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At least 1,369 records · Page 76Linked to original sources
PubMed2006

Sagittal knee kinematics following hamstring lengthening.

The purpose of this study was to analyze sagittal knee kinematics following hamstring lengthening. A retrospective analysis was performed of 16 children (32 knees) with cerebral palsy who underwent hamstring lengthening as an isolated surgical procedure. Gait analysis was performed prior to surgery and at a minimum of one year after surgery. Decreased stance maximum knee flexion, stance minimum knee flexion, swing maximum knee flexion, and swing minimum knee flexion were noted. Total knee excursion increased. The present study confirmed the previously reported increase in total knee excursion with decrease in stance minimum and swing maximum knee flexion after hamstring lengthening.

Adolescent↗
PubMed1996

Organization of hindlimb nerve projections to the rat spinal cord: a choleragenoid horseradish peroxidase study.

The aim of the present study has been to investigate the projections of hindlimb muscle afferent fibers to the spinal cord with particular emphasis on the ventral horn and the column of Clarke. Following transections of the appropriate ventral roots, injections of the B-subunit of cholera toxin conjugated to horseradish peroxidase were made into the tibial, peroneal, hamstring, superior gluteal, femoral, and obturator nerves in one group of adult rats. In another group of rats, similar experiments were done with intact ventral roots in order to map the location in the ventral horn of the motoneuron cell columns supplying each investigated nerve. An extensive overlap was found for the different nerve projections to Rexed's laminae V-VII. A somatotopic organization of the nerve projections was seen in the lamina IX cell groups of the ventral horn as well as in the column of Clarke, even though an overlap existed. The densest primary afferent projection from each injected nerve was to its homonymous motoneurons. Only a small to moderate overlap between the projections of the tributary branches of the sciatic nerve was found in the ventral horn, whereas the obturator and femoral nerve projections showed more profound overlap. In the column of Clarke, hindlimb nerves innervating distal muscles projected medially, and nerves innervating proximal muscles projected laterally.

Animals↗
PubMed2005

Hamstring injury management--Part 2: Treatment.

The management of hamstring injuries can be described as vexed at best. One reason for this may be because of a lack of high-quality research into the methods of treatment, rehabilitation and prevention. As a result, an evidence-based approach to injury management does not exist. Management is based on clinical experience, anecdotal evidence and the knowledge of the biological basis of tissue repair. Previous hamstring injury is the most recognized risk factor for injury, which indicates that treatment approaches may be suboptimal under certain conditions. The identification of these risk factors and the methods best designed to manage them should be addressed with future research efforts. Much anecdotal and indirect evidence exists to suggest that several non-local factors contribute to injury. Despite the knowledge that these factors may exist, the literature appears almost devoid of research investigating their possible identification and treatment. Treatment has traditionally been in the form of altering the muscle repair process through the application of electrophysical therapy and various soft-tissue-based and exercise-based techniques. Little research has investigated the role of other forms of manual therapy particularly when directed at non-local structures. This paper will explore and speculate on this potential connection and offer some new contributive factors for hamstring injury management.

Animals↗
PubMed2002

The interaction between leading and trailing limbs during stopping in humans.

While the initiation of gait has been well studied, the mechanisms of stopping the forward progression of the center of mass have received less attention. The purpose of this current experiment was to examine the effects of constraining cadence on how the body is brought to a stop. Lower limb electromyogram (gluteus medius, hamstrings and soleus (SOL)) and force plate data were compared between two gait conditions, walking and planned stopping, at three different cadences (100, 125 and 150% of normal cadence). As cadence increased, the onset of muscle activity prior to heel-strike decreased for all muscles except SOL. SOL activity was evident prior to heel-strike during stopping and after heel-strike during walking. As cadence increased, onset times before heel-strike were shorter in stopping and SOL became active more rapidly after heel-strike in walking. The normalized duration of muscle activity remained invariant as cadence increased. This activity was always longer under the lead limb during stopping at each cadence. This was reflected by increases in the braking forces produced by the leading limb. The rate at which force was generated was not different between gait conditions but increased with increasing cadence. Thus, subjects relied less on the trailing limb and more on the leading limb as cadence increased.

Adult↗
PubMed1990

[Unusual pathology of the popliteal space. Popliteal artery entrapment].

