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PubMed2002

Outcomes after trans-tibial amputation: the relationship between quiet stance ability, strength of hip abductor muscles and gait.

BACKGROUND AND PURPOSE: Previous research regarding the symmetry of trans-tibial amputees has examined weight distribution and various gait parameters between prosthetic and sound limbs. However, to date, no known research has determined if asymmetry is present in the strength of the hip abductor muscles or if correlations exist between these categories of symmetry. The purpose of the present study was, therefore, to document asymmetry present in stance, strength and gait measures, and to determine the relationship between these variables. METHOD: Twenty-three elderly, unilateral trans-tibial amputees stood on two adjacent forceplates whilst the weight distribution and standard deviation (SD) of the anterior-posterior and the medio-lateral centre of pressure excursion (COPE) under each limb was recorded during four 40 s trials: quiet stance (QS), with eyes open and eyes closed; and even stance (ES), with eyes open and eyes closed. Gait measures (velocity, cadence, step and stride lengths, stance:swing ratio and period of double support) over 10 m of fast, yet safe walking and measures of the strength of hip abductor muscles were also obtained by use of a stride analyser and a dynamometer, respectively. RESULTS: No significant differences were found between QS and ES measures. However, significantly more weight was taken on the sound limb than on the amputated limb. Notably, more anterior-posterior movement occurred under the sound limb than the amputated limb, with this becoming more apparent with the eyes closed. Movement in the medio-lateral direction was found to be the same between sides. No differences in muscle strength or gait measures between limbs were demonstrated. However, strong hip abductor muscles were correlated with increased weight-bearing on the amputated limb, improved gait parameters and reduced medio-lateral COPE under the amputated limb. CONCLUSIONS: This research confirms the asymmetrical nature of amputee stance and demonstrates symmetry of strength and gait measures between limbs. The correlations between hip abductor muscle strength, weight distribution and gait measures illustrates the importance of pre- and post-operative training of these muscles.

Aged↗
PubMed1994

Comparison of muscle cross-sectional area and strength between untrained women and men.

The cross-sectional areas (CSA) of fat, muscle and bone tissues of the limb as well as maximal voluntary isokinetic strength were measured in untrained men (n = 27) and women (n = 26) aged 18-25 years. Anatomical CSA of the three tissues were determined by ultrasound on the upper arm and thigh. The isokinetic strength of the elbow and knee extensor and flexor muscles were measured by an isokinetic dynamometer (Cybex II) at 1.05 rad.s-1. The women had significantly (P < 0.001) larger fat CSA and smaller bone and muscle CSA than the men in both the upper arm and thigh. Among tissue CSA, the largest difference between the women and men was found in fat CSA regardless of the measurement sites. The sex differences in bone and muscle CSA were found largely in the upper arm compared to the thigh, even when expressed per unit second power of the limb length. Regression analyses of the data for respective samples for the men and women showed significant correlations (r = 0.411-0.707, P < 0.05-P < 0.001) between CSA and strength in all muscle groups except for the elbow extensors of the men (r = 0.328, P > 0.05) and the elbow flexors of the women (r = 0.388, P > 0.05). No significant difference between sexes was observed when strength was expressed per unit of muscle CSA (F.CSA-1) for the elbow flexors and extensors. However, the men showed significantly higher F.CSA-1 than the women for the knee flexors and extensors (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1998

Relationship between age-associated endocrine deficiencies and muscle function in elderly women: a cross-sectional study.

