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PubMed1998

Geometrical analysis of hip and knee joint mobility in cerebral palsied children.

The present investigation attempted to define a geometrical hexagon model for representing the sagittal range of motion (ROM) of hip and knee joint. The effect of both monoarticular and biarticular muscles on joint mobility in children with spastic cerebral palsy (SCP) were analyzed by this geometrical method. Photographic analysis was used to measure hip and knee joint angle at six different boundary positions. The ROM in normal children indicated age dependent reduction of maximal hip flexion and shortening of hamstring and rectus femoris muscles. A number of SCP children showed greater reduction of both hip flexion and extension and shortening of hamstring and rectus femoris muscles, whereas the ROM of knee joint was similar to that in normal children. The deteriorated hip joint mobility seems to be associated with shortening of muscle due to their intrinsic spasticity. The impaired ROM was more noticeable in SCP non-ambulator child than in independent ambulator. Thus, more extended range and frequent opportunity of joint motion may play an important role in improving the joint mobility in this patient group. Copyright 1998 Elsevier Science B.V.

Journal Article↗

PubMed2004

The role of stretching in rehabilitation of hamstring injuries: 80 athletes follow-up.

UNLABELLED: For years, stretching has been an integral part of fitness, practice, and rehabilitation programs to decrease muscle stiffness and relieve pain associated with it. The increased joint range of motion (ROM), indicating the degree of muscle flexibility, has a benefit of stretching proven for healthy tissues. PURPOSE: The objective of our study was the assessment of the effects of stretching in the rehabilitation of hamstring injuries. METHODS: We followed up 80 Greek athletes, of average age 20.5 yr, with "second-degree" strain of the hamstring muscles. The athletes were divided into two groups, A and B. For both groups, we estimated the time required for the rehabilitation of the decreased knee ROM and the total time before the athletes could return to a full training program. RESULTS: Group B, which carried out a more intensive stretching program, was found to have a statistically significant shorter time of regaining normal ROM (5.57 +/- 0.71 d) and rehabilitation period (13.27 +/- 0.71 d) in comparison with group A (7.32 +/- 0.525 d and 15.05 +/- 0.81 d, respectively). CONCLUSION: Our results suggest that stretching is of great importance in treating muscle strain injuries in that it improves the effectiveness of the rest rehabilitation program.

Adult↗

PubMed1989

Electrical muscle stimulation in combination with a reciprocating gait orthosis for ambulation by paraplegics.

Commercially available electrical muscle stimulators (EMS) provide functional electrical stimulation and are interfaced with reciprocating gait orthosis (RGO). The system which has been developed is described here as an EMS-RGO. Advantages of the system include: medically prescriptable subsystems available from manufacturers, and commercially recommended subsystems for applications such as gait training. The system itself employs four EMS units worn on a belt. It is controlled by remote switches and is interfaced to electrodes placed over the quadriceps, hamstring and gluteal muscle groups of each leg. Two EMS units (for quadriceps stimulation) function primarily for stand-up and sit-down. Two other EMS units (for stimulation of the hip extensors) function primarily for ambulation. Each EMS unit is powered by a nine volt alkaline transistor battery which provides about 36 stand-uphs and sit-down's and approximately 3.1 km of walking before replacement is necessary. The system has been evaluated on a T-5 level paraplegic individual who sustained a motor complete lesion (Frankel Class B) of the spinal cord over seven years ago. It is emphasized that successful EMS-RGO walking exercise must be preceded by a physical conditioning programme of active physical therapy. New battery technology (such as lithium batteries) may improve the useful lifespan of the system, and new electrode technology (such as TTGs) may improve patient acceptance of the system.

Adult↗

PubMed1978

Biokinetical analysis of the movements of the pelvic limb of the horse and the role of the muscles in the walk and the trot.

