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At least 217 records · Page 12Linked to original sources
PubMed1997

Two years of growth hormone (GH) treatment increase isometric and isokinetic muscle strength in GH-deficient adults.

GH deficiency in adults is associated with reduced muscle mass and muscle strength. The objective of this trial was to follow the effect of 2 yr of GH treatment in GH-deficient adults on muscle performance in relation to a reference population. Knee extensor and flexor strengths for isometric and isokinetic concentric muscle strength were measured using a Kin-Com dynamometer. Hand-grip strength was measured in both hands. The fatigue index was calculated as the percent reduction in peak torque at 50 repeated isokinetic knee extensions. Superimposed, single twitch electrical stimulation was performed. The GH-deficient subjects had lower isometric knee extensor, knee flexor, and hand-grip strength than the reference population. Two years of GH treatment increased and normalized the mean isometric knee extensor and flexor strengths. The concentric knee flexor and extensor strength at an angular velocity of pi rad/s increased, as did the concentric knee flexor strength at an angular velocity of pi/3 rad/s. The increase in muscle strength was more marked in younger patients and in patients with lower initial muscle strength than predicted. Quadriceps endurance decreased, whereas the effect of superimposing single twitches on isometric contraction and hand-grip strength was unaffected by the GH treatment. Two years of GH therapy in GH-deficient adults increased and normalized isokinetic and isometric muscle strength studied in proximal muscle groups. Hand-grip strength and the degree of lack of maximal motor unit activation on voluntary isometric knee extensor force did not change. The dynamic local muscle fatigue index decreased.

Adult↗
PubMed1997

Muscle strength in rheumatoid elbow: quantitative measurement and comparison to Larsen's X-ray grade.

Accurate assessment of elbow function is important to determine the total ability of the arm. The purpose of this study was to clarify the relationship between isometric muscle strength of the elbows of patients with rheumatoid arthritis (RA) and Larsen's X-ray evaluation. Fifty-six elbows of 45 RA patients aged 47 to 77 years (mean age, 63 years) were tested. Muscle strength was measured with an isometric torque-cell dynamometer. Test-retest reliability of the dynamometer was proven by measuring 12 elbows of 6 healthy young men. In RA patients, elbow flexion and extension strength decreased in proportion to increases in the severity of Larsen's grades from Grade 1 to 4. However, Grade 5 elbows had greater muscle strength than those in Grade 4. Forearm pronation and supination strength also decreased in proportion to increases in the severity of Larsen's grades from Grade 1 to 5. This quantitative study made it clear that the muscle strength of RA patients' elbows almost completely correlates to X-ray finding according to the grade of Larsen's evaluation based on X-rays. With regard to muscle strength of postoperative elbows, both flexion strength and supination strength after total elbow replacement (TER) were about two times greater than before TER, and after synovectomy it was as great as those in non-operative RA patients of Grade 2.

Adult↗
PubMed1999

Isokinetic strength of elbow extensor muscles correlates with race time in wheelchair half marathon racers.

It has been reported that grasping power and isometric muscle strength of elbow extensors in fine wheelchair racers were greater than the poor racers in the wheelchair full marathon. The purpose of the present study was to investigate the relationship between muscle strength of elbow extensors and flexors and the race time in wheelchair half marathon race. Four wheelchair half marathon racers who completed the half marathon division of the 16th Oita International Wheelchair Marathon (OIWM) in 1996 participated in the present study. The day before the race, all subjects reported to the training room and the isokinetic muscle strength of elbow extensor and flexor muscle groups was measured at angular speeds of 60 degrees, 120 degrees and 240 degrees/sec using the isokinetic dynamometer. There was a significant correlation between race time and isokinetic muscle strength of the elbow extensors at 60 degrees, 120 degrees and 240 degrees/sec, but not flexor muscles. Our findings suggest that increased muscle strength of elbow extensors may improve the race time in wheelchair half marathon race.

Adult↗
PubMed2001

Do oarsmen have asymmetries in the strength of their back and leg muscles?

