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At least 865 records · Page 48Linked to original sources

PubMed1996

Lower extremity injuries in college athletes: relation between ligamentous laxity and lower extremity muscle tightness.

OBJECTIVE: Two components of flexibility, muscle tightness, and ligamentous laxity in college athletes were studied to determine whether these factors were associated with the incidence of lower extremity injuries. DESIGN: Prospective cohort study. SETTING: College athletic department. PARTICIPANTS: 201 college athletes. OUTCOME MEASURES: College men and women athletes were tested for ligamentous laxity with the Beighton scale and for muscle tightness with a new scale based on the tightness of the iliopsoas, iliotibial band, hamstring, rectus femoris, and gastrocsoleus muscles. Lower extremity injuries incurred during practice and play were recorded during the following year. RESULTS: Of the 201 athletes tested, 71 sustained 115 injuries. For each additional point on the 9-point ligamentous laxity scale (9 = hyperlax), the risk of injury decreased 16%. For each additional point on the 10-point muscle-tightness scale (10 = all muscles tight), the risk of injury increased 23%. The two scores were moderately inversely correlated (Spearman's rho = -0.3; p < .001). Women had greater mean (+/- SD) laxity scores than men (3.3 +/- 2.2 vs. 1.8 +/- 2.0; p < .001) and lower mean overall muscle tightness scores (1.5 +/- 1.6 vs. 3.5 +/- 2.1; p < .001). Among Women athletes, the rate of lower extremity injury was unrelated to ligamentous laxity or to flexibility. Among men, lower extremity injuries were associated with lower ligamentous laxity scores (p = .008) and greater muscle tightness (p = .04). CONCLUSIONS: This study introduces a new scale for lower extremity muscle tightness. Tight ligaments and muscles are related to injury in men, but not women, college athletes. A preseason flexibility program may decrease injuries in college men athletes.

Adult↗

PubMed2000

Cycling by means of functional electrical stimulation.

The goal of this paper was the development of an optimized stimulation pattern of leg muscles that would allow paraplegic subjects to perform the movement of pedaling and thereby to drive a tricycle by means of functional electrical stimulation (FES). To obtain maximum average power output with minimum muscle force, the start, duration and amplitude of the stimulation signal applied to the individual muscles had to be optimized depending on the pedaling frequency. For the basic theoretical investigations the rider-tricycle system was modeled as a rigid body system on which the muscle forces are applied as joint moments. The muscles gluteus maximus, rectus femoris, vastii, and hamstrings were stimulated and the passive forces of some other muscles were considered. The modeling and simulation approach was then used to produce maximum power pedaling and steady-state pedaling at 35 rpm. Hamstrings (41.9%) and vastii (35.8%) were the primary contributors to the optimization cost function of maximum power with minimum muscle loading. Based on these theoretical investigations an efficient stimulation pattern could be provided, taking into account the realistic possibilities of today's practical applications.

Bicycling↗

PubMed2004

Can functional electric stimulation-assisted rowing reproduce a race-winning rowing stroke?

OBJECTIVE: To compare the ergometer rowing technique of a person with spinal cord injury (SCI), using functional electric stimulation (FES) of his leg muscles, with that of a well-defined group of able-bodied rowers. DESIGN: Whole-body kinematics and kinetics and electric activity of selected muscles were measured during ergometer rowing. SETTING: A hospital-based motion analysis laboratory. PARTICIPANTS: Five male university varsity-level rowers and 1 male rower with SCI. INTERVENTIONS: Eight rowing trials were collected on the university-level rowers, 2 trials each at 20, 24, 28, and 32 strokes/min. The rower with SCI had surface electrodes applied to his medial hamstrings and medial quadriceps muscle bellies. The electrodes were attached to a stimulator that was activated using a button in the ergometer handle. The subject with SCI rowed at a self-selected stroke rate. MAIN OUTCOME MEASURES: Forces at the ergometer handle and foot cradle, 3-dimensional whole-body kinematics, net joint moments, and phasic activity of muscles. RESULTS: Motion of the arms, ankles, and knees of the rower with SCI was similar to those of the university-level rowers; other joint motions and forces applied to the ergometer differed. CONCLUSIONS: FES-assisted rowing in its current implementation cannot reproduce a race-winning rowing stroke. Further development work is required.

