 - 14 days. For those patients who experience pain both during and after acti-vity, treatment was the same as in phase 1, but a form of heat was applied to the involved area prior to activity. Steroid injection into the tendon was the last choice, and avoided i f at a l l possible due to its weakening effect on the tendon ultrastructure. With prolonged pain in phase three, Blazina felt that rest was the most important. At this stage, surgical intervention was not uncommon. He advised the following approaches: (i) drilling of the involved pole to increase blood supply to the area to facilitate healing of the tendon. (ii) excising the degenerated portion of the tendon with resuturing of the defect. ( i i i ) resection of the involved pole, reattachment of the tendon and re-moval of the degenerated or calcified portions of the tendon. 16 Although the authors were fairly successful with the surgical techniques, the conservative treatment protocols were ineffective and inappropriate. Grossman and Nicholas (1977) advocated that the treatment of pate-llar tendonitis be preventative in nature. They attempt to find the athlete a sport that will " f u l f i l l he needs for competition" and at the same time avoids the mechanism contributing to the injury (kicking, jumping or running). To limit range of motion of the patella, they place their patients in a two layered, hinged patella restraining brace. They utilize an exercise program to improve leg power consisting of thigh flexion and hip abduction. They em-phasize that active resistive quadricep exercises through a range of motion may not be tolerated by the patient and hence be dangerous. Grossman's con-servative treatment regimen is relatively the same as Blazinai's with the ex-ception that they "practically never inject corticosteroids locally". When conservative measures f a i l , they may surgically attempt to resect the in-volved pole of the patella or to remove the degenerated quadricep or patellar tendon with supplemental reefing. Subotnick's (1978) treatment protocol consists of exercises to build up and strengthen the quadriceps and hamstrings. Straight leg raises and isometric quadricep exercises are indicated. Foot orthotics are also indicated to provide stability at the knee by reducing independent rotation between the leg and the foot which occurs with excessive pronation. Roels (1978) presented clinical and radiological findings and re-sults of treatment on 36 patients with patellar tendonitis. Similarly to Blazina (1973), phase one of Roel's treatment program included an adequate warm-up with some flexibility exercises, ice massage and local anti-inflammatories with an elastic knee sleeve for support. Phase two followed the initial phase with the addition of some form of heat prior to activity, and possibly a steroid injection. Phase three included a prolonged period of rest that ultimately ended with phase four i f the symptoms were not re-lieved. This necessitated surgery. Roels concluded, along with Blazina, that patellar tendonitis is not a benign, self-limiting affliction. The long term history and progres-sion of symptoms which are often resistant to conservative measures such as'J prolonged rest and even immobilization, suggest that patellar tendonitis is not a self-limiting phenomenon. 17 Krissoff (1979) confirmed jumper's knee as point tenderness over the patellar tendon and outlined his approach to treatment which included ice, aspirin and isometric exercise. He feels that a counter support brace or orthotic may be helpful if there is a static or dynamic malalignment problem. Surgery would only be indicated in chronic cases, and should include arthro-scopy prior to actually exploring the tendon. Rubin (1980) reported that he frequently saw patellar tendonitis in association with chondromalacia patella. Rubin's treatment plan included rest, ice and oral anti-inf1animatories. When the pain is severe enough to prevent running, a steroid injection is administered accompanied with appropriate counselling concerning tendon weakness that is associated with corticosteroid injections. If the patients did not respond to these treatments, surgery was indicated to excise the involved area as well as the involved pole of the patella, and to reattach the tendon. Taunton and Clement (1979) conducted a retrospective study to in-vestigate the etiological factors operative in knee injuries in runners. Pre-liminary results indicated that in 8 - 12 weeks of daily muscle retraining, most pre-existing muscle imbalances and insufficiencies of the knee flexors and extensors are compensated for when combined with other specific means of treatment (anti-inflammatories and orthotics when indicated). The program enabled their athletes to return to pre-injury training in a minimal period of time. Chronic patellar tendonitis, however, proved more resistant to this conservative treatment. It became apparent to the authors from their retro-spective clinical review that further research into the area of the etiology and treatment of patellar tendonitis is warranted. Lamb and Stanish (1979) proposed as described that lesions to the tendon ultrastrueture characteristic of chronic tendonitis occurs primarily during the eccentric phase of movement. They rationalized that since tendon is constantly opposed to large eccentric forces, optimal overload and subse-quent hypertrophy of tendon tissue can only be achieved through graded eccen-tric exercise. They implemented a program that consisted of the following five steps: (i) warm-up, (ii) flexibility exercises for the hamstrings and quadri-ceps, ( i i i ) specific eccentric exercises (three sets of ten repetitions), (iv) flexibility post exercise and (v) ice application. This program was per-formed once daily for a minimum of six weeks. All subjects were instructed to 18 continue a l l athletic activities during the six week period unless pain made it impossible. Contrary to a l l previous treatment programs described, en-forced rest is not part of this treatment regimen. The specific eccentric exercise for patellar tendonitis consisted of performing a knee "drop and stop" movement and then return to upright. Although official results from this program are forthcoming, init i a l results were subjectively reported as very "gratifying" (Lamb 1980). Of the 17 patients on the patellar tendonitis program, 11 were "better but pain was s t i l l occurring", 5 "had no longer any pain or disability", and only 1 became "worse" from the procedure. Another common location of tendonitis in the runner is in the achilles tendon. The achilles tendon has been examined and treated in much the same manner as the patellar tendon. Leach et al. (1981) treated his patients who were suffering from chronic achilles tendonitis with a modifi-cation of their running mileage, a heel elevation in their shoe to take some strain off the tendon complex, oral anti-inflammatory agents and a vigorous stretching routine. With the competitive or dedicated runner with persisting debilitating pain, surgery was indicated. Again, the author had some success with the surgical intervention but the chronic patient that was treated con-servatively met with a variety of success rates. Standard conservative measures of ice, rest and anti-inflammatory medication have predominated as the conservative treatment for patellar ten-donitis. Blazina (1974) felt that the necessity for surgical intervention represents our failure to manage the tendonitis problem on a conservative basis. Our inability to arrest the disease progression with conservative methods illustrates our lack of knowledge about the basic mechanics in-volved, and points out our inability to develop an effective anti-inflamma-tory medication. Other longstanding treatment procedures have been examined as to their contribution to the overall treatment plan for tendonitis. The admini-stration of local corticosteroids is well recognized as an important thera-peutic measure in the conservative treatment of local inflammatory conditions. Kennedy (1976) has brought to our attention serious complications that follow local steroid injection. Steroids injected into normal tendon weaken it sig-nificantly for up to two weeks. This effect may be even more pronounced with repetitive injections. This biomechanical disruption is directly related to 19 collagen necrosis. Kennedy emphasized that avoidance of vigorous muscular activity for a period of at least two weeks post injection is essential. Al-though controlling the inflammatory process, there is some evidence that the corticosteroid injection may retard the natural repair process and along with the associated decrease in tensile strength, predispose the involved tendon to further injury. Long term rest also appears to be of l i t t l e value in the treatment of chronic tendonitis (Lamb and Stanish 1980). Rest is initially useful in controlling the inflammatory response, but it has been demonstrated repeated-ly that rest only further weakens the tendon and predisposes i t to further in-jury upon resumption of activity (Booth and Gould 1975, Tipton 1975). Long term rest is also rarely acceptable to the athlete who is usually intent upon maintaining his or her activity level. Clearly some form of muscle retraining is essential in attempting to resolve patellar tendonitis. 