OBJECTIVE: Muscle receptors and selected anabolic effects have been identified for both insulin-like growth factor I (IGF-I) and 1,25-dihydroxyvitamin D (1,25(OH)2D3). The aim of the present study was to test the hypothesis that the decreasing concentrations of these endocrine factors might be involved in the decline in muscle function that characterizes normal human ageing. DESIGN: Cross-sectional study. STUDY PARTICIPANTS: A community-based sample of 245 healthy elderly women aged 70-90 years. Exclusion criteria were diseases or medications known to affect muscle function or the somatotrophic axis. MEASUREMENTS: Knee extension strength was evaluated using an isokinetic dynamometer. A standardized questionnaire was used to assess habitual physical activity. IGF-I and 1,25(OH)2D3 were measured by radioimmunoassay. Vitamin D binding protein (DBP) was measured by single radial immunodiffusion and the free 1,25(OH)2D3 concentration calculated as the molar ratio of total 1,25(OH)2D3 to DBP. RESULTS: The differences in isometric and isokinetic strength over the age range were equivalent to losses of 0.9-2.4% per year. However, no relationship was found between the somatotrophic axis or vitamin D status and knee extension strength, despite markedly decreasing concentrations of circulating IGF-I and free 1,25(OH)2D3 with age. CONCLUSION: Levels of circulating IGF-I and free 1,25(OH)2D3 appear not to be involved in the loss of muscle function that characterizes normal human ageing.

Aged↗
PubMed1998

The effect of passive stretching on delayed onset muscle soreness, and other detrimental effects following eccentric exercise.

The aim of this study was to measure if passive stretching would influence delayed onset muscle soreness (DOMS), dynamic muscle strength, plasma creatine kinase concentration (CK) and the ratio of phosphocreatine to inorganic phosphate (PCr/P(i)) following eccentric exercise. Seven healthy untrained women, 28-46 years old, performed eccentric exercise with the right m. quadriceps in an isokinetic dynamometer (Biodex, angle velocity: 60 degrees.s-1) until exhaustion, in two different experiments, with an interval of 13-23 months. In both experiments the PCr/P(i) ratio, dynamic muscle strength, CK and muscle pain were measured before the eccentric exercise (day 0) and the following 7 d. In the second experiment daily passive stretching (3 times of 30 s duration, with a pause of 30 s in between) of m. quadriceps was included in the protocol. The stretching was performed before and immediately after the eccentric exercise at day 0, and before measurements of the dependent variables daily for the following 7 d. The eccentric exercise alone led to significant decreases in PCr/P(i) ratio (P < 0.001) and muscle strength (P < 0.001), and an increase in CK concentration (P < 0.01). All subjects reported pain in the right m. quadriceps with a peak 48 h after exercise. There was no difference in the reported variables between experiments one and two. It is concluded that passive stretching did not have any significant influence on increased plasma-CK, muscle pain, muscle strength and the PCr/P(i) ratio, indicating that passive stretching after eccentric exercise cannot prevent secondary pathological alterations.

Adult↗
PubMed1997

Muscular strength and bone mineral density in haemodialysis patients.

PURPOSE: The objective of this study was to determine the relationship between muscular strength and bone mineral density (BMD) in patients undergoing regular haemodialysis. METHODS: The BMD was measured in the lumbar spine (L2-L4) and in the proximal femur (femoral neck and trochanter) with dual-energy X-ray absorptiometry DEXA (Lunar DPX). Muscular strength of the extensors, flexors and abductors muscles of the femur (proximal muscles) and the extensors muscles of the back was measured with an isometric dynamometer. Thirty patients, 15 women with a mean age of 33.7 years (18-43) and 15 men with a mean age of 45.5 years (18-65) were included in the study. RESULTS: There was a positive and significant correlation between the BMD of the femoral neck and muscular strength of the flexors (r = 0.490, P < 0.005), the extensors (r = 0.658, P < 0.01) and the abductors muscles of the femur (r = 0.671, P < 0.0008), as well as between the muscular strength of the flexors (r = 0.413, P < 0.02) and extensors muscles of the femur (r = 0.433, P < 0.01) with BMD of the trochanter. There was no correlation between the muscular strength of the back extensor muscles and the BMD of the lumbar spine (r = -0.119, P NS). There was no correlation between the BMD and the number of years of haemodialysis therapy (r = -0.032, P NS), the patient's age (r = -159, P NS), or the value of serum PTH (r = 0.369, P NS) respectively. However, there was a significant correlation between the BMD of the femoral neck with muscular strength (r = 0.602, P < 0.05). CONCLUSION: This study reveals the close relationship that exists between muscular strength of the proximal muscles and the BMD of proximal femur in patients undergoing haemodialysis.