The movements of the right hind limb of horses with normal locomotion were studied using cinephotography and electromyography. A model of the cycle of a stride in the walk and the trot was constructed and the kinetic parameters of the segments of the limb were calculated. A good correlation was obtained between the kinetics and the periods of the cycle of a stride during which individual muscles display activity. The results of this study demonstrate that: at placing and lifting, i.e., when a change occurs in the direction of the movement of the limb; b) At the walk, the greatest forces operant at the centres of gravity of the limb segments in the direction of the progression are present in the beginning and the end of the support phase. The first top in the acceleration curve is produced by activity in the retractors of the limb (hamstrings, gluteus medius muscles). At the end of the support phase, when activity in the retractors of the limb no longer exists, the dynamic effect of the moment of the weight about the point of support of the stabilized inclined limb, as well as the elastic resilience of the muscular tissue are responsible for the push-off. At the trot, the greatest forces in the direction of progression are exerted in the middle of the support phase and are largely due to muscular action; c) In the second part of the support phase in the walk, the stifle flexes and the hock extends, which results in stretching the tendinous peroneus tertius and subsequently in flexion of the hock as soon as the hoof starts rolling over; d) The gastrocnemius and cranial tibial muscles in the reciprocal tendinous apparatus centre the line of action of the resultant load on the tibia during the locomotion and reduce the strain due to bending; e) At the end of the support phase, the action of the rectus femoris muscle is replaced by that of the vastus lateralis, which prevents hooking of the patella on the medial ridge of the femoral trochlea by rotating it laterally around a longitudinal axis.

Animals↗

PubMed2002

Reduction of spastic hypertonia during repeated passive knee movements in stroke patients.

OBJECTIVES: To quantify changes in spastic hypertonia during repeated passive isokinetic knee movements in stroke patients and to assess the role of muscle activity. DESIGN: A between-groups design with repeated measures. SETTING: Rehabilitation center for stroke patients. PARTICIPANTS: Ten stroke patients with hypertonia and 10 healthy subjects matched for age and gender. INTERVENTION: With an isokinetic apparatus, movements were imposed on the knee in series of 10 repetitions at speeds of 60 degrees /s, 180 degrees /s, and 300 degrees /s. MAIN OUTCOME MEASURES: Spastic hypertonia was assessed on the basis of torque measurement and electromyographic activity of the quadriceps, hamstrings, and gastrocnemius muscles. RESULTS: Compared with the controls, stroke patients presented a significantly stronger torque reduction during the mid- and endphases of movements at all speeds tested (P<.05). The strongest torque decline occurred during knee flexion and during the first movements. The effect increased toward the end phase of movements and with increasing speeds. The effect of movement repetitions on torque measurements was unchanged after electromyographic activity was included in the statistical analysis, except during extension movements at 180 degrees /s and 300 degrees /s. CONCLUSION: Passive movements of the knee induced a decrease of spastic hypertonia in stroke patients through a combination of reflexive and mechanical factors. The role of these mechanisms is velocity dependent and differs for flexion and extension movements.

Biomechanical Phenomena↗

PubMed2006

Gender comparisons of dynamic restraint and motor skill in children.

OBJECTIVES: To assess differences in neuromuscular dynamic restraint between high-skilled and low-skilled prepubescent girls and boys. To determine the contribution of sport experience and physical characteristics to motor skill. SUBJECTS: Nineteen girls and 17 boys (8.89-9.40 y) participated. INTERVENTION: Isometric hamstring and quadriceps muscle strength was assessed. Subjects performed 3 landing trials for measurement of preparatory EMG and vertical leg stiffness. Motor skill was assessed through analysis of 12 fundamental tasks. Sport experience was reported as hours per week and total years in organized and nonorganized activity. OUTCOME MEASURES: Dynamic restraint variables of isometric strength, preparatory EMG activity, and vertical leg stiffness were measured between groups. The contributions of time in sport, type of sport, and physical characteristics on skill were analyzed. RESULTS: No significant gender or skill differences were found in quadriceps strength (P = 0.73), hamstring strength (P = 0.96), hamstring-to-quadriceps ratio (P = 0.71), or vertical leg stiffness (P = 0.38). Low-skilled children exhibited significantly greater (47.8%) preparatory hamstring-quadriceps coactivation than high-skilled subjects (P = 0.03). Participation in organized and nonorganized sport accounted for 29% of the variance in motor skill. CONCLUSIONS: Neuromuscular differences between genders were not observed, but dynamic restraint EMG measures differed between skill levels. The factors predisposing females to noncontact injuries may develop prepuberty to postpuberty from a combination of variables. Greater coactivation in the low-skilled group appears consistent with immature feedforward neuromuscular control strategies. These unrefined motor skills are less economical, may compromise dynamic restraint, and appear partially determined by sport experience.

