Hamstring tightness and Scheuermann's disease. Commentary.
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Contracture↗
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Results for “Hamstring Muscles”
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Electric potentials generated by antidromic volleys in quadriceps and hamstring motoneurons.
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Humans↗
[Transplantation of the femoral hamstrings in the treatment of cerebral lesions].
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Cerebral Palsy↗
Control of knee stability after ACL injury or repair: interaction between hamstrings contraction and tibial translation.
OBJECTIVE: The aim of this study was to investigate the interaction between hamstrings contraction and tibial translation during isometric quadriceps contraction (IQC) and their effects on cruciate ligament forces. METHODS: A mathematical model of the knee in the sagittal plane was used with simple geometric representation for the model muscles, ligaments and bones. A mechanical analysis was used to calculate muscle, ligament and contact forces. RESULTS: The results show that isolated IQC requires a posterior force applied to the tibia at the knee over the range 0-85 degrees flexion, usually applied by the anterior cruciate ligament (ACL). The model hamstrings can provide this posterior force, except near extension, resulting in reduced anterior tibial translation (ATT) and, therefore, reduced ACL force. ATT varied inversely with the hamstrings force. The interaction between the two was highly dependent on flexion angle, the hamstrings force being least effective in reducing ATT near extension. CONCLUSIONS: Flexing loads placed distally on the tibia can stretch an injured or repaired ACL. The analysis suggests that modest hamstrings forces during IQC can help protect the ACL. In the complete absence of an ACL, hamstrings contraction as well as ATT may be inevitable while using quadriceps near extension.
Journal Article↗
The clinical features of early bleeding into the muscles of the lower limb in severe haemophiliacs.
The clinical features, management and outcome of 178 early bleeding episodes into the musculature of the thigh and lower limb of 37 severe haemophiliacs are reported. Ninety-five per cent of all bleeds were treated in under three hours from onset of symptoms and the mean time to complete restoration of function was 3.5 days. The most frequent site of bleeding was the quadriceps (44 per cent) followed by the calf (35 per cent), anterior tibial compartment (seven per cent), adductors of the thigh (seven per cent), hamstrings (six per cent) and sartorius (one per cent). Bleeds of the quadriceps took longest to resolve (mean, four days), significantly longer than bleeds of the calf muscle (3.1 days). The first symptom in 66 per cent of bleeds was pain on movement. When the quadriceps was involved, this rapidly progressed to pain at rest. There was a significant prolongation of recovery time when bleeds of this muscle group were treated more than two hours after the onset of symptoms. Bleeds of the calf muscle required less transfusions and no prolongation in recovery time occurred in bleeds treated up to three hours from the onset of symptoms. The results of this study contrast markedly with earlier reports based on later presentations.
Blood Transfusion↗
Ensemble firing of muscle afferents recorded during normal locomotion in cats.
1. The main purpose of this study was to collate population data on the firing characteristics of muscle afferents recorded chronically during normal stepping in cats. 2. Ensemble firing profiles of forty-seven muscle spindle and tendon organ afferents were compiled from stored data. The relationships between the firing profiles and the displacement and force signals were analysed with the help of mathematical models of the response characteristics of spindle primary and secondary afferents and tendon organs. 3. Whereas the firing of hamstring spindle afferents could be predicted with reasonable accuracy from the length and velocity signals alone, the firing profiles of triceps surae spindle afferents deviated from the predicted profiles, particularly during electromyogram (EMG) activity. This indicated that the components of fusimotor action linked to extrafusal muscle activity were significant in triceps surae, possibly because this muscle is more strongly recruited in the cat step cycle. 4. From the limited data available, it was not possible to identify the 'best' or most general mathematical function to predict spindle secondary firing. In the two triceps surae spindle secondary units studied, firing was well predicted by using the simplest possible model, rate proportional to displacement, whereas in the hamstring spindle secondary data, a more complex linear transfer function was needed. The results of modelling the spindle secondary data were consistent with a modest amount of phasic, static fusimotor action linked to EMG activity. 5. The averaged ensemble of tendon organ afferent activity from the triceps surae gave predictions of whole-muscle force that agreed well with separate triceps force measurements in normal cat locomotion. This supports the idea that ensembles of tendon organ afferents signal whole-muscle force. 6. Our overall conclusion is that to a first approximation, large muscle afferents in the cat hindlimb signal muscle velocity, muscle length and muscle force, at least in movements of the speed and amplitude seen in locomotion.
