The relative strength of the hamstrings during hip extension.
Explore the source record for details and available documents.
Action Potentials↗
SEARCH · PubMed Health
Results for “Hamstring Tendons”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[Pindolol-induced rhabdomyolysis in sarcoid myopathy].
A 72-year-old man suddenly developed severe muscle weakness following the treatment with pindolol (Calvisken) for three days. Neurological examination on admission disclosed marked proximal muscle weakness with absent deep tendon reflexes. Laboratory data showed significant increase of serum CK, aldolase and myoglobin. Electromyography revealed both neurogenic and myogenic changes in all muscle tested. Skeletal muscle CT showed patchy low density areas in muscles of thigh and leg, especially in the hamstrings. Femoral muscle biopsy demonstrated a granulomatous nodule with multinucleated giant cells in the degenerated muscle fibers showing small-grouped atrophy. By Mb-PAP staining, Mb-negative fibers were randomly distributed among normally stained ones. Leu 1, 3a, 4, HLA-DR positive cells were found adjacent to the granuloma by immunoperoxidase staining. After immediate withdrawal of pindolol and treatment with steroid, he recovered muscle strength and enzyme activities were normalized in a week. Beta blockers have been known to induce muscle cramps or pain and moderate elevation of serum muscle enzymes. However, severe muscle weakness with highly elevated enzyme activities leading to rhabdomyolysis as noticed in the present case was rarely reported in the literature. Underlying sarcoid myopathy might be suspected to exaggerate this unusual case of pindolol-induced rhabdomyolysis. A careful use of pindolol is emphasized.
Aged↗
Maintenance of hamstring strength following knee surgery.
Following a variety of surgical procedures on the knee, routine clinical Cybex testing demonstrated that the hamstring muscle group loses less strength than the quadriceps group, regardless of whether the hamstrings were exercised during the rehabilitation. Two groups of postsurgical patients were randomly selected to evaluate the effects of surgery on the muscle strength of the quadriceps and hamstrings. Group I (N = 15) underwent arthrotomy and medial meniscectomy. Group II (N = 20) underwent an extraarticular substitution of the anterior cruciate ligament. All subjects were tested on a Cybex II at 60 degrees/s: Group I at 5-10 wk (mean, 7.0), and Group II at 15-22 wk (mean, 18.6). Peak torque for the quadriceps and hamstrings was measured at 30, 60, and 90 degrees. The percent deficits of the quadriceps and hamstrings were analyzed by a three-way ANOVA. The hamstring deficit was significantly less (P = 0.041) than the quadriceps deficit. A significant difference (P less than 0.001) was found between the two surgery groups. No significant difference in percent strength deficit was found at the various joint angles (30, 60, and 90 degrees). Lastly, the factors examined in the ANOVA did not contribute to a significant first or second order interaction. The authors conclude that specific hamstring strengthening postsurgically is not always indicated.
Adolescent↗
Muscle afferent contribution to control of paw shakes in normal cats.
1. The discharge of various hindlimb muscle afferents was recorded during paw shakes in normal cats with the use of floating dorsal root electrodes. 2. Muscle spindle group Ia-afferents and tendon organ group Ib-afferents fired during muscle lengthening, reaching very high peak discharge rates and then silencing at or shortly after the onset of shortening. The timing of Ia firing was consistent with the predictions of a linear model as well as the responses of Ia endings subjected to identical length variations in separate anesthetized cats. 3. In the latter "reconstruction" experiments, waxing and waning dynamic fusimotor action straddling whole paw-shake sequences gave the most consistent matches with the data from the normal cats. The reproducibility of the inferred fusimotor action justifies the inclusion of paw shakes as a class of movement in which fusimotor set is high. 4. The peak ensemble Ia activity from single hindlimb muscles was estimated to be approximately 20 kiloimpulses/s (Kips). Ankle extensor and hamstrings length variations were nearly in phase in the first cycles of a paw-shake sequence. From published data on spindle populations in these muscles, this indicated that peak Ia input to the spinal cord exceeded 0.2 megaimpulses/s (Mips). 5. The phase relationship between origin-to-insertion muscle length and Ia firing during paw shakes was little affected by doubling or tripling the moment of inertia of the foot. We argue that this refutes the notion that in paw shakes phase reversals occur between muscle fibers and tendons in the muscles studied. 6. Inertial loading of the foot led to small but significant reductions in mean paw-shake frequency. This is consistent with an afferent contribution to the generation of these movements. 7. We conclude that in paw shakes in normal cats, the CNS "chooses" to sensitize Ia-afferents to muscle length variations by increasing dynamic fusimotor action. The resulting ensemble Ia input is very large and is likely to play a significant role in reflexly shaping the alpha-motoneuronal activity responsible for the paw shakes.