20 Chapter 3 PROCEDURES This chapter reviews the testing procedures used in determining the success of the exercises in question. Subjects Nineteen patients (13 male, 6 female) with chronic patellar tendon-itis were studied. A l l subjects were patients of one of the three sports medicine physicians at the B.C. Sports Medicine Clinic. Criteria for selec-tion were that the subject must have a history of athletic participation, wear no orthotics and must have had the symptoms of patellar tendonitis for greater than four weeks. The subjects ranged in age from 15 to 50 years. Treatment Protocol Subjects were randomly placed in either of two groups;: training using the "eccentric squat" exercise, or training using the "leg extension/ leg curl" exercise. A detailed step by step instruction of each exercise protocol is found in Appendix A. Testing Procedures The subjects were examined by the physician and were evaluated according to the assessment form in Appendix B. The patient was then random-ly placed in one of the exercise programs and tested initially as follows: 1. Thigh circumferences were measured at 4.4 and 10 centimeters above the medial knee joint line. A l l girth variables were measured with a cloth tape. The tape was checked three times for accuracy on each measure-ment. It was found that the tape had not stretched throughout the course of the testing. 2. The patients subjectively evaluated their estimation of their own pain on a scale of 1 to 10. One denoted being "pain free", progressing to ten which denoted severe pain and disability caused by the patellar tendonitis. 21 3. Quadricep and hamstring moment of force were evaluated for both legs. AH moments of force were measured on the Cybex II isokinetic dynomometer in the J.M. Buchanan Research Centre at the University of British Columbia. Lever length and torque were recorded at a speed of 30 degrees per second. The machine was calibrated before each session for each subject. Each subject was required to read and sign a consent form outlining the testing and timing requirements. Subjects had a follow-up examination by the physician at six weeks, when clinical changes in their condition were noted, and a ful l evaluation of girths and moments of force were carried out. This was repeated again at twelve weeks at which time the program terminated with a final examination and evaluation. Subjects were required to keep a daily training log of their exercise programs and progressions and to note any other activities they participated in. The subjects were not told to refrain from activity, however modification of activity was recommended until control of symptoms was achieved. Analysis of Data The experimental design was a 2*3*2 analysis of variance with re-peated measures on the last two factors with the two groups: "eccentric squat" group, and "leg extension/leg curl" group being the two levels of the independent variable. The dependent variables; the injured leg and the non-injured leg were examined at three different time periods: 0 weeks, 6 weeks and 12 weeks. With alpha set at 0.05, the hypotheses were tested for significance using four separate analyses of variance to analyze changes in: (1) Quadricep moment of force. (2) Hamstring moment of force. <i (3) Thigh girth. (4) Pain. This provided information regarding the relative importance of the dependent variable within each level of the independent variable. The analysis was ac-complished using BMD: P2V biomedical statistical package available at the computing center of the University of British Columbia (Dixon 1973). 22 With the retrospective clinical data, frequency distributions and graphic representations were used to evaluate the relationships that exist between the incidence of patellar tendonitis, and the biomechanical malalign-ments of the leg and foot that these patients present with. 23 Chapter 4 RESULTS AND DISCUSSION In this chapter, the group training with the universal gym "leg extension/leg c u r l " exercise w i l l be referred to as the concentric group, and the group training using the "eccentric squat" exercise w i l l be refer-red to as the eccentric group. Four separate analyses of variance analyz-ed changes in (1) quadricep moment of force, (2) hamstring moment of force, (3) thigh girth, and (4) pain. A l l moments of force are reported in New-tons, having taken the length of the Cybex lever arm into account. Results The nineteen subjects whose mean age was 26.3 years (range 15 to 50 years) were examined by one of the three sports physicians at the B.C. Sports Medicine Cl i n i c . The 13 males and 6 females were biomechanically assessed and the results are represented in Table 4.1. A l l subjects exhibit ed symptoms of lower pole patellar tendonitis in the absence of any other knee disorders. Nine subjects presented with symptoms confined to the l e f t knee, while seven had symptoms a f f l i c t i n g only the right knee. Three sub-jects complained of bilateral knee pain, however, in each case, one knee was definitely the most painful (in each case this was the l e f t knee) and this remained constant over the course of the study. Quadricep Moment of Force Quadricep variables aare summarized in Table 4.2. There was no significant difference in quadricep moment of force over the treatment period of twelve weeks, nor was there any significant difference between the concentric group, training on the universal gym performing leg exten-sions and leg curls and the eccentric group who performed the eccentric squat exercise. Although there was no significant difference between the group and treatment effects, Figure 4.1 illustrates that the eccentric 24 Table 4.1 Subject Clinical Evaluation and Biomechanical Assessment DESCRIPTIVE N Age (Mean ± SD) Height (cm) (Mean + SD) Weight (kg) (Mean t SD) Location of pain Swelling Crepitus 19 (13 male, 6 female) 26.3 + 9.7 174.8 + 10.8 71.9 + 13.6 19 0 3 7 3 inferior pole superior pole Bilateral BIOMECHANICAL ASSESSMENT N % N Varus leg/foot alignment 17 897. Valgus leg/foot alignment 0 0 Genu Varum 11 587. Genu Valgum 0 0 Tibial Varum 1 57. Leg Length Discrepancy 1 57. Pes Cavus 0 0 Pes Planus 2 107. Patellar Squint 4 217. Increased Q Angle 0 0 DEGREE Mild -Moderate -Severe -Mild -Moderate Severe -14 3 0 9 2 0 Less than 1 cm. 25 group over the 12 week period showed larger gains as compared to the concen-tric group. There was a significant difference (p< 0.0003) between the injur-ed and non-injured leg (Figure 4.3 and 4.4). As would be expected, the in-jured leg was weakest in a l l cases at the initial Cybex test (0 weeks). At the end of the program (12 weeks), the injured leg was an average of 66.3 N weaker in'±he concentric group and an average of 57.4 weaker in the eccentric group. Although there was no statistical evidence that the injured and non-injured legs changed significantly in quadricep moment of force over the 12 week period, a trend showed that at the end of the twelve weeks, the in-jured leg in the eccentric group was on the average able to exert a larger force by 76.1 N and the concentric group was on the average 30I>3 N weaker (Figure 4.2). The non-injured leg was able to exert a larger force by 33.8 N on the Cybex in the eccentric group but was an average of 28.0 N weaker in the concentric group (Figure 4.1). For the injured leg, seven subjects in the eccentric group recorded larger quadricep moment of force readings at 12 weeks as. compared to their in i t i a l test at 0 weeks. The mean increase was 114.8 N. One subject remain-ed unchanged while two subjects decreased in quadricep moment of force. The mean decrease was 45.4 N. In contrast, the data from the concentric group had only four subjects recording larger quadricep moment of force readings at the 12 week mark. This mean increase was 45.4 N. The remaining five sub-jects in the concentric group decreased in moment of force from the initial value. The mean decrease was 97.9 N. Similarly, looking at the data for the other leg, of the seven sub-jects in'.the eccentric group who demonstrated moment of force gains in 1 the in-jured leg, six of these people recorded moment of force gains over the 12 week period in ..the non-injured leg. The mean increase was 74.3 N. Four subjects in this group decreased in moment of force an average of 26.7 N. In the con-centric group, three subjects increased in moment of force (X = 71.2 N), and six subjects actually recorded decreases in moment of force (X = 81.9 N). Three of these subjects who recorded moment of force decreases in the non-injured leg were those who presented with bilateral symptoms. 