Adolescent↗
PubMed2004

Relationships between muscle strength and bone mineral density of three body regions in sedentary postmenopausal women.

This cross-sectional study was designed to investigate correlations between muscle strength and regional bone mineral density (BMD) in sedentary postmenopausal women. Sixty-two women who ranged in age from 41 to 76 years were investigated. Hip and trunk muscle strength was measured by isokinetic dynamometry. Grip strength of the nondominant hand was measured using a hand-held dynamometer. Bone mineral density of the lumbar spine, femur, and distal radius was measured by dual-energy X-ray absorptiometry. Only the correlation between hip abductor strength and femoral BMD was significant (P = 0.009, r = 0.327). There was no correlation between trunk muscle strength and lumbar vertebral BMD or between grip strength and distal radius BMD. Subjects with osteoporosis (T score < -2.5) or osteopenia T (-2.5 to -1) and normal subjects (T > -1) exhibited similar isokinetic hip and trunk muscle strength. Women with osteoporotic distal radii had significantly lower grip strength than subjects who were osteopenic or normal at this site, but the osteoporotic group was also significantly older. In conclusion, our results indicate that the isokinetic strength of hip abductors weakly correlates with femoral BMD in postmenopausal women with and without osteoporosis. Trunk muscle strength did not correlate with lumbar vertebral BMD in either of these groups. The weaker handgrip we observed in the women with osteoporotic radii may be attributed to older age.

Absorptiometry, Photon↗
PubMed1991

Isokinetic strength aspects of human joints and muscles.

The need to develop objective methods for determining muscle strength has been a major concern in rehabilitation, biomechanics, work physiology, and other related research areas for several decades. Because of the growing need for better standardization and control of resistive exercises in dynamic conditions, not only in clinical but in research settings also (as training/testing devices, and as a method for scientific evaluation of the force-velocity relationship), development of special devices or dynamometers using computerized techniques became relevant. This article examines the perspectives of muscle function with respect to the particular characteristics of strength and velocity in general and to isokinetic strength aspects in particular in human joints and muscles. The "isokinetic" movement condition as a tool for assessing and rehabilitating strength, clinical, and ergonomic applications, and the limitations of the methodology, is critically reviewed.

Animals↗
PubMed1991

Isokinetic and isometric muscle strength combined with transcutaneous electrical muscle stimulation in primary fibromyalgia syndrome.

Twenty women with primary fibromyalgia syndrome and 20 age matched healthy women were investigated. The subjects performed maximum voluntary isokinetic contractions of the right quadriceps in an isokinetic dynamometer. Maximum voluntary isometric contractions of the right quadriceps were performed with superimposed transcutaneous electrical stimulation. The examination protocol was repeated after 1 h of resting. Isokinetic and isometric muscle strength was found to be, respectively, 45% (p = 0.0001) and 44% (p = 0.0001) lower in the patient group compared to the healthy subjects. The frequency of superimposed twitches was 65% in the patient group and 15% in the control group (p = 0.003). Patients with primary fibromyalgia have a lower maximum voluntary muscle strength than expected. The increased presence of superimposed electrically elicited twitches during maximum voluntary contraction indicates submaximal force application in primary fibromyalgia syndrome.

Adult↗
PubMed2002

Neck muscle strength across the sagittal and coronal planes: an isometric study.

OBJECTIVE: To determine the maximal isometric strength of neck muscles across different anatomical positions in the body sagittal and coronal planes. DESIGN: A descriptive study involving maximal isometric strength measurements of the cervical musculature in extension, flexion, and left and right lateral bending. Before measurements, the new device was tested for reliability. BACKGROUND: The literature contains only a few studies on cervical musculature strength assessment. Of these, measurement methods have displayed weak reliability. No studies existed reporting neck strength at various positions in the body coronal plane. METHODS: A new device incorporating local population anthropometry was developed for neck strength assessment on an isokinetic dynamometer. The device's repeatability attributes at measuring the strength of functionally different groups of neck muscles were first evaluated. The isometric apparatus was next used to determine the maximal strength of the cervical musculature of 17 healthy volunteers at different anatomical positions across the body sagittal and coronal motion planes. RESULTS: The results showed good intratester repeatability for intraday and day-to-day studies for all measured parameters. Strength values demonstrated that extensor muscles yielded the greatest torque and that flexor muscles provided the least torque. Linear regression analyses showed strong association of isometric strength with anatomical positions in the two body planes. CONCLUSIONS: Maximal isometric strength of neck muscles in four directions was quantified. Cervical musculature strength levels vary in discernible patterns with head-neck positions and contraction directions. RELEVANCE: Knowledge of normative values of neck muscle strength is essential for designing and implementing appropriate rehabilitation programmes. Results from the present study contribute to such literature.