After reviewing the main anatomical anomalies responsible for the popliteal artery entrapment syndrome, the author emphasizes the need for early diagnosis prior to onset of complications. Whenever confronted with hamstring pain due to sports-related physical stress in a youngster, loss of posterior tibial and pedal pulse should be checked for during static contraction, and then during forced passive stretching of the gastrocnemius muscle; modifications in arterial Doppler tracings during these maneuvers will confirm the diagnosis. Should this fail to occur at this early stage, severe complications will develop in time, manifested primarily by thrombosis of the popliteal artery; ectasia of this artery in itself carrying a risk of further peripheral embolism, thrombosis and rupture.

Adolescent↗
PubMed2001

Hip adductor muscle strength in patients with varus deformed knee.

The isometric muscle strength of the muscles around 49 medial compartmental osteoarthritic knees of 32 women was measured quantitatively using a Musculater GT-50 (osteoarthritis group). The patients pushed up a pad containing an electrical sensor and values were compared with those obtained from the nonaffected knees of subjects (control group). The mean age of the patients in the osteoarthritis group was 62.3 years (range, 43-78 years). The control group consisted of 13 women (13 knees) with a mean age of 60.5 years (range, 49-73 years). In the osteoarthritis group, the medial joint space was preserved in 17 knees (Grade A), 23 knees had narrowing of the joint space (Grade 2), and nine knees showed joint space obliteration (Grade 3). Quadriceps strength was significantly weaker in Grade 2 knees than in Grade 0 knees; however, there was no significant difference in quadriceps to hamstrings ratio between each grade. The hip adductors to hamstrings ratio was significantly greater in Grade 2 knees than in Grade 0 knees, and was greater in Grade 3 knees than in Grade 0, Grade 1, and Grade 2 knees. The findings suggested that in patients with medial compartmental osteoarthritis of the knee, the hip adductor muscles may become strengthened to decrease varus decrease varus deformity of the limb.

Adult↗
PubMed2004

The effect of creatine supplementation on strength recovery after anterior cruciate ligament (ACL) reconstruction: a randomized, placebo-controlled, double-blind trial.

BACKGROUND: Creatine supplementation has been shown to augment training-induced strength gains. The purpose of this study was to examine the effect of creatine supplementation on recovery of muscle strength after anterior cruciate ligament (ACL) reconstruction. HYPOTHESIS: Creatine supplementation will facilitate strength gains after ACL reconstruction. STUDY DESIGN: Double-blind, prospective, and randomized clinical trial. METHODS: Sixty patients were randomized into creatine or placebo groups. Quadriceps and hamstring strength and power were measured isokinetically. Hip flexor, abductor, and adductor strengths were measured with a handheld dynamometer prior to surgery and at 6 weeks, 12 weeks, or 6 months after surgery. RESULTS: From 6 weeks to 12 weeks after surgery, there were significant increases in strength on the involved side for knee extension (47%), knee flexion (27%), hip flexion (20%), hip abduction (9%), and hip adduction (17%). These strength improvements were unaffected by creatine supplementation with similar effects in the creatine and placebo groups. From 6 weeks to 12 weeks after surgery, there were significant increases in power on the involved side for knee extension (46%) and knee flexion (26%), but these effects were not affected by creatine supplementation. At 6 months, creatine supplementation did not affect outcome as measured by the single leg hop test for distance or the knee outcome score. CONCLUSIONS: The results demonstrate that patients do not benefit from creatine supplementation during the first 12 weeks of rehabilitation after ACL reconstruction.

Administration, Oral↗
PubMedDate not supplied

[Treatment results of modified Glorion-Rideau release in Duchenne muscular dystrophy].

Although the cause of Duchenne muscular dystrophy has been recently found, there is no causal treatment to alter the natural course of this disease. Based on the recommendations by Glorion and Rideau with early treatment of contractures of the hips and the lower limbs we performed a modified release of the spina muscles, resection of tensor fasciae latae and a lengthening of the tendo calcaneus in 32 patients. The mean ae of DMD patients at time of operation was 6.1 yrs. The mean follow-up was 3.4 yrs. All children underwent mobilization the day after surgery. Complete correction of all contractures was immediately achieved after operation and kept in all but two cases up to the follow-up examination. No loss of ambulation was observed. Our results demonstrate that early selective surgery in DMD patients before or just at the onset of contractures without performing an additional aponeurectomy of the iliotibial band and percutaneous tenotomy of the hamstrings according to the original Glorion-Rideau-technique safely prevents severe contractures and should prolong ambulation.

Achilles Tendon↗
PubMed1990

Comparison of hamstring/quadriceps isokinetic strength ratios and power in tennis, squash and track athletes.