Athletic Injuries↗

PubMed2005

A TA-repeat polymorphism in the gene for the estrogen receptor alpha does not correlate with muscle strength or body composition in young adult Swedish women.

OBJECTIVES: There are conflicting data in the literature whether estrogens affect muscle strength. Prospective studies with hormone replacement therapy have not been able to convincingly demonstrate a muscular effect and the putative role of estrogen in the development of lean body mass is not established. Both lean mass and fat mass are known to be under strong genetic control and therefore we have investigated the relation between a TA-repeat in the gene for the estrogen receptor alpha (ERalpha) and muscle strength and body composition. METHODS: 175 healthy Swedish women, aged 20-39 were randomly selected from the population registry and included in the study. Body mass measurements (lean mass, fat mass, body weight and BMI) and muscle strength (quadriceps, hamstring and grip strength) were evaluated. The TA-repeat in the ERalpha gene was amplified by polymerase chain reaction. RESULTS: Alleles with a TA-repeat length of 16 repeats or shorter were denoted short (e), and repeat length of 17 repeats or longer were denoted long (E). Women homozygous for the short and long genotype were denoted ee (31%) and EE (21%), respectively, while heterozygous individuals were denoted Ee (48%). The frequencies were in Hardy-Weinberg equilibrium. No associations were found between ERalpha genotypes and muscle strength or body composition. CONCLUSION: The TA-repeat in the human ERalpha gene does not correlate with muscle strength or body mass measurements, indicating that body composition is not as sensitive to genetic variation in this receptor as other target organs for estrogen.

Adult↗

PubMed1990

Task specificity in the control of intrinsic trunk muscles in man.

The human trunk is a complex mechanical system comprised of large and small segments interconnected with several layers of muscles. An accurate control of this system is important during a variety of everyday tasks such as voluntary movements of the trunk, walking and running. This study was designed to investigate the interaction between muscles controlling the pelvis and the trunk during a variety of movements requiring a finely tuned coordination. Four subjects carried out seven different forms of fast oscillatory movements of the pelvis and trunk in the sagittal and transverse planes. Electromyographical activity (EMG) was recorded with surface electrodes from the abdominal muscles rectus abdominis (RA), obliquus externus (OE), obliquus internus (OI), and erector spinae (ES), from the hip flexor muscle rectus femoris (RF), the hip extensor muscle gluteus maximus (GM) and from the hip extensor/knee flexor muscles of the hamstrings group (HAM). Movements were recorded with an optoelectronic system (Selspot). The results indicate that during spontaneous flexion-extension movements of the trunk there was a basic alternating activation between a pure flexor (RF-RA-OE-OI) and an extensor synergy (ES-GM-HAM). Different mixed synergies appeared when more specific patterns of coordination of the pelvis and spine were performed. For example, during pelvic tilts in the sagittal plane, RA-OE-OI-GM formed a synergy which was activated reciprocally with ES. The neural circuitry controlling muscles of the pelvis and trunk is apparently adaptable to a variety of different tasks. Individual muscles were shown to either cause, brake or prevent a movement and to be integrated in several different task-specific motor synergies.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗

PubMed1997

[Botulinum toxin in spastic infantile cerebral palsy: results in 27 cases during one year].