26 Table 4.2 Mean and Standard Deviations of Quadricep Moment of Force (Newtons) Over the Twelve Week Period TIME LEG GROUP 0 Weeks 6 Weeks 12 Weeks Injured Non Injured Injured Non Injured Injured Non Injured CONCENTRIC 620.3 t 113.9 684.0 t 179.8 590.9 + 121.5 694.2 + 113.0 590.1 + 130.8 655.9 + 125.5 ECCENTRIC 520.7 t 156.6 620.3 + 171.3 570.0 + 162.4 677.7 + 218.1 596.7 + 160.6 654.2 + 192.2 Table 4.3 Mean and Standard Deviations of Hamstring Moment of Force (Newtons) Over the Twelve Week Period TIME LEG GROUP 0 Weeks 6 Weeks 12 Weeks Injured Non Injured Injured Non Injured Injured Non Injured CONCENTRIC 287.0 t 98.3 299,9 + 87.2 320.4 + 92.6 328.0 + 89.4 338.2 t 90.8 332.4 t 84.6 ECCENTRIC 271.0 + 123.3 282.6 + 110.8 286.1 + 113.9 292.8 + 106.8 309.3 + 122.4 312.4 + 108.1 27 Figure 4.1 Quadricep Moment of Force (Mean Values and Standard Deviations in Newtons) Non Injured Leg MOMENT OF FORCE (NEWTONS) 700 680 -J 660 640 -620 -600 -694.2+ H3.0 684.ot 179.8 55.9+ 125.5 . Concentric ,4.2 + 192.2 Eccentric 620.3t 171.3 6 WEEKS I T Figure 4.2 Quadricep Moment of Force (Mean Values and Standard Deviations in Newtons) Injured Leg MOMENT OF FORCE (NEWTONS) 700 650 600 550 500 620.3+ 113.9 590.9± 121.5 ^ 596.7+ 160.6 570.0± 162.4 390.1 t 130.8 itccentric Concentric 520.71 156.6 5 WEEKS T2~ Figure 4.3 Quadricep Moment of Force (Mean Value and Standard Deviations in Newtons) Concentric Group Figure 4.4 Quadricep Moment of Force (Mean Values asnd Standard Deviations in Newtons) Eccentric Group MOMENT OF FORCE (NEWTONS) 750 H 700 650 600 550 500 -1 620.3 + 171.3 677^1 ± 218A 2 ± l 9 2 2 * Non Injured Injured 96.7 + 160.6 570.0+ 162.4 520.7"t 156.6 I WEEKS 12 Hamstring Moment of Force Hamstring variables are summarized in Table 4.3. Over the 12 weeks of training, hamstring moment of force significantly increased (p^O.OOOl). On the average, this treatment effect showed, for the concentric group, average increases of 50.7 N and 32.5 N in the injured and non-injured legs respectively, and for the eccentric group, increases of 38.3 N and 34.7 N (Figure 4.5 and 4.6). There was no significant group effect. There was no significant difference between the injured and non-injured legs in hamstring moment of force (Figure 4.7 and 4.8)* The injured leg was either of equal moment of force, as measured on the Cybex, as the non-injured leg, or was slightly weaker (on the average 4.5 - 8.9 N). This did not significantly^alter over the testing sessions. Thigh Girths Thigh girth measurements taken at both 4.4 and 10 centimeters above the medial knee joint line, on the whole did not significantly alter during the study, and there was no difference between the concentric and eccentric groups (Table 4.4). On the average, however, thigh girth as measured in centimeters did increase over the course of-the three testing sessions for both the in-jured and non-injured legs. This was a significant increase for the measure-ment taken at 4.4.centimeters above the medial knee joint line (p<0.03). For the value taken at 4.4 centimeters, in the concentric group, the injured leg increased an average of 0.2 centimeters, the same for the non-injured leg, and in the eccentric group, the injured leg increased 0.7 centimeters and the non-injured leg by an average of 0.25 centimeters. The remaining measurements did not alter significantly over the treatment period. There was no significant differences in thigh girth between the injured and non-injured legs. However, on the average, each girth measure-ment was smaller for the injured side. 3D Figure 4.5 Hamstring Moment of Force (Mean Values and Standard Deviations in Newtons) Injured Leg MOMENT OF FORCE (NEWTONS) 350 330 310 290 276 250 + 92.6 338.2t 90.g oncentric Eccentric 3 + 122.4 286.1+ 113.9 271.0 ± 123.3 6 WEEKS 12 Figure 4.6 Hamstring Moment of Force (Mean Values and Standard Deviations in Newtons) Non Injured Leg MOMENT OF FORCE (NEWTONS) 350 -330 -310 290 270 250 i 332.4 t 84.6 328.0 ± 89.4-^ Concentric Eccentric .4+ 108.1 292*.8 ± 106.8 282.6 t 110.8 6 WEEKS 12 3a Figure 4.7 Hamstring Moment of Force (Mean Values and Standard Deviations in Newtons) Concentric Group MOMENT OF FORCE (NEWTONS) 350 -| 330 310 290 270 250 -I 287.0t 98.3 328.0± 89.4 320.4± 92.6 6 WEEKS 338.2± 9 0 ^ j u r e d Non Injured 12 Figure 4.8 Hamstring Moment of Force (Mean Values and Standard Deviations in Newtons) Eccentric Group 350 -330 -310 -290 270 • 250 • ± 106.8 312 4 - 108.1 Non Injured Injured 309.3± 122.4 286.lt H3.9 271.0+ 123.3 12 WEEKS 32 Pain There was a significant difference in pain ratings between the con-centric and eccentric group averaged over the three testing sessions (p<0.01). Initially, the concentric "average" pain rating was 6.2 on the continuum scale of 1 (no pain) to 10 (severe pain) and the eccentric group 5.6. By the end of the 12 weeks, the concentric group's pain had diminished on the aver-age by 1.1 scale points, while the eccentric group's pain had diminished by an average of 3 points (Figure 4.8). This change over the three testing sessions was also significant (p<0.01). The interaction between the groups and the three testing sessions was not significant suggesting that the trend of pain to decrease is similar in both the concentric and eccentric groups, m however the eccentric group significantly decreases more. Overall, in the concentric group, two subjects were pain free (one after six weeks, one after twelve weeks), four subjects improved their con-dition slightly (average of 2.2 scale points), two subjects showed an in-crease in pain (average of 1.5 scale points), and one subject remained the saraffl. In contrast, in the eccentric group, four subjects were pain free (two after six weeks and two after twelve weeks), five subjects improved their condition (average of 2.8 scale points), while one subject had an in-crease in pain (by 3 scale points) (Table 4.4 and 4.5). Clinical Data Over a three year period, 1978 - 1981, 129 patients presented at the B.C. Sports Medicine Clinic with patellar tendonitis. This accounted for 4.5 per cent of a l l running induced injuries seen in ictae clinic during that period. In a l l , 93 patients were male, and 36 patients were female (72 per cent and 28 per cent respectively). 