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PubMed1994

Relationship between bone mineral density of the proximal femur and lumbar spine and quadriceps and hamstrings torque in healthy Japanese subjects.

The purpose of this study was to examine the correlations between the muscle torque of the leg extensors (quadriceps femoris) and leg flexors (hamstrings) and the bone mineral density (BMD) of the proximal femur and lumbar spine. To investigate the decline in BMD of proximal femur and lumbar spine, we examined the relative importance of muscle torque, age, and body weight in the prediction of BMD in 340 healthy volunteers (109 males, and 231 females). Age and body weight were independent predictors of femoral BMD in men. Body weight and quadriceps torque were independent predictors of femoral BMD in premenopausal women. Body weight and years after menopause were independent predictors of BMD in postmenopausal women. The BMD was greatly affected by menopause, whereas the muscle torque was independent of the menopause, and showed the negative relationship to age. These results suggest that muscle-building exercise may have the potentiality to elevate the BMD in the proximal femur in premenopausal women.

Adult↗

PubMed2002

Anterior cruciate ligament reconstruction with a multistrand hamstring graft fixed with a Ligament Tension Screw: a new device that can be used to readjust graft tension after fixation.

We developed a new fixation device for reconstruction of the anterior cruciate ligament with a multistrand hamstring graft. This device allows the graft tension to be readjusted after fixation. This device, called a Ligament Tension Screw, consists of three parts, a screw, a washer, and a post. To create the graft, the tendons were formed into a loop. The device was hung from one end of the loop of the graft and a Kennedy-ligament augmentation device (LAD) artificial ligament was hung at the other end. The Kennedy-LAD artificial ligament was used extraarticularly for fixation at the tibia with double staples. Graft tension was increased by turning the screw, which pulls on the post suspending the graft. Fifty-two patients were evaluated after a minimum 2-year follow-up. The evaluation included physical examination, stability measurement with a KT2000 arthrometer, a Cybex muscle strength measurement, a functional test, and scoring of the knee according to the International Knee Documentation Committee (IKDC). Pivot test was negative in 47 patients (91%), but glide occurred in 5 patients (9%). No patient had a "clunk" or markedly poor result on the pivot test. All patients recovered full extension. Seven patients lost full flexion, but the loss of flexion was less than 5 degree in all seven. The KT 2000 arthrometer measurement with 133 N anterior drawer force indicated that 46 patients (88%) had less than 3-mm side-to-side difference. The mean muscle strength of the quadriceps and hamstrings was 91% and 94%, respectively, compared with the findings in the contralateral limb. The functional test showed a one-leg hop distance equal to 94% of that the opposite side. According to the final IKDC evaluation, 48 patients were graded as normal or nearly normal, and 4 patients as abnormal; none was severely abnormal. This study demonstrated satisfactory results for the reconstruction with a multistrand hamstring graft fixed with the new Ligament Tension Screw.

Adolescent↗

PubMed2004

Recovery of function after closed femoral shortening.

This prospective, longitudinal study documents the muscle strength and baseline function of 18 patients undergoing closed femoral shortening for discrepancy in limb length. Patients were studied for two years following surgery. Function was measured by a self-reported questionnaire, timed tests of performance and measurements of muscle strength and power. After two years, the self-reported function and ability to complete timed functional tests had returned to or improved on the pre-operative values. Muscle strength remained slightly below the pre-operative value and was more marked in the quadriceps than the hamstrings. This study suggests that small decreases in muscle strength and power following closed femoral shortening do not adversely affect the patients' ability to perform everyday activities.

Adolescent↗

PubMedDate not supplied

Motor unit recruitment strategy of antagonist muscle pair during linearly increasing contraction.