The aim of this study was to establish whether asymmetry of the strength of the leg and trunk musculature is more prominent in rowers than in controls. Nineteen oarsmen and 20 male controls matched for age, height and body mass performed a series of isokinetic and isometric strength tests on an isokinetic dynamometer. These strength tests focused on the trunk and leg muscles. Comparisons of strength were made between and within groups for right and left symmetry patterns, hamstring: quadriceps ratios, and trunk flexor and extensor ratios. The results revealed no left and right asymmetries in either the knee extensor or flexor strength parameters (including both isometric and isokinetic measures). Knee extensor strength was significantly greater in the rowing population, but knee flexor strength was similar between the two groups. No difference was seen between the groups for the hamstring: quadriceps strength ratio. In the rowing population, stroke side had no influence on leg strength. No differences were observed in the isometric strength of the trunk flexors and extensors between groups, although EMG activity was significantly higher in the rowing population. Patterns of asymmetry of muscle activity were observed between the left and right erector spinae muscles during extension, which was significantly related to rowing side (P < 0.01). These observations could be related to the high incidence of low back pain in oarsmen.

Adult↗
PubMed2005

Does handgrip exercise training increase forearm ischemic vasodilator responses in patients receiving hemodialysis?

In patients receiving hemodialysis, exercise capacity is extremely limited. Although vasodilation is one of the key phenomena for blood perfusion into working skeletal muscles during exercise, it is not clear whether the vasodilator capacity is increased after physical training in this population. We attempted to clarify whether handgrip exercise training increases forearm vasodilator responses to arterial occlusion, and to determine the relationship between muscle contraction function and the vasodilator responses in patients receiving hemodialysis. Eight patients and 7 age-matched healthy controls were tested. The patients participated in handgrip training four times a week for 6 weeks. Before and after the training the maximum muscle strength and endurance were measured with a handgrip dynamometer, and the forearm vasodilator responses to 3-minute arterial occlusion were measured by the near infrared spectroscopy technique. Maximum strength and endurance were significantly lower in the patients than in the controls. Maximum strength (from 183+/-84 to 228+/-92 Newtons, p<0.05) and endurance (from 19+/-6 to 31+/-8 sec, p<0.05) were both increased after the training in the patients. Vasodilator responses estimated by the ratio of the maximum value of oxyhemoglobin after relief of arterial occlusion to its minimum value before the relief were significantly smaller in the patients compared with those in the controls (132+/-20 vs 161+/-27%, p<0.05). In contrast to the findings in muscle function, the decreased vasodilator responses were not improved after the training (141+/-17%). Additionally, no improvement in the vasodilator responses was observed in the parameters estimated by oxygen saturation. These data suggest that exercise capacity increased by physical training is produced by the functional improvement of skeletal muscles per se, but not by alterations in blood perfusion for oxygenation of the muscles in patients receiving hemodialysis.

Exercise↗
PubMed2000

The relation between lower extremity strength and shoulder overuse symptoms: a model based on polio survivors.

OBJECTIVE: To determine the relation between lower extremity weakness and shoulder overuse symptoms among polio survivors. We predicted that individuals with moderate weakness in their leg extensor muscles would use their arms to help compensate for this weakness and would be at high risk for developing symptoms of shoulder overuse. DESIGN: A cohort study of polio survivors recruited from the Einstein-Moss Postpolio Management Program (Philadelphia), the community, and the surrounding region. SETTING: A research laboratory at Moss Rehabilitation Research Institute, Philadelphia, PA. PARTICIPANTS: One hundred ninety-four polio survivors. Demographic and medical history data, symptom data, and strength data were obtained for each. MAIN OUTCOME MEASURES: Presence or absence of shoulder symptoms and ratings of pain by visual analogue scale were recorded. Strength was measured using a hand-held dynamometer and manual muscle testing. RESULTS: Shoulder symptoms could be grouped into two distinct clusters based on the type of testing used for assessment. Symptoms elicited by palpation were present in 26% of the subjects and were strongly related to knee extensor strength and weight. These symptoms were more common among women than men (42% and 10%, respectively). Symptoms elicited by resistance tests were present in 33% of the subjects and were seen with equal frequency in both sexes. These symptoms were also related to lower extremity strength, but the specific relationship was not as clear as for the palpation-related symptoms. CONCLUSIONS: Lower extremity weakness predisposes individuals to shoulder overuse symptoms. Sex and body weight are contributing factors. These results may be generalized to other populations with lower extremity weakness, including the elderly.

Adult↗
PubMed2000

William Hammond, the dynamometer, the dynamograph.

The dynamometer came into general use by neurologists in the late 19th century. Various dynamometers were developed and adopted by neurologists at that time to measure muscle strength, in keeping with the general trend of adopting instrumentation to distinguish our specialty and aid observation and diagnosis. Many dynamometers were adaptations of the French Mathieu dynamometer, which was initially promoted by American neurologist William Hammond. Another variation, the Mathieu dynamograph, used to graphically record measurements made with a dynamometer, was also initially studied, used, and promoted by Hammond. The high cost of the dynamograph and the lack of demonstrated clinical utility contributed to its limited dissemination. The history of the dynamometer and the dynamograph illustrate both the practical difficulties associated with developing a new instrument, and the numerous modifications that such an instrument goes through, some of which have little to do with practical application.