Animals↗
Muscle activation differences between eccentric and concentric isokinetic exercise.
PURPOSE: The purpose of this study was to compare electromyographic (EMG) activity and joint moment of agonists and antagonists between isokinetic eccentric and concentric knee muscle actions. METHODS: Twelve females (20.5 +/- 2.9 yr) performed maximum knee extension and flexion effort on a Biodex dynamometer isometrically and at concentric and eccentric angular velocities ranging from 30 degrees.s-1 to 150 degrees.s-1. EMG activity of vastus lateralis, rectus femoris, vastus medialis, and hamstrings was also recorded. The moment and agonist EMG values were normalized as a percentage of the maximum isometric values. The antagonist EMG was normalized as a percentage of the IEMG activity of the same muscle group when acting as agonist at the same angular velocity and angular position and taking into consideration the effects of muscle action. RESULTS: Three-way ANOVA designs indicated significantly greater normalized eccentric moments compared with concentric moments (P < 0.05), whereas the eccentric normalized integrated EMG (IEMG) of agonists and antagonists was significantly lower compared with the respective concentric IEMG values (P < 0.05). These differences were more evident at fast angular velocities. CONCLUSIONS: The present results demonstrate that neural activation and the resulting muscular action are different between isokinetic eccentric and concentric tests and depend also on the angular velocity of the movement. The antagonist IEMG activity is different depending on the muscle examined. The IEMG activity of the antagonists in this study indicate that the antagonist activity is an important factor that affects the resultant joint moment during isolated isokinetic maximum voluntary joint movements.
Adult↗
Criterion-related validity of sit-and-reach tests in university men in Hong Kong.
To examine the criterion-related validity of traditional, modified, and YMCA sit-and-reach tests and the relationships of these with abdominal muscular strength and endurance measured by the sit-up test, 52 university men of mean age 20.7 yr. were administered two trials of six measurements in counterbalanced order, including traditional, modified, and YMCA sit-and-reach tests, passive straight-leg raise, low-back flexibility evaluation, and 1-min. sit-up test. Pearson product-moment correlations were significant (p < .05) for traditional and modified sit-and-reach tests with hamstrings' flexibility (rs = .71 and .77, respectively). Also, the YMCA sit-and-reach test was significantly associated with hamstrings' flexibility (r = .64) and low-back flexibility (r = .47). Stepwise multiple regression indicated hamstrings' flexibility was the only significant predictor of traditional and modified sit-and-reach tests, explaining the variances of 59.1% and 49.8%, respectively. However, both hamstring and low-back flexibility were significant predictors for the YMCA sit-and-reach test, which in total accounted for 52.2% of explained variance. Traditional and modified sit-and-reach tests are valid in assessing hamstrings' flexibility only, whereas the YMCA sit-and-reach test is valid for measuring both the hamstring and low-back flexibility.
Abdominal Muscles↗
Lateral hamstring transfer and gait improvement in the cerebral palsy patient.
A retrospective analysis of twenty-three spastic patients who underwent forty-three transfers of the semitendinosus muscle to the lateral intramuscular septum and of the semimembranosus muscle to the biceps is presented. Decreased knee-flexion deformity as well as improved walking function were achieved in 91 per cent. An unsatisfactory result was associated with complications of the procedure. Only one knee of the forty-three that were operated on showed late genu recurvatum. This procedure appears to be both effective and relatively free of late comlications.
Adolescent↗
Relationships between peak torque, peak angular impulse, and average power in the thigh muscles of subjects with knee damage.