Adult↗
PubMed2002

Muscle strength as a predictor of onset of ADL dependence in people aged 75 years.

The aim of this prospective study over 5 years was to examine maximal isometric strength of multiple muscle groups as a predictor of losing independence in activities of daily living (ADL). The participants were from the Nordic Research on Aging (NORA75). These analyses are restricted to 567 people who at baseline were independent in ADL and participated in strength tests, and who five years later participated in follow-up ADL assessments. Tests on maximal isometric strength of hand grip, elbow flexion, knee extension and trunk flexion and extension were done using adjustable dynamometers. For each muscle group tested, three equal groups were formed for men and women separately based on distributions of results. Those who reported being unable or needing help for eating, dressing, bathing, toileting, walking indoors or transferring from a bed or a chair were rated as ADL dependent. Of the 227 initially ADL independent men, 21 (9.3%) became dependent in ADL. In women, the figures were 30 (8.8%) of 340. Multiple logistic regression models were used to predict the risk of ADL dependence in groups based on strength tertiles. After confirming that the association of muscle strength and incident ADL-dependence was similar in men and women, both genders were included in the same analyses adjusted for body weight and height, gender and research locality. Gender specific cut-offs were used for strength tertiles. All the strength tests predicted ADL dependence, with those being in the lowest tertile having two to three times greater risks than those in the highest tertile of strength. Further adjustments for chronic diseases did not materially change the results. Strength tests could be used to identify people who are still independent in ADL but who are at increased risk of becoming dependent because of poor muscle strength, and who could reduce their risk by strengthening exercises.

Activities of Daily Living↗
PubMed1996

Force analysis of rotator cuff muscles.

A 3-dimensional static biomechanical model of the glenohumeral joint was used to investigate rotator cuff muscle forces during maximal isometric exertions (abduction, adduction, internal rotation, and external rotation) and static arm elevation. Muscle moment arms and cross sectional areas were determined from studies of cadaveric specimens, and maximal isometric strength data were collected using a Cybex II dynamometer. Predicted posterior deltoid forces were very low during abduction in the scapular plane. The model predicted the highest rotator cuff muscle forces during maximal internal rotation (subscapularis) and external rotation (infraspinatus, teres minor, and supraspinatus) exertions. The results indicate that abduction exertions may not produce the greatest loads on the supraspinatus tendon, and that analyses of arm elevation may underestimate the potential loads on the rotator cuff. The strong effect of external rotation exertions on supraspinatus and infraspinatus forces suggest that ergonomic efforts to prevent rotator cuff disease should include reduction of internal rotation loading on the arm. Moreover, it may be important to include warnings about external rotation exertions, in addition to arm elevation, in patient education.

Adult↗
PubMed1994

A strength training program for postmenopausal women: a pilot study.

This pilot study examined a specific exercise program designed for skeletal muscle strengthening in postmenopausal women. The program consisted of patterns of movement using diagonal and spiral patterns, superimposed on a progressive weight-bearing sequence from prone lying to standing. Progressive resistance was provided with the use of progressively thicker elastic straps. Eighteen of an initial 22 healthy volunteer women aged 50 to 64 years completed 8 weekly hour-long group exercise sessions supplemented with twice weekly sessions at home to pilot test the program's safety, acceptability, and effectiveness in changing muscle strength. A physical therapist conducted baseline and final quadriceps, hamstrings, and grip strength assessments using a portable isokinetic dynamometer. Participants achieved a 21% increase in quadriceps (p < or = .001), 9% increase in hamstrings (p < or = .07), and a 14% increase in grip strength (p < or = .002). A positive dose-response relationship was observed between strength gains and compliance with the program. This approach to strength training in postmenopausal women is feasible and effective in increasing muscle strength. It has considerable promise and deserves further testing and evaluation.