Equipment Design↗
PubMed1994

Shoulder weakness in professional baseball pitchers.

The purposes of this study were to: 1) compare shoulder range of motion and strength in professional baseball pitchers (N = 47) compared with age-matched controls (N = 16), and 2) examine the relationship of injury history to strength and range of motion. Based on injury history pitchers were categorized as: 1) none (N = 26), 2) injury requiring conservative intervention (N = 9), or 3) injury requiring surgical intervention (N = 12). Range of motion was measured for internal rotation (IROM) and external rotation (EROM). Eccentric strength was measured by hand-held dynamometer for internal rotation (IR), external rotation (ER), abduction (ABD), and supraspinatus muscle (SUP) strength. Injury history had no effect on strength and range of motion. Dominant EROM was greater in pitchers, P < 0.0001, and controls, P < 0.05, with pitchers having greater EROM motion bilaterally, P < 0.0001. Pitchers were weaker in SUP on the dominant vs nondominant side, P < 0.0001, and on the dominant side for weight adjusted ER, ABD, P < 0.01, and SUP, P < 0.0001, compared with controls. In conclusion, dominance and pitching resulted in soft tissue adaptation. Pitchers displayed weakness in three of four tests by comparison with controls, suggesting that the demands of pitching are insufficient to produce eccentric strength gains and may in fact lead to weakness. Dominant-side SUP weakness in pitchers may reflect subclinical pathology or chronic fatigue.

Analysis of Variance↗
PubMed1990

Laboratory testing of muscle function in the management of neuromuscular disease.

A laboratory was set up to assess muscle weakness and physical disability in patients with peripheral neuromuscular diseases. Muscle strength was mainly measured with a hand held dynamometer and results were expressed in relationship to a "guideline" range for sex: disability was expressed in terms of ordinal data with a performance score and as interval data with simple timed tests. Of 17 patients with polymyositis on immunosuppressive medication followed for a mean of 2.9 years (range 1.1 - 4.7 years) only eight became stronger one of whom died. Assessment of weakness (the major impairment), disability, body weight, creatine kinase and the patient's subjective view of their state were essential to obtaining a clear view of progress.

Adult↗
PubMed2001

Effects of heat and cold application on turns and amplitude in surface EMG.

The purpose of this study was to investigate the effects of cooling and heating of muscles on parameters of surface EMG (SEMG) under various well defined grades of isometric muscle contraction. In 32 healthy volunteers, aged 20-30 years, turns and amplitude (RMS) analysis was done in SEMG from the hand extensors. Muscle strength was defined by a new developed hand dynamometer. Values for RMS and turns in case of maximal voluntary contraction (MVC) over periods of 20 sec were determined for each volunteer and subsequently RMS and turns were measured during isometric contractions of 10%, 30%, 50% and 80% of MVC, interrupted each by rest periods. This procedure was repeated after cooling and warming the forearm with thermo packs. For control purposes the same investigations with three measurement periods of SEMG were done following the same time schedule without thermic stimuli. With increasing isometric contractions turns increased after heat application and decreased after ice application, compared to the values achieved without thermic stimuli. The differences were significant from a level of 30% of MVC (p < 0.05). No corresponding changes were seen for RMS. In the control experiment values of turns and RMS did not differ in the three measurement periods. It is concluded, that the amplitude in SEMG tracings seems to be a reliable parameter of muscle force, whereas turns are sensitive to temperature. They might be useful markers for therapeutic approaches targeted at the muscle.

Adult↗
PubMed2005

Test methods to detect hip and knee muscle weakness and gait disturbance in patients with hip osteoarthritis.

