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PubMed1989

[The effect of anabolic androgenic steroids on muscle strength, body weight and lean body mass in body-building men].

A review of the effects of anabolic-androgenic steroids (AAS) on muscle strength, body weight and lean body mass in body-building men is presented. In about half of the placebo-controlled studies, a significant effect on the above mentioned response variables is found. In all cases where an effect was achieved, the drug used was methandrostenolone or stanozolol. Whether this is connected with a special quality of these AAS or whether the negative results achieved with the other AAS are caused by type 2 error is not yet known. The use of AAS as ergogenic drugs must be deprecated because of their marginal effects, the risks of side effects and the unsporting, unethical aspects.

Adult↗
PubMed1998

Changes in muscle strength properties caused by harvesting of autogenous semitendinosus tendon for reconstruction of contralateral anterior cruciate ligament.

A prospective study was conducted of how the muscle strength of the donor knee is affected by harvesting of the autogenous semitendinosus tendon (St) for use as a substitute graft material in cruciate ligament reconstruction. There were 25 patients from whom only the St was harvested from the contralateral (i.e., healthy/donor) knee. Using a Biodex System II (Biodex, New York, NY), the strength of the donor knee was measured during both extension and flexion, both before and 12 months after the tendon harvesting procedure. A comparative study was made of the preharvest and postharvest values for the peak torque and peak torque angle in the isokinetic contraction. There were no statistically significant differences between the preharvest and postharvest peak torque values of the donor knee. However, the peak torque angle decreased significantly after the tendon harvest; the range of the mean decrease was from 11.7 degrees to 15.0 degrees. This indicates that there was a change to a small flexion angle (P < .05). After the tendon harvest, regardless of the applied angular velocity, more than 80% of the cases showed a change of torque curve shape in which there was no peak in the latter half, and the position of the peak was shifted to the left. In conclusion, the results of this study indicate that harvesting of the autogenous St does not affect the peak torque, but the peak torque angle during flexion of the donor knee is reduced.

Adolescent↗
PubMed2002

Use of inspiratory muscle strength training to facilitate ventilator weaning: a series of 10 consecutive patients.

BACKGROUND AND PURPOSE: We instituted a low-repetition, high-intensity inspiratory muscle strength training (IMST) program and progressively longer spontaneous breathing periods (SBPs) in a group of medically complex patients who were dependent on mechanical ventilation (MV) and had failed to wean. CASE DESCRIPTIONS: IMST was provided to 10 consecutive patients (four men, six women; mean [+/- SD] age, 59 +/- 15 years) who had failed to wean from MV by conventional methods for >or= 7 days. Prior to initiating IMST, patients had received MV support for a mean of 34 +/- 31 days. Daily IMST consisted of four sets of six breaths through a threshold inspiratory muscle trainer that had been set at an intensity to yield an exertion rating of 6 to 8 of a maximal value of 10. At the start of IMST, patients were tolerating 2.1 +/- 3.4 consecutive hours of SBPs. The duration of the SBPs was increased daily, as tolerated. Patients were considered to have been weaned from MV when they were able to breathe without MV support for 24 consecutive hours. OUTCOMES: After 44 +/- 43 days of IMST, 9 of 10 patients were weaned from MV. The initial IMST pressure was 7 +/- 3 cm H(2)O, and it was increased to 18 +/- 7 cm H(2)O (p < 0.05). DISCUSSION: These results indicate that an IMST protocol that produces significant increases in threshold training pressure, in combination with progressive SBPs, aids in weaning patients from MV. Although promising, these preliminary observations must be tested in a controlled trial.

Adult↗
PubMed1996

Reliability of tests to determine peak aerobic power, anaerobic power and isokinetic muscle strength in children with spastic cerebral palsy.

Test-retest reliability of measurements of peak aerobic power (cycle ergometer), anaerobic power (cycle ergometer), and isokinetic muscle strength of the knee (Cybex) was established in 12 young children with cerebral palsy (spastic diplegia/tetraplegia; mean age 8.8 years) and in addition in 39 healthy controls (mean age 9.2 years). The cycle ergometer tests were found to be reliable in both the group with CP and the control group (test-retest correlations varying from 0.72 to 0.96). The isokinetic strength test in the group with CP was only reliable at 30 degrees/s, whereas in the control group high test-retest correlations were also found at 60 degrees/s and 120 degrees/s.

Cerebral Palsy↗
PubMed2004

Site specificity of regular health club exercise on muscle strength, fitness, and bone density in women aged 29 to 45 years.

OBJECTIVE: To determine the effect of regular exercise with use of stepper or skier machines on muscle strength, cardiovascular fitness, bone mineral density, and markers of bone turnover in women aged 29 to 45 years. SUBJECTS AND METHODS: We evaluated 14 women: 5 who used a stepper machine for at least 3 hours each week for 2 years, 4 who used a skier machine for at least 3 hours each week for 2 years, and 5 who did not exercise (controls). All women were healthy, had no history of disease or medication use known to affect bone metabolism, and had normal levels of estradiol-17beta. Differences between the exercise and control groups were analyzed with the Kruskal-Wallis test. RESULTS: No significant differences were noted between the exercise groups and the control group with respect to age, height, total body bone mineral density, calcium intake, and metabolic bone markers. Significant differences were noted between the groups in body weight (stepper vs control, P=.03; skier vs control, P=.02), body mass index (stepper vs control, P=.03; skier vs control, P=.02), Physical Activity Score (stepper vs control, P=.009; skier vs control, P=.01), percentage body fat (stepper vs control, P=.03; skier vs control, P=.02), and maximum oxygen consumption (stepper vs control, P=.009; skier vs control, P=.009). Bilateral hip extensor strength was significantly stronger in the stepper group than in the skier group (P=.03). Grip strength was significantly stronger in the stepper group than in the skier group (right, P=.01; left, P=.049). CONCLUSION: Although comparable health club exercises can contribute to fitness, their site-specific effect varies. Stepper machines are preferred over skier machines for improving hip extensor strength.

Adult↗
PubMed1998

Muscle strength and endurance after surgery for primary hyperparathyroidism.

OBJECTIVE: To evaluate the effect of surgery on muscular strength and endurance in patients with primary hyperparathyroidism (HPT). DESIGN: Prospective open study. SETTING: University hospital, Sweden. SUBJECTS: Nine patients undergoing HPT surgery and nine matched patients undergoing thyroid resection who acted as controls. INTERVENTIONS: Concentric and eccentric endurance was evaluated with a test comprising 100 repeatedly executed muscle action at 90 degrees.s-1. Blood samples obtained before and after operation were analysed for calcium, phosphate, thyroid stimulating hormone (TSH), and parathyroid hormone (PTH) concentrations. MAIN OUTCOME MEASURES: Peak torque during maximum voluntary concentric and eccentric muscle actions at 90 degrees.s-1 before, three months and one year after operation. RESULTS: There were no differences in concentric and eccentric peak torque before and after operation either within or between groups. Concentric and eccentric endurance were similar in the HPT group and controls before as well as after operation. The return of calcium and PTH concentrations to their reference ranges after parathyroidectomy did not correlate with changes in concentric and eccentric peak torque. CONCLUSIONS: The subjective improvement in muscle endurance which is often encountered in patients with HPT after operation is not associated with an objective increase in muscle strength or endurance as measured by isokinetic muscle performance.

Calcium↗
PubMed1988

A new dynamometer measuring concentric and eccentric muscle strength in accelerated, decelerated, or isokinetic movements. Validity and reproducibility.

A new computerized dynamometer (the SPARK System) is described. The system can measure concentric and eccentric muscle strength (torque) during linear or nonlinear acceleration or deceleration, isokinetic movements up to 400 degrees.s-1, and isometric torque. Studies were performed to assess: I. validity and reproducibility of torque measurements; II. control of lever arm position; III. control of different velocity patterns; IV. control of velocity during subject testing; and, V. intra-individual reproducibility. No significant difference was found between torque values computed by the system and known torque values (p greater than 0.05). No difference was present between programmed and external measurement of the lever arm position. Accelerating, decelerating and isokinetic velocity patterns were highly reproducible, with differences in elapsed time among 10 trials being never greater than 0.001 s. Velocity during concentric and eccentric isokinetic quadriceps contractions at 30 degrees.s-1, 120 degrees.s-1 and 270 degrees.s-1 never varied by more than 3 degrees.s-1 among subjects (N = 21). Over three days of testing, the overall error for concentric and eccentric quadriceps contraction peak torque values for 5 angular velocities between 30 degrees.s-1 and 270 degrees.s-1 ranged from 5.8% to 9.0% and 5.8% to 9.6% respectively (N = 25). The results indicate that the SPARK System provides valid and reproducible torque measurements and strict control of velocity. In addition, the intra-individual error is in accordance with those reported for other similar devices.

Adult↗
PubMed2005

[Sport climbing with adolescents: effect on spine stabilising muscle strength].

Indoor climbing and boulder facilities gain importance in therapy for patients with back pain or with psychic disorders. The effect of climbing on strength of the spine musculature has hardly been investigated in young men and women. To address this question 17 high school students agreed to enrol into a 10-week climbing course twice a week and 9 to serve as controls. All participants were measured before and after training on special devices for measuring the isometric strength of cervical extensors and lateral flexors as well as for thoracic/lumbal spine, the flexors, extensors, the right and left rotators and lateral flexors. The mobility was measured for the transversal and frontal plane. After the climbing course, a gain in strength was measured in all but two muscle groups, the thoracic/lumbal extensors and left lateral flexors, in the control group only for the thoracic/lumbal flexors and left lateral flexors. The gain in strength was higher in the climbing group. The ratio of maximal strength of the right to left rotators was smaller after climbing. Sport climbing in adolescence leads to increased muscle strength of the spine muscles and to an increased muscular balance; thus, for prevention of back pain climbing courses may be introduced in high schools.

Adolescent↗
PubMedDate not supplied

Digital measurement of pelvic muscle strength in childbearing women.

Fourteen primigravidas were evaluated at 32 and 36 weeks antepartum (AP) and 6 weeks postpartum (PP) to test the reliability and validity of a digital measure of pelvic muscle strength using urine control as the criterion. Interrater reliabilities ranged from .67 to .77. Convergent validity was shown by negative correlations between clinical muscle scores and time required to interrupt urine flow at 32 weeks AP (r = -.41), 36 weeks AP (r = -.64) and 6 weeks PP (r = -.71). Validity was also demonstrated in a pattern of lower scores in women who had urine loss during coughing or reported incontinence as compared with those who did not. Women who had cesarean births had higher postpartum pelvic muscle scores with progressively lower scores demonstrated by those who gave birth vaginally without laceration, with episiotomy, and with laceration, F(3, 10) = 5.40, p = .02.

Adult↗
PubMed1993

Relationship between hamstring strains and leg muscle strength. A follow-up study of collegiate track and field athletes.

The purpose of the present study was to assess the relationship between hamstring strains and leg muscle strength. The bilateral isometric extensions and flexion maximum voluntary contraction (MVC) of knee and hip were measured among 64 collegiate track and field athletes (128 legs). The values of MVC per body-weight, flexion to extension ratio and bilateral legs imbalance index were calculated as the parameters for the investigation. The follow-up research was performed within the following two years. Among the 64 subjects (128 legs): 26 subjects (31 legs), 24.2 percent had suffered from hamstring strains. Then, the subjects were divided into injured (31 legs) and uninjured (97 legs) groups respectively. The parameters of the lower extremities measured at the beginning were compared for the two groups. The different rates of the hip flexion and knee extension of bilateral legs of the injured group were significantly higher than those of the uninjured group (p < 0.05). In the injured group, the value of MVC per body-weight of the knee flexor and the flexion-extension ratio were significantly lower than in the uninjured group (p < 0.05). In conclusion, the imbalance of the bilateral legs, the hamstring strength and the ratio of the flexor to extensor were shown to be parameters related to the occurrence of hamstring strains.