The motor unit recruitment control strategy of the antagonist thigh muscles was determined during linearly increasing isometric flexion and extension of the knees. The median frequency (MF) of the power density spectrum of surface electromyograms recorded from eighteen subjects was used as an indicator of motor units recruitment. The results showed that different recruitment strategies were used by the muscles that are antagonist to each other. When quadriceps and hamstrings acted as agonist most of the motor units were recruited in a linear manner up to 60% of maximal voluntary contraction (MVC). When the muscles acted as antagonist, quadriceps motor units were recruited up to 40% MVC during flexion while during extension the antagonist hamstrings recruited motor units up to 60% MVC. In both muscles, when acting as antagonist, the MF decreased after the recruitment phase, whereas when functioning as agonists, the MF remained relatively constant past the recruitment phase. The results suggested that a single muscle can employ different motor units recruitment strategies in accord with the type of contraction it performs and while acting as an agonist muscle as well as an antagonist.

Adult↗

PubMed1989

Short-term effects of intrathecal baclofen in spasticity.

Six patients with long-lasting spasticity resistant to different drug therapies including oral baclofen received a bolus injection of lumbar intrathecal baclofen. Electromyographic (EMG) reactions of leg muscles (soleus, tibialis anterior, quadriceps, and hamstrings) to standard stimuli and during attempts at voluntary activation were recorded before the drug injection and up to 3 h after the injection. Responses to joint movements, H-reflexes, ankle clonus, and defensive reactions were noticeably suppressed within 30-45 min after the injection and had practically disappeared after 2 h. Ankle clonus was seen only in patients with H-reflexes, and clonus disappeared when the reflex responses to the n. tibialis stimuli were absent. A decrease in clonus EMG burst amplitudes was accompanied by a decrease in the clonus frequency. These observations favor the autooscillation hypothesis of clonus. Baclofen injection led to improvement in selective voluntary activation of leg muscles in patients with residual motor control. These results suggest that execution of voluntary motor commands in the patients suffered from functionally abnormal spinal circuitry rather than from changes in the descending motor commands. Intrathecal baclofen appears to be an effective way of eliminating increased muscle tone and spasms which can allow for voluntary motor function when it is present.

Administration, Oral↗

PubMed2004

Shortwave diathermy and prolonged stretching increase hamstring flexibility more than prolonged stretching alone.

STUDY DESIGN: A randomized, counterbalanced 2x3x5 repeated-measures design. OBJECTIVE: To compare changes in hamstring flexibility after treatments of pulsed shortwave diathermy and prolonged stretch, sham diathermy and prolonged stretch, and control. BACKGROUND: Heat and stretch techniques have been touted for years. To date, the effect of shortwave diathermy and hamstring stretching has not been studied. Because diathermy heats a large area and penetrates deep into the muscle, use of this device prior to or during hamstring stretching may increase flexibility. METHODS AND MEASURES: Thirty college-age students (mean age, 21.5 years) with tight hamstrings (inability to achieve greater than 160 degrees knee extension at 90 degrees hip flexion) participated. Subjects were assigned to 1 of 3 groups: diathermy and stretch, sham diathermy and stretch, and control). Range of motion was recorded before and after each treatment for 5 days and on day 8. A straight leg-raise stretch was performed using a mechanical apparatus. Subjects in the diathermy-and-stretch group received 10 minutes of diathermy (distal hamstrings) followed by 5 minutes of simultaneous diathermy and stretch, followed by 5 minutes of stretching only. Subjects in the sham-diathermy-and-stretch group followed the same protocol, but with the diathermy unit turned off. Subjects in the control group lay on the table for 20 minutes. Data were analyzed using an ANOVA and post hoc t tests. RESULTS: Mean (+/- pooled SE) increases in knee extension after 5 days were 15.8 degrees 2.2 degrees for the diathermy-and-stretch group, 5.2 degrees +/- 2.2 degrees for the sham-diathermy-and-stretch group, and -0.3 degrees +/- 2.2 degrees for the control group. Seventy-two hours after the last treatment, the diathermy-and-stretch group lost 1.9 degrees +/- 2.2 degrees, the sham-diathermy-and-stretch group lost 3.0 degrees +/- 2.2 degrees, and the control group changed -0.4 degrees +/- 2.2 degrees. CONCLUSION: These results suggest that hamstring flexibility can be greatly improved when shortwave diathermy is used in conjunction with prolonged stretching.