Action Potentials↗
Hamstring muscle strain treated by mobilizing the sacroiliac joint.
The purpose of this study was to compare the effectiveness of two types of treatment of hamstring muscle strains. Twenty patients with hamstring muscle strains were assigned randomly to an Experimental Group (n = 10) or a Control Group (n = 10). Peak torque production of the quadriceps femoris and hamstring muscles and hamstring muscle length were measured before and after treatment. The hamstring muscles of the Experimental and Control groups were treated with moist heat followed by passive stretching. The Experimental Group also received manipulation of the sacroiliac joint. The change in hamstring muscle peak torque was significantly greater for the Experimental Group than for the Control Group (p less than .005). No significant differences existed between the two groups in either quadriceps femoris muscle peak torque or hamstring muscle length. The results of this study suggest a relationship between sacroiliac joint dysfunction and hamstring muscle strain.
Adolescent↗
Proximal hamstring release for knee flexion and crouched posture in cerebral palsy.
Explore the source record for details and available documents.
Adolescent↗
[Long-term follow up of anterior cruciate ligament reconstruction using autologous tendon graft augmented with alloplasty (Kennedy LAD)].
From October 1983 to January 1990 in 493 patients 499 injured anterior cruciate ligaments were reconstructed by a composite tendon graft. The autogenous graft, semitendinosus tendon or quadriceps-patella periost-patellar tendon, both anatomically attached distally, was augmented with the polypropylene braid (Kennedy LAD). In the period of January to November 1984 in 81 patients anterior cruciate ligament replacement was performed. A retrospective 2-years follow-up in 72 patients and a second 5-years follow-up in 67 of those 72 patients was possible. There were 38 patients with an acute rupture and 34 patients with chronic instability. Clinical and instrumented laxity revealed a mean displacement difference of not more than 3 mm in 84% of the patients in comparison of the involved with the normal knee at the 2-years and 5-years follow-up. 80% of strength analyses showed a physiological balance of quadriceps and hamstrings in the 5-years follow-up. In the 2-years follow-up only 41% of patients practiced former sports activities again, whereas in the 5-years follow-up 80% of the patients were able to join former sports. 80 to 100 points of Lysholm score demonstrating good to very good results were reached in 91% of the patients. Especially cartilage damages in cases of chronic instabilities worsened the results mentioned by the patients.
Adult↗
The hamstring syndrome. A new diagnosis of gluteal sciatic pain.
A series of 59 patients was treated and operated on for pain felt over the area of the ischial tuberosity and radiating down the back of the thigh. This condition was labeled as the "hamstring syndrome." Pain was typically incurred by assuming a sitting position, stretching the affected posterior thigh, and running fast. The patients usually had a history of recurrent hamstring "tears." Their symptoms were caused by the tight, tendinous structures of the lateral insertion area of the hamstring muscles to the ischial tuberosity. Upon division of these structures, complete relief was obtained in 52 of the 59 patients.
Adolescent↗
The medial hamstring reflex in the level-diagnosis of a lumbar disc herniation.
Evaluation of the medial hamstring reflex (MHR) was included in the routine neurological examination of 52 hospitalized patients with a suspected lumbar disc protrusion. The MHR was tested in the supine patient with the hip slightly flexed, externally rotated and abducted. The ipsilateral knee was semiflexed and supported by one of the examiner's hands. The reflex muscle contraction was elicited by striking the index finger of the supporting hand placed on the tendons in question with a reflex hammer. The positive predictive value of an abnormal MHR as a sign of herniation from the fourth lumbar disc was found to be 85-89 per cent and the negative predictive value to be 51-61 per cent. The corresponding values when considering an abnormal Achilles tendon reflex as a sign of herniation from the fifth lumbar disc were calculated to be 67-84 per cent and 79-84 per cent, respectively. It is therefore recommended to include the MHR in the neurological examination of patients with a suspected lumbar disc protrusion.
Adult↗
The effect on gait of lengthening of the medial hamstrings in cerebral palsy.
The purpose of this study was to analyze the effect of lengthening of the medial hamstrings on the gait of patients who had spastic cerebral palsy. Thirty-one patients had preoperative and postoperative gait analyses. Standard parameters, such as velocity, cadence, and stride length, were evaluated, as were motion graphs of the hip, knee, and ankle. There was little difference between the preoperative and postoperative mean values for velocity, cadence, and stride length, which were expressed as percentages of normal for the patient's age. The contours of the postoperative motion graphs of the knees changed very little compared with those of the preoperative graphs; when a graph showed restricted motion preoperatively, it did so postoperatively. Although extension of the knee in stance phase improved postoperatively, the improvement was accompanied by decreased flexion of the knee during swing phase. When spasticity of both the hamstrings and the quadriceps was noted on the preoperative electromyogram, motion of the knee in the sagittal plane was markedly restricted.
Adolescent↗
Physiologic loading of the anterior cruciate ligament does not activate quadriceps or hamstrings in the anesthetized cat.
We attempted to elicit quadriceps and hamstring electromyographic responses in seven chloralose-anesthetized cats by loading the ACL with controlled anterior displacement of the tibia on the femur using rigid fixation and an MTS testing machine. We did not detect reflex activity in the quadriceps or hamstring muscles of any of the cats in response to anterior tibial displacements of up to 4 mm, with rise times ranging from 1.0 to 0.1 seconds. In four of the cats we loaded the ACL using a wire loop. Loads of up to 125 N (4 to 5 times body weight) produced no reflex activity in any of the four animals, although we consistently observed monosynaptic reflex responses to tendon taps. Whole nerve recordings from the posterior articular nerve revealed substantial activity from afferents in response to tugging on the ACL, although we could not differentiate receptors in the ACL from those in other periarticular tissues. Thus, while traction on the intact ACL causes signals in the afferent nerves, those signals are not translated into direct monosynaptic reflexes.
Animals↗
Isolated avulsion of the biceps femoris insertion. A case report.
The clinical, roentgenographic, and operative findings of an isolated biceps femoris avulsion in a 21-year-old man demonstrated the significance of the static stabilizers about the knee, menisci, and articular cartilage. Examination of the dynamic structures about the knee, however, may present a diagnostic problem. A systematic examination of the musculature (hamstrings, quadriceps, and patellofemoral mechanism) should be included in the evaluation of every acute knee injury. Special attention should be given to the surface anatomy as well as function of the knee.
Adult↗
Nonoperative treatment of acute knee ligament injuries. A review with special reference to indications and methods.
Nonoperative treatment has received little attention in the numerous scientific reports on knee ligament injuries. Great controversy still exists concerning the proper treatment of a knee with a ruptured ligament, especially the anterior cruciate ligament. However, according to the studies of the authors and an extensive review of the literature the indications for conservative management can be established to be all grade I and II sprains (partial tears) of knee ligaments as well as an isolated grade III sprain (complete tear) of the posterior cruciate ligament. In addition, an isolated complete rupture of an anterior cruciate, or medial or lateral collateral ligament may be treated nonoperatively in an older sedentary person. Other injuries obviously call for an operative approach at the acute stage. Nonoperative therapy protocols must be based on the knowledge of the biological phenomenon occurring during connective tissue healing process. In the first phase of ligament healing the injured knee needs 2 to 3 weeks immobilisation for undisturbed fibroblast invasion and proliferation of collagen fibres. This is achieved by immobilising the knee in a rehabilitative knee brace locked in 40 to 45 degrees of flexion. Thereafter, a gradually increasing controlled mobilisation is allowed in the brace to avoid the deleterious effects of immobilisation to cartilage, bone, muscles, tendons and ligaments, and to enhance the orientation of collagen fibres to the stress lines of the healing ligament. After 4 to 8 weeks the goal for rehabilitation is rapid and full recovery to work and sports. A functional knee brace may be used at this phase to give extra protection before final strengthening of the injured ligament. During the mobilisation and muscle training of the therapy protocol various specific techniques can be used for strengthening of the hamstring and quadriceps muscles, including isometric, isotonic, isokinetic and eccentric exercises with or without resistive equipments. In addition, electrical stimulation may help prevent muscle wasting due to immobilisation, and continuous passive motion may be used to correct persistent extension or flexion deficit. Normally, jogging is allowed approximately 3 to 6 months after the injury, and an athlete is generally able to return to full activity and competitive sports after 6 to 12 months. Quite frequently the whole question of successful rehabilitation after a knee ligamentous injury is more motivational rather than methodological and is thus often independent of attending physician's or physiotherapist's skill or will. Therefore, one of the most important things during rehabilitation is to motivate and encourage the patient for longstanding, intensive work.
Biomechanical Phenomena↗
Management of severe spondylolisthesis in children and adolescents.