55 patients were diagnosed as having inferior pole patellar tendonitis, while 14 clinically demonstrated superior pole symptoms. Of these 69 patients, 13 had bilateral involvement. A summar of the clinical biomechanical evaluation appears in Table 4.7. In general, results show that the patellar tendonitis patient is one who possesses a varus foot/leg relationship, with a degree of genu varum. Moment of force data for the quadricep and hamstring groups was available only on 26 of the 129 tendonitis patients (19 of whom participated1 33 Table 4.4 Mean and Standard Deviations of Thigh Girth (centimeters) Over the Twelve Week Period 4.4 Centimeters Above Medial Knee Joint Line Concentric Eccentric 0 Weeks injured non-injured 37.it 1.6 37.9+ 1.2 38.Gt 2.0 38.4+ 1.8 6 Weeks injured non-injured 37.8+ 1.4 38.2+ 1.3 38.5+ 1.3 38.6+ 2.6 12 Weeks injured non-injured 37.9+ 1.5 38.1+ 1.4 38.7+ 2.0 38.7+ 2.3 10 Centimeters Above Medial Knee Joint Line Concentric Eccentric 0 Weeks injured 44.4+ 2.5 44.0+2.2 non-injured 44.5+ 2.5 44.9+2.9 6 Weeks injured 45.lt 2 - 4 4 4 - 5 t 2.4 non-injured 45.0+2.6 45.4+3.4 12 Weeks injured 44.4+ 2.3 44.6+ 2.4 non-injured 45.2+ 3.1 44.8+2.7 34 in the study). In examining the quadricep/hamstring ratio, only 7 patients had an acceptable ratin of 50 per cent or better (hamstrings being at least 50 per cent as strong as the quadriceps). Refer to Table 4.6. The remainder of the patients had marked muscle imbalance in both the injured and non-injured legs that were well below the 50 per cent ratio. These ratios were essentially similar for both groups. Discussion The results appear to indicate that the "eccentric squat" exercise produces a more superior result in terms of controlling the symptoms of chronic patellar tendonitis than does the conventional universal gym "leg extension/leg curl" exercise. Controlling the symptoms of patellar tendonitis is directly related to controlling the patient's subjective feeling of pain, and not directly dependent on increases in quadricep or hamstring mom-ent of force, or thigh girth. However, i t became evident that those patients who became totally pain-free after the twelve week program were those who actually demonstrated an increase in both quadricep and hamstring moment of force, a decrease in muscle imbalance in both the injured and non-injured legs, a l l secondary to a decrease in their perceived pain. Although i t was not significant (there was a large variance), the quadricep moment of force of those in the eccentric group improved a fair amount (75.7 N in the injured leg and 35.6 N in the non-injured leg). On the average, the quadricep moment of force of those in the concentric group actu-ally decreased (31.1 N in the injured leg and 26.7 N in the non-injured leg). The average decrease in moment of force associated with the concentric group can be largely accounted for by two subjects in particular who dramatically decreased in moment of force as a direct result of the aggravation caused by the particular exercise and training schedule leading to a great increase in pain. Average moment of force decreases for those in the concentric group in the non-injured leg can possibly be explained by the three subjects who pre-sented with bilateral complaints. The course of the exercise appeared to ag-gravate this leg (the non-injured), in which only minimal signs of patellar tendonitis were initially apparent, and cause an associated moment of force decrease. Exercise compliance and the use of submaximal weights to attempt to induce moment of force gains in a normal leg may also be factors. 35 Figure 4 . 9 Pain Ratings (Mean Values) 36 Figure 4.10 Pain Ratings: Concentric Group Subject Weak Continuum Scale 2 3 4 5 6 7 8 9 0 • 6 12 0 6 12 0 6 12 0 6 12 * * 0 6 12 0 6 12 0 6 12 0 6 12 0 6 12 resumption of hard training * denotes pain free 3iZ Figure 4.11 Pain Ratings: Eccentric Group Subject Week 0 6 12 0 6 12 Continuum Scale 0 6 12 0 6 12 0 6 12 0 6 12 QO 6 12 * * 0 6 12 0 6 12 J 10 0 6 12 * denotes pain free Table 4.5 Patellar Tendonitis Patients (N= 129)* Biomechanical Assessment N Sex: Male Female Varus leg/foot alignment Valgus leg/foot alignment Genu Varum Genu Valgum Tibial Varum Leg Length Discrepancy Pes Cavus Pes Planus Patellar Squint Increased Q angle Plantar Flexed 1st Ray Good Alignment Bilateral Involvement Superior Pole Involvement Inferior Pole Involvement Surgical Intervention 129 93 36 105 64 14 27 11 6 1 7 1 3 14 13 14 55 5 Mild 48 Moderate 51 Severe 6 Mild Moderate Severe 3 0 0 Mild 44 Moderate 20 Severe 0 Mild Moderate Severe 12 2 0 Less than 1 cm Greater than 15° (3.8 per cent of Total N) *These statistics include the 19 subjects involved in the study Table 4.6 Quadricep/Hamstring Ratios (%) at Initial Examination Group Subject Concentric 1 2 3 4 5 6 7 8 9 Eccentric 10 11 12 13 14 15 16 17 18 19 Other 20 21 22 23 24 25 Injured Leg Non-Injured Leg 39.0 39.0 38.5 50.0 46.0 45.0 46.5 44.9 42.8 42.0 63.0 48.8 78.2 57.6 33.3 34.2 41.6 36.7 45.0 50.0 52.0 45.0 57.1 52.6 35.6 34.8 61.7 43.0 83.2 38.9 30.0 40.0 56.7 53.9 32.8 30.9 33.3 27.6 27.7 37.9 38.5 34.2 77.9 54.8 56.3 61.0 35.0 31.0 41.0 46.0 £0 The eccentric squat program appeared to better control the muscle imbalance between the quadricep and hamstring groups within each leg than did the leg extension/leg curl program. Also important in any rehabilitation pro-cedure is the fact thatfithe injured leg should become as close in moment of force to the non-injured leg as soon as possible. Wyatt and Edwards (1981) suggest ratios between 95 per cent and 98 per cent between the injured and non-injured knees as criteria. At the beginning of the study, this ratio was 90 per cent for the concentric group and 83 per cent for the eccentric group. By the end of the twelve weeks, the injured leg was 89 per cent and 91 per cent as strong as the non-injured leg in the concentric and eccentric groups respec-tively. In terms of the initial hypotheses of this study, the leg extension/ leg curl group did not increase in moment of force more so than the eccentric squat group. Conversely, as stated, the eccentric group had a larger gain in quadricep moment of force (although not significant). The hamstrings, on the whole, increased in moment of force-(p^O.OOOl) similarly in both groups. In other words, the eccentric squat exercise appears to provide sufficient stimulation to cause an increase in moment of force for the hamstrings as well as for the quadriceps.- This suggests that hamstring strength is of some importance during an eccentric contraction of the quadri-cep muscle, and a weakness in this area could certainly be one of the contri-buting factors in causing the tendonitis. As an athlete, for example, is land-ing from a jumping situation, or is performing the eccentric squat exercise, the hamstrings must function in assisting initially as a braking force and then again as the athlete initiates action in resuming a standing position. Although hamstring moment of force increments in this study are not large, (average 35.6 N - 53.4 N), the low variability;;of hamstring strength values contributed to the significance of this gain. As would be expected, there was no difference between the injured and non-injured legs in hamstring mo-ment of force in either group. Girth measurements have been found to be valuable in estimating relative limb disuse atrophy following an injury. We found an average of a 0.5 to 1 centimeter difference between the injured and non-injured sides. Girth measurements at 4.4 centimeters above the medial knee joint line ap-pear the most imbalanced between the injured and non-injured, possibly due to atrophy in vastus medialis. 4J These girth measurements do not reflect injury rehabilitation and associated moment of force gains. We did, however, find that on the average, thigh girths taken at both 4.4 and 10 centimeters above the medial knee joint line increased over the twelve week period (not significant). This does not reflect injury rehabilitation, and i t would not be practical to correlate this increase in thigh girth to increases in leg moment of force. In essence, thigh girth is an unreliable measure in predicting injury rehabilitation, how-ever, it does give the physician an estimation of injury associated atrophy. Subjective patient evaluation of pain proved beneficial in this study in the evaluation of the exercises. Each subject evaluated his or her own feeling and estimation of pain on a given scale, and were subsequently asked to compare each rating with the next in order to obtain a general course of progress. The subject's estimation of the pain on the average decreased over the twelve weeks significantly more so for those in the eccentric group (p<0.01). The eccentric group also produced twice as many "pain free" sub-jects by the end of the program than did the concentric group. Al l subjects were required to maintain their activity level as high as possible throughout the program. In other words, as in Lamb and Stanish's protocol, enforced rest was not part of the study. The subjects whose con-ditions deteriorated (in either group) were a l l collegiate level athletes and two out of the three in particular, were volleyball players who were in the midst of exceptionally hard training schedules that included stair running, continual jumping