Adult↗

PubMed1989

Motor patterns of a fast voluntary postural task in man: trunk extension in standing.

The co-ordination between muscles controlling the primary movement and associated postural adjustments during fast trunk extension movements was studied in six male subjects. Myoelectrical activity (EMG) was recorded from antagonistic muscle pairs at the trunk, hip, knee and ankle. Horizontal displacements of the upper trunk, hip and knee were recorded with an opto-electronic system (Selspot). A backward displacement of the trunk was accompanied by a forward displacement of the hip and knee. In general, the trunk started to move 30 ms before the hip and knee. Muscle activity first appeared in the ankle extensors (soleus/gastrocnemius) up to 150 ms prior to onset of prime mover muscles (trunk extensor, erector spinae; and hip extensors/knee flexors, hamstrings). This pre-activation was seldom followed by any detectable ankle joint movement. Prime mover muscles were activated simultaneously followed by the hip extensor gluteus maximus. Time to activation of muscles braking the movement (rectus abdominis, rectus femoris and vastus lateralis) was correlated with the amplitude of the primary movement (r = 0.63 0.75, P less than 0.01). Onset of activity in vastus lateralis was highly correlated with the amplitude of the forward displacement of the knee (r = 0.93, P less than 0.01). An associated postural adjustment appeared as an ankle flexion accompanied by activity in the ankle flexor tibialis anterior, and often also in the ankle extensors. This co-activation of antagonistic ankle muscles can under certain conditions have interesting functional implications for the control of posture.

Adult↗

PubMed1993

Quantitative effects of physical therapy on muscular and functional performance in subjects with osteoarthritis of the knees.

Osteoarthritis (OA) of the knees is a functionally limiting disability. Physical therapy (PT) is considered a useful treatment for OA, although evidence is qualitative. The purpose of this study was to quantitatively measure the effects of a 3-month PT program (n = 40; 20 men and 20 women) with knee OA. Muscle function and functional assessment parameters were measured. All data were analyzed by repeated measures analysis of variance (p < 0.05). There were no significant changes in handgrip strength and endurance, limb volume, or angular velocity after PT. Maximal muscle length was significantly increased. Muscle strength significantly increased for the hamstrings (9% and 19%) and quadriceps (8% and 24%) for the men and women, respectively. Endurance improved for the quadriceps (26% and 39%) and hamstrings (18% and 28%) for men and women, respectively. Functionally, there were significant improvements in the ability to climb stairs, rise from a chair, and walk. Walking time (50 ft) and the difficulty and pain of performing various activities decreased. Most improvements had occurred after 1 month of PT. For the first time, the effects of a PT program have been quantitatively measured for patients with knee OA.

Activities of Daily Living↗

PubMed1994

[Changes in muscle activity of the lower extremities during forward-inclining-posture gait. Comparative study with free walking of healthy geriatric persons].

Using a force plate and electromyographic recordings, changes in the muscle activity of the lower extremities during forward-inclining-posture walking and the free walking of healthy young adults were studied and compared with the free gait of healthy geriatrics. The movement of the hamstring, and the tibialis anterior and calf muscles caused a negative quadric curve during the forward-inclining gait and a positive curve during the free walking. However, the movements of the rectus femoris muscle caused a positive curve during the forward-inclining gait and a negative curve during the free walking. It also was found that geriatrics are thrown off balance by changes in cadence while walking. Further, greater muscular activity of the lower extremities is needed by geriatrics than by young adults during free walking, and the muscular movements of geriatrics during free walking showed no relation to the forward-inclining muscular movements of the young adults.

Adult↗

PubMed1986

[Electromyographic studies on the musculature of the knee with osteoarthritis].

Action of muscles around the knee in walking on a treadmill was studied by electromyography in young normal subjects and in patients with osteoarthritis of the knee. The followings were concluded. The quadriceps femoris stabilizes the knee joint in the sagittal plane, showing higher activity with an increase in faster walking. The tensor fasciae latae and gluteus medius muscles are important in the frontal plane stability, working primarily in the slow walk. Hamstring controls finely the knee joint under various circumstances. The muscle of those with osteoarthritis of the knee on walking slowly shows a similar pattern of activity as that of the normal fast walking. All of the muscles apparently are put into stabilizing mechanism of the joint in the stance phase leaving less reserve in their activity. A forward bending in posture results in changes of muscle activity around the knee, which can play an important role in the development of osteoarthritis of the knee.