Isokinetic assessment of elite squash, tennis and track athletes confirms the accepted ratio of 60 to 80 per cent hamstring to quadriceps when testing at 90 deg-sec-1 for peak strength (torque). However, significant variations occur at higher test speeds up to 300 deg.sec-1 with the hamstrings becoming more prominent especially (p less than 0.001) in the nonpreferred (NP) leg. There was no significant difference between sports, and wide individual differences occurred. Analysis of (work.sec-1.kg-1 body weight) power showed a significantly higher work output (p less than 0.01) by track athletes than squash and tennis players, but, unlike hamstring/quadriceps ratio, no significant difference between preferred (P) and nonpreferred leg. The maximum power output was achieved around 220 to 250 deg.sec-1. Power between preferred and nonpreferred legs was the same but the torque ratio differed indicating that the hamstrings provided proportionately more work in the NP leg at higher speeds.

Biomechanical Phenomena↗
PubMed1995

Self-selected manual lifting technique: functional consequences of the interjoint coordination.

The pattern of movement self-selected by 39 subjects to lift light loads from 9 cm above the ground is described in kinematic and electromyographic terms. Hamstring length changes were estimated from hip and knee angular kinematics. Subjects adopted a posture at the start of the lift intermediate between stoop and full-squat postures. A consistent coordination between knee, hip, and lumbar vertebral joints during lifting was described through calculation of the relative phase between adjacent joints and found to be exaggerated with increases in load mass. During the early phase of lifting, knee extension leads hip extension, which in turn leads extension of the lumbar vertebral joints. Early in the lifting movement, when load acceleration is greatest, the erectores spinae are thus relatively long and shortening slowly. Both of these factors produce greater back extensor strength. Rapid hamstring shortening is also delayed, which enhances their strength, and coactivation of the monoarticular knee extensors and biarticular hamstring observed early in the lifting movement suggested that the knee extensors contribute to hip extension through a tendinous action of the hamstrings.

Adult↗
PubMedDate not supplied

[Surgical treatment of recent severe sprains of the knee. Does the anterior cruciate ligament of the knee merit suturing?].

The authors have reviewed 62 cases of acute ligamentous injury of the knee, all surgically treated. They emphasize the importance of good co-ordination of muscles and ligaments in the function of the knee. The menisci should be preserved wherever possible. Direct suture of the anterior cruciate ligament gives poor results (20 per cent successful). They recommend immediate transplantation of a hamstring (semi-tendinosus) tendon by the Lindeman's technique. They conclude that the anterior cruciate ligament should not be sutured. In three cases it was resected with good results.

Humans↗
PubMed2006

A prospective study of 3-day versus 2-week immobilization period after anterior cruciate ligament reconstruction.

BACKGROUND: Aggressive early rehabilitation is recommended after reconstruction of the anterior cruciate ligament (ACL) using a patellar tendon-bone graft. However, rehabilitation after reconstruction of ACL using the multistranded hamstring is controversial. In this study, we compared the clinical results of 3-day immobilization after reconstruction of ACL using the multistranded hamstring, with those of 2-week immobilization prospectively. METHODS: A total of 30 consecutive patients with ruptured ACL underwent single-socket ACL reconstruction. 10 male and 5 female patients (mean age of 29.2+/-10.0 years) were prospectively randomized for a 3-day immobilization period, and 6 male and 9 female patients (mean age of 27.3+/-10.9 years) were randomized for a 2-week immobilization period. We measured the anterior laxity with a KT-2000 arthrometer, joint position sense, and thigh muscle strength at 3, 6 and 12 months after surgery. RESULTS AND CONCLUSIONS: There were no statistically significant differences between the two groups. We concluded that the post-operative 3-day immobilization period is preferable to the longer 2-week period in our rehabilitation program from the viewpoint of psychological load to the patients and the duration of hospitalization after ACL reconstruction using multistranded hamstring tendons.

Adolescent↗
PubMed1995

Reliability of dynamic strength knee muscle testing in children.

The isokinetic knee test is reliable in young individuals in a broad age range between 6 years of age to puberty, but not specifically in the youngest subgroup, in which cooperation may be less dependable. Hence, the purpose of this study was to investigate the reliability of isokinetic knee flexor/extensor muscle torque in a narrow age range: 6-8 years old. The sample consisted of 12 boys tested in three sessions with 3 days of rest between sessions. During each session, two tests were performed with each knee. Intrasession correlation coefficients ranged between .94 and .99 for quadriceps and between .78 and .96 for hamstrings. Interclass correlation coefficients, which express the reliability of a single test, were high (ranging from .85 to .95). Analysis of variance for repeated measurements showed that sixfold repetition of the test had no significant effect on peak torque measurements. These data suggest that the isokinetic knee flexion/extension torque is reliable in boys 6-8 years old.