Biomechanical Phenomena↗
PubMed1998

The side-to-side differences of bone mass at proximal femur in female rhythmic sports gymnasts.

This cross-sectional study examined the side-to-side differences of the bone mineral density (BMD) at proximal femora in female rhythmic sports gymnasts (RSGs). The hypothesis on which the study is based is that gymnasts use a different leg in take-off (left leg) and in landing (right leg) and therefore differ in the loading for the left and right legs. The gymnasts made up two groups: the regular group, which consisted of 15 regular players who had trained for about 28 h/week, and the substitutes group, which consisted of 8 substitute players who had trained for about 12 h/week. The control group consisted of 10 nonathletic college women who had not participated in any kind of regular sports activity. BMD (g/cm2) was measured in three hip sites using the XR-26 dual-energy X-ray absorptiometer scanner. Muscle strength at knee extensors (EXT) and flexors (FLX) was examined using an isokinetic dynamometer (CYBEX6000), and the vertical ground reaction force was determined with a force platform during take-off and landing movements. In the regular players, the BMDs of the left leg were significantly higher than those of the right leg at the femoral necks, greater trochanters, and Ward's triangles (p < 0.01 to approximately 0.005). The side-to-side differences were 4.7 to approximately 9.6%. Regarding the strength parameters, the left side was greater than the right side significantly at EXT 60 degrees/s (p < 0.01), although the overall side-to-side difference was small. In the substitutes, the BMDs at the three sites mentioned above were also higher in the left leg than the right, but the side-to-side difference was statistically significant only at Ward's triangles (93%, p < 0.05). The side-to-side difference of strength was not significant. In the controls, there were small left-to-right differences of the BMDs, ranging from -1.8 to 0.5%, which was significantly lower than in the regular players at each site. The overall average strength measurements were larger in the right leg than in the left except at the 120 degrees/s. The side-to-side difference was statistically significant at EXT 30 degrees/s and 60 degrees/s (p < 0.05). The peak force was greater in take-off than in landing, and the unit time force during take-off was significantly greater than that during landing (p < 0.001). In conclusion, regarding the side-to-side difference of the BMD at proximal femora, our results demonstrate: that the left leg for take-off had higher measurements than the right leg for landing in both gymnasts' groups, which accounts for the vertical ground reaction force during take-off being greater than that during landing; that the difference in the regular players group was greater than that in the substitute group, which can be explained because the regular players practiced much more than the substitutes did; and that there was no difference in the control group.

Adolescent↗
PubMed1991

A cross-sectional study of muscle strength and mass in 45- to 78-yr-old men and women.

The isokinetic strength of the elbow and knee extensors and flexors was measured in 200 healthy 45- to 78-yr-old men and women to examine the relationship between muscle strength, age, and body composition. Peak torque was measured at 60 and 240 degrees/s in the knee and at 60 and 180 degrees/s in the elbow by use of a Cybex II isokinetic dynamometer. Fat-free mass (FFM) was estimated by hydrostatic weighing in all subjects, and muscle mass (MM) was determined in 141 subjects from urinary creatinine excretion. FFM and MM were significantly lower (P less than 0.001) in the oldest group. Strength of all muscle groups at both testing speeds was significantly (P less than 0.006) lower (range 15.5-26.7%) in the 65- to 78- than in the 45- to 54-yr-old men and women. When strength was adjusted for FFM or MM, the age-related differences were not significant in all muscle groups except the knee extensors tested at 240 degrees/s. Absolute strength of the women ranged from 42.2 to 62.8% that of men. When strength was expressed per kilogram of MM, these gender differences were smaller and/or not present. These data suggest that MM is a major determinant of the age- and gender-related differences in skeletal muscle strength. Furthermore, this finding is, to a large extent, independent of muscle location (upper vs. lower extremities) and function (extension vs. flexion).