Adolescent↗

PubMed1983

Role of reflex responses of knee musculature during the swing phase of walking in man.

Muscle activation patterns of the quadriceps and hamstrings were studied in normal human subjects walking at comfortable speed on a treadmill. In addition knee angular velocity patterns and swing and stance phases of the step cycle were recorded. Data were collected from normal paces and from paces in which a momentary unexpected resistance was applied to the leg during swing. The application of the resistance caused an advance in the onset of both quadriceps and hamstrings activity. The latency of the onset of activity following the resistance in the quadriceps was 78.2 +/- 26.4 ms and this was considered to indicate a long latency stretch reflex. There was a close association between the onset of quadriceps and hamstrings activity both in the normal and resistance paces. The changes observed in knee angular velocity upon application of the resistance indicate tight control of angular velocity patterns. The results have important implications regarding neural control of muscle during purposive movement and the regulation of sensitivity of muscle receptors during such movements, especially during the periods when the muscle is normally inactive.

Adolescent↗

PubMed2006

Averaged EMG profiles in jogging and running at different speeds.

EMGs were collected from 14 muscles with surface electrodes in 10 subjects walking 1.25-2.25 ms(-1) and running 1.25-4.5 ms(-1). The EMGs were rectified, interpolated in 100% of the stride, and averaged over all subjects to give an average profile. In running, these profiles could be decomposed into 10 basic patterns, 8 of which represented only a single burst. Muscles could be divided into a quadriceps, hamstrings, calf and gluteal group, the profiles of which were composed of the same basic patterns. The amplitude of some bursts was constant, but other ones varied with running speed. This speed dependency was generally different between muscles of the same group. Many muscles show a similar profile in running as in walking. The most notable exception is the calf group, which shows activation in early stance (86-125%), together with quadriceps, instead of in late stance (26-55%) as in walking. This is also visible in low-speed running, 'jogging', where stance extends to 46% or 57%, instead of 30-37% as in normal running. Jogging shows some additional differences with normal running, related to this prolonged stance phase.

Acceleration↗

PubMed2001

Dysferlinopathy (LGMD2B): a 23-year follow-up study of 10 patients homozygous for the same frameshifting dysferlin mutations.

The limb-girdle muscular dystrophies are a group of inherited neuromuscular disorders which are clinically and genetically heterogeneous. We have been able to carry out a follow-up study on 10 patients from a large Palestinian family with a confirmed mutation in the dysferlin gene. These patients have been followed for more than 23 years since the onset of the disease. They all had normal developmental milestones. The onset of the disease was usually in the second decade, more rarely in the third and fourth decades. The first symptoms were difficulty with running and climbing stairs. Patients showed a distinct type of gait due to the unique pattern of muscle involvement which was characterised by early involvement of the posterior muscle compartment of the thighs and legs (hamstrings, adductors, gastrocnemius and soleus). The shoulder and upper limb musculature became involved later, especially supra and infraspinatus and biceps. In the early stages of disease these patients may clinically show only proximal lower limb-girdle muscle weakness; however, the use of muscle imaging techniques were very important, always detecting in these patients also distal lower limb muscle involvement, so that the pattern of muscle involvement found in dysferlin deficiency may not strictly conform to the definition of limb-girdle muscular dystrophy. The pattern of muscular dystrophy is essentially uniform and has clearly distinct features (involving mainly the initial pattern of muscle involvement and the mode of gait) which differ significantly from the well reported clinical features associated with sarcoglycanopathy, calpainopathy and Miyoshi myopathy.

Adolescent↗

PubMed2003

Ultrasound-guided botulinum toxin injection technique for the iliopsoas muscle.

