SEARCH · PubMed Health

Results for “Hamstring Muscles”

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.

At least 1,585 records · Page 88Linked to original sources

PubMedDate not supplied

Biomechanical analysis of rehabilitation in the standing position.

Biomechanical analysis of the two-dimensional models composed from roentgenographic pictures and electromyographic analysis of the shear force exerted on the tibia during standing on both legs were conducted in 21 young adult males. The simultaneous contraction of the quadriceps and hamstrings was observed in all electromyograms. Amplitude observed on electromyograms of the hamstrings increased as the trunk flexion angle increased. The calculated average values of shear force 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 be the main factor that influenced these results. Standing on both legs with knee and trunk flexion was considered to be applicable in the early stages after anterior cruciate ligament reconstruction.

Adult↗

PubMed2006

The effects of plyometric vs. dynamic stabilization and balance training on power, balance, and landing force in female athletes.

Neuromuscular training protocols that include both plyometrics and dynamic balance exercises can significantly improve biomechanics and neuromuscular performance and reduce anterior cruciate ligament injury risk in female athletes. The purpose of this study was to compare the effects of plyometrics (PLYO) versus dynamic stabilization and balance training (BAL) on power, balance, strength, and landing force in female athletes. Either PLYO or BAL were included as a component of a dynamic neuromuscular training regimen that reduced measures related to ACL injury and increased measures of performance. Nineteen high school female athletes participated in training 3 times a week for 7 weeks. The PLYO (n = 8) group did not receive any dynamic balance exercises and the BAL (n = 11) group did not receive any maximum effort jumps during training. Pretraining vs. posttraining measures of impact force and standard deviation of center of pressure (COP) were recorded during a single leg hop and hold. Subjects were also tested for training effects in strength (isokinetic and isoinertial) and power (vertical jump). The percent change from pretest to posttest in vertical ground reaction force was significantly different between the BAL and PLYO groups on the dominant side (p < 0.05). Both groups decreased their standard deviation of center of pressure (COP) during hop landings in the medial/lateral direction on their dominant side, which equalized pretested side to side differences. Both groups increased hamstrings strength and vertical jump. The results of this study suggest that both PLYO and BAL training are effective at increasing measures of neuromuscular power and control. A combination of PLYO and BAL training may further maximize the effectiveness of preseason training for female athletes.

Adolescent↗

PubMed1979

The passive hamstring stretch test: clinical evaluation.

The passive hamstring stretch test is described. Using a modified goniometer it is shown that independent measurements taken by trained examiners approximate very closely to each other. This establishes the test as a valid objective measurement. The possible value of this test as a research tool in low back pain problems is discussed.

Back Pain↗

PubMed1997

Cryotherapy-induced common peroneal nerve palsy.

PURPOSE: To report an uncommon complication of distal hamstring icing, cryotherapy-induced common peroneal nerve palsy. CASE SUMMARY: A 22-year-old football player applied ice to his distal hamstring for 20 min because of soreness. This application of ice resulted in foot drop and sensory changes in the anterior lower leg and dorsum of the foot. Over the next year, full clinical neurologic function returned. DISCUSSION: Previously reported cases of cryotherapy-induced common peroneal nerve palsy involved lateral knee or circumferential thigh icing with nerve injury at the fibular neck. This case involved distal hamstring icing, and nerve injury occurred more proximally. RELEVANCE: This case demonstrates that caution should be used even when using a modality as common as ice. Ice exposure should be limited in patients with low body fat or in areas where a nerve is not well protected by subcutaneous tissue.

Adult↗

PubMed2004

Semitendinosus regrowth: biochemical, ultrastructural, and physiological characterization of the regenerate tendon.

BACKGROUND: Previous studies have suggested that hamstring tendons can regenerate following harvesting for anterior cruciate ligament reconstruction. HYPOTHESIS: This "neo-tendon" is a true, functional tendon, not scar tissue. STUDY DESIGN: Controlled laboratory study. METHODS: Semitendinosus tendons were harvested from 35 New Zealand white rabbits using a standard tendon stripper. The rabbits were sacrificed 9 to 12 months following the index procedure and thoroughly evaluated. RESULTS: Thirty-one rabbits were available at the time of sacrifice. The neo-tendon was present in 26 rabbits but was highly variable in size and location of its tibial insertion. Histologic and immunohistochemical staining confirmed that the regenerate tissue was indeed tendon with normal cellularity, organization, and immunolocalization of type I collagen. Electron microscopy showed regeneration of organized collagen tissue that simulated native tendon but with a smaller cross-sectional diameter. Functionally, the neo-tendon was able to transmit force across the musculotendinous junction but at a significantly slower rate than the opposite, control leg. Biomechanical properties of the neo-tendon were significantly less than the control side. Biochemical analysis revealed that the neo-tendons contained glycosaminoglycans and collagen, but levels were significantly lower than normal tendons. CONCLUSIONS: Semitendinosus tendons regenerate with biologically reactive tendinous tissues in an animal model. This tissue has many of the characteristics of a normal tendon but appears to be inferior to the original musculotendinous unit at 9- to 12-month evaluation. Further characterization of the "lizard tail phenomenon" is still needed. CLINICAL RELEVANCE: Hamstring tendon regrowth may have a dramatic impact on postoperative function of patients who undergo anterior cruciate ligament reconstruction with these tendons. Further modulation of this regeneration may further reduce graft harvesting morbidity.

Animals↗

PubMedDate not supplied

Recurrent compartment syndrome in the posterior thigh. Report of a case.

Recurrent compartment syndromes of the lower extremity, which usually occur in conjunction with intense use of muscle groups, can be briefly defined as an uncomfortable circulatory disturbance associated with a pathologic increase in total intramuscular pressure. This syndrome has been reported in each of the four compartments of the leg but not in the thigh. Characteristic features of clinical presentation and physical examination are reviewed in this report. We have found that an intracompartmental pressure test (Whitesides Jr, TE, Haney TC, Morimoto K, et al: Tissue pressure measurements as a determinant for the need of fasciotomy. Clin Orthop 113: 43-51, 1975) is an invaluable diagnostic aid. A case involving the medial hamstring groups, with characteristic historical presentation, intracompartmental pressure elevation, and excellent response to fasciotomy, is presented and discussed. The only effective treatment in this case was fasciotomy.

Acute Disease↗

PubMed1993

Clinical evaluation of the BackMate lower lumbar rehabilitation system: results of a preliminary study.

Back pain profoundly affects daily activities and quality-of-life parameters. It was the intent of the present study to evaluate a procedure of stretching and strengthening the lower back musculature with the aid of a pelvic stabilization device, the BackMate, for the treatment of lower back pain. Subjects suffering from chronic back pain (> 3 months in duration) were studied. The treatment program consisted of three therapy sessions per week for 3 weeks. Sitting time, walking distance, and lower back pain, parameters reported by the subjects, significantly improved regardless of age and sex of the subjects. Similarly, objective parameters, including forward bend, straight leg raise, and hamstring flexibility, significantly improved. This preliminary experience suggests that stretching and strengthening procedures performed with the aid of a pelvic stabilization device may prove to be a significant addition to current clinical treatment procedures for lower back pain.

Activities of Daily Living↗

PubMed1999

Effects of a 2-hour cheerleading practice on dynamic postural stability, knee laxity, and hamstring extensibility.

STUDY DESIGN: One group; pretest, posttest design. OBJECTIVE: To assess the effect of a 2-hour cheerleading practice on the anterior knee laxity, hamstring extensibility, and dynamic postural stability (preferred stance leg during vision-denied unilateral stance) of 17 nonimpaired members of a college cheerleading team (8 females, 9 males; 18-25 years old). BACKGROUND: Anterior knee laxity and hamstring extensibility increase following exercise. The relationship between exercise induced anterior knee laxity, hamstring extensibility, and dynamic postural stability, however, has not been examined. METHODS AND MEASURES: Pre- and postpractice measurements were compared using paired t tests and Bonferroni's correction for multiple comparisons. A 3 x 2 analysis of variance (force level applied to the arthrometer by condition) and Tukey honest significant difference post hoc test were used to evaluate specific arthrometer force level by condition effects (P < .05). RESULTS: Mean laxity at 133 N and hamstring extensibility increased (mean +/- SD) 1.5 +/- 1 mm and 3 +/- 4 degrees, respectively, following practice. Mean medial-lateral stabiliometer platform angulation (frontal plane position) moved medially following practice (2.9 +/- 3 degrees) and produced a weak correlation with increased knee laxity (r = 0.58). Hamstring extensibility did not significantly relate to stabiliometry or knee laxity variables. CONCLUSIONS: The relationship between the medially directed platform angulation and the increase in anterior knee laxity following cheerleading practice suggests a relationship between subtalar joint position and anterior cruciate ligament strain.

Adolescent↗

PubMedDate not supplied

Implications of muscular defense in testing for the anterior drawer sign in the knee. A stress radiographic investigation.

This study was performed with the aim of shedding some light on the effect of muscular guarding during clinical testing of the knee for anteroposterior laxity. Twenty physicians were tested on a knee phantom, for force used during testing for the anterior drawer sign. The force used averaged 109 N (range, 70 to 180 N). Fifteen patients were examined by stress radiography. Radiographs were taken with the knee flexed to 90 degrees (the drawer test position) and with the knee flexed to 15 degrees (the Lachman position). A comparison was made between the laxity measured on forward traction in the relaxed knee, and during traction while the patient was instructed to counteract the forward displacement of the tibia by tensing the hamstrings, thus simulating muscular defense. The test procedure was executed first with 80 N and then with 160 N applied. The opposing effect of tensing the hamstrings on the anterior shift of the tibia was significantly less at 15 degrees of knee flexion (with 80 N, P less than 0.02; with 160 N, P less than 0.05) than at 90 degrees. With the hamstrings tensed and the knee flexed to 90 degrees, no statistically significant gain in drawer sign was achieved by increasing the force from 80 to 160 N. With the knee in the Lachman position, increasing the force produced a significantly greater anterior drawer sign (P less than 0.01).

Biomechanical Phenomena↗

PubMedDate not supplied

Selective lengthening of the psoas and rectus femoris and preservation of the iliacus for flexion deformity of the hip in cerebral palsy patients.

Between 1978 and 1983, 52 Japanese patients with cerebral palsy underwent operative correction of flexion deformity of the hip. The results of lengthening of the psoas, rectus femoris, and proximal hamstrings were satisfactory. The iliacus was left intact. Improvement in gait and activities of daily living was attained. Concentric reduction was obtained in 27 of 33 dislocated or subluxated hips. Sitting and perineal care were facilitated, and pain was alleviated. We conclude that preservation of the iliacus is important.

Adolescent↗

PubMed2006

Determinants of self efficacy for physical tasks in people with knee osteoarthritis.

OBJECTIVE: Self efficacy, the confidence an individual has to perform a task, is an important determinant of physical performance in individuals with knee osteoarthritis (OA). The purpose of this study was to determine what personal, pathophysiologic, and impairment factors relate to self efficacy for physical tasks in community-dwelling adults with knee OA. METHODS: Fifty-four persons with radiographically confirmed knee OA (mean +/- SD age 68.3 +/- 8.7 years, range 50-87 years) participated. The Functional Self-Efficacy subscale of the Arthritis Self-Efficacy Scale was the dependent measure. Independent measures included age, education, scores from the Center for Epidemiologic Studies Depression and State-Trait Anxiety Inventory questionnaires, medial joint space and varus/valgus tibiofemoral angle from radiographs, body mass index, and isokinetic quadriceps and hamstrings strength. Knee pain and stiffness, assessed using the Western Ontario and McMaster Universities Osteoarthritis Index, were independent measures. RESULTS: Fifty-one percent of the variance of Functional Self Efficacy was explained by knee stiffness, hamstrings strength, age, and depression scores. Pain, education, anxiety, radiographic joint space, and body weight did not significantly contribute to the variance in Functional Self-Efficacy scores. Substituting quadriceps strength for hamstrings strength resulted in a regression model that included only stiffness, age, and depression, which explained nearly as much variance as the original model. CONCLUSION: Self efficacy for physical tasks is related to the sensation of stiffness, hamstrings strength, age, and level of depressive symptoms in persons with knee OA. Clinicians and researchers could consider these variables when assessing the level of self efficacy for physical tasks in persons with knee OA.

Activities of Daily Living↗

PubMed1992

Effect of very low calorie diet on body composition and exercise response in sedentary women.

The effect of very low calorie diet (VLCD) on fat-free mass (FFM) and physiological response to exercise is a topic of current interest. Ten moderately obese women (aged 23-57 years) received VLCD (1695 kJ.day-1) for 6 weeks. FFM, estimated by four conventional techniques, and heart rate (fc), blood lactate (la(b)), mean arterial pressure (MAP), respiratory exchange ratio (R) and rating of perceived exertion (RPE) were measured during a submaximal cycle ergometry test 1 week before, in the 2nd and 6th week, and 1 week after VLCD treatment. Strength and muscular endurance of the quadriceps and hamstrings were tested by isokinetic dynamometry. The 11.5-kg reduction in body mass was approximately 63% fat and 37% FFM. The latter was attributed largely to the loss of water associated with glycogen. Whilst exercise fc increased by 9-14 beats.min-1 (P < 0.01), there were substantial decreases (P < 0.01) in submaximal MAP (1.07-1.73 kPa), la(b) (0.75-1.00 mmol.l-1 and R (0.07-0.09) during VLCD. R and fc returned to normal levels after VLCD. Gross strength decreased (P < 0.01) by 9 and 13% at 1.05 rad.s-1 and 3.14 rad.s-1, respectively. Strength expressed relative to body mass (Nm.kg-1) increased (P < 0.01) at the lower contraction velocity, but there was no change at the faster velocity. Muscular endurance also decreased (P < 0.01) by 62 and 82% for the hamstrings and quadriceps, respectively. We concluded that the strength decrease was a natural adaptation to the reduction in body mass as the ratio of strength to FFM was maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2005

Analysis of the risk factors regarding anterior cruciate ligament reconstruction using multiple-looped semitendinosus tendon.

The purpose of this study was to investigate the risk factors regarding anterior cruciate ligament (ACL) reconstruction using autogenous semitendinosus tendon by subjective evaluation of the patients. We studied 63 patients who had been followed for 18 months or longer after surgery. They comprised 31 men and 32 women aged 15-45 (mean, 25.5) years. The patients were divided into two groups by subjective scores. Subjective clinical evaluation was performed using 100 mm visual analogue scale (VAS). In the high score group (group H), the VAS score was 80 mm or higher, and in the low score group (group L), the score was less than 80 mm. Forty three patients were in group H and 20 patients were in group L. The parameters examined were age, gender, sports activity level, preoperative period, complicated meniscus injury, articular cartilage status, graft tendon size, joint stability, and knee extension muscle strength. There were 26 men and 17 women in group H, and 5 men and 15 women in group L. There were significantly more women in group L (p<0.01). The mean preoperative period after injury was 23+/-38 months in group H, and was 52+/-67 months in group L (p<0.05). The average side-to-side differences in anterior laxity were 1.3+/-1.0 mm in group H and 2.2+/-1.6 mm in group L (p<0.01). There were no significant differences in other parameters between the two groups. In this study the risk factors for poor subjective outcome following hamstring ACL surgery was female gender and prolonged delay from injury to operation.

Adolescent↗

PubMed1996

Isokinetic strength following knee arthroscopy.

This study objectively evaluates recovery of quadriceps and hamstring strength following knee arthroscopy in a group of 43 patients given rehabilitation instructions, but limited supervised rehabilitation. Although the patients did not complain of weakness or functional limitation, isokinetic testing 1, 3, and 8 weeks following surgery revealed persistent weakness in many patients. Incomplete recovery was most apparent when patients were categorized by the degree to which they had recovered normal strength. Results expressed as a mean for the entire group indicated reasonably good recovery and obscured the significant weakness persisting in some patients. Knee extension strength tested at 60 degrees/sec had returned to normal 8 weeks after arthroscopy in only 32% of the subjects. Hamstring strength recovery was better, with 71% having normal strength. Patients may not recognize or report muscular weakness following arthroscopy, yet following 8 weeks of self-supervised rehabilitation many will have objective evidence of persistent weakness. In asymptomatic patients the clinical significance of this weakness is unknown.

Adult↗

PubMed1997

Hamstring release for fixed knee flexion contracture in hemophilia.

Sixteen hamstring tenotomies and posterior capsulotomies were assessed retrospectively in 10 patients with hemophilia. The average age of the patients was 17 years (range, 16-24 years). The main indication for surgery was a fixed knee flexion contracture of 30 degrees to 45 degrees, associated with repeated hemarthroses, and failure of conservative treatment after 6 months. A posterior transverse capsulotomy and a Z shaped hamstring tenotomy were performed. The postoperative treatment consisted of repeated stretching exercises for a 6-month period. An average decrease of 25 degrees in the amount of fixed knee flexion contracture was obtained (range, 10 degrees-40 degrees). Followup for an average of 9.5 years showed 11 good, four fair, and one poor result regarding their joint scores. It is concluded that hamstring release is an effective surgical procedure for fixed knee flexion contracture in hemophilia. It seems to reduce the incidence of hemarthrosis relating to such a deformity.

Adolescent↗

PubMed1995

Clinical results of early orthopaedic management in Duchenne muscular dystrophy.

Although the primary defect of Duchenne muscular dystrophy has been 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 muscle and a lengthening of the tendo calcaneus in 32 patients. The mean age of DMD patients at time of operation was 6.1 years. The mean follow-up was 3.4 years. All children underwent mobilisation 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 after 3.4 years. No loss of ambulation was observed. Our results demonstrate that early selective surgery in DMD patients just at or better before 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 thereby delays the progression of scoliosis.

Child↗

PubMed2005

Stability results of hamstring anterior cruciate ligament reconstruction at 2- to 8-year follow-up.

PURPOSE: The purpose of this study was to test the hypothesis that hamstring (HS) anterior cruciate ligament (ACL) reconstructions using EndoButton (Smith & Nephew, Andover, MA) femoral and whipstitch/screw tibial fixation can produce a high rate of objective stability in a population of reconstructed patients with low morbidity. TYPE OF STUDY: Case series. METHODS: We retrospectively reviewed 153 consecutive primary HS ACL reconstructions in skeletally mature patients without other ligament reconstructions. All knees had EndoButton femoral and whipstitch/screw tibial fixation; 139 patients were located and 133 were tested. Thirteen were geographically distant and tested subjectively only. Evaluations included KT-1000 testing; radiographs; and Noyes, Lysholm, and Single Assessment Numeric Evaluation (SANE) ratings. Follow-up was 24 to 104 months (mean, 54.4 months). RESULTS: There were no graft failures. No patient had rupture of an implanted graft. No patient had repeat surgery for instability; 96.9% of reconstructions had maximum manual side-to-side differences of < or =3 mm, 85.7% had < or =2 mm; 3% of the knees had a 4-mm difference; none had > or =5-mm difference. There was no objective stability difference between male and female patients and no deterioration in results with increasing follow-up time. Median ratings were: Noyes, 94; Lysholm, 94.5; and SANE, 90. Radiographs showed that no EndoButtons had migrated. No EndoButton or tibial screw had to be removed due to symptoms from the implant. One hundred eighteen of 120 patients had full extension; the other 2 patients had a 2 degrees flexion loss. One patient required repeat arthroscopy for arthrofibrosis but had full range of motion at follow-up. There were no deep knee infections. One patient had a superficial wound infection requiring intravenous antibiotics. One patient had a calf deep vein thrombosis that resolved with treatment. CONCLUSIONS: Hamstring ACL reconstructions can produce (1) reliable, durable stability in both males and females with no graft failures, (2) good clinical ratings, (3) excellent range of motion, and (4) low morbidity, without hardware problems. LEVEL OF EVIDENCE: Level IV, Case Series.

Anterior Cruciate Ligament↗

PubMed2005

Relationship between hamstring activation rate and heel contact velocity: factors influencing age-related slip-induced falls.

The purpose of this research was to determine whether a decreased hamstring activation rate among the elderly is responsible for a higher horizontal heel contact velocity and increased likelihood of slip-induced falls compared to their younger counterparts. Twenty-eight subjects from two age groups (14 young and 14 old) walked across a linear walking track with embedded force platforms while wearing a fall arresting harness attached to an overhead arresting rig for safety. In order to obtain realistic unexpected slip-induced fall data, a soapy vinyl floor surface was hidden from the subjects and unexpectedly introduced. Synchronized kinematics, kinetic and electromyography (EMG) analyses during the heel contact phase of the gait cycle while walking over slippery and non-slippery floor surfaces were examined in the study. Normalized EMG data were examined in terms of hamstring activation rate and evaluated with heel contact velocity and friction demand characteristic (as measured by peak required coefficient of friction (RCOF)) on the dry vinyl floor surface. Furthermore, slip parameters (i.e. slip distances and slipping velocity) were assessed on the soapy vinyl floor surface. The results indicated that younger adults' hamstring activation rate was higher than older adults, whereas younger adults' heel contact velocity was not different from older adults. These results suggested that heel contact velocity in younger adults was sufficiently reduced before the heel contact phase of the gait cycle. This could be due to the outcome of higher hamstring activation rate in younger adults in comparison to older adults. However, lower friction demand (peak RCOF), shorter slip distances, slower peak sliding heel velocity and more falls among older adults suggested that the slip initiation characteristics were not the only factors contributing to slip-induced falls among the elderly.

Accidental Falls↗