Adipose Tissue↗
PubMed1996

Normal insulin release during sustained hyperglycaemia in hypokalaemic periodic paralysis: role of the potassium channel opener pinacidil in impaired muscle strength.

1. Hypokalaemic periodic paralysis is characterized by attacks of muscle weakness. Glucose, insulin and an abnormal regulation of ATP-sensitive potassium channels may be involved in these attacks. We studied the effect of hyperglycaemia and of the potassium channel opener pinacidil on insulin release and muscle strength in patients with hypokalaemic periodic paralysis. 2. Insulin release was assessed on two occasions in four patients with hypokalaemic periodic paralysis and in eight matched control subjects, with and without treatment with 25 mg pinacidil orally, during a hyperglycaemic glucose clamp at a blood glucose level of 10 mmol/l, in a placebo-controlled, double-blind study. Muscle strength was measured in the hypokalaemic periodic paralysis patients before and during hyperglycaemia using a handheld dynamometer. 3. During the clamp, the mean glucose concentration (10-180 min) in control subjects was 9.9 +/- 0.07 and 10.0 +/- 0.03 mmol/l with and without pinacidil respectively, and in patients with hypokalaemic periodic paralysis was 10.0 +/- 0.04 and 10.1 +/- 0.06 mmol/l respectively (not significantly different). In both groups, the areas under the insulin curve from 0 to 10 min (first-phase insulin release) and from 30 to 180 min (second phase) were not different on the pinacidil study day compared with on the placebo day. The areas under the insulin curve of the first and second phases also did not differ between control subjects and patients with hypokalaemic periodic paralysis (with or without pinacidil). The M/I ratio, a measure of insulin sensitivity, was not different in the two groups. On the placebo day, baseline muscle strength in patients with hypokalaemic periodic paralysis was 165 +/- 16 N for the hip abductors and 168 +/- 19 N for the knee flexors. During the period of hyperglycaemia on the placebo day, muscle strength did not decrease in either muscle group. On the pinacidil study day, an increase in muscle strength was found only in the two hypokalaemic periodic paralysis patients with the lowest mean muscle strength (< 150 N) on the placebo day. The two hypokalaemic periodic paralysis patients with a mean muscle strength on the placebo day > 150 N showed no increase in muscle strength with pinacidil. 4. Insulin secretion and sensitivity were normal in patients with hypokalaemic periodic paralysis. Hyperglycaemia during hyperglycaemic clamping did not provoke paralytic attacks and did not result in a decrease in muscle strength. The potassium channel opener pinacidil had no effect on insulin secretion in hypokalaemic periodic paralysis patients or in normal subjects. Pinacidil may enhance muscle strength in those hypokalaemic periodic paralysis patients who suffer partial paralytic attacks.

Adult↗
PubMed1999

Upper motor neuron lesions: their effect on muscle performance and appearance in stroke patients with minor motor impairment.

OBJECTIVE: To evaluate muscular performance and appearance in patients with prior stroke who were ambulatory. DESIGN: Nonrandomized study. SETTING: University hospital laboratory. SUBJECTS: Sixteen persons (11 men, 5 women) with minor motor impairments, 6 to 24 months after stroke, were included. As reference, data were used from a population-based sample of 144 men and women. MAIN OUTCOME MEASUREMENTS: Muscle performance was evaluated using a Kin-Com dynamometer in both the affected and the nonaffected leg. Peak isometric strength was measured at a 60 degree angle in both extension and flexion. Maximal isokinetic strength was measured at 60 degrees/sec and at 180 degrees/sec. Endurance was evaluated during isometric and dynamic knee extensions. Muscle biopsies were taken on nine patients and muscle tissue areas were determined with computed tomography. RESULTS: The affected leg was weaker but not different in relative endurance compared with the nonaffected side. The performance of the nonaffected side was somewhat lower than that of a matched reference population. No major difference in fiber composition between the affected and nonaffected legs was noted, except for a lower degree of capillarization in the affected leg. CONCLUSION: In well-functioning stroke patients with good motor performance, further muscle training that includes resistance exercise might be indicated.

Adult↗