Intramuscular botulinum toxin A injections are beneficial for the treatment of functional shortening of the iliopsoas muscle, but it is difficult to achieve precise needle positioning and injection. As a solution to this we present an ultrasound-guided injection technique for the iliopsoas muscle using an anterior approach from the groin. The procedure was performed 26 times in 13 patients (seven males, six females; mean age 11 years, SD 9 years 8 months; age range 4 to 31 years), 10 times bilaterally. Indications were functional iliopsoas shortening due to cerebral palsy (17 hips), hereditary spastic paraplegia (four hips), and Perthes disease (five hips). In all cases the iliopsoas muscle was identified easily by ultrasound; the placement of the injection needle and injection into the site of interest were observed during real time. No complications were encountered. Botulinum toxin A (BTX-A) injections have become established as a standard procedure for the treatment of functional shortening of different muscles in persons with spasticity or dystonia (Kessler et al. 1999, Bakheit et al. 2001, Kirschner et al. 2001). Optimal needle placement is essential to avoid severe side effects and to assess lack of response to the drug or incorrect region of injection. While injection into superficial, very palpable muscles is quite easy, the approach to other muscles such as the iliopsoas muscle may be more difficult and the placement of the needle for an optimal injection site is harder to control. As a solution to this, we present an ultrasound-guided injection technique. The main indications for BTX-A injections in the iliopsoas muscle are dynamic hip flexion deformities mostly due to spastic conditions which may compromise walking (increased anterior pelvic tilt during the whole gait cycle, decreased hip extension at terminal stance, increased peak hip flexion during swing; Molenaers et al. 1999. Another indication might be decentration of the femoral head (as part of an injection programme which also includes other muscles like the adductors and the medial hamstrings) for pain relief, reducing care difficulties and, possibly, prevention of further decentration (Porta 2000, Foster et al. 2001, Deleplanque et al. 2002, Lubik et al. 2002). In Perthes disease, BTX-A injections in the iliopsoas muscle and the adductors may prevent a fixed deformity, which is a negative prognostic factor.

Adult↗

PubMed1987

Exercise after anterior cruciate ligament reconstruction. The force exerted on the tibia by the separate isometric contractions of the quadriceps or the hamstrings.

The anterior or posterior drawer force exerted on the tibia by the separate isometric contractions of the quadriceps or hamstrings at various angles of knee flexion was examined in 20 healthy males. A two-dimensional model was analyzed using roentgenographic films. In separate isometric contractions of the quadriceps, the mean value of the anterior drawer force was equivalent to 14% of the tension of the quadriceps at 5 degrees knee flexion. The value decreased with the increase in the angle of knee flexion. The mean angle at which the anterior drawer force became zero was 45.3 degrees +/- 12.5 degrees. When the angle was increased further, the posterior drawer force gradually increased. In separate isometric contractions of the hamstrings, the posterior drawer force was exerted at all angles of flexion. Thus, during the early stage of rehabilitation after the anterior cruciate ligament injury, the quadriceps exercise by isometric muscle contraction should be performed with the knee flexion at more than 70 degrees (mean +/- 1.96). Exercise of the hamstrings by isometric muscle contractions can be carried out regardless of flexion angle.

Adult↗

PubMed2004

Modulation of coordinated muscle activity during imposed sinusoidal hip movements in human spinal cord injury.

