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Results for “Hamstring Muscles”

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At least 55 records · Page 3Linked to original sources

PubMed1992

The effect of training on endurance and the cardiovascular responses of individuals with paraplegia during dynamic exercise induced by functional electrical stimulation.

Endurance for dynamic exercise, cardiac output, blood pressure, heart rate, ventilation, and oxygen consumption was measured in eight individuals with paraplegia at the end of 4-min bouts of exercise on a friction braked cycle ergometer. Movement of the subjects' legs was induced by electrically stimulating the quadriceps, gluteus maximus and hamstring muscles with a computer-controlled biphasic square--wave current at a frequency of 30 Hz. The friction braked cycle ergometer was pedalled at work rates which varied between 0 and 40 W. Measurements were repeated after 3 and 6 months to assess the affect of training. After 3 months of training it was found that endurance increased from 8 min at a work rate of 0 W to 30 min at a work rate of 40 W. Compared to the cardiovascular responses in non-paralyzed subjects, computerized cycle ergometry was found to be associated with higher relative stresses for a given level of absolute work. Mean blood pressure, for example, increased by over 30% during maximal work in individuals with paralysis compared to the typical response obtained for able-bodied subjects. Analysis of the data showed that instead of the 20-30% metabolic efficiency commonly reported for cycle ergometry, the calculated metabolic efficiency during computer-controlled cycle ergometry was only 3.6%.

Adult↗

PubMed1992

Spinal substance P and N-methyl-D-aspartate receptors are coactivated in the induction of central sensitization of the nociceptive flexor reflex.

We have studied the effects and interactions of the neurokinin-1 receptor antagonist CP-96,345 and the N-methyl-D-aspartate receptor/channel blocker MK-801, both applied intravenously, on the flexor reflex and on the facilitation of the flexor reflex by conditioning stimulation of cutaneous C-afferents in decerebrate, spinalized, unanesthetized rats. The flexor reflex was evoked by subcutaneous electrical stimuli applied to the sural nerve innervation area 1/min at an intensity that activated C-fibers and was recorded as electromyogram from the ipsilateral hamstring muscles. The magnitude of the baseline flexor reflex was usually highly stable in the course of the experiments without experimental manipulations. The same stimulus was used as a conditioning train (0.9 Hz, 20 shocks) and caused a brief facilitation of the flexor reflex, which was maximal 0.5 and 1 min after stimulation (255.1 +/- 23.6% over baseline). During the course of the conditioning stimulus train, the reflex magnitude was gradually increased (wind-up). MK-801 (0.1 and 0.5 mg/kg) consistently depressed the polysynaptic flexor reflex. At a dose of 0.5 mg/kg, but not 0.1 mg/kg, MK-801 reduced the wind-up and blocked the facilitation of the flexor reflex induced by the conditioning stimulus by 90%. The facilitatory effect of 7 pmol intrathecal substance P was also partially reduced by MK-801. CP 96,345 (1 and 3 mg/kg) did not depress the flexor reflex, but dose-dependently antagonized reflex facilitation by the conditioning stimulus train, similarly to its antagonism of intrathecally applied 7 pmol substance P-induced facilitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

The management of decubitus ulcers by musculocutaneous flaps: a five-year experience.

Large decubitus ulcers can be treated by using many methods, including musculocutaneous flaps. Musculocutaneous flaps provide reliable, well-vascularized cover and often can be revised in patients with secondary recurrence. We have treated 30 patients with large decubitus ulcers during a 5-year period by using musculocutaneous advancement flaps of the gluteus maximus, the hamstring muscle, and the tensor fasciae latae. There were two complications treated by debridement with flap advancement in 1 patient and the use of another flap in the second patient. Four patients developed a recurrent ulcer, which was treated by reelevation and advancement of the original flap in all patients. The general management and overall results are presented.

Buttocks↗

PubMed1976

Fresh and cultured thyroid gland: survival and function after implantation.

Isogeneic or allogeneic thyroid glands were implanted into thyroidectomized recipeint rats. These grafts, either fresh or cultured, were placed in hamstring muscle pocket or under the renal capsule. Survival and function of the grafts were evaluated by: restoration of normal levels of serum thyroxine, weight gain, kidney transamidinase (a thyroxine-induced enzyme), and histological appearance of re-excised implants. A isografts, fresh and cultured, functioned well as ectopic thyroid glands, though restoration of normal serum thyroxine levels was more rapid for the fresh implants. Fresh allografts functioned transiently but then failed due to rejection. No function was detected for cultured allografts, and rejection was seen histologically. The rat thyroid allograft therefore differs from the rat parathyroid allograft, which often can function for several months despite histological evidence of rejection. Maintenance in tissue culture prior to implantation does not appear to alter the longterm immunogenicity of either organ.