exercises and long weekend tournaments that sometimes en-tailed as many as five matches per day. While i t appears that tendonitis patients can attempt to maintain their activity levels, the physician must caution the athlete to limit some activity and restrict themselves from cer-tain detrimental exercises (stair running and jumping drills in particular) until the symptoms have been controlled and the injured leg is gaining strength. Level and intensity of activity varied greatly with the subjects. For the collegiate athletes, tournament and practice schedules greatly de-creased over a holiday period, and this rest from high level activity allowed one subject in particular to become pain free after the firstasix weeks of his exercise program (Subject 9, Figure 4.10). Upon resumption of high level participation this subject again became symptomatic with an associated in-crease in his pain rating over the last six weeks. It can be speculated that despite the rest and the rehabilitation program he adhered to, he attempted to resume intense activity without sufficient time for adaptation after the rest. Lamb and Stanish (1980) reported that during the first three weeks of the eccentric squat exercise, pain may actually increase. Upon examining the exercise logs each subject was required to keep, specific days associated with pain tended to appear more frequently for the eccentric group during the first few weeks of the program. Muscle tends to become sore in the early stages of eccentric training most probably due to high production of tension, or after fatigue loading with repeated maximal eccentric contraction (Komi 1973). Exercise compliance is difficult to control for in a study such as this one. Over the twelve week period, i t was recommended that the subjects perform their specific exercise routine five times per week, in conjunction with their regular activities. This would entail, over the twelve weeks, sixty exercise bouts. The average number of exercise periods for those in the eccentric group was 46.6 while for the concentric group i t was 37.6. Most subjects were able to maintain their activity level throughout the course of the study (three subjects to an excess, while three subjects were very minimally active). Those who were minimally active over the twelve weeks either lacked motivation, or as in most cases, pain was their limiting factor. It was apparent in two cases that after an initial gain in moment of force and a "pain free" rating at the six week mark, motivation to continue working at their exercises decreased, and an attitude that they no longer required ex-ercise therapy developed. They did, however, continue to exercise although not to the same extent as during the first six weeks. In a l l , i t appeared that exercise compliance was related to the fact that for the eccentric squat exercise, convenience and availability of equip-ment played a major role. The availability of a universal gym, and the nature of the weight increments make i t difficult to be used as a rehabilitative tool. In some cases, patients attempting to slowly increase their resistance will jump from 10 to 15 kg because of convenience rather than purchase and utilize small 1 kg weights in order to increase more slowly. Although this was recom-mended to those in the concentric group, only three took that advice. In some cases, i t can be postulated that overloading an already weakened structure too quickly causes further aggravation. 4 3 While i t appears that the eccentric exercise is a successful rehab-ilitative exercise, the exact physiological response of the tendon is unknown. The physiological changes, especially with respect to tendon hypertrophy, as-sociated with eccentric work have yet to be examined. In both concentric and eccentric work, the activation of muscle increases linearly with the increase in force output. Production of muscle tension can be much higher in eccentric contraction, and the difference in tension between maximal eccentric work and concentric work increases with the increase in contraction velocity (Asmussen 1965, Komi 1973). While the two exercises (the eccentric squat and the leg. ex-tension/leg curl) were neither uniquely eccentric or concentric respectively, nor were they of maximal stress, the major component of each exercise (the period during which the most loading took place), occurred either during an eccentric phase or a concentric phase. The speed of muscle contraction is an integral component of the load-ing phase during the eccentric squat exercise, and i t has also been found to be important to rehabilitation in terms of reproducing sport specific speeds (Wyatt 1981). While the leg extension/leg curl exercise must be performed slowly, the eccentric squat exercise must be performed progressively faster. The exercise would then be simulating a jumping/landing situation in terms of the speed of quadricep contraction. It is plausible that in this manner the eccentric squat exercise not only^can be useful as a therapeutic exercise but can also have implications in the prevention of such overuse tendonit-ides. Lamb and Stanish (1980) suggest that strengthening the tendon during the eccentric phase of muscle contraction may lead to less susceptibility to microtearing of the tissue associated with tendonitis. It may also be the case that in performing the exercise at sport specific speeds, the athlete might be better prepared to re-enter high level competition after a minimal period of time. The signs and symptoms of patellar tendonitis in the 129 patients seen at the B.C. Sports Medicine Clinic over the three year period appear consistent with those described by others (Blazina 1973} Roel 1978, Smillie 1978, Krissoff 1979, Magee 1980). The clinical diagnosis was based upon the recognition of common specific signs elicited during the physical examination, as described by Blazina (1973) and Roel (1978). The usual progression of sym-ptoms was common in nearly a l l patients. The majority of the patients clinic-ally demonstrated tenderness at the patellar insertion of the patellar tendon 414 (lower pole), while only a few exhibited signs at the quadriceps insertion (superior pole). Out statistics showed that a variety of athletes may experience patellar tendonitis (Table 4.7), and on the average, they possess some degree of varus foot alignment and some genu varum. In terms of etiology, one can first look at the biomechanics of the athlete. While i t seems convenient to attempt to correlate biomechanical abnormalities with the injury, i t appears that the average structural malalignment of the patellar tendonitis patient is no different from the average biomechanical problems any athlete may pre-sent with who has any number of different overuse problems. For example, a runner's predisposition to injury increases with his degree of functional overpronation (Taunton and Clement 1980). The majority of the tendonitis patients did have some degree of varus heel and/or forefoot alignment. Causes of overuse injuries have been placed in four categories as described by James et al. (1978) and subsequently by Taunton and Clement (1980). Briefly these are: (1) Training errors including persistent high intensity training, and sudden increases in training and/or competition. (2) Anatomi-cal factors including leg length discrepancies, femoral neck anteversion, '.) quadriceps and/or hamstring insufficiency and/or imbalance, genu valgum, varum and recurvatum, Q angle greater than 15°, patella alta. tibial torsion, tibial varum, lower leg-heel and/or heel-forefoot malalignment, pes cavus, and pes planus. (3) Running shoes. (4) Training surfaces. The most common factors directly implicated in patellar tendonitis (i.e. that occurred in twenty or more patients) were (i) a single severe session of activity that lead to progressive symptoms, and (ii) quadricep in-sufficiency (poor flexibility and/or muscle dysfunction). The most prevalent sport the patellar tendonitis patients were in-volved in were running followed by basketball, volleyball, and soccer (Table 4.7). This could be slightly misleading since by far the majority of patients seen in the clinic are runners. A l l patients were able to report that the acti-vity that they were most involved in did subject the extensor mechanism to ex-cessive repetitive types of strain. Of a l l patellar