INTRODUCTION AND OBJECTIVES: Positive outcome of patients with spastic cerebral palsy treated with botulinum toxin reported in the last three years has led us to perform this study with the aim to show our experience in the management of spastic cerebral palsy with the toxin, determine its indications, analyze the results and propose new possible indications in the future. MATERIAL AND METHODS: We include 10 hemiplegic and 17 diplegic patients with an average age of 6 years and 7 months, followed up between 5 and 17 months. Clinical improvement was monitored using the PRS and EVFEL scales and articular motion range was measured 6 months before and after the injection while continuing physiotherapy. The injected muscles were adductor, hamstrings, triceps and posterior tibialis, and the doses were 1-2 U/muscle/kg body weight. RESULTS: The values on PRS improved an average of 24%, adductor angle 66% (p < 0.01), knee angle 40% (p = 0.05) and ankle angle 52% (p < 0.01); 96% of patients could get more physiological static or walking patterns because of the decrease of spasticity and those persisted after the effect of the toxin had worn off. It was maximum at 2 months, stabilized 4 to 6 months later and decreased during further 2 months. CONCLUSIONS: This experience leads us to propose higher starting dosage and to take into account the stability of postural pattern of each patient to choice the muscle to be injected. Other therapeutic possibilities are also proposed in children with fixed shortening e.g. combining the toxin with stretching casts.

Adolescent↗

PubMed1991

Instrumental straight-leg raising: a new approach to Lasègue's test.

In clinical practice the outcome of Lasègue's test is interpreted with respect to two variables: (1) the maximum angle between the leg and the horizontal plane to which the leg can be lifted, and (2) the pain that is provoked by the movement. For a number of reasons it is difficult in many patients to interpret the test outcome; predominantly, it is because of the lack of information it yields concerning the activity of the muscles. To get more information, an instrumental test was developed that imitates Lasègue's test. In this setup, which is based on a simple biomechanical model, the leg is passively raised in a lift installation. During lifting, the angles between leg and horizontal plane and between leg and pelvis are measured with electrogoniometers; the lift moment is determined with the help of a force transducer; pelvic rotation is assessed with a lordosis meter; and surface electromyography is used to record electric transducer; pelvic rotation is assessed with a lordosis meter; and surface electromyography is used to record electric activity in the erector spinae, the gluteus maximus, and the semimembranosus. The method, called instrumental straight-leg raising, makes it possible to determine the extensibility, elasticity, and electric activity of the hamstrings and back muscles during Lasègue's test. This information provides a better basis for the interpretation of the test outcome.

Adult↗

PubMed1996

Assessment of muscle electrical activity in spinal cord injury subjects during quiet standing.

Disturbed motor control due to a spinal cord lesion is generally considered to be the cause of unusual standing utilized by those people suffering from spinal cord injury (SCI). Electromyographic (EMG) leg muscle activity during quiet standing was analyzed in four functional groups of SCI subjects and compared to the data of healthy people. A rating system for visual assessment of the stripchart recording was developed and its adequacy was confirmed by comparison of the rating system with computerized integrated EMG values of some of the recordings. The division of 47 subjects into functional groups was based on their ambulatory capabilities ie a non-support group, crutches, cane and walker user groups. Mean total muscle EMG activity was the highest in the group of subjects standing without support and it was significantly higher when compared to the other groups including the control group. Comparison between more and less active legs within each group showed significant differences in the non-support and crutches groups, whereas cane, walker and control groups showed nearly symmetric EMG patterns during standing. Analysis of the contribution of single muscles to the asymmetry of standing showed significantly higher activity in hamstring and triceps surae muscles than in other muscles in the non-support group. No significant differences in the activity of single muscles compared to their contralateral pair between more and less active leg were obtained in the remaining groups. It is evident, however, that different support devices used by SCI subjects greatly influence EMG patterns of postural muscles. The present findings suggest that disturbed conduction in the spinal cord is related to altered motor strategies employed by SCI subjects in attempts to perform the same volitional act as before the injury.