The purpose of this study was to determine the relationship between the isometric and isokinetic peak torque (PT) (speed of movement 0, 60, and 180 deg/s) and the peak angular impulse (PAI) and average power (AP) of multiple contractions (180 deg/s) of the quadriceps and hamstrings in 29 patients with a chronic, complete deficiency of the medial collateral ligament (MCL) of the knee. At every test speed the Pearson product moment (r) and the Spearman rank (rs) correlation coefficients between the PT and PAI were highly significant for both muscle groups in the uninjured (r = .81-.97, rs = .77-.97) as well as in the MCL deficient (r = .77-.97, rs = .75-.95 knees. The results were the same between the PT and AP (uninjured knee: r = .83-.98, rs = .82-.98; MCL deficient knee: r = .78-.97, rs = .76-.97). In both knees and in both muscle groups the correlation coefficients increased toward the highest speed of the isokinetic movement, obviously because the PAI and AP were registered at that speed. In conclusion, concerning MCL deficient or uninjured knees the PAI or AP analysis may offer little additional information about thigh muscle function to that attained by more simple measurement, the PT analysis.
Adult↗
[CT findings of muscular dystrophy: limb girdle type (LG), myotonic type (MYD) and Duchenne type (DMD)].
CT scans of muscles in patients with LG, MYD and DMD were obtained at five different body levels: the neck, L3 vertebral body, pelvic girdle, thigh and lower leg. CT numbers, cross sectional areas (CSA) and %CSA of muscle or fat were evaluated in each muscle. The characteristic CT patterns for each type of muscular dystrophy were obtained. Compared with DMD, the gracilis and soleus were more severely damaged in LG and the biceps femoris remained relatively preserved among the hamstrings. In addition, the multifidus of the neck and sternocleidomastoid also were more severely damaged in MYD. This study suggests that CT scan will be useful in the differential diagnosis of these types of muscular dystrophy as well as in planning appropriate rehabilitation and detecting damaged muscles.
Adolescent↗
Topographical organization of group II afferent input in the rat spinal cord.
The organization of neurons in the lumbar enlargement of the rat spinal cord processing information conveyed by group II afferents of hind-limb muscle nerves has been investigated by using cord dorsum and intraspinal field potential recording. Group II afferents of different muscle nerves were found to evoke their strongest synaptic actions in specific segments of the lumbar cord. Group II afferents of quadriceps and deep peroneal nerves evoked potentials mainly at the rostral end of the lumbar enlargement (L1-rostral L3), whereas group II afferents of gastrocnemius-soleus and hamstring nerves evoked their main synaptic actions at the caudal end of the lumbar enlargement (L5). In the central lumbar segments (caudal L3-L4), the largest group II potentials were produced by afferents of tibialis posterior and, to a lesser degree, flexor digitorum longus. Field potentials evoked by group II afferents of quadriceps, tibialis posterior, and flexor digitorum longus were largest in the dorsal horn (up to 600 microV), but also occurred in the ventral horn where they were sometimes preceded by group I field potentials. In contrast, field potentials evoked by group II afferents of gastrocnemius-soleus and hamstring nerves were restricted to the dorsal horn. These results indicate that neurons in different segments of the rat lumbar spinal cord process information from group II afferents of different hind-limb muscles. Furthermore, the topographical organization of group II neuronal systems in the rat is similar in several respects to that in the cat and may therefore represent a general organizational feature of the mammalian spinal cord.
Afferent Pathways↗
[Changes in knee kinematics and quadriceps and hamstrings moment arms after high valgus and varus tibial "dome" osteotomy: An in vitro study].