tendonitis patients seen over this three year period, to date, five have resulted in surgery (3.8 per cent). This is a much lower incidence of surgical treatment than that described by Roel (36 percent) and by Blazina (12 to 20 percent). These higher surgical statistics from a few 45 years past could reflect the disappointing results these authors had reported with conservative treatment regimens for patellar tendonitis. Table 4.7 Athletic Involvement of Patellar Tendonitis Patients SPORT NUMBER % N NUMBER OF SUBJECTS IN STUDY (N=129) (N = 19) Running 84 65.0 3 Basketball 16 12.0 6 Volleyball 11 8.5 2 Soccer 4 3.0 3 Tennis 3 2.0 1 Rowing 3 2.0 1 Ballet 2 1.5 0 Football 1 1.0 1 Gymnastics 1 1.0 1 Hiking 1 1.0 0 Ice Hockey 1 1.0 0 Rollerskating 1 1.0 0 Squash 1 1.0 1 46 Chapter 5 SUMMARY AND CONCLUSIONS Summary The main purpose of this study was to determine which method of exercise rehabilitation - the "eccentric squat" exercise or the universal gym "leg extension/leg curl" exercise - produced a more significant result in terms of recovery in the treatment of chronic patellar tendonitis. A second objective was to determine i f a relationship existed between patients who pre-sent with patellar tendonitis, and certain biomechanical malalignments and/or muscle imbalances. Nineteen patients a l l with chronic patellar tendonitis were placed in one of two groups in which they either performed the "eccentric squat" exercise of the "leg extension/leg curl" exercise. Moment of force evaluations were performed on the Cybex II isokinetic dynomometer for both the quadricep and hamstring muscle groups in each leg, thigh girth measure-ments both 4.4 and 10 centimeters above the medial knee joint line were taken, and subjective evaluations of pain were collected. This occurred at three testing sessions during the twelve week program: initially at 0 weeks, at 6 weeks and again at 12 weeks. Results showed that the "eccentric squat" exercise produced a more superior result in terms of controlling the symptoms of patellar ten-donitis than did the conventional universal gym "leg extension/leg curl" ex-ercise. Both groups significantly improved rtheir hamstring moment of force over the twelve weeks, but only the "eccentric squat" group averaged larger moment of force readings for the quadriceps. This increase, however, was not found to be significant. There was a significant decrease in pain for those performing the "eccentric squat" exercise, and while the group exercising on the universal gym experienced ah average decrease in pain, i t was neither sig-nificant nor was it of the same extent as experienced by the "eccentric squat" group. Girth measurements did not significantly differ over the twelve weeks. A relationship appears to exist between patients who present with patellar tendonitis, and certain biomechanical malalignment problems these people display. This relationship, however, appears similar to the relationship found with any type of athlete who subjects himself to repeti-tive activity and presents with any number of overuse problems. The most common etiological factors implicated in patellar tendonitis cases were: (i) quadricep insufficiency and/or muscle imbalance, and ( i i ) a single severe session of activity. It appears indicated to recommend the use of the "eccent-r i c squat" exercise as an approach toward the conservative managment of chronic patellar tendonitis. In addition, attention must be paid to the correction of any biomechanical malalignment problems the patient may poss-ess. While i t seems apparent that these athletes can continue to be active while being treated, the type and level of activity should be monitored and modified i f warranted. Conclusions 1. The "eccentric squat" exercise appears to control3?the painful symptoms of chronic patellar tendonitis better than the "leg extension/leg c u r l " ex-ercise. 2. Moment of force gains in the associated muscle group do not necessarily correspond to the patient's diminishing pain symptoms. The a b i l i t y to in-crease ones moment of force in the affected limb, however, is f e l t to be im-portant in terms of being essential to a f u l l recovery and to the a b i l i t y to return to pre-injury activity levels. 3. Girth measurements of limbs do not necessarily reflect strength or moment of force increments. They appear to be of l i t t l e value as a c r i t e r i a for de-termining injury rehabilitation. 4. It seems apparent that an athletes predisposition to an overuse injury such as patellar tendonitis increases with certain etiological factors and biomechanical malalignment problems, but those who present with patellar ten-donitis are generally no different than those who may present with any vari-ety of other commonly seen overuse type injuries. 5. The subjects own evaluation of their pain progressions over the twelve weeks proved valuable in this study. 48 Recommendations 1. Further research should be conducted using a similar protocol to ex-amine the effects of an "eccentric" type of exercise on other areas commonly associated with chronic tendonitides. An "eccentric" type of exercise could be performed for the achilles tendon and for the wrist extensor tendons associated with tennis elbow. 2. The physiological mechanism of adaptation within a tendon exposed to eccentric forces must be examined and possibly correlated to the clinical management of the tendonitis symptoms. 3. In order to fully evaluate the merits of the "eccentric squat" ex-ercise as a rehabilitative tool in the management of chronic patellar tendonitis, long term follow-up data should be collected on the patients. Ideally, one would like to see a patient continue with full activity with no recurrence of tendonitis symptoms. 4. The role of specialized, graded eccentric type exercise that has been based upon scientific training principals in'the prevention of chronic tendonitis should be investigated. 4$ REFERENCES Abrahams, M. Mechanical behavior of tendon in vitro. Medical and Biolo-gical Engineering. 5:433-443, 1967. Blazina, M.E., R. Kerlan, F. Jobe, V. Carter and G. Carlson. Jumper's knee. Orthop. Clinics of N.A. 4(3):665-678, 1973. Blazina, M.E., J.M. Fox and G. Carlson. Certain basketball injuries. Phys. and Sports Med. Booth, F.W., and E.W. Gould. Effects of training and disuse of connective tissue. Exercise and Sports Sciences Reviews. 82-112, 1975. Brody, D.M. Running injuries. Clinical Symposia. 32(4):2-36, 1980. Cavagna, G.A. Storeage and utilization of elastic energy in skeletal muscle. Exercise and Sports Sciences Review. 5:89-129, 1977. Chavpil, M. Physiology of connective tissue. Prague: Czechoslovakia Medical Press, 1967. Clancy, W.G., Neidhart, and R.L. Brand. Achilles tendinitis in runners: A report of five cases. Amer. J . of Sports Med. 4(2): 46-56, 1976. Clark, D.H. Adaptations in strength and muscular endurance resulting from exercise. Exercise and Sports Sciences Reviews Vol. 1. New York: Academic Press, 1973. Coonrad, R., and R. Hooper. Tennis elbow: It's course, natural history, conservative management. J. Bone and Joint Surg. 55A: 1117-1182, 1973. Dixon, W.J. (Ed.) BMDP - Biomedical computer programs. Los Angeles: Uni-versity of California Press, 1973. Feigel, W.P., and D. Zamzow. The runner's knee. Runners World. 5: 37-40, 1980. Ficat, P.R., and D.S. Hungerford. Disorders of the patello-femoral joint. Baltimore: Williams and Wilkins, 1977. Gleim, G.W., J.A. Nicholas, and J.N. Webb. Isokinetic evaluation following leg injuries. Phys. and Sports Med. 6(8): 54-56, 1978. Grossman, R., and J. Nicholas. Common disorders of the knee. Orthop. Clin.  N.A. 8: 619-639, 1977. Harkness, R.D. Mechanical properties of collagenous tissues in treatise on collagen, ed. B.S. Gould. 2: 247-310. New York: Academic Press, 1968. Heikkinen, E. and I. Vuori. Effect of physical activity on the connective tissue metabolism in mice. Scand. J. Clin. Lab. Invest. 113:36 (suppl.) 1970 Helfet, A.J. Disorders of the knee. New York: J.B. Lippincott, 1974. Jakob, R.P. and B. Segesser. Extension training of the quadriceps - A new concept in therapy of tendinoses of the knee extensor apparatus (Jumper's knee). Orthopade. 9: 201-206, 1980. James, S.L. Chondromalacia of the patella in the adolescent'. The Injured  Adolescent Knee. 205-249, 1981. James, S.L., B.T. Bates and L.R. Osternig. Injuries to runners. Amer. J. Sports Med. 6: 40-50, 1978. Johnson, B.L. and J.W. Adanczyk. A comparison of concentric and eccentric muscle training. Med. Sci. Sports. 