Adult↗

PubMed1976

[Electromyographic study of movements in infants with cerebral palsy (author's transl)].

In 43 infants between 3 and 16 months old electromyographic studies were performed by recording movement patterns. Surface electrodes were fixed to the legs, recording the activities of adductors, small gluteal muscles, M. rectus and hamstrings. The impulses were fed into the computer. Synergistic and antagonistic muscles were compared by correlation analysis. Certain movement patterns were provoked by turning the infants from supine to the sides, pulling up to sitting, tilting sideways, vertical hanging and standing. Synergistic and antagonistic muscle groups were compared by correlation anaysis. Significant differences in motor behavior were shown to exist between spastic and healthy infants: The spastic infants showed widely spread synchronous innervations. Besides, comparison of mean activity values exposed a significant preponderance of mean activity values exposed a significant preponderance of adductor activity to gluteal activity in spastic infants. - In qualitative analysis by a rating system diagnostic differentiation of individual cases was possible. This proved of special value in infants with postural asymmetries or abnormal musculatur tone.

Cerebral Palsy↗

PubMed2003

Muscle performance after anterior cruciate ligament reconstruction.

We measured muscle strength in 36 patients after anterior cruciate ligament (ACL) reconstruction with autogenous bone-patellar tendon-bone graft. Quadriceps and hamstring isokinetic strength was assessed during concentric contraction at 60 and 180 degrees /s and was measured at 1, 6, 12 and 24 months postoperatively. At 24 months quadriceps muscle strength had recovered to approximately 90% of the level of the uninvolved side, both at 60 and 180 degrees /s. In contrast, hamstring muscle strength had already recovered to approximately 90% at 6 months. Age, gender, activity level, and anterior tibial laxity did not affect the muscle performance. However, the recovery of muscle strength was delayed in patients with anterior knee pain.

Adolescent↗

PubMed1997

Effects of contract-relax stretching training on muscle performance in athletes.

The effects of an 8-week unilateral contract-relax (CR) stretching training program (passive stretch after isometric contraction) on muscular performance were investigated in a group of 16 athletes. The flexibility, maximum torque and angular position as well as contraction work in movements of the knee joint were determined before training and after 4 and 8 weeks of training. The torque measurements were performed under isokinetic conditions, eccentrically at angular velocities of 60 degrees x s(-1) and 120 degrees x s(-1), isometrically at five different joint positions, and concentrically at angular velocities of 60, 120, 180 and 240 degrees x s(-1) using an isokinetic dynamometer. A surface electromyogram (EMG) of the thigh muscles (quadriceps and hamstrings) was recorded simultaneously. As compared to untrained control limbs, significant improvements in active and passive flexibility (up to 6.3 degrees in range of motion), maximum torque (up to 21.6%) and work (up to 12.9%) were observed, and these were especially pronounced under eccentric load conditions. A comparison between integrated EMG recordings during eccentric and concentric loads, as well as the interpretation of the training-induced changes in the EMG, suggest that muscular activity under eccentric loads may be impaired by mental processes.

Adaptation, Physiological↗

PubMed2005

Medial hamstring tendon regeneration following harvest for anterior cruciate ligament reconstruction: fact, myth, and clinical implication.

It has been demonstrated that the medial hamstring tendons regenerate in the majority of patients following their harvest for anterior cruciate ligament reconstruction. The anatomy and morphology of these regenerated tendons have been radiographically and surgically documented. The neotendons originate within the appropriate muscle belly but display an altered insertion anatomy. Their histological composition is largely tendinous but has regions that resemble scar tissue. Concordantly, an animal model indicates that the neotendon has decreased mechanical strength, which has implications for tendon re-harvest. The regenerated tendons do restore a muscle tendon complex that is able to generate force; however, strength testing indicates that the function of the hamstring muscles is altered by harvest and regeneration. The most significant strength deficits are present in deep knee flexion and internal rotation of the tibia, whereas the peak torque of knee flexion is minimally affected. Additional harvest of the gracilis tendon results in greater deficits. The current literature indicates that hamstring tendon regeneration does indeed occur, but with structural and functional alterations.