Individuals with chronic spinal cord injury (SCI) often demonstrate multijoint reflex activity that is clinically classified as an extensor spasm. These responses are commonly observed in conjunction with an imposed extension movement of the hips, such as movement from a sit to a supine position. Coincidentally, afferent feedback from hip proprioceptors has also been implicated in the control of locomotion in the spinalized cat. Because of this concurrence, we postulated that extensor spasms that are triggered by hip extension might involve activation of organized interneuronal circuits that also have a role in locomotion. If true, imposed oscillations of the hip would be expected to produce activity of the leg musculature in a locomotor pattern. Furthermore, this muscle activity would be entrained to the hip movement. The right hip joints of 10 individuals with chronic SCI, consisting of both complete [American Spinal Injury Association (ASIA) A] and incomplete (ASIA B,C) injuries, were subjected to ramp and hold (10 s) movements at 60 degrees /s and sinusoidal oscillations at 1.2, 1.88, and 2.2 rad/s over ranges from 40 to -15 degrees (+/-5 degrees ) using a custom servomotor system. Surface EMG from seven lower extremity muscles and sagittal-plane joint torques were recorded to characterize the response. Ramp and hold perturbations produced coactivation at the hip, knee, and ankle joints, with a long duration (5-10 s). Sinusoidal perturbations yielded consistent muscle timing patterns that resulted in alternating flexor and extensor joint torques. EMG and joint torques were commonly entrained to the frequency of movement, with rectus femoris, vastus medialis, and soleus activity coinciding with hip extension and medial hamstrings activity occurring during hip flexion. Individual muscle timing patterns were consistent with hip position during normal gait, except for the vastus medialis. These results suggest that reflexes associated with extensor spasms may occur through organized interneuronal pathways, such as spinal centers for locomotion.

Adult↗

PubMed2007

Effect of multilevel botulinum toxin a and comprehensive rehabilitation on gait in cerebral palsy.

To evaluate the effect of multilevel botulinum toxin A and comprehensive rehabilitation on gait pattern, muscle length, and spasticity, a multicenter randomized trial was performed in 46 children with spastic cerebral palsy who walk with flexed knees. Their mean age was 8.0 years (range 4 to 11 years). They were randomly allocated to the intervention group (multilevel botulinum toxin A and comprehensive rehabilitation) or the control group (usual care). After 6 weeks, a significant treatment effect in the intervention group was observed on: improved knee extension during midstance and terminal swing (7 degrees and 5 degrees , P < 0.01, respectively); hip rotation during terminal swing (4 degrees , P = 0.02); gait score (1.7, P < 0.01); decreased spasticity in hamstrings (11 degrees , P < 0.01), gastrocnemius (6 degrees , P = 0.01), and soleus (5 degrees , P = 0.02); and increased muscle length in hamstrings (9 degrees , P < 0.01) and gastrocnemius (5 degrees , P < 0.01). The improved muscle length was maintained up to 24 weeks. This study demonstrated that multilevel botulinum toxin A and comprehensive rehabilitation improves knee extension during gait, increases muscle length, and decreases spasticity in injected muscles after 6 weeks in children who walk with flexed knees. Although the effect on muscle length was maintained after 24 weeks, the effect on gait and spasticity had disappeared.

Botulinum Toxins, Type A↗

PubMed1976

Characteristics of the output from the dentate nucleus to spinal neurons via pathways which do not involve the primary sensorimotor cortex.

Experiments were performed to determine the action of the dentate output on neurons in the spinal cord mediated by pathways which do not involve the primary sensorimotor and premotor cortices. The dentate nucleus was electrically stimulated by stereotaxically placed electrodes in Rhesus monkeys whose contralateral sensorimotor and premotor cortices were ablated. The resultant changes in excitability of lumbar alpha motorneurons activated by Ia afferents from nerves innervating femoral, hamstring, gastrocnemius-soleus and peroneal muscles were measured by intracellular recordings and by determining the percent change in the amplitude of the monosynaptic reflex recorded from ventral roots. The effect of stimulation of the dentate nucleus on proprioceptive reflexes was determined by recording the changes in postsynaptic potentials evoked by selective stimulation of Ia and Ib afferent fibers. The results demonstrated that dentate nucleus exerts a significant action on the excitability of spinal neurons via pathways which do not include the sensorimotor and premotor cortices. Whether the dentate stimulus produced an increase or decrease in the excitability of these neurons was dependent upon the site within the dentate nucleus at which the stimulus was applied, demonstrating that, in the decorticate preparation, the output from this nucleus is quite heterogeneous. In addition, stimulation of the dentate nucleus in these monkeys did not affect the Ia reflex pathway but significantly changed the amplitude of the inhibitory postsynaptic potential evoked by Ib afferents in lumbar alpha motorneurons.

Animals↗