8(1): 35-38, 1976. Kastelic, J.,\«A. Galeski and E. Baer. The multicomposite structure of tendon. Connective Tissue Research. 6: 11-23, 1978. Kennedy, J.C. (Ed.). The injured adolescent knee. Baltimore: Williams and Wilkins, 1979. Kennedy, J.C. and R.B. Willis. The effects of local steroid injections on tendons: A biomechanical and microscopic correlative study. Amer. J. Sports Med. 4(1): 11-21, 1976. Kiiskinen, A. Physical training and connective tissues in young mice. Physical properties of achilles tendons ?and long bones. Growth. 41: 123-137, 1977. Klein, K.K. Evaluation of running injuries. Phys. Sports Med.8( ): 141-143, 1980. Klein, K. Strength maintenance following specific rehabilitation, valida- tion of a specific rehabilitation apparatus and exercise potential  related to injury potential. Texas, 1963. Klein, K.K. and F.L. Allman. The knee in sports. New York: Pemberton Press, 1969. Klein, K.K. and W.L. Hall. The knee in athletics. AAHPER, 1963. Komi, P. Measurement of force-velocity relationship in human muscle under concentric and eccentric contractions. Medicine and Sport. Momechry, anics III. Baltimore: University ParkrPress, 224-229, 1973. Komi, P. Changes in motor unit activity and metabolism in human skeletal muscle during and after repeated eccentric and concentric contractions. ActaPhys. Scand. 100: 246-254, 1977. Krissoff, W.B., and W.D. Ferris. Runner's injuries. Phys. and Sports Med. 7(12): 55-64, 1979. • § 1 Lamb, H.F., W.D. Stanish, and S. Curwin. The relationship of eccentrically produced muscular tension to the etiology of chronic tendinitis. Unpublished paper. Halifax, 1980. Leach, R.E., S. James, and S. Wasilewski. Achilles tendinitis. Amer. J. Sports Med. 9(2): 93-98, 1981. Magee, D. Orthopaedics: Conditions, assessment and treatments. Vol. 1, 1979. Maquet, P.G. Biomechanics of the knee. New York: Springer-Verlag, 1976. Margies, S., and M. Lewis. Bilateral spontaneous rupture of patellar tendon without apparent associated disease. Clin. Orthop. 136: 186-187, 1978. Nelson, R.C., and R. Gregor. Biomechanics of distance running: A longitudi-nal study. Research Quarterly. Noesberger, B. The jumper's knee. Helv. Chir. Acta. 43(5,6): 447-450, 1976. Oakes, B.W., and B. Bialkower. Biomechanical and ultrasctructural studies on the elastic wing tendon from domestic fowl. J. Anatomy. L123(2): 369 -387, 1977. O'Donohue, D.H. Treatment of injuries to athletes. Philadelphia: W.B. Saunders, 1975. Peusner, D.N., J.R. Johnson, and M. Blazina. The patellofemoral joint and its implications in 'the rehabilitation of the knee. Physical Therapy. 59(7): 869-874, 1979. Pipes, T.V., and J.H. Wilmore. Isokinetic versus isotonic strength training in adult men. Med. Sci. Sports. 7(4): 262-274, 1975. Rao,'J., and K. Siwels. Bilateral spontaneous rupture of the patellar tendons. Orthop. Rev. 7: 49-51, 1978. Rathburn, J.B., and I. McNabb. The microvascular pattern of the rotator cuff. J. Bone Joint Surg. 52B: 540-553, 1970. Reilly, D.T., and M. Martens. Experimental analysis of the quadriceps muscle force and patello-femoral joint reaction force for various activities. Acta. Orthop. Scand. 43: 126-137, 1972. Roels, J., M. Martens, J.C. Mulier, and A. Burssens. Patellar tendinitis (jumper's knee). Amer. J. Sports Med. 6(6): 362-368, 1978. Rubin, B.D., and H.R. Collins. Runner's knee. Phys. and Sports Med. 8(6): 49-58, 1980. Saywell, S. Physiotherapy in major knee surgery. London: William Heinemann Medical Books, 1965. Scharzker, M.D., and P.I. Branemark. Intravital observation on the microvascular anatomy and microcirculation of the tendon. Acta  Orthop. Scand. Suppl. 126, 1969. 52 Sheehan, G.A. An overview of overuse syndromes in distance runners. Annals of N.Y. Acad, of Sciences. 301: 877-879, 1977. Smillie, I.S. Injuries of the knee joint. New York: Churchill Livingstone, 1978. Steadman, J.R. Non operative measures for patellofetnoral problems. Amer. J. Sports Med. 7(6): 374-375, 1979. Subotnick, S.I. Variations in angles of gait in running. Phys. Sports  Med. 7(4): 110-114, 1979. Subotnick, S.T. A biomechanical approach to running injuries. Milry, 1978. Tarnsey, F.F. Catastrophic jumper's knee: A case report. Amer. J. Sports  Med. 9(1): 60-61, 1981. Taunton, J.E., D. Clement, and G. Smart. Conservative treatment land management of overuse knee injuries. Unpublished paper, 1979. Taunton, J.E., and D. Clement. A guide to the prevention of running injuries. Can. Fam. Physician. 26: April, 1980. Taunton, J.E., and D. Clement. A survey of overuse running injuries. Phys. and Sports Med. 9(5): , 1981. Tipton, CM., J.A. Maynard, and R.A. Carey. The influence of physical activity on ligaments and tendons. Med. Sci. Sports. 7(3): 165-175, 1975. Vailas, A.C., CM. Tipton, H.L. Laughlin, T.K. Tcheng, and R.D. Matthes. Physical activity on ligaments and tendons. Med. Sci. Sports. 7(3): 165-175, 1975. Vidiik, A. On the relationship between structure and mechanical function of soft connective tissue. Anat. Gest. 72: 75-79, 1978. Vidiik, A. Tensile strength properties of achillesitendon systems in trained and untrained rabbits. Acta. Orthop. Scand. 40: 261-272, 1969. Vidiik, A. The effect of training on the tensile strength of isolated rabbit tendons. Scand. J. Plastic Reconstr. Surgery. 1: 141-147, 1967. Wahrenberg, H. Knee muscular movement, tendon tension force and EMG during vigorous movement in man. Scan. J. Rehab. Med. 10(2): 99-106, 1978. Welsh, P. Stress syndromes in athletes. New Zealand Med. J. 3: 223-225, 19/79. Wise, D. Physiotheraputic treatment of athletic injuries to the muscle tendon complex of the leg. Can. Med. Ass. J. 117(6): 635-639, 1977. 53 Wyatt, M.P., and A. Edwards. Quadricep femoris and knee flexor muscle torque during isokinetic loading. Physical Therapy. 60(5): 587, 1980. Wyatt, M.P. and A. Edwards. Comparison of quadriceps and hamstring torque values during isokinetic exercise. J . Orthop. and Sports Physical  Therapy. 3(2): 48-55, 1981. Yamamoto, S.K., C.W. Hartman, J.A. Feagin, and G. Kimball. Functional rehabilitation of the knee: A preliminary study. Amer. J . Sports  Med. 3: 228-291, 1975. 5& Appendix A TREATMENT PROTOCOL 53 B.C. SPORTS MEDICINE CLINIC Concentric (Isometric/Isotonic) Rehabilitation Protocol for Patellar Tendinitis Phase 1 To achieve the earliest possible control of the symptoms, avoid symptom producing activities where possible and minimize those symptom producing activities that cannot be avoided. Occasionally, more complete rest with crutches or immobilization is neces-sary to obtain initial control of the symptoms. Anti-inflammatory medication and regular ice packs (10 minutes every 2-3 hours) is advisable. A progressive weight program should be started as soon as possible during phase 1. The progressive isometric/isotonic weight program consists of 3 sets of 10 l i f t s for each of two exercises. These exercises are to be performed once daily, 5 days per week. The isometric quadricep exercise is the start of the program (Table 1). First attempts at this exercise will not produce three sets of ten repititions. Slowly progress to 10 repititions as pain diminishes and strength increases. Figure 1 illustrates the 'Universal weight machine' isometric quadricep exercise. Insert pin at 10 lbs. (5 kgs.). Grasp the top footpiece normally used for the hamstring exercise and l i f t the top footpiece until the bottom footpiece is level with the bench top. Then, fully extend the knee, lower the weight on to the foot and hold the leg in the extended position for 5 seconds. Do not attempt to hyper-extend the knee. At the end of 5 seconds, l i f t the weight off the foot, lower the leg «?nd rest 5 seconds. Repeat to a maximum of 10 repititions. To correct or prevent the establishment of a dynamic imbal-ance, i t is important that the same weight is used and the same number of re-pititions are performed on each leg. Alternate sets of ten l i f t s between left and right legs, allowing one leg to rest while the other is working. Phase 2 Lift support up Extend knee and hold 5 sec. FIGURE 1 Isometric Leg Extension 56-Figure 2 illustrates the 'Universal weight machine' used to perform the isotonic quadricep exercise after the Start level is mastered. The pin is inserted into the weight stack as