PURPOSE OF THE STUDY: Analysis of the correction or over-correction of high valgus and varus tibial osteotomies is generally limited to the frontal plane. Most likely however, the deformation observed radiographically in the frontal plane is simply a one-dimensional expression of a more complex three-dimensional deformation. This might be one of the causes for certain failures after surgery and recurrent problems which are difficult to solve. We proposed using 3D electrogoniometric to measure of the effect of a "dome" osteotomy on patellar and femoro-tibial kinematics and the changes in the moment arms of the knee muscles. MATERIAL AND METHODS: We used five lower limbs harvested from non-fixed cadavers. A "dome" osteotomy was stabilized by external fixation. Three-dimensional analysis of the femoro-tibial and femoro-patellar kinematics was performed using two electrogoniometers with six degrees of freedom. Changes in the lengths of the hamstrings and quadriceps was measured using four LVDT linear variable differential transformers. The muscles lever arms were measured with the tendon excursion method. RESULTS: At 90 degrees flexion, varus osteotomy induced internal rotation while valgus osteotomy induced the opposite effect. Beyond 40 degrees flexion, there was a clear internal rotation of the patella for varus and neutral corrections. Valgus corrections however induced external rotation. The peak lever arm of the quadriceps increased with valgus, while the angle of the peak was higher for varus correction. Valgus appeared to increase the lever arm of the semitendinous. DISCUSSION: Our study demonstrated that the effect of tibial osteotomy is not limited to the frontal plane. Tibial rotations are observed systematically for all corrections in the frontal plane. Varus correction tends to create internal rotation while valgus correction tends to have the opposite effect. Axial correction also affects patellar kinematics. Interanal rotation is induced by varus correction and external rotation by valgus correction. This patellar rotation could result from tibial rotations induced by the different corrections. The loss of the parallelism between the patellar crest and the trochlear groove could produce changes in femoropatellar surface contact and pressure, potentially leading to pain or cartilage degeneration. The maximal value of the quadriceps moment arm appears to increase with valgus. The efficacy of the quadriceps could thus be improved with valgus, potentially increasing extension force. Valgus increases the moment arm, improving limb flexion, while varus correction has the opposite effect. This could explain a loss in flexion amplitude in patients with varus or who underwent varus osteotomy. Tibial osteotomy is designed to correct the deviation solely in the frontal plane but also has effects in all three planes. Further 3D analyses of the morphology and physiology of the knee joint would be needed to better understand the physiological and pathological processes involved.
Biomechanical Phenomena↗
Physiological and psychological correlates of success in track and field athletes.
Twenty-four collegiate distance runners and 20 power athletes (sprinters and jumpers) of various success levels were tested on a number of physiological and psychological parameters. Multiple regression analysis indicated that physiological factors could explain over 81% of the variance related to successful distance running while physiological and psychological factors could explain over 80% of the of the variance related to successful sprinting and jumping. Body weight, fibre type, low density lipoprotein-cholesterol, and hamstring strength were significant singular correlates to successful distance running. Year in school, percent body fat, quadriceps strength, and leg muscle balance were significant single correlates to successful sprinting and jumping performance.
Adolescent↗
Anthropometric and physiological characteristics of junior elite volleyball players.
OBJECTIVES: To investigate the anthropometric and physiological characteristics of junior elite volleyball players. METHOD: Twenty five national level volleyball players (mean (SD) age 17.5 (0.5) years) were assessed on a number of physiological and anthropometric variables. Somatotype was assessed using the Heath-Carter method, body composition (% body fat, % muscle mass) was assessed using surface anthropometry, leg strength was assessed using a leg and back dynamometer, low back and hamstring flexibility was assessed using the sit and reach test, and the vertical jump was used as a measure of lower body power. Maximal oxygen uptake was predicted using the 20 m multistage fitness test. RESULTS: Setters were more ectomorphic (p<0.05) and less mesomorphic (p<0.01) than centres. Mean (SD) of somatotype (endomorphy, mesomorphy, ectomorphy) for setters and centres was 2.6 (0.9), 1.9 (1.1), 5.3 (1.2) and 2.2 (0.8), 3.9 (1.1), 3.6 (0.7) respectively. Hitters had significantly greater low back and hamstring flexibility than opposites. Mean (SD) for sit and reach was 19.3 (8.3) cm for opposites and 37 (10.7) cm for hitters. There were no other significant differences in physiological and anthropometric variables across playing positions (all p>0.05). CONCLUSION: Setters tend to be endomorphic ectomorphs, hitters and opposites tend to be balanced ectomorphs, whereas centres tend to be ectomorphic mesomorphs. These results indicate the need for sports scientists and conditioning professionals to take the body type of volleyball players into account when designing individualised position specific training programmes.
Adolescent↗
Proprioception after rupture of the anterior cruciate ligament. An objective indication of the need for surgery?
