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At least 235 records · Page 13Linked to original sources
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↗
PubMed2002

Muscle torques in total knee arthroplasty with subvastus and parapatellar approaches.

The current study was designed to compare muscle torques when using the subvastus and parapatellar approaches for unilateral total knee arthroplasty. Twelve female patients had unilateral total knee arthroplasty with the subvastus approach from January 1997 to June 1998. The historic control group consisted of 16 female patients who had unilateral total knee arthroplasty with the parapatellar approach from July 1994 to January 1997. Six and 12 months after surgery, a Cybex dynamometer was used to measure isometric and isokinetic muscle strength. Two parameters were used to compare the two approaches, the first parameter was the difference in peak torque between the surgically treated knee and the baseline value for the healthy knee, and the second parameter was the hamstring to quadriceps peak-torque ratio, again using the value for the healthy knee as baseline. The subvastus approach resulted in an initial higher peak torque in the quadriceps 6 months after surgery, but this difference became insignificant 12 months postoperative. Using the subvastus approach, the hamstring to quadriceps peak-torque ratio reached the normal range (0.50-0.80) sooner than was the case using the parapatellar approach. There is a phenomenon of cross adaptation of the untreated knee to the surgically treated knee, and knees operated on by the subvastus approach showed functional recovery at an earlier date than those operated on by the parapatellar approach.

Adult↗
PubMedDate not supplied

The effect of a patella brace on performance in a knee extension strength test in patients with patellar pain.

The object of this study was to analyze the quadriceps muscle peak strength with the Cybex-II isokinetic dynamometer in patients with patellofemoral arthralgia with and without a patella brace. Twenty-four patients, 18 women and 6 men, were studied. All had patellofemoral arthralgia. The diagnosis was made on typical clinical findings, but was supplemented with arthroscopy in seven patients with pain also over the medial joint line. After a 2 week adaptation period with the brace, a Cybex-II test was done with and without the brace. The other leg was tested as control. Twenty-one patients (88%) improved their performance in the strength test with the brace (mean difference 13.7 +/- 9.1%). With the brace, 14 patients (58%) performed at 95% of their control leg or more compared to 6 (25%) without the brace. Patients under the age of 30 years had a better effect than patients over that age.

Adolescent↗
PubMed1992

Objective assessment of spasticity, strength, and function with early exhibition of dantrolene sodium after cerebrovascular accident: a randomized double-blind study.

A double-blind, placebo-controlled trial was conducted to determine whether early exhibition of Dantrium (Dantrolene Sodium) in patients with cerebrovascular accidents, before the onset of significant spasticity, would enhance the functional outcome of rehabilitation. Thirty-eight patients were enrolled in the trial and 31 satisfactorily completed the study. A modified Cybex isokinetic dynamometer was used to gather information on strength and muscle tone. Clinical, functional, and biochemical data were also collected. It was found that Dantrium reduced strength in the unaffected limbs but did not alter strength in the paretic limbs. Dantrium produced no alteration in clinical tone, functional outcome, or biochemical tests at the dosage (200 mg per day) used in this study.

Aged↗
PubMed2001

[Physical examination--measurement of muscle strength].

Measuring muscle strength and establishing paretic symptoms are done first of all by having the patient perform actions or movements that require normal muscle strength. Measuring or grading the strength of separate muscle groups is usually done by means of the so-called Medical Research Council (MRC) scale that runs from 0 to 5, with the movement against gravity as an important criterion. This scale is not very valid in tract 4 (more strength than needed to overcome gravity, but still subnormal). Using a manual dynamometer or a fixed dynamometer it is possible to measure the strength of most clinically important muscle groups of the extremities and to compare them with values found in a normal population. For following the individual patient with a neuromuscular disorder, strength measurement with the dynamometer is more reliable than grading using the MRC scale.

Diagnosis, Differential↗
PubMed2000

The efficacy of Farabloc, an electromagnetic shield, in attenuating delayed-onset muscle soreness.

OBJECTIVE: To assess the hypothesis that Farabloc, a fabric with electromagnetic shielding properties, would attenuate the symptoms, signs, and muscular strength deficit secondary to delayed-onset muscle soreness (DOMS) induced by two exposures to eccentric exercise in humