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PubMed1999

[Muscle strength after surgical treatment of ruptures of the long biceps tendon by refixation to the short head].

Operative treatment for ruptures of the long biceps tendon still is discussed controversially. In the present literature surgical repair is advised for sporting and high demand patients due to favourable functional results and low loss of strength. Until now only few objective and reproducible results were published. In the present literature the keyhole-technique is recommended due to favourable bio-mechanical conditions. To evaluate postoperative strength 19 patients were investigated after an average follow-up of 6.5 years, by clinical examination and isokinetic measurement. Compared with the non-operated shoulder isokinetic determination of isometric maximal peak torque and strength during concentric stress for elbow-flexion, shoulder-abduction and shoulder-flexion yield to almost identical results for the operated shoulder. According to the criteria of the Constant-Score all patients achieved very good and good results. Refixation to the short head can be advised for treatment of ruptures of the long biceps tendon due to the certain technique with a low complication rate and very good functional outcome.

Adult↗

PubMed1991

Ambulatory outcome of children with myelomeningocele: effect of lower-extremity muscle strength.

The relationship between patterns of strength and mobility was studied in 291 children with myelomeningocele, graded as community ambulators, partial (household) ambulators and nonambulators. Iliopsoas strength was found to be the best predictor of ambulation, with the quadriceps, anterior tibialis and glutei also contributing significantly. Grade 0 to 3 iliopsoas strength was always associated with partial or complete reliance on a wheelchair. No patient with grade 4 to 5 iliopsoas and quadriceps function relied completely on wheelchairs and the majority were community ambulators. Grade 4 to 5 gluteal and anterior tibialis function was associated with community ambulation, without aids or braces. Deterioration in mobility was most common in those with strong iliopsoas/quadriceps and grade 0 to 3 gluteus medius, and was not age-related.

Adolescent↗

PubMed2003

Electrical stimulation of gluteus maximus in children with cerebral palsy: effects on gait characteristics and muscle strength.

The purpose of this study was to determine whether electrical stimulation of the gluteus maximus would improve hip extensor strength, decrease excessive passive and dynamic internal hip rotation, and improve gross motor function in children with cerebral palsy (CP). Twenty-two ambulant children (15 females, 7 males, mean age 8 years 6 months, SD 2 years 9 months, aged 5 to 14 years) with diplegic (n = 14), hemiplegic (n = 7), and quadriplegic (n = 1) CP participated in this study. All were randomly assigned to either the stimulation or control group. The stimulation group (n = 11) received electrical stimulation of the gluteus maximus of the most affected legs for 1 hour a day, 6 days a week for a period of 8 weeks. Electrodes were applied proximally and distally over the gluteus maximus, with the active electrode initially positioned over the motor points. The control group (n = 11) did not receive any extra treatment. Measurements of hip extensor strength, gait analysis, passive limits of hip rotation, and section E of the Gross Motor Function Measure were made before and after treatment for both groups. Subjectively, 7 of the 11 parents thought that the treatment made a difference to their child. However, no statistically or clinically significant improvement was found in the stimulation group when compared with the control group.

Adolescent↗

PubMed1989

Quantitative muscle strength testing: a comparison of job strength requirements and actual worker strength among military technicians.

In this study the authors investigate the percentage of mismatch between job demands and worker physical capacity in Utah National Guard mechanics. This population had demonstrated a higher incidence of low back trouble than other job descriptions reviewed. The authors utilized onsite still and videotape photography and a computerized biomechanical strength prediction model to assess loads on the lumbosacral spine due to various job tasks. Job demands were then compared to the actual physical capacity of the individual workers based on static strength testing in job-related positions. A load cell on the testing apparatus entered the force generated into a computer which averaged the force of the last three seconds of a five-second lift. It was determined that as much as a 38% mismatch existed within this population for some job tasks which these workers were exposed to. Suggestions for preventing job-related low back cumulative trauma disorders are presented, including: engineering redesign, worker selection programs, work hardening, and others.

Back Pain↗

PubMed1997

Effects of high-intensity resistance exercise on bone mineral density and muscle strength of 40-50-year-old women.

OBJECTIVE: The purpose of the study was to determine the effect of six months of heavy resistance training (weightlifting) on the bone density of premenopausal women. EXPERIMENTAL DESIGN: A 6-month prospective design with random assignment to groups. SETTING: Measurements of bone mineral density (BMD) were obtained from the Radiology Clinic at North Carolina Memorial Hospital. Exercise sessions were completed in the Physical Education Department facilities at the University of North Carolina, Chapel Hill, NC. PARTICIPANTS: Thirty-five premenopausal women, 40-50 years of age, were randomly assigned to either a resistance training (RT) and sedentary control (CON) group. The study finished with 12 women exercising and 14 in the control group. INTERVENTION: The resistance training consisted of three days per week of high-intensity weightlifting specifically designed to place strain on the spine and hips. MEASURES: Bone density of the lumbar vertebrae, femoral neck, and distal radius, were determined prior to and at the end of the exercise program using dual energy X-ray absorptiometry (DEXA). RESULTS: Resistance-training produced strength gains: overhead press = 125%, leg press = 86%, and calf raises = 91% (p < 0.001). RT tended to increased lumbar BMD 1.03%, while the CON decreased 0.36% (p = 0.072). Both groups lost radial BMD (CON = -0.45%; RT = -1.04%). Both groups gained femoral neck BMD (CON = 1.26%; RT = 1.22%). CONCLUSIONS: These results suggest that even a short-term weight training program can either maintain or improve the BMD of the femoral neck and lumbar vertebrae in premenopausal women.

Absorptiometry, Photon↗

PubMed2005

Gender-related changes in body composition, muscle strength and power output after a short-term multidisciplinary weight loss intervention in morbid obesity.

Obese men and women have notably different body composition, which contributes to a different functional motor impairment, but it is unknown whether they respond differently to the same intervention for body weight (BW) reduction and motor capability improvement. The aim of this investigation was to compare changes in body composition, strength production and power output observed in severely obese men and women after a BW reduction intervention, and to test the hypothesis that changes in body composition may be related to changes in motor functionality. Ninety-five obese men and women of the same age (29.3 +/- 7.0 SD yr) and body mass index (41.2 +/- 4.4 kg/m2) participated in a short-term (3 week) mass reduction program (5 days/week) entailing exercise (aerobic and strength training) and energy-restricted diet. BW and body composition, maximum voluntary total isotonic strength (ST), and maximum leg power output (W) were evaluated before and after the program. After the intervention, BW decreased significantly in both men and women, but males lost a significantly higher amount of their initial BW than females (5.12 +/- 0.91 vs 4.27 +/- 1.42%, p<0.01). In men the BW loss was composed by a similar amount of fat mass (FM) and fat-free mass (FFM), whereas women lost FM almost entirely. Both men and women significantly improved ST after the intervention, but no difference in improvement was detected between genders, while W increased significantly in females (p<0.001), and no change was detected in males, although W per unit BW and FFM increased significantly in both genders (p<0.05-0.001). In spite of the positive correlation of ST and W with FFM (p<0.001), there was no detectable relation between the changes in body composition and those in motor performance, the improvement in ST and W being better attributable to factors other than muscle mass change. The present diet/exercise intervention induced significant effects on BW changes and composition as well as on ST and W, with a different impact in males and females.

Adult↗

PubMed1988

Electro-mechanical response times and muscle strength after sleep deprivation.

This study examined the effect of 60 h of sleep deprivation (SD) on electromechanical response times (EMRT), maximal voluntary isometric contraction (MVC), rate of force development (RFD), and times required to reach various percentages of MVC, during a maximal voluntary isometric contraction of both the forearm flexors and leg extensors. Eleven male subjects were either sleep deprived for 60 h (E) or performed similar daily activities and slept 7 h per night (C). Performance variables were evaluated at the same time intervals during both conditions. No significant differences were observed between the E and C conditions for EMRT (pre-motor time, electro-mechanical delay, total reaction time) or muscular performance (MVC, RFD). The results suggest that subjects who have undergone 60 h of SD can react as fast, and with as much force, as those who have had 7 h of sleep per night.

Adult↗

PubMed1990

Reproducibility of isokinetic muscle strength measurements in normal and arthritic individuals.

The serial reproducibility of an individual's isokinetic torque was assessed in order to establish a reliable baseline value for future comparison. Thirty-two controls and twenty arthritic patients were tested for their peak isokinetic torque on knee flexion and extension and hip flexion at three velocities on five occasions, at fortnightly intervals. The first test was found to provide a reliable baseline for controls and subjects who could generate a peak torque of 54 Newton meters (Nm) or more. The second test was found to be more representative of the series for groups containing weaker subjects. Variation related to torque: for subjects who generate a peak torque of 54 Nm or more, a range of +/- 20% accommodates the variability of 95% of tests. We conclude that a +/- 20% range applied to either the first or second test, depending on the nature of the group to be studied, serves as a representative baseline value.

Aged↗

PubMedDate not supplied

A digital test for pelvic muscle strength in women with urinary incontinence.

This article reports further experience with a Version 2 digital test performed on 208 community-residing women, 25 to 87 years old. Test-retest (n = 208) and interrater reliability (n = 36) scores for pressure, displacement, and duration were r = .54, .51, and .53 and r = .67, .73, and .55, respectively. Interrater reliability percentage agreement figures were exact for 94% of the women on pressure and 67% on displacement. With duration permitted to vary by 1 second, agreement was 75%. Validity was tested using vaginal electromyography scores with correlation coefficients ranging from .37 to .63. A weak but significant correlation was found between the digital score and the stand-up test pad gain (r = -.12). No significant relationship was found between the digital test and a history of being able to stop the urine stream or other leakage measures. To address limitations in Version 2, a third version of the digital scale is proposed.

Adult↗

PubMed1992

Effect of yoga training on reaction time, respiratory endurance and muscle strength.

There is evidence that the practice of yoga improves physical and mental performance. The present investigation was undertaken to study the effect of yoga training on visual and auditory reaction times (RTs), maximum expiratory pressure (MEP), maximum inspiratory pressure (MIP), 40 mmHg test, breath holding time after expiration (BHTexp), breath holding time after inspiration (BHTinsp), and hand grip strength (HGS). Twenty seven student volunteers were given yoga training for 12 weeks. There was a significant (P < 0.001) decrease in visual RT (from 270.0 +/- 6.20 (SE) to 224.81 +/- 5.76 ms) as well as auditory RT (from 194.18 +/- 6.00 to 157.33 +/- 4.85 ms). MEP increased from 92.61 +/- 9.04 to 126.46 +/- 10.75 mmHg, while MIP increased from 72.23 +/- 6.45 to 90.92 +/- 6.03 mmHg, both these changes being statistically significant (P < 0.05). 40 mmHg test and HGS increased significantly (P < 0.001) from 36.57 +/- 2.04 to 53.36 +/- 3.95 s and 13.78 +/- 0.58 to 16.67 +/- 0.49 kg respectively. BHTexp increased from 32.15 +/- 1.41 to 44.53 +/- 3.78s (P < 0.01) and BHTinsp increased from 63.69 +/- 5.38 to 89.07 +/- 9.61 s (P < 0.05). Our results show that yoga practice for 12 weeks results in significant reduction in visual and auditory RTs and significant increase in respiratory pressures, breath holding times and HGS.

Adolescent↗

PubMed2001

Neural adaptations to fatigue: implications for muscle strength and training.

PURPOSE: This paper investigates the neural mechanisms responsible for the increase in strength that occurs during serial isometric contractions. METHODS: A three-session design was used. Thirteen subjects (N = 13) were asked to perform five maximal isometric elbow extension strength trials to serve as baseline. After a 5-min rest, the subjects were administered a 30-trial fatigue protocol. This process was repeated two more times at 2-wk intervals. Elbow extension torque and surface electromyography (EMG) of the triceps and biceps brachii were monitored concurrently. The criterion measures were elbow extension torque, root-mean-square EMG amplitude, and mean power frequency (MPF). RESULTS: Intraclass reliability ranged from good to excellent. Within each experimental session, the fatigue protocol resulted in a decrease in maximal isometric elbow extension torque as well as biceps and triceps EMG amplitude and MPF (P < 0.05). However, the mean of the 30 trials and the magnitude of the linear decrease in elbow extension torque increased across the three sessions (P < 0.05). Biceps and triceps EMG amplitude increased and MPF decreased as the number of sessions increased (P < 0.05). CONCLUSIONS: These findings suggest that the fatigue protocol served as a training stimulus to down regulate motor-unit firing frequency.

Adult↗

PubMed2003

Perceived exertion and maximal quadriceps femoris muscle strength during dynamic knee extension exercise in young adult males and females.

The objectives of the present study were to: (1) examine perceived exertion across different target voluntary-contraction intensities; (2) compare perceived exertion ratings with actual target intensities, and (3) compare perceived exertion ratings between males and females. Subjects for this study included 30 healthy, college-aged male (n=15) and female (n=15) volunteers. All subjects were free of orthopedic, cardiopulmonary, systemic and neurological disease. Subjects were evaluated for their one-repetition maximum (1-RM) during inertial knee extension exercise. All subjects then completed, in a random order, two sub-maximal inertial contractions at 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% of their 1-RM. Perceived exertion was measured by asking subjects to provide a number that corresponded to the feelings in their quadriceps after completion of the two repetitions, by viewing a modified category-ratio (CR-10) scale. The results showed that males lifted a significantly greater absolute (P<0.05) and relative (P<0.05) amount of mass than females; allometric-modeled strength values also demonstrated significant sex differences. The results revealed a significant intensity main effect (P<0.001) but no significant gender main effect (P=0.97) nor intensity-by-gender interactions (P=0.50) for the perceived exertion responses. The findings demonstrated that perceived exertion was significantly (P<0.05) lower than the specific expected values on the CR-10 scale from 10% to 60% of 1-RM, but was not different from 70% to 90% 1-RM. The results revealed that the increase in perceived exertion was fit to both linear and quadratic trends, and that the exponent of the power function was found to be 1.437 (SD 0.22) for the males, and 1.497 (0.295) for the females. The major findings demonstrate that although males were able to lift more absolute and relative mass than females, the perceptual response to relative load was similar between genders. The increase in perceived exertion, as a function of relative load, showed a strong linear trend; however, enhanced perceptual sensitivity at high contraction intensities was evident from the positively accelerating power function.

Adult↗

PubMedDate not supplied

Bone mineral density and muscle strength of lower extremities after long-term strength training, subsequent knee ligament injury and rehabilitation: a unique 2-year follow-up of a 26-year-old female student.

Physical training is shown to have potential to increase the mass of healthy bones. In contrast, immobilization, used as a treatment of soft tissue and bone injuries, is shown to result in atrophy of these tissues. In this unique 26-month follow-up of a 26-year-old female student, we determined the effects of a 1-year strenuous unilateral lower limb strength training and subsequent anterior cruciate ligament (ACL) rupture on bone mineral density (BMD) of lumbar spine and lower extremities (femoral neck, distal femur, patella, proximal tibia, calcaneus), measured repeatedly (11 times) by dual-energy X-ray absorptiometry (DXA). Also, the strength and functional characteristics of the lower extremities were repeatedly examined. This prospective study strikingly demonstrated the deleterious effects of an ACL rupture on the BMD of the affected limb in contrast to beneficial but modest effects of the preceding controlled training. The site-specific increases in the BMD were 1.8-3.1% during the training. The posttraumatic decrease in the BMD of the injured knee was rapid and corresponded to approximately 2 SD (approximately 20%) observed in the age- and sex-matched population. A year after the injury, the subject's knee function and muscular performance as well as the usage of the injured limb were completely recovered, but the site-specific BMDs were still approximately 1 SD below the subject's baseline BMD, although continuously increasing. This study suggests that considerable posttraumatic osteopenia at the affected bone sites occurs quickly regardless of appropriate preventive and rehabilitative actions, and the time needed for steady-state and recovery will be long.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗

PubMed1991

Effect of negative pressure ventilation on arterial blood gas pressures and inspiratory muscle strength during an exacerbation of chronic obstructive lung disease.

The effects of intermittent negative pressure ventilation have been studied in 20 patients with chronic obstructive pulmonary disease during an exacerbation of their disease. Measurements of arterial blood gas tensions and maximal inspiratory pressure (MIP) were performed before and after six hours of negative pressure ventilation or standard treatment (control day) given in random order on two consecutive days. After negative pressure ventilation the mean (SD) value of MIP increased from 68.1 (21.5) to 74.8 (20) cm H2O;* arterial oxygen tension (PaCO2) fell from 60.6 (12.2) to 50.9 (8.9) mm Hg* but PaO2 changed little (from 48.4 (7.4) to 47.6 (8.2) mm Hg). There were no significant changes on the control day in arterial blood gas tensions (PaO2 47.8 (8.1) and 48.9 (9.4) and Paco2 59.8 (10.9) and 57.5 (8.06) mm Hg) or in MIP (69.4 (22.4) and 70.9 (22.9) cm H2O). Six patients tolerated negative pressure ventilation poorly and these patients showed less improvement after negative pressure ventilation. Our results suggest that intermittent negative pressure ventilation can increase alveolar ventilation in patients with an exacerbation of chronic obstructive lung disease, particularly in those who tolerate the procedure well. Most subjects showed a fall in PaCO2 and an increase in MIP. The fact that PaO2 was unchanged despite the fall in PaCO2 suggests that gas exchange may deteriorate with negative pressure ventilation in these patients.

Aged↗

PubMed2005

Differences in thoracic kyphosis and in back muscle strength in women with bone loss due to osteoporosis.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To determine if thoracic kyphosis was different in older women grouped based on their bone mineral density (BMD) and back extensor strength (BES), and to determine if an association between and these variables exist. SUMMARY OF BACKGROUND DATA: Changes in kyphosis might be related to back extensor weakness in patients with osteoporosis. Disproportionate weakness in back extensor musculature considerably increases the possibility of deformities in the fragile osteoporotic spine. METHODS: A total of 189 female subjects 50 to 80 years of age were grouped by their BMD and additionally by their BES. All were evaluated for thoracic kyphosis, maximal isometric strength of the back extensors, and BMD of the lumbar spine and the hip. RESULTS: There was no significant difference in thoracic kyphosis among all groups. Multivariate analyses of BES and BMD showed that only BES might influence thoracic kyphosis (P = 0.02). There was no correlation between BES and BMD. Statistically significant deficit in BES was observed only between the osteoporotic and osteopenic group (P < 0.05). The importance of BES in maintaining posture was observed when the study population was divided according to their BES level. With respect to thoracic kyphosis and BMD values, there were no statistical differences between strong women (BES more than 60 N) and those with medium BES (BES between 60 and 35 N). But the weakest group (BES less then 35 N) had significantly higher (P < 0.05) mean values of thoracic kyphosis in comparison to strong women (BES more than 60 N) and those with medium BES (BES between 60 and 35 N). CONCLUSION: The severity of thoracic kyphosis may be influenced especially by changes in BES. Therefore, provision of strong, natural extrinsic support for the spine seems to be important to decrease the incidence of spinal deformity.

Aged↗

PubMed1999

Effects of training and creatine supplement on muscle strength and body mass.

The purpose of this study was to test the effect of creatine supplement on the size of the extra- and intracellular compartments and on the increase of isokinetic force during a strength training-program. Twenty-five healthy male subjects (age 22.0+/-2.9 years) participated in this experiment. Seven subjects formed the control-group. They did not complete any training and did not have any dietary supplement. The eighteen other subjects were randomly divided into a creatine- (n = 8) and a placebo-group (n = 10). They were submitted to a controlled strength-training program for 42 days followed by a detraining period of 21 days. Creatine and placebo were given over a period of 9 weeks. The size of the body water compartments was assessed by bioimpedance spectroscopy and the isokinetic force was determined during a single squat by means of an isokinetic dynamometer. These measurements were completed beforehand, at the end of the training period, and after the determining period. Both placebo- and creatine-group increased the isokinetic force by about 6% after the training period, showing that creatine ingestion does not induce a higher increase of the force measured during a single movement. No change in body mass was observed in the control- and placebo-groups during the entire experiment period while the body mass of the creatine-group was increased by 2 kg (P < 0.001). This change can be attributed partially to an increase (P = 0.039) in the body water content (+1.11), and more specifically, to an increase (P < 0.001) in the volume of the inter-cellular compartment (+0.61). Nevertheless, the relative volumes of the body water compartments remained constant and therefore the gain in body mass cannot be attributed to water retention, but probably to dry matter growth accompanied with a normal water volume.

Adult↗

PubMed2006

Study of respiratory muscle strength, vital capacity, and ventilometry in the postoperative period of spinal surgery by posterior access.

STUDY DESIGN: Prospective. OBJECTIVE: To analyze tidal volume (TV), minute volume (VE), respiratory frequency (f), vital capacity (VC), maximal inspiratory (PImax), and expiratory (PEmax) pressures in patients submitted to spinal surgery for tumor or herniated disc by posterior access, and to investigate a possible association of respiratory function with surgery duration, site of surgical access, and diagnosis. SUMMARY OF BACKGROUND DATA: A reduction in pulmonary volumes is usually seen in patients submitted to thoracic or upper abdominal surgery, and recent studies have demonstrated such alterations during the postoperative period in patients submitted to craniotomy. METHODS: A total of 45 patients (mean age, 42 +/- 14 years) were submitted to spinal surgery in an University Hospital, and TV, VC, MV, f, PImax, and PEmax were measured in the preoperative period, and in the first and second postoperative days. RESULTS: Patients submitted to spinal surgery showed a decrease in the first and second postoperative days in VC, respectively (17% and 10%), TV (18% and 13%), PImax (17% and 12%), PEmax (12% and 7%), and an increase in f (18% and 12%) (P < 0.05). Reduction in TV, VC, PImax, and PEmax and the increase in f were associated with surgical time > or =240 minutes, diagnosis of tumor, and cervicothoracic surgical access (P < 0.05). CONCLUSIONS: Alterations in the respiratory function in the postoperative period of elective spinal surgery by posterior access for tumor removal or herniated disc were related to surgical time > or =240 minutes, tumor, or cervicothoracic surgical access.

Adolescent↗

PubMed1992

A factor analysis of dyspnea ratings, respiratory muscle strength, and lung function in patients with chronic obstructive pulmonary disease.

The purpose of this study was to demonstrate that clinical ratings of dyspnea and physiologic function are separate dimensions underlying the pathophysiology of chronic obstructive pulmonary disease (COPD). We used principal-components factor analysis to confirm these dimensions using data collected prospectively in 86 symptomatic patients with COPD. Three different instruments were used to rate dyspnea: a modified Medical Research Council (MRC) scale, the oxygen cost diagram (OCD), and the baseline dyspnea index (BDI). Measures of physiologic function included standard spirometric measures (forced vital capacity [FVC] and forced expiratory volume in one second [FEV1]) and maximal inspiratory (PImax) and expiratory (PEmax) mouth pressures. Age of the 65 male and 21 female subjects was 62.9 +/- 1.2 yr (mean +/- SEM). All three clinical scales were significantly correlated with physiologic function (range of r values, 0.32 to 0.45; p less than 0.05), except for the relationship between the MRC scale and PEmax (r = -0.14; p = NS). The factor analysis yielded three factors that accounted for 71.9% of the total variance of the data: clinical ratings of dyspnea (MRC scale, OCD, and BDI) loaded on the first factor; maximal respiratory pressures and gender loaded on the second factor; and lung function and age loaded on the third factor. Additional post hoc factor analysis provided similar results when the sample was divided into two subgroups by randomization, by severity of dyspnea ratings, or by severity of airflow obstruction. We conclude that dyspnea ratings, maximal respiratory pressures, and lung function are separate factors or quantities that independently characterize the condition of patients with COPD.(ABSTRACT TRUNCATED AT 250 WORDS)

Dyspnea↗