per the quide-lines of Table 1. Hook the injured side foot underneath the bottom footpiece, then slowly l i f t the weight (with the injured leg) to full extension. Hold the knee fully extend-ed for two seconds, then slowly lower. Each l i f t from start to finish should take at least 5 seconds. Repeat this l i f t up to 10 times (1 set) then rest. Repeat these repetitions twice more. As before, repeat with the other leg. The Universal weight machine is in graduations of 10 pounds (5 kilograms) It is advisable to purchase four 2 pound fish weights to allow a smaller poundage increase. This also allows a progression between levels in Table 1. Slowly l i f t Hold 2 seconds Slowly lower FIGURE 2 Quadricep Extension Isotonic TABLE Guidelines for Concentric Knee Extensions Body Weight (pounds) 100 131 161 to to to 130 160 200 Progression Stack Weight Start 10 10 10 Isometric Level 1 10 20 25 Isotonic Level 2 20 30 40 Isotonic Level 3 25 40 55 Isotonic Level 4 30 50 70 Isotonic Activity Level modified rest jogging-alternate days \ speed 3/4 speed full speed daily running 5? When three sets of 20 drops can be performed easily, progress to the next level as per Table 1. If knee pain occurs during or after a session, immediately apply ice to the area for 10 minutes and do the previous level of intensity the following day. As this is a new activity pattern, there may be some discomfort inlyour quadriceps and/or knee area, this doesn't indicate damage. Again, ice the area for at least 10 minutes. Figure 3 illustrates the isotonic hamstring exercise. The pin is in-serted into the weight stack at the desired weight. This weight should be approximately \ the weight used in the quadricep extension (as outlined in Table 1). To perform the weight-machine isotonic hamstring exercise, lie prone on the weight machine bench and position the back of the lower calf under the top footpiece with the leg extended. Slowly flex the knee to 90 degrees, .hold the knee in the flexed position for 2 seconds, and then slowly return the weight to the starting position.- Each l i f t , from start to finish, should take at least 5 seconds. Repeat the exercise. As in the quadricep exercise, attempt to complete 3 sets of 10 repetitions with the same weight on each leg, once daily, 5 days per week. Start Lift to 90° Flexion Leg Extended Hold 2 seconds, then lower FIGURE 3 Isotonic Leg Flexion Exercise Athletes who present with minor knee pain may be permitted to follow a modified running program before the symptoms are competely controlled. However, this decision is to be made by the examining doctor- not by the athlete. Phase 3 The graduated running program is not to be started until the symptoms are completely controlled and the isometric l i f t s can be performed easily at level 1. To start, running is done on alternate days, beginning with 1 km. and increasing by 1 km. every third run. Begin with jogging and grad-ually progress to full speed running, according to the intensity level in Table 1. Initially, running should be restricted to straight ahead on smooth, flat, even surfaces. Upper body weights, swimming or cycling, i f tolerated, should be performed on 'rest' days to maintain fitness. Daily running can commence once Level 4 is reached, providing there are no symptoms. 58 Phase 4 The maintenance program begins once Level 4 is attained and daily run-ning has been achieved, free of any symptoms. The maintenance program consists of unrestricted physical activity as tolerated, continuing the level 4 isotonic l i f t s 2-3 times per week, and a daily program of quadricep, hamstring and lower leg flexibility exercises. Avoid kneeling on hard surfaces and wear knee pads to protect the knee from direct trauma when the risk presents itself. Eccentric Rehabilitation Protocol for Patellar Tendinitis Phase 1 To achieve the earliest possible control of the symptoms, avoid symptom producing activities where possible and minimize those sympton producing activities that cannot be avoided. Occasionally, more complete rest with crutches or immobilization is neces-sary to obtain in i t i a l control of the symptoms. Anti-inflammatory medication and regular ice packs (10 minutes every 2-3 hours) is advisable. A progressive weight program should be started as soon as possible during phase 1. Phase 2 The eccentric weight program consists of three sets of 20 drops perform-ed once daily, 5 days per week. Figure 1 illustrates the start and finish positions for the eccentric drop. To start, stand erect, place your hands at your sides. Your feel should be flat on the ground, approximately shoulder width apart. Unlock your knees quickly and allow yourself to drop just short of your thighs being parallel to the ground. Then stop your f a l l with your quadriceps of both legs. Do not let your thighs go beyond the parallel line to the ground.' The first time you perform these drops, have someone watch you or watch your-self in a mirror, so as not to go too far on the drop. a) Start position: i) Knees straight ii ) Feet shoulder width apart © b) Finish position: i) Thighs parallel to ground ii ) Hands to side for balance FIGURE 1 ECCENTRIC DROP 59 When three sets of 20 drops can be performed easily, progress to the next level as per Table 1. If knee pain occurs during or after a session, immediately apply ice to the area for 10 minutes and do the previous level ttf intensity the following day. As this is a new activity pattern, there may be some discomfort in your quadriceps and/or knee area, this doesn't indicate damage. Again, ice the area for at least 10 minutes. Athletes who present with minor knee pain may be permitted to follow a modified running program before the symptoms are completely controlled. How-ever, this decision is to be made by the examining doctor - not by the athlete. TABLE 1 Guidelines for Eccentric Drop Body Weight (pounds) 100 131 161 to to to 130 160 200 Progression Hand Weights Activity Level Start 0 0 0 modified rest Level 1 5 5 10 jogging - alternate days Level 2 10 10 20 \ speed Level 3 15 20 30 3/4 speed Level 4 20 30 40 full speed daily running Phase 3 The graduated running program is not to be started until the symptoms are completely controlled and the eccentric drops can be performed easily at level 1. To start, running is done on alternate days, beginning with 1 km. and increasing by 1 km. every third run. Begin with jogging and gradually progress to full speed (running, according to the intensity level in Table 1. Initially, running should be restricted to straight ahead on smooth, flat, even surfaces. Upper body weights, swimming or cycling, i f tolerated, should be performed on 'rest' days to maintain fitness. Daily running can commence once Level 4 is reached, providing there are no symptoms. Phase 4 The maintenance program begins once Level 4 is attained and daily running has been achieved, free of any symptoms. The maintenance program consists of unrestricted physical activity as tol-erated, continuing the level 4 eccentric drops 2-3 times per week, and a daily program of quadricep, hamstring and lower leg flexibility exercises. Avoid kneeling on hard surfaces and wear knee pads to protect the knee from direct trauma when the risk presents itself. Appendix B PATIENT ASSESSMENT FORM 613. B.C. SPORTS MEDICINE CLINIC Patellar Tendinitis Patient History: 1. Name: , 2. Sex: m f 5. Weight: 7. Training Program: 7.1 Sport: _ 7.3 Duration per Activity: 7.4 Experience: 7.5 Shoe Design: Brand: Model: Brand: Model: 7.6 Other Comments: ___________ Date:_ . Birthdate: — A e e Height: 7.2 Frequency: _ Evaluation/comments: 8.1 Patient: 8.2 Examiner: 8.3 Cybex: Right Quad Hamstring, Left Quad Hamstring 8.4 Thigh Circumference: R 4.4 cm. 10 cm L 4.4 cm. 10 cm Biomechanical Considerations: 9.1 genu var val 9.2 tibial var L R val L R 9.3 subtalar var L R 9.4 forefoot var L R val L R val L R 9.5 9.6 lee length discrepance L oatellar sauint R 9.7 Q angle L R 9.8 swelling Follow-up (6 weeks): Date: 11 10.1 Patient: 10.2 Examiner: 10.3 Cvbex: Right Quad Hamstring Left Quad Hamstring 10.4 Thieh Circumference: R 4.4 cm 10 cm L 4.4 cm 10 cm Follow-up (12 weeks) 11.1 Patient: 11.2 Examiner: 11.3 Cybex: Right Quad Hamstring Left Quad Hamstring 11.4 Thigh Circumference: R 4.4 cm 10 c m L 4.4 cm 10 ' cm 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0077278/manifest

Comment

Related Items