OBJECTIVE: To evaluate test methods for hip and knee muscle weakness and gait disturbance. DESIGN: Test-retest. SETTING: Orthopedic university clinic. PARTICIPANTS: Ten young (age, 36+/-6 y) and 13 elderly (age, 69+/-8 y) healthy volunteers and 11 patients (age, 69+/-8 y) with unilateral hip osteoarthritis (OA) were tested for muscular strength. Twenty-five volunteers (age, 42+/-14 y) underwent gait analysis. INTERVENTIONS: A dynamometer assessing maximal voluntary isometric force of hip and knee muscles and an optosensor walkway detecting limp were developed. Tests evaluated reproducibility and tolerance in patients with OA and elderly subjects. MAIN OUTCOME MEASURES: Relative coefficient of variation (CV%) and force (in newtons). RESULTS: CV% for unilateral strength measurements ranged from 7% to 12% for specific muscle groups. CV% for gait parameters ranged from 4% to 8%, except for the double-support phase. Tests were well tolerated, and no patient had to discontinue because of fatigue. Differences related to sex, age, and disease were detected. CONCLUSIONS: Our dynamometer system provides reliable measurements of hip and knee muscle strength in young and old people, and variation is comparable to previous data. Our photocell technique for gait analysis is reliable in people with normal gait. Both methods are attractive because they are affordable, nonstationary, and easy to use.

Adult↗
PubMed2005

The effects of five-year growth hormone replacement therapy on muscle strength in elderly hypopituitary patients.

OBJECTIVE: Little is known of the long-term effects of GH replacement therapy on muscle strength in elderly adults with adult onset GH deficiency (GHD). In this study, the effects of 5 years of GH replacement therapy on muscle function were determined in adults over 60 years of age with adult onset GHD. DESIGN: A prospective, open-label, single-centre study. Patients Twenty-six (12 male and 14 female) consecutive hypopituitary adults with adult onset GHD, mean age 65.0 (range 61-74) years. MEASUREMENTS: Upper leg muscle strength was measured using a Kin-Com dynamometer. Right and left handgrip strength were measured using an electronic grip force instrument. RESULTS: The mean insulin-like growth factor-I (IGF-I) SD score increased from -1.10 at baseline to 1.21 at end of the study. Body weight was unchanged during the 5-year study. A sustained increase in lean body mass and a sustained reduction of body fat was observed as measured using dual-energy X-ray absorptiometry (DEXA). The GH replacement therapy induced a sustained increase in isometric (60 degrees ) knee flexor strength. After statistical correction for age and sex variables using observed/predicted value ratios, a sustained increase was also observed in concentric knee flexor strength at an angular velocity of 60 degrees /s, concentric knee extensor strength at 60 degrees /s and 180 degrees /s, and peak right handgrip strength. At baseline, knee flexor strength was 90-96% of predicted, knee extensor strength was 85-87% of predicted, and hand-grip strength was 74-80% of predicted values. At study end, knee flexor strength was 98-106% of predicted, knee extensor strength was 90-100% of predicted, and hand-grip strength was 80-87% of predicted values. CONCLUSION: Elderly patients with adult onset GH deficiency had decreased baseline muscle strength also after correction for age and sex. The 5-year GH replacement therapy normalized knee flexor strength and improved, but did not fully normalize, knee extensor strength and handgrip strength.

Absorptiometry, Photon↗
PubMed2002

Normative database of isometric cervical strength in a healthy population.

OBJECTIVES: This was a descriptive study involving maximal and average isometric strength measurements of the cervical musculature. The purpose of this study was 1) to determine the test-retest reliability of a computerized dynamometer for measuring muscular strength of the neck flexor and extensor muscles in a healthy population, and 2) to afford a normative database of the maximal and averaged isometric strength of the cervical flexors and extensors in a healthy population of 94 volunteers. The literature contains only a few descriptive studies pertaining to strength levels of the cervical musculature; none of these studies used a computerized dynamometer to determine cervical isometric strength. Only a few studies include cervical flexor and extensor isometric strength, evaluating its normal ratio as well as their correlation to body mass index. METHODS: Testing was carried out using a computerized dynamometer to measure isometric cervical strength at 0 degrees (neutral), 5 degrees, and 10 degrees of flexion and extension of the neck. RESULTS: Men show approximately 30 to 40% more strength than women both for flexion and extension at all angles and age groups. Neutral positioning showed the maximum strength values for both flexion and extension. CONCLUSION: There was a significant negative correlation between age and cervical strength and a significant positive correlation between weight and strength and between height and strength. However, the flexor/extensor ratio was maintained around 0.6 in all ages.

Adult↗
PubMed1992

Differential muscle strength decline in osteoarthritis of the knee. A developing hypothesis.