Activities of Daily Living↗

PubMed1995

Femoral varus derotational osteotomy in cerebral palsy.

The records concerning 64 hips in 36 cerebral palsy patients treated with varus derotational osteotomy (VDO) alone (2 hips), VDO with muscle releases (adductors, iliopsoas, hamstrings; 46 hips), and VDO, soft-tissue release, and innominate bone osteotomy (16 hips) were reviewed. There were 23 quadriplegic and 13 diplegic patients. Average age at surgery was 7 years. Average follow-up period was 3.8 years. All hips that had VDO, soft-tissue release, and innominate osteotomy were stable at follow-up. Nine hips of the 44 treated with VDO and muscle release alone dislocated, and required second osteotomies.

Adolescent↗

PubMed2003

The effects of ibuprofen on delayed muscle soreness and muscular performance after eccentric exercise.

The purpose of this study was to examine the effects of ibuprofen on delayed onset muscle soreness (DOMS), indirect markers of muscle damage and muscular performance. Nineteen subjects (their mean [+/- SD] age, height, and weight was 24.6 +/- 3.9 years, 176.2 +/- 11.1 cm, 77.3 +/- 18.7 kg) performed the eccentric leg curl exercise to induce muscle soreness in the hamstrings. Nine subjects took an ibuprofen pill of 400 mg every 8 hours within a period of 48 hours, whereas 10 subjects received a placebo randomly (double blind). White blood cells (WBCs) and creatine kinase (CK) were measured at pre-exercise, 4-6, 24, and 48 hours after exercise and maximal strength (1 repetition maximum). Vertical jump performance and knee flexion range of motion (ROM) were measured at pre-exercise, 24 and 48 hours after exercise. Muscle soreness increased (p < 0.05) in both groups after 24 and 48 hours, although the ibuprofen group yielded a significantly lower value (p < 0.05) after 24 hours. The WBC levels were significantly (p < 0.05) increased 4-6 hours postexercise in both groups with no significant difference (p > 0.05) between the 2 groups. The CK values increased (p < 0.05) in the placebo group at 24 and 48 hours postexercise, whereas no significant differences (p > 0.05) were observed in the ibuprofen group. The CK values of the ibuprofen group were lower (p < 0.05) after 48 hours compared with the placebo group. Maximal strength, vertical jump performance, and knee ROM decreased significantly (p < 0.05) after exercise and at 24 and 48 hours postexercise in both the placebo and the ibuprofen groups with no differences being observed (p > 0.05) between the 2 groups. The results of this study reveal that intake of ibuprofen can decrease muscle soreness induced after eccentric exercise but cannot assist in restoring muscle function.

Adult↗

PubMed2005

Design of a controlled-release ergometer for the measurement of musculotendinous stiffness of the knee flexors.

The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athletic performance to injury risk. Presently the controlled-release technique of measuring MTU stiffness has been applied almost exclusively to the distal joints of the body, i.e., the ankle. This is primarily because of the mechanical limitations of implementing this technique. However, in order to better understand how the elastic properties of the MTU affect both performance and injury potential, measurements of MTU stiffness of the more proximal joints must be made. The knee flexors are a logical choice because of the integral role of MTU stiffness of this muscle group in both hamstring strains and knee injury. The purpose of this study was to modify a commercial ergometer so that it could be used to measure the musculotendinous stiffness of the knee flexors. Data are presented for a representative participant to illustrate the feasibility and capability of this ergometer, and the measured MTU stiffness was 519 N.m.rad(-1) at a knee flexion moment of 100 N.m. Our results indicate that it is indeed possible to modify a commercial ergometer and measure musculotendinous stiffness of large muscle groups crossing proximal joints.

Adult↗

PubMed1995

Hamstrings and gastrocnemius co-contraction protects the anterior cruciate ligament against failure: an in vivo study in the rat.