Amidinotransferases↗

PubMed1976

The treatment of intoed gait in spina bifida patients by lateral transfer of the medial hamstrings.

The operation of lateral transfer of the medial hamstring muscles is described. Its applicating in the management of intoed gait in spina bifida is discussed, and the results of eight such operations, performed on four children, are recorded. The operation was effective in correcting the intoed gait in all; however, there was no activity in the transferred muscles in one child.

Child, Preschool↗

PubMed1992

Intrathecal neurokinin A facilitates the spinal nociceptive flexor reflex evoked by thermal and mechanical stimuli and synergistically interacts with substance P.

The neuropeptide neurokinin A was injected intrathecally and its effect on the spinal nociceptive flexor reflex was examined. The reflex, which was evoked by electrical, thermal or mechanical stimulation of the foot and was recorded from the ipsilateral hamstring muscles, was substantially facilitated by 7 pmol intrathecally injected neurokinin A. The facilitatory effect of neurokinin A to thermal stimulation was, however, significantly stronger than to electrical or mechanical stimuli. Furthermore, co-administration of neurokinin A with substance P induced a significant synergistic facilitation of the reflex. It is suggested that neurokinin A, like substance P, may be released in association with activation of polymodal C-nociceptors.

Animals↗

PubMed1977

C0-contraction and stretch reflexes in spasticity during treatment with baclofen.

Surface electromyograms were recorded from the quadriceps and hamstring muscles of 11 spastic patients during cyclical flexion and extension movements of the knee. A potentiometer strapped to the knee recorded the angle of the joint, the output signal being displayed on an oscilloscope. The patient used this signal to track a sine wave target for 20 cycles. The observer then moved the patient's limb through a further 20 cycles tracking the same target. Recordings were repeated at intervals for four hours after an oral dose of baclofen. Analysis of the recordings showed that the response of a spastic muscle to lengthening is not the same during passive movement as during voluntary movement. In mild spasticity stretch reflexes appear to be suppressed by voluntary effort whereas in severe spasticity they are enhanced. Baclofen suppressed the response to passive stretch by over 30% at plasma concentrations of over 250 ng/ml and by 50% at concentrations of over 400 ng/ml, but this effect was largely extinguised during voluntary movement.

Adolescent↗

PubMed1976

Synchronization of respiratory frequency by somatic afferent stimulation.

In cats anesthetized with chloralose-urethan, vagotomized, paralyzed, and artifically ventilated, superficial radial (cutaneous) and hamstring (muscle) nerve afferents were stimulated while phrenic nerve electrical activity was recorded. The results obtained with both types of nerves were similar. Stimulation in mid and late expiration advanced the onset of the next inspiration, shortening its duration. Stimulation in early inspiration advanced, while that in late inspiration delayed, the onset of the next expiration. These effects were often accompanied by changes in phrenic motoneuron firing patterns (earlier recruitment, increased discharge frequency, increased slope of integrated phrenic neurogram). Repetitive somatic afferent stimulation produced sustained increases in respiratory frequency in all cats and in half of them entrainment of respiratory frequency to the frequency of stimulation occurred at ratios such as 4:3, 4:5, 1:2, 1:3, 1:4, and 1:7. The lowest stimulus intensity required for evoking these phase shifts was between 5 and 10T (threshold of most excitable fibers) for muscle afferents and between 1 and 2T for cutaneous afferents. These results demonstrate the existence of a reflex mechanism capable of locking respiratory frequency to that of a periodic somatic afferent input. They also provide an experimental basis for the hypothesis that reflexes are resposible for the observed locking between step or pedal frequency and respiratory rate during exercise in man.

Animals↗

PubMed1992

MR lymphography with iron oxide compound AMI-227: studies in ferrets with filariasis.

OBJECTIVE: The purpose of this study was to assess the MR lymphographic potential of AMI-227 to reduce the signal intensity of hyperplastic inflammatory lymph nodes by using ferrets with filariasis as the animal model. Both interstitial and IV modes of administration were studied. MATERIALS AND METHODS: Twelve ferrets were infected with the filaria Brugia malayi and six control ferrets were injected with super-paramagnetic iron oxide AMI-227, either interstitially or IV. Signal intensities of the left popliteal lymph node, left hamstring muscle, and left inguinal fat were measured before, 48 hr after, and up to 138 days after contrast injection with the use of both spin-echo and gradient-echo techniques. The signal intensity data were statistically analyzed. The lymph nodes, liver, spleen, and lungs were studied with light and electron microscopy. RESULTS: Forty-eight hours after the interstitial injection of AMI-227, the signal intensities of the ipsilateral popliteal nodes of the infected and control ferrets were significantly reduced (p less than .0005) without significant changes in the signal intensities of the surrounding tissues on both spin-echo and gradient-echo MR images. No nodal signal reduction occurred with the IV route of injection in ferrets. Light microscopy revealed iron to be localized within nodal marginal zones exclusively. Lymphatic trunks were visualized after interstitial injection. Signal reduction persisted to our end point at 138 days. CONCLUSION: AMI-227 shows regional specificity with significant enhancement of nodal structures and demonstrates potential as an interstitial MR lymphographic agent.

Animals↗

PubMed1992

A new model of plastic ankle foot orthosis (FAFO (II)) against spastic foot and genu recurvatum.

A plastic ankle foot orthosis (AFO) was developed, referred to as functional ankle foot orthosis Type 2 (FAFO (II)), which can deal with genu recurvatum and the severe spastic foot in walking. Clinical trials were successful for all varus and drop feet, and for most cases of genu recurvatum. Electromyogram studies showed that the FAFO (II) reduced the spasticity of gastrocnemius and hamstring muscles and activated the quadricep muscles. Gait analysis revealed a reduction of the knee angles in the stance phase on the affected side when using the FAFO (II). Mechanical stress tests showed excellent durability of the orthosis and demonstrated its effectiveness for controlling spasticity in comparison with other types of plastic AFOs.

Adolescent↗

PubMed1975

Evaluation of aorto-iliac disease with Doppler ultrasound and isotope clearance techniques.

The clearance of 99mTc from the hamstring muscle compartment of patients with aorto-iliac or iliac disease was examined with the patients at rest and after exercise. The values were compared with those obtained in a group of controls and another group with superficial femoral, or femoropopliteal arterial occlusion. A statistically significant difference in the rate of 99mTc clearance was found in patients with proximal vascular disease.

Ankle↗

PubMed1992

[Clinical application of biomechanic and functional anatomical findings of the knee joint].

In order to study the functional anatomy of the knee joint, careful anatomical dissections were conducted on over 130 fresh-frozen cadaveric knee specimens. We found no evidence to support the two-bundle and three-bundle theories of cruciate ligament fiber patterns. The longest fibers in the anterior cruciate ligaments (ACL) measured 37 mm, and the longest in the posterior cruciate ligament (PCL), 41 mm. Cruciate ligament insertions follow a transition line on tibia and femur. Usually not all the fibers of the cruciate ligaments are taut at the same time. They are progressively recruited according to the biomechanical demands placed on them. Fibre recruitment in the ACL is from knee flexion to extension and in the PCL from extension to flexion. The concept of fiber recruitment was recently evaluated mathematically. As a working hypothesis, the knee joint can be looked upon as a biological realization of the crossed four-bar linkage, even in three dimensions. In vitro measurements have shown that correct graft placement in cruciate reconstructions is critical for knee biomechanics. Incorrect placement of grafts may lead to decreased range of motion and/or increased laxity. Distance changes of 3 mm between femoral origin and tibial insertion of a graft may lead to a 400% increase of graft preload and will thus easily reach published pull-out forces for some of the graft fixation methods (button = 248 N). Precise drill guides and isometers may be helpful in any operative technique (open, arthroscopic). Using the IKDC evaluation form and the KT-1000 arthrometer, our studies on 25 patients demonstrated a direct correlation between intraoperative graft tracking and the clinical outcome 2 years after operation. Biomechanical studies to investigate in vivo strain patterns of the anterior cruciate ligament and in vitro strain patterns of isometrically placed cruciate graft reconstructions showed that they did not reach critical fixation failure or graft rupture loads. The highest values were measured in Lachman and anterior drawer testing. In the 20-kg Lachman test the maximum load was 96 +/- 6 N. This was twice the maximum loads of any of the quadriceps exercises (40-50 N). With an isometrically placed graft, full active range of motion postoperatively and exercises with isolated or combined contractions of quadriceps and hamstring muscles will result in small graft loads. Postoperative immobilization with plaster and/or protection with braces may therefore become obsolete.

Anterior Cruciate Ligament↗

PubMedDate not supplied

[Trypanosoma cruzi: induction of changes in the peripheral nervous system in different strains of mice].