Forty-three patients with a fifth lumbar-first sacral spondylolisthesis of 50 per cent or greater were reviewed. Four had been treated non-operatively; eleven, by arthrodesis; eighteen, by decompression and arthrodesis; and ten, by reduction and arthrodesis. The angle of slipping (measurement of the kyphotic relationship of the fifth lumbar to the first sacral vertebra) was found to be as important a measurement as the percentage of slipping in measuring instability and progression of slipping. Hamstring tightness did not correlate with neural deficit. Arthrodesis alone, even in the presence of minor neural deficits, tight hamstrings, or both, gave relief of pain and resolution of neural deficits and tight hamstrings. Our experience with a limited number of patients suggests that management by postoperative extension casts may achieve a significant reduction in percentage of slipping and in angle of slipping. Progression of the spondylolisthesis may occur following a solid arthrodesis.
Achilles Tendon↗
Anterior cruciate ligament injury: evaluation of intraarticular reconstruction of acute tears without repair. Two to seven year followup of 155 athletes.
To evaluate the effectiveness of our treatment regimen, we retrospectively studied the surgically treated knees of 155 athletes, aged 15 to 42 years, who had sustained acute ACL tears. All were treated with ligament excision and intraarticular bone-patellar tendon-bone reconstruction followed by early motion with emphasis on full extension. The follow-up period ranged from 2 to 7 years. Of the 155 patients, 140 were available for final followup at a minimum of 2 years after reconstruction. The patients were evaluated by objective measures (KT-1000, Cybex, Lachman test, range of motion, and postoperative competition level) and subjective assessment scores (pain, swelling, stability, activity level, walking, stair climbing, running, jumping, or twisting). The subjective scores were tabulated for stability level, total score, and activity level. After the patients achieved full range of motion, the KT-1000 measurements at a 20 pound force revealed an average difference of 1.3 mm between the injured and noninjured knees. All but 3 of the 140 patients had a firm endpoint on the Lachman test, and the Cybex tests showed a mean hamstring strength of 98% and mean quadriceps strength of 90%. Sixty of the 69 varsity athletes who were eligible to play returned to preinjury competition level the following season. One had reconstruction failure and eight chose not to continue competition for academic reasons. The questionnaire score average was 92.7 (maximum, 100 points, normal athletic knee score 93.5). We concluded that the surgical procedure, with emphasis on early full extension postoperatively, achieved excellent results and provided a stable knee.
Adolescent↗
[Analysis of the shear force exerted on the tibia during standing on bilateral legs with knee flexion].
Biomechanical analysis of the two-dimensional models composed of roentgenographic pictures and electromyographic analysis about the shear force (Fs) exerted on tibia during standing on bilateral legs was conducted in 21 young adult males. The simultaneous contraction of the quadriceps and hamstrings was observed in all electromyograms (EMGs). Amplitude observed on EMGs of the hamstrings increased as the trunk flexion angle increased. The calculated average values of Fs were negative at every knee flexion angle; Negative value means posteriorly directed force. As the trunk flexion angle increased, posterior drawer force increased at knee flexion angles of 30 degrees and 60 degrees. The simultaneous contraction of the quadriceps and the hamstrings was considered to represent the main factor that influenced these results. The standing on bilateral legs with knee and trunk flexion was considered to be applicable in the early stages after anterior cruciate ligament reconstruction.
Adult↗
Electromyographic study of the anterior cruciate ligament-hamstrings synergy during isometric knee extension.
The purpose of this investigation was to determine the role the hamstrings group may play in augmenting passive articular mechanisms during activity in which anterior drawer force may detrimentally affect the anterior cruciate ligament (ACL). Nine male subjects performed non-weight-bearing isometric knee extension at 10% increments of maximum voluntary contraction (MVC). Electromyographic (EMG) signals were detected and recorded from the vastus lateralis, vastus medialis oblique, vastus medialis longus, and the long head of the biceps femoris. The EMG signals were rectified and integrated over 1000 ms and normalized to subject-specific values. The data were subjected to a repeated-measures analysis of variance. The results demonstrated that expected significant increases in quadriceps excitation accompanied increases in knee extensor torque. Hamstrings excitation was not found to change significantly (total change = 3.4%). It was concluded that functionally adequate knees do not require posterior drawer force in excess of that provided passively by articular structures.
Adult↗
Hamstrings stretch reflex in human spasticity.
In 16 patients with spastic paralysis the hamstrings stretch reflex was found to increase as the velocity of stretch increased, and generally to subside after movement ceased. These effects are attributable to the dynamic property of the primary spindle ending. The stretch reflex commonly appeared in only the last third of the stretching movement and was maximal as the knee became fully extended. This is consistent with the static properties of the primary and secondary spindle endings, and accounts for the absence of the clasp-knife phenomenon in the spastic hamstrings. The difference in the nature of the stretch reflex in spastic flexor and extensor muscles is best explained by the differential reflex effects of group II afferent fibres which facilitate flexor motoneurones and inhibit extensor motoneurones.
Electromyography↗