The ratio of quadriceps to hamstrings muscle strength (Q/H ratio) is important for the stability of the knee and for protection from excessive stress. The purpose of this study was to explore whether the Q/H ratio is altered in patients with osteoarthritis (OA). Subjects were 43 patients with physician-diagnosed OA of the knee (mean age, 65.61 years; SD, 12.74). Isometric knee flexor and extensor strength was measured with a hand-held dynamometer. Both muscle groups were weak, with relatively greater weakness in the quadriceps muscles. The mean Q/H ratio of 1.43 (SD, 0.39) was below ratios reported for young healthy adults (2.0). The low Q/H ratio might be caused by the inability to correct the measurement for gravity, but a liberal estimate of gravity correction raised the ratio only to 1.71 (SD, 0.47). The low Q/H ratio was probably not caused by physiologic changes due to aging, because the correlation between the ratio and age was low (-0.04). Since the correlation of the Q/H ratio with the usual level of pain (measured by a visual analogue scale) was negative (-0.26), the low ratio might be explained by reflex inhibition due to pain associated with disease.

Adult↗
PubMed1998

Spasticity and strength changes as a function of selective dorsal rhizotomy.

This investigation quantified pre- and postsurgery (8 months) hamstring muscle spasticity and strength in children with cerebral palsy (CP) undergoing a selective dorsal rhizotomy. Nineteen children with CP (CP group) and six children with able bodies (AB group) underwent testing with a dynamometer. For the spasticity measure, the dynamometer measured the resistive torque of the hamstring muscles during passive knee extension at four different speeds. Torque angle data were processed to calculate the work done by the machine to extend the knee for each speed. Linear regression was used to calculate the slope of the line of best fit for the work velocity data. The slope simultaneously encompassed three key elements associated with spasticity (velocity, resistance, and stretch) and was considered the measure of spasticity. For the strength test, the dynamometer moved the leg from full knee extension to flexion while a maximum concentric contraction of the hamstring muscles was performed. Torque angle data were processed to calculate the work done on the machine by the child. Hamstring spasticity values for the CP group were significantly greater than similar values for AB group prior to surgery; however they were not significantly different after surgery. Hamstring strength values for the CP group remained significantly less than those for the AB group after surgery, but were significantly increased relative to their presurgery values. The results of spasticity testing in the present investigation agreed with previous studies indicating a reduction in spasticity for the CP group. The results of strength testing did not agree with those in the previous literature; a significant increase in strength was observed for the CP group.

Journal Article↗
PubMed1982

Intrinsic motor recovery--a long-term study of ulnar nerve repair.

This retrospective study was made in the middle 1970s when 41 patients with ulnar nerve laceration were examined 1 to 6 years after repair by epineurial suture. The original nerve gaps ranged from 1 to 5 cm. Intrinsic motor recovery was measured by clinical muscle testing, and strength assessment by using the Jamar dynamometer and the Osco pinch gauge. Results were expressed as a percentage of normal power. Young patients with high lesions showed variable results, often fairly good. Adults with high lesions never recovered acceptable function. Young patients with low lesions showed excellent results by 2 years. Adults with low sutures usually showed no recovery for 2 years but, on recall examination, were found to have recovered very good intrinsic motor power 2 1/2 to 6 years after repair. There was no clear correlation between the end result and either the delay in repair (up to 6 months) or in the measured nerve gap (maximum 5 cm). The results from the use of different suture materials was not studied except to note no obvious complications resulting from the materials used.

Adolescent↗
PubMed2001

Bone mineral density of visually handicapped women.

While physical activity is an essential factor for muscle performance and development and also for the maintenance of bone mass in the loaded bones, apparently low intensity of physical activity of blind persons may compromise the muscle performance and bone mineral density (BMD). Therefore, the aim was to study whether there are differences in BMD of the weight-bearing or non-weight-bearing bones between visually handicapped persons and those with normal sight. Nineteen visually handicapped premenopausal women and their matched pairs were recruited to the study. The mean age of the visually handicapped women was 39.9 years (SD 8.1) and that of the women with normal vision 39.7 years (6.5). BMD of the distal radius, femoral neck and trochanter was measured with dual energy X-ray absorptiometry (DXA), and isometric muscle strength of the extremities and trunk with a dynamometer. Between-group differences were compared with paired Student's t-test. The BMD at the femur was 8% higher in favour of the group with normal sight, whereas radial BMD was similar in the two groups. The t-score was -1.0 (95% confidence interval -1.5 to -0.5) for the femoral neck BMD and -0.7 (-1.1 to -0.2) for the trochanter BMD in the group with impaired vision. The respective t-scores for the group with normal sight were -0.3 (-0.9 to 0.3) for the femoral neck and 0 (-0.7 to 0.7) for the trochanter. Visual handicap seems to be a risk for lower BMD of the weight-bearing proximal femur, but not for lower BMD of the non-weight-bearing distal radius.

Activities of Daily Living↗