Failure of conservative treatment is the usual indication for the reconstruction of a knee with deficiency of the anterior cruciate ligament (ACL) and this depends on subjective judgement. The ability of muscles to protect the subluxing joint by reflex contraction could provide an objective measurement. We have studied 30 patients with unilateral ACL deficiency by measuring the latency of reflex hamstring contraction. We found that the mean latency in the injured leg was nearly twice that in the unaffected limb (99 ms and 53 ms respectively). There was a significant correlation between the differential latency and the frequency of 'giving way' indicating that functional instability may be due, in part, to loss of proprioception. Measures of proprioception, including reflex hamstring latency, may be useful in providing an objective assessment of the efficacy of conservative treatment and the need for surgery.
Adult↗
Electromyographic analysis of knee rehabilitation exercises.
Many exercises are used to strengthen the knee muscles, yet limited studies that evaluate the exercises exist. The purpose of this study was to describe and compare the muscle firing patterns in five knee muscles during five rehabilitative exercises, which were presumed either to strengthen a specific muscle group or to elicit a cocontraction. During short-arc knee extension, the medial and lateral vasti were significantly more active during the last 15 degrees of extension than during other arcs (p < .05). The short-arc knee extension with hamstring cocontraction demonstrated significantly more activity in the rectus femoris, vastus medialis oblique, and vastus lateralis than the biceps femoris and semimembranosus in the final 15 degrees of extension (p < .05). With isometric knee cocontractions, no significant difference in muscle activity occurred in any of the arcs tested. During squatting, the rectus femoris, vastus medialis oblique, and vastus lateralis were significantly more active than the biceps femoris and semimembranosus during the descending, holding, and arising phases (p < .05). This information offers suggestions in selecting optimal knee rehabilitation exercises.
Adult↗
Ankle and knee coupling in patients with spastic diplegia: effects of gastrocnemius-soleus lengthening.
BACKGROUND: Empirical observations of subjects with an equinus gait have suggested that there is coupled motion between the ankle and knee such that, during single-limb stance, the ankle moves into equinus as the knee extends. Since the gastrocnemius-soleus muscle-tendon unit spans both joints, we hypothesized that this muscle-tendon unit may be responsible for the coupling and that lengthening of the gastrocnemius-soleus muscle alone would result in greater ankle dorsiflexion as well as greater knee extension in single-limb stance, effectively uncoupling these joints. The concept that gastrocnemius-soleus lengthening may promote knee extension is counter to the popular notion that crouch gait may result if the hamstrings are not lengthened concomitantly. METHODS: A retrospective review identified thirty-four subjects with specific kinematic characteristics of equinus gait, and their gait was compared with that of normal children. Of the thirty-four subjects, eleven (twenty-two limbs) subsequently underwent isolated midcalf lengthening of the gastrocnemius and soleus muscles with use of a recession technique. Gait analysis including joint kinematics and joint kinetics, electromyography, and physical examination were performed to test the hypothesis. RESULTS: We found that, unlike the normal subjects, the patients with an equinus gait pattern had a positive correlation (r = 0.7) between ankle and knee motion during single-limb stance. As hypothesized, ankle plantar flexion occurred while the knee moved into extension during single-limb stance. Calculations of the lengths of the gastrocnemius-soleus muscle-tendon units showed them to be short throughout the gait cycle (p < 0.0001). After gastrocnemius-soleus recession, peak ankle dorsiflexion (p < 0.001) and peak ankle power (p < 0.001) shifted to occur later in stance than they did in the preoperative gait cycle. Furthermore, the magnitude of peak power increased (p < 0.001) in late stance despite the added length of the gastrocnemius-soleus muscle-tendon unit. The electromyographic amplitude of the gastrocnemius-soleus was reduced during loading (p < 0.02), and this finding, together with the kinetic changes, suggested that muscle tension was reduced. Changes at the knee were less pronounced but included greater knee extension at foot contact (p < 0.01). No increase in the knee flexion angle or extension moment occurred in midstance after the surgery. CONCLUSIONS: Patients with an equinus gait pattern function with a shortened gastrocnemius-soleus muscle-tendon unit, and this results in coupled motion between the ankle and knee during single-limb stance. Lengthening, with use of a recession technique, shifted ankle power generation and dorsiflexion to a later time in stance with no tendency to increase midstance knee flexion. Knee extension did increase at foot contact, but excessive midstance knee flexion persisted and was likely due to concomitant contracture of the hamstrings.
Adolescent↗