Adult↗
PubMed2004

Peripheral muscle strength training in COPD: a systematic review.

BACKGROUND: Skeletal muscle weakness, and the associated impact on exercise tolerance, provides a strong theoretical rationale for strength training intervention for people with COPD. AIM: The purpose of this review was to examine systematically the current evidence for peripheral muscle strength training in people with COPD. METHOD: Empirical trials and reviews relating to strength training in COPD were obtained by searching electronic databases and citation tracking, using the keywords of COPD with strength/resistance training and skeletal muscle. Two reviewers completed data extraction and quality assessment independently, using the PEDro (physiotherapy evidence database) scale and a checklist for review articles. Effect sizes and 95% confidence intervals were determined for empiric trials and metaanalysis used where appropriate. RESULTS: The search strategy yielded 13 articles (9 empirical trials and 4 reviews). Strength training was found to have strong evidence for improving upper body and leg strength. However, no strong evidence for strength training was found for other outcome measures. CONCLUSIONS: Further research is required to investigate the effects of strength training on functional activities, such as balance, upper limb function, self care, and participation in daily life.

Exercise Therapy↗
PubMedDate not supplied

Effects of muscle-strength training on the functional status of patients with osteoarthritis of the knee joint.

This study was designed to determine whether an 8-week isokinetic muscle-strength-training program improved the functional health status of patients with osteoarthritis of the knee joint. Twenty volunteers with osteoarthritis of the knee joint were randomly assigned to either an experimental (n=10) or control (n=10) group. The experimental group completed six sets of five maximal contractions three times per week for 8 weeks on a Cybex II dynamometer at 90 degrees per second. Both groups were pre- and posttest for extension and flexion strength of the right and left legs, the 50-foot walk time, range of motion at the knee joint, the Osteoarthritis Screening Index (OASI), and the Arthritis Impact Measurement Scale (AIMS). There was a significant decrease in pain and stiffness, and a significant increase in mobility. There was also a significant decline in arthritis activity in the experimental group as measured by the OASI and AIMS. The experimental group significantly increased in all strength measures, while the control group increased in only right leg flexion and left leg extension across the training period.

Activities of Daily Living↗
PubMed1993

Muscle strength testing following surgery for acetabular fractures.

A retrospective clinical analysis was performed on 30 patients who underwent surgery for acetabular fractures. In addition to clinical and radiographic evaluations, muscle strength was tested using an isokinetic dynamometer. Average follow-up time was 21 months. Joint surface and congruency were restored within 3 mm in 29 of 30 cases. The average hip score was 83. Eight patients had an unsatisfactory result. Only 14 patients had a normal gait, while seven patients had a Trendelenburg gait. The overall strength deficit was 27%. This mean strength deficit was highly correlated with the hip-rating score. The greatest loss of strength was in abduction, where the average deficit was 50%. The loss of abduction strength was significantly greater for patients operated on through posterior approaches. Among patients operated on through a Kocher-Langenbeck approach, those with transverse fractures had significantly larger losses of abduction strength than those with posterior wall fractures.

Acetabulum↗
PubMed1981

Muscle strength and fatigue after selective glycogen depletion in human skeletal muscle fibers.

Two groups of male subjects were studied to examine the effects of different exercise protocols on performance of an isokinetic, short-time strength test, the performance of which is related to fast twitch (FT) muscle fiber recruitment. The laboratory group (LG) (n = 10) cycled (30 min, 70% VO2 max), ran (75 min), and performed repeated bouts of "sprint" cycling and rapid, maximal contractions of the quadriceps. The marathon group (MG) (n = 7) participated in and completed Stockholm's Marathon 1979. A strength test was performed before and within 1-2 h after completion of the group exercise protocol. The m. vastus lateralis was biopsied and muscle fibers classified as slow twitch (ST) or FT. After periodic acid-Schiff staining fibers were qualitatively classified as to glycogen content. In LG significant glycogen depletion occurred in both fiber types and in MG predominantly ST fibers were exhausted of glycogen after the exercise protocol. The glycogen exhaustion from both fiber types in LG was associated with impaired maximal muscular strength produced during a single dynamic contraction, as well as with reduced muscle fatigue patterns. When glycogen exhaustion was induced in ST muscle fibers only in the MG, no impairment was observed for maximal muscular strength but fatigue during 50 consecutive contractions was significantly increased.

Adult↗
PubMed1999

Total shoulder and relative muscle strength in the scapular plane.

Strength profiles of the shoulder joint are measured experimentally for two arm positions in "the scapular plane" in order to present quantitative data on the shoulder strength. Apart from yielding the actual force a subject can exert in various directions, these measurements also exhibit e.g. the strongest and weakest directions, in fact the relative strength in all directions. The inter-individual variation of the direction of maximal force was at most 14 degrees (sd). The experimental profiles are compared with the corresponding theoretical profiles, obtained by using a shoulder model. The calculations were made both with default muscle parameters and individually adapted parameters. The results show that the employed shoulder model, which is based on data from an elderly population, may be adapted to other populations and that the necessary changes in relative muscle strength are those expected on biomechanical grounds. Without model changes the difference between measured (in the mean) and predicted maximal force directions was at most 50 degrees. Muscle parameter adjustment reduced this difference to 23 degrees. The strength profiles clearly indicate in what direction a person can produce larger forces and which muscles that contribute.

Adult↗
PubMed2005

Validation of an abdominal muscle strength test with dynamometry.

Adequate abdominal strength prevents work- and sports-related injuries and stabilizes the spine for athletic activities. The double-leg-lowering maneuver (DLLM) is a popular test to assess abdominal strength because of its simplicity; however, its validity and reliability have not been studied thoroughly. To determine the validity and reliability of the DLLM, 4 examiners evaluated 28 subjects. The validity of the DLLM was evaluated with the Nicholas Hand-Held Dynamometer (NHHD) as the gold standard. The DLLM scores were compared to themselves for reliability and to NHHD scores for validity. Reliability for the DLLM was very high (r = 0.932). Validity of the DLLM was low (r = -0.338 to -0.446). The DLLM is reliable, but it has low validity to assess abdominal strength. The DLLM may be a useful tool to assess pelvic tilt motor control for spine stability, but it is not suitable for assessing muscle strength.

Abdominal Muscles↗
PubMed2002

[Indirect evaluation of respiratory muscle strength with the help of markers of maximal inspiratory and expiratory pressure in the mouth of healthy individuals].

The aim of the study was the evaluation of respiratory muscle strength by measurement of maximal inspiratory (PImax) and expiratory (PEmax) pressures values. Results for 166 clinically normal subjects (79 female and 87 male) were obtained. The results were as follow: in woman PImax ranged 38-104 cm H2O, average 60 cm H2O, PEmax ranged 46-140 cm H2O average 87.5 cm H2O, in men PImax was 40-120 cm H2O, average 73.2 cm H2O, PEmax ranged 46-140 cm H2O, average 115.9 cm H2O. PImax was negatively correlated with age in both groups. There was no correlation between age and PImax or PEmax in both groups (p > 0.05). There was no correlation between PImax and PEmax and height in women group and men group treated apart. The correlation was found between PImax as well as PEmax and height for whole group (p = 0.00019). There were observed positive correlation between PImax, PEmax and weight in both (male and female) groups. The comparison of results of present study with those obtained in former studies reveals important differences of norms for different populations. The normal values of maximal inspiratory and expiratory pressures in the mouth (PImax, PEmax) should be qualified individually for studied population. The normal values recommended by producers of medical equipment might be inadequate for studied population.

Adolescent↗