An anesthetized rat model was used to study the effects of muscle contraction on the ultimate tensile load and the energy absorption at failure of the anterior cruciate ligament. In both knees, the joint capsule and ligaments, except for the anterior cruciate ligament, were divided, and the menisci were removed with the aid of a stereomicroscope. The cruciate ligament of the right knee was tested in tension until failure by femorotibial distraction during contraction of the hamstrings and calf muscles induced by electrical stimulation of the ischiatic nerve. The cruciate ligament of the left knee, which was loaded to failure with nonstimulated (relaxed) muscles, served as the control. The mean ultimate tensile load during muscle contraction was 86 N compared with 53 N when tested with relaxed muscles (p < 0.001). The energy absorption at failure was 0.41 and 0.19 J during contraction and relaxation, respectively (p < 0.05). This study suggests that previous investigations evaluating the force and energy necessary to rupture the anterior cruciate ligament (with use of a femur-anterior cruciate ligament-tibia complex stripped of all soft tissues and without gastrocnemius-hamstring muscle contractions) are incomplete and probably not representative of the in vivo situation.

Animals↗

PubMed1999

Eccentric kinetic chain exercise as a conservative means of functionally rehabilitating chronic isolated insufficiency of the posterior cruciate ligament.

OBJECTIVE: To determine the efficacy of a home eccentric kinetic chain exercise program in improving isokinetic strength, knee function, and symtomatology in athletes with isolated posterior cruciate ligament (PCL) injury. DESIGN: Experimental design. SETTING: Allan McGavin Sports Medicine Centre, University of British Columbia, Vancouver, British Columbia, Canada. PARTICIPANTS: The study included 13 athletes with isolated PCL injury (n = 13) and 13 healthy sedentary subjects (n = 13). All participants were men and between 18 and 35 years of age. The group with isolated PCL injury all had been diagnosed at the Allan McGavin Sports Medicine Centre, all had been treated without surgery, and had been injured at least 6 months ago. Diagnosis was based on presentation of a positive posterior sag and posterior drawer. INTERVENTION: The group with isolated PCL injury (treatment group) underwent 12 weeks of eccentric kinetic chain exercise. The control group of healthy sedentary individuals did not undergo any form of rigorous training during the course of this study. Both groups were tested for isokinetic strength, knee function, and symptomatology at weeks 0, 6, and 12. Compliance was insured through frequent phone contact and progressive journal records of completion of daily exercise. Only those who completely executed the 12-week exercise program were included in the study. MAIN OUTCOME MEASURES: Hamstring and quadriceps isokinetic torque (Nm) at constant velocities of 60 and 120 degrees per second (degrees/s), Tegner Hop Test (meters), and Lysholm Knee Scale scores. RESULTS: A subject-versus-treatment data analysis clearly indicated significant increases in eccentric and concentric torque over the 12-week period in the treatment group. Tegner Hop Test and Lysholm Knee Scale scores also increased significantly after the eccentric squat exercise program. Quadriceps eccentric/concentric ratios at both testing velocities increased significantly after 12 weeks of rehabilitation. There were no significant differences in strength between extremities in the treatment group at any time during the course of this study. Before rehabilitation, there were no significant differences between eccentric and concentric torque values in either muscle group (quadriceps and hamstrings) of the treatment group. After the eccentric exercise program, the quadriceps in the injured extremity did exhibit significantly greater eccentric than concentric torque. The treatment group was significantly weaker than the control group in eccentric torque at both testing velocities at week 0. After the 12-week exercise program, however, there were no significant differences between groups in eccentric quadriceps strength. CONCLUSION: The results of this investigation support the eccentric squat program as a viable means of functionally rehabilitating chronic PCL insufficiency.

Adolescent↗

PubMed1997

Muscle force and endurance in untreated and human growth hormone or insulin-like growth factor-I-treated patients with growth hormone deficiency or Laron syndrome.

Muscle force and endurance of four muscle groups (biceps, triceps, hamstrings and quadriceps) were measured by a computerized device in three groups: (A) 4 boys with isolated growth hormone deficiencies (IGHD) examined before at 10 and 24 months of hGH treatment; (B) 5 children (2 F, 3 M) with Laron syndrome were examined 3.5-4 years after initiation of insulin-like growth factor-I (IGF-I) treatment, and (C) comprised 8 untreated adults (5 F, 3 M) with Laron syndrome. For each patient, 2 matched controls, by age, sex, physical activity and height below the 50th percentile, were examined. GH- or IGF-I-deficient patients before treatment revealed reduced muscle force and endurance. GH treatment (0.6 U/kg/week) restored muscle force and endurance, progressively, mainly in the boys with puberty. Three to 4 years of IGF-I treatment (150 micrograms/kg/day) in patients with Laron syndrome proved to have a weaker effect than GH in restoring muscle force. The difference in effectiveness between hGH and IGF-I in restoring muscle force may be due to either the more marked muscle underdevelopment in Laron syndrome patients than in patients with IGHD or a difference in action potential between the two hormones.

Adolescent↗

PubMedDate not supplied

Electromyographic analysis of hip and knee musculature during running.

The purpose of this study was to describe the firing pattern of 11 hip and knee muscles during running. Thirty recreational runners volunteered to run at 3 different paces with indwelling electromyographic electrodes while being filmed at 100 frames per second. Results demonstrated that medial and lateral vasti muscles acted together for knee extension during terminal swing and loading response, possibly providing a patella stabilizing role. The vastus intermedius muscle functioned with the other vasti, plus eccentrically controlled knee flexion during swing phase. The rectus femoris muscle fired with the vastus intermedius muscle and assisted the iliacus muscle with hip flexion. The hamstrings fired primarily to eccentrically control hip flexion. The adductor magnus, tensor fascia lata, and gluteus maximus muscles afforded pelvic stabilization while assisting with hip flexion and extension. Forward propulsion was provided mainly by hip flexion and knee extension, which is contrary to the view that posterior calf muscles provide propulsion during toe off. Faster running paces lead to increased activity in the muscles. This may lead to more injuries, primarily in the muscles that were contracting eccentrically.

Adult↗

PubMed1994

High sciatic lesion mimicking peroneal neuropathy at the fibular head.

We report 4 patients with severe, axon-loss, high sciatic mononeuropathies affecting exclusively the peroneal fibers: a boy with a slowly-growing nerve tumor, a woman with an injection injury, and 2 patients who had undergone proximal femur surgery. Clinically, the findings mimicked those seen with common peroneal neuropathy at the fibular head. The peroneal conduction studies were very low in amplitude/unelicitable. Conversely, the tibial studies and H-responses were normal in all; the sural responses were normal in one while low in amplitude/unelicitable in the remaining three. The biceps femoris, short-head, and all peroneal-innervated muscles showed fibrillations and profound motor unit loss. Conversely, the remaining hamstrings and all tibial-innervated muscles were normal. We conclude that a sciatic lesion can imitate a more distal peroneal lesion. Needle EMG of the biceps femoris, short head, is essential for correct diagnosis.

Action Potentials↗

PubMed2004

Endurance and strength training in patients with COPD.

STUDY OBJECTIVES: The purpose of this study was to compare the effects of endurance training only to endurance plus strength (combined) training in a randomized trial of patients with COPD. METHODS: Twenty-four patients completed the study: 11 patients in the combined training group (FEV(1) 45 +/- 5% predicted), and 13 patients in the endurance training group (FEV(1) 40 +/- 4% predicted) [mean +/- SE]. Muscle strength, quality of life, exercise performance, and quadriceps fatigability were measured before and after rehabilitation. RESULTS: Combined training led to significant improvements in quadriceps (23.6%), hamstring (26.7), pectoralis major (17.5%), and latissimus dorsi (20%) muscle strength. Endurance training alone did not produce significant improvements in muscle strength: quadriceps (1.1% decrease), hamstring (12.2% increase), pectoralis major (7.8% increase), and latissimus dorsi (2.8% decrease). The increase in strength after training was significantly greater in the combined group compared to the endurance group for the quadriceps and latissimus dorsi muscles but not for the hamstring and pectoralis major muscles. Six-minute walk distance, endurance exercise time, and quality of life (as measured by the Chronic Respiratory Questionnaire) significantly increased in both groups after rehabilitation with no significant differences in the extent of improvement between groups. The extent of improvement in quadriceps fatigability after training (assessed by quadriceps twitch force before and after exercise) was not significantly different between groups. CONCLUSION: Strength training can lead to significant improvement in muscle strength in elderly patients with COPD. However, this improvement in muscle strength does not translate into additional improvement in quality of life, exercise performance or quadriceps fatigability compared to that achieved by endurance exercise alone.