Analysis of Variance↗
PubMed1985

Maximal perfusion of skeletal muscle in man.

Five subjects exercised with the knee extensor of one limb at work loads ranging from 10 to 60 W. Measurements of pulmonary oxygen uptake, heart rate, leg blood flow, blood pressure and femoral arterial-venous differences for oxygen and lactate were made between 5 and 10 min of the exercise. Flow in the femoral vein was measured using constant infusion of saline near 0 degrees C. Since a cuff was inflated just below the knee during the measurements and because the hamstrings were inactive, the measured flow represented primarily the perfusion of the knee extensors. Blood flow increased linearly with work load right up to an average value of 5.7 l min-1. Mean arterial pressure was unchanged up to a work load of 30 W, but increased thereafter from 100 to 130 mmHg. The femoral arterial-venous oxygen difference at maximum work averaged 14.6% (v/v), resulting in an oxygen uptake of 0.80 l min-1. With a mean estimated weight of the knee extensors of 2.30 kg the perfusion of maximally exercising skeletal muscle of man is thus in the order of 2.5 l kg-1 min-1, and the oxygen uptake 0.35 l kg-1 min-1. Limitations in the methods used previously to determine flow and/or the characteristics of the exercise model used may explain why earlier studies in man have failed to demonstrate the high perfusion of muscle reported here. It is concluded that muscle blood flow is closely related to the oxygen demand of the exercising muscles. The hyperaemia at low work intensities is due to vasodilatation, and an elevated mean arterial blood pressure only contributes to the linear increase in flow at high work rates. The magnitude of perfusion observed during intense exercise indicates that the vascular bed of skeletal muscle is not a limiting factor for oxygen transport.

Adult↗
PubMed2002

Acute effects of The Stick on strength, power, and flexibility.

The Stick is a muscle massage device used by athletes, particularly track athletes, to improve performance. The purpose of this project was to assess the acute effects of The Stick on muscle strength, power, and flexibility. Thirty collegiate athletes consented to participate in a 4-week, double-blind study, which consisted of 4 testing sessions (1 familiarization and 3 data collection) scheduled 1 week apart. During each testing session subjects performed 4 measures in the following sequence: hamstring flexibility, vertical jump, flying-start 20-yard dash, and isokinetic knee extension at 90 degrees x s(-1). Two minutes of randomly assigned intervention treatment (visualization [control], mock insensible electrical stimulation [placebo], or massage using The Stick [experimental]) was performed immediately prior to each performance measure. Statistical analyses involved single-factor repeated measures analysis of variance (ANOVA) with Fisher's Least Significant Difference post-hoc test. None of the variables measured showed an acute improvement (p < or = 0.05) immediately following treatment with The Stick.

Adolescent↗
PubMed1997

Relationship between isokinetic muscle strength and exercise capacity in chronic heart failure.

The exercise intolerance and excessive ventilatory response to exercise of chronic heart failure is associated with abnormalities of skeletal muscle function, in particular a reduction in muscle strength. Isometric and isokinetic leg muscle strength were measured in 10 patients with chronic heart failure and 10 age-matched controls. Each subject undertook maximal exercise testing to measure peak oxygen consumption (V(O2)) and the ventilatory response to exercise as measured by the slope of the relation between ventilation and carbon dioxide production (V(E)/V(CO2) slope). Quadriceps strength (mean (S.D.)) was reduced in heart failure as measured by isometric (444.9 (129.6) N vs. 556.0 (136.0); P<0.01) and isokinetic (123.6 (30.2) Nm vs. 146.8 (40.0); P=0.04). Hamstring strength was also reduced as measured by isokinetic testing (53.6 (15.6) Nm vs. 71.1 (28.1); P=0.02). Isokinetic and isometric strengths correlated, but not closely (r=0.52, P<0.001). There were negative correlations between the V(E)/V(CO2) slope, and isokinetic measures: with average torque, r=-0.62, P<0.004; with peak torque, r=-0.64, P=0.002. We have found evidence for reduced muscle function affecting both knee flexors and extensors. This reduction in muscle strength correlates with the ventilatory response to exercise. These observations lend support to the muscle hypothesis of the generation of symptoms in chronic heart failure.

Angiotensin-Converting Enzyme Inhibitors↗