This study has been designed to find an easy method to evaluate the motor unit alterations induced during experimental T. cruzi infections. Different mouse strains infected with three strains of T. cruzi were used to perform conventional needle electromyography, in one of the lower limb hamstring muscles; amplitude, duration and number of phases of single motor unit potentials were measured. The following parasite strain to mouse strain relationship was investigated, in mice inoculated intraperitoneally with bloodstream forms of T. cruzi: Tulahuen and C3H/HeN, C57Bl, Balb/c, Swiss; CA-I and C3H/HeN, Rockland, NIH; RA and C3H/HeN, Rockland. T. cruzi-induced denervating alterations were found in both C3H/HeN and C57Bl mice infected with the Tulahuen strain, as well as in C3H/HeN mice inoculated with the CA-I strain. Moreover, CA-I trypomastigotes could produce primary muscle changes in C3H/HeN and NIH mice. The technique employed in this investigation proved to be an easy and adequate way to detect changes within the motor unit during T. cruzi infection in mice.

Animals↗

PubMed1991

[Covering of ischial pressure sores using a fasciocutaneous flap from the posterior surface of thigh (modified Griffith method) after mattressing with the biceps femoris. Apropos of 11 cases].

The ischial region is the commonest site for pressure sores in paraplegics capable of sitting. The choice of treatment must be guided by two imperatives: the need for a thick tissue cover (mattressing) and perfect trophicity, the risk of recurrence which always remains possible. The association of a modified Griffith fasciocutaneous flap from the posterior surface of the thigh and a hamstring muscle flap (preferably biceps femoris) providing mattressing of the ischial region, appears to satisfy these imperatives. The other repair procedures are discussed in order to ensure the best management of the paraplegic patient's cutaneous capital, due to the continual risk of a new pressure sore or a recurrence of the ischial pressure sore.

Adult↗

PubMed1991

The hamstring syndrome--a new gluteal sciatica.

The condition in which pain is felt over the area at the ischial tuberosity and radiating down the back of the thigh is labelled the hamstring syndrome. The pain is typically incurred by assuming a sitting position, stretching the affected leg or/and running fast. The symptoms are caused by tight, tendinous structures of the hamstring muscle at the area of its insertion into the ischial tuberosity. Following division of these structures, complete relief is obtained.

Adolescent↗

PubMed1991

Knee function after surgical or nonsurgical treatment of acute rupture of the anterior cruciate ligament: a randomized study with a long-term follow-up period.

One hundred fifty-six patients with a total rupture of the anterior cruciate ligament (ACL) were reexamined 41 to 80 months after injury. They were randomized to three treatment groups: (1) repair and augmentation of the ACL with an iliotibial strip, (2) repair without augmentation, and (3) nonsurgical ACL treatment. Associated injuries of menisci and other ligaments were treated in the same way for the three groups. Two-thirds of the patients in the nonsurgically treated group complained of instability and 17% had had a subsequent reconstruction of the ACL at the follow-up examination. The group treated with an augmented repair had a less abnormal laxity measured by a laxity-testing device. Sixty-three percent returned to competitive sports, as compared with 27% in the nonsurgical group and 32% in the only repair group. Relative strength of the quadriceps and hamstrings muscles were similar for all groups. The augmented-repair group had better hop tests, reflecting a superior stability, whereas running was not affected by treatment but was correlated with the activity level.

Adolescent↗

PubMed1979

The passive hamstring stretch test: a comparison of clinical estimates with tension gauge measurements.

A comparison of the clinical estimate of the available passive stretch in the hamstring muscles is made against the changing tension in a spring gauge, as the leg is raised. It was found that the angle at which rotation was palpable in the contralateral anterior superior spine occurred after there was a sharp rise in the tension measurements. The spring gauge was incorporated in a pulley system which allowed the leg to be pulled up and the tension readings were taken at 5 degrees increments of raise. Comparison of the clinical estimates with the tension gauge measurements show the latter to be a more reliable and objective research tool.

Biomechanical Phenomena↗

PubMed1979

Semimembranosus insertion syndrome: a treatable and frequent cause of persistent knee pain.

The semimembranosus insertion syndrome causes pain at the medial aspect of the knee. This pain is aggravated by exercise, walking downstairs and sharp bending of the knee. The patient experiences tender, moderately puffy swelling at the lowest part of the medial hamstrings muscles and painful passive rotation of the knee, while finger pressure over the insertion of the semimembranosus tendon elicits sharp pain. One hundred patients with semimembranosus insertion syndrome were treated with local injection of lidocaine hydrochloride and triamcinolone. All experienced temporary relief of pain immediately. Long-lasting relief of signs and symptoms was achieved in 58 patients, 30 of whom required repeat injections in 3 to 5 months. Pain decreased and disability was less severe in 9 other patients. There were 18 treatment failure, and 15 patients were lost to follow-up.

Adrenal Cortex Hormones↗