Aged↗

PubMed1999

Therapeutic options in the management of articular contractures in haemophiliacs.

Haemophilic contracture is seen most commonly as an equinus deformity of the ankle, or at the knee or elbow in the form of a flexion deformity. Treatment options are varied, and decision-making is based on the degree of the contracture, its chronicity, the presence of articular subluxation, the patient's ability to participate in treatment, and the available medical facilities. The treatments available fall into four categories: physiotherapy, orthotics, corrective devices, and surgical procedures. Treatment should be primarily by physiotherapy, splintage, and corrective devices. The late or severe case may require surgical correction in the form of soft-tissue procedures. Soft-tissue correction of muscle shorthening may be performed such as lengthening of the Achilles tendon for equinus deformity of the ankle, or hamstring release of the flexor muscles of the knee. Lower femoral osteotomy has been used for correction of flexion deformity at the knee joint. Mechanical distraction using external fixators for treatment of severe knee flexion contractures has been recently reported with satisfactory results. The main principle underlying the treatment of haemophilic contracture is the restoration of the patient's lifestyle and mobility, rather than anatomic or radiographic normality.

Contracture↗

PubMed2003

[Strength training with elastic bands: measure of its effects in cardiac rehabilitation after coronary diseases].

OBJECTIVES: To compare high intensity strength training with weightlifting exercises or with elastic bands. SETTING: Outpatient unit of cardiac rehabilitation. TYPE: Prospective randomised clinical trial. POPULATION: Inclusion of coronary patients in phase II after medical or surgical treatment of a myocardiac infarction, without cardiac insufficiency; beta-blockers were accepted. METHOD: Evaluation of coronary patients at beginning and at the end of a 4 week cardiac rehabilitation program. It included progressive aerobic training according to Karvonen method for all the patients, associated with weightlifting exercises (Koch press) in the control group, or use of elastic bands in the experimental group. Cardiac rate, oxygen consumption at rest and at maximum power were the main criteria with also muscle strength of quadriceps, hamstrings, biceps brachii, latissimus dorsi and triceps brachii, body mass indexes, quality of life with SF-36, anxiety (stay T test) and perceived exertion with the Borg 10-point category-ratio scale, myotendinous injuries (Shaw scale). RESULTS: Twenty-six coronary patients, all male from 45 to 65 years old, all receiving beta-blockers, were included, 13 in each group. Control and experimental groups were initially similar. At the end of the 4 week program, all the two groups improved significantly their strength and power and there were no differences between the two groups. Perceived exertion was lower in the group using elastic bands and there were no myotendinous lesions. CONCLUSION: Strength training with elastic bands is a low-cost, attractive, playful technique, proposed to a group of coronary patients, which appears as effective in cardiac rehabilitation as individual weightlifting training.

Aged↗

PubMed1996

Abnormalities in alpha-, beta- and gamma-sarcoglycan in patients with limb-girdle muscular dystrophy.

We have identified 12 cases from a group of 45 patients with early onset limb-girdle muscular dystrophy (LGMD), who have a deficiency of the 50 kDa dystrophin-associated glycoprotein, alpha-sarcoglycan. An additional male sibling of one case was also studied clinically. All 12 patients showed a concomitant, but variable, deficiency of alpha-, beta- and gamma-sarcoglycan. None of our patients had a defect in only one component of the sarcoglycan complex. Molecular analysis confirmed that a total absence of one sarcoglycan, associated with reduced expression of the other two, indicates a primary defect. Immunocytochemistry is thus useful for directing molecular studies. Morphological features not usually observed in Xp21 dystrophies were peripheral accumulations of mitochondria, discrete core-like areas, and nemaline rods in one case. Clinical severity and progression was variable between and within families but early loss of ambulation, at or before the age of 12 years, was associated with a total absence of gamma-sarcoglycan. Common clinical features were calf hypertrophy, contractures of the tendo achilles, lumbar lordosis, winging of the scapulae, weak hamstrings and weak neck muscles. All cases had grossly elevated serum creatine kinase. In contrast to patients with Duchenne muscular dystrophy (DMD), our patients with sarcoglycan deficiencies had normal early motor milestones, normal intellect, and good respiratory and cardiac function. Our data confirm that the sarcoglycan complex acts as a unit and that morphological and clinical features can distinguish patients with defects in the sarcoglycans from those with Xp21 dystrophy. In our group of patients prognosis is better than in DMD, but clinical variability makes this difficult to predict in isolated cases.

Age of Onset↗

PubMed1995

Cycling patterns in children with and without cerebral palsy.

Pedaling smoothness and electromyography patterns were quantified in children with spastic diplegic cerebral palsy (CP) and a cohort of children with typical development. Video analysis of the pedaling rhythm yielded equivalent time periods for the control group and irregular time periods in the group with CP, with greater time spent at the bottom of the pedaling cycle. Electromyography patterns of the tibialis anterior, rectus femoris, medial hamstring and lateral gastrocnemius muscle groups yielded greater percentages of muscle activity time and co-contraction time at both the ankle and knee in the group with CP; however, the control group had longer ankle co-contraction times than were expected from previous adult studies.

Bicycling↗

PubMed2004

Resistance training improves strength and functional capacity in persons with multiple sclerosis.

The purpose of this study was to evaluate the effect of an eight-week progressive resistance training programme on lower extremity strength, ambulatory function, fatigue and self-reported disability in multiple sclerosis (MS) patients (mean disability score 3.7 +/- 0.8). Eight MS subjects volunteered for twice weekly training sessions. During the first two weeks, subjects completed one set of 8-10 reps at 50% of maximal voluntary contraction (MVC) of knee flexion, knee extension and plantarflexion exercises. In subsequent sessions, the subjects completed one set of 10-15 repetitions at 70% of MVC. The resistance was increased by 2-5% when subjects completed 15 repetitions in consecutive sessions. Isometric strength of the quadriceps, hamstring, plantarflexor and dorsiflexor muscle groups was assessed before and after the training programme using an isokinetic dynamometer. Magnetic resonance images of the thigh were acquired before and after the exercise programme as were walking speed (25-ft), number of steps in 3 min, and self-reported fatigue and disability. Knee extension (7.4%), plantarflexion (52%) and stepping performance (8.7%) increased significantly (P < 0.05). Self-reported fatigue decreased (P < 0.05) and disability tended to decrease (P = 0.07) following the training programme. MS patients are capable of making positive adaptations to resistance training that are associated with improved ambulation and decreased fatigue.

Adult↗

PubMed1995

The relationships between lumbar curves, pelvic tilt and joint mobilities in different sitting postures in young adult males.

The lumbar lordosis and pelvic tilt of twenty male subjects were measured in standing and in three different sitting postures with the trunk-thigh angles of 120 (sitting A), 90 (sitting B), and 60 (sitting C) degs and the knee angle was constant at 90 deg. Ten more male subjects participated in the supplemental study, in which additional condition of the knee angle was employed in postures of the trunk-thigh angles of 90 and 60 degs. Some joint mobilities were also measured to investigate the relations of the mobilities to lumbar lordosis and pelvic tilt. The lumbar curve decreased and the pelvis rotated rearward significantly as the trunk-thigh angle and the knee flexion decreased. The great alteration of the lumbar curve was observed between standing and sitting A, which was much different from the results of Keegan (1953) studied in the subjects of lateral recumbent position. There was a high correlation coefficient between the lumbar curve and the pelvic tilt (r = 0.909), so that the relations of the pelvic tilt to the joint mobilities were investigated. When the knee angle was constant, the pelvic tilt is related significantly to the hamstrings between standing and sitting A and to the gluteus maximus between sitting A and sitting C. However, at different sitting postures with the trunk-thigh angles of 90 and 60 degs involving different knee flexions, hamstrings added to gluteal muscles affected significantly lumbar curve and pelvic tilting.(ABSTRACT TRUNCATED AT 250 WORDS)

Hip Joint↗