Animals↗

PubMed1989

Conservative treatment of patellofemoral subluxation.

As pointed out in the preface of this book, patellofemoral subluxation is probably the most common knee problem seen in many orthopedists' offices today. Whereas the other authors have emphasized the anatomy and diagnosis, this article should serve as a dry but basic instruction on the exercise program that has been used in our clinic. We have had a success rate with this program of approximately 80 per cent. Certainly not all of the 20 per cent that fail require surgery. The classic exercises are quadricep sets, straight leg raises, hip abductors, hip adductors, hip flexors, and hamstring stretches, which have endured the test of time. The prevention of flexion extension activity, such as running the stadium stairs in order to strengthen the quadriceps of the patient with patellofemoral subluxation should be emphasized. Complications of conservative treatment, such as low back pain, iliopsoas tendinitis, and muscle soreness and the treatment of these is described. Finally, the importance of stretching the hamstring muscles is a cornerstone in the treatment of patellofemoral problems. Likewise, a tight IT band can put abnormal stress on the lateral aspect of the patella. In this article I have tried to point out our approach to conservative treatment of patellofemoral subluxation.

Exercise Therapy↗

PubMed2005

Flexion contracture after total knee arthroplasty in a patient with Parkinson's disease: successful treatment with botulinum toxin type A.

The few reports in the orthopedic literature that discuss outcomes after total knee arthroplasty in patients with Parkinson's disease cite mixed results. These patients are at increased risk for the development of flexion contracture, which has been shown to significantly worsen functional scores. The present report describes the development of a flexion contracture in a patient with Parkinson's disease after total knee arthroplasty. This contracture was successfully treated with manipulation under anesthesia and injections of botulinum toxin type A into the hamstring and gastrocnemius muscles, in conjunction with a static progressive extension orthosis and rigorous physical therapy.

Arthroplasty, Replacement, Knee↗

PubMed2006

The effect of an impulsive knee valgus moment on in vitro relative ACL strain during a simulated jump landing.

BACKGROUND: We tested the hypothesis that impulsive compression, flexion and valgus knee moment loading during a simulated one-footed jump landing will significantly increase the peak relative strain in the anteromedial region of the anterior cruciate ligament compared with loading without the valgus moment. METHODS: Ten cadaveric knees [mean (SD) age: 67.9 (7.6) years; 5 males; 5 females] were mounted into a custom fixture to simulate a lower extremity impact loading of approximately 1600 N. Triaxial load cells monitored the 3D tibial and femoral impulsive force and moments at 2000 Hz, while 3D tibiofemoral kinematics were measured at 400 Hz. Pre-impact quadriceps, hamstring and gastrocnemius muscle forces were simulated using pretensioned steel cables. A differential variable reluctance transducer measured the relative strain in the anteromedial aspect of the anterior cruciate ligament. With the knee initially in 25 degrees flexion, 10 trials were conducted with the impulsive force directed 4 cm posterior to the knee joint center in the sagittal plane ("neutral" loading) to cause a flexion moment, 10 trials were conducted under a similar loading, but with the force directed 15 degrees lateral to the knee sagittal plane ("valgus" loading), and the 10 neutral loading trials were then repeated. A non-parametric Wilcoxon signed rank test was used to test the hypothesis using a P<0.05 significance level. FINDINGS: The peak normalized anterior cruciate ligament strain was 30% larger for the impulsive compression loading in valgus and flexion compared with an impulsive compression loading in isolated flexion (P<0.05). INTERPRETATION: Minimizing the abduction loading of the knee during a jump landing should help reduce anterior cruciate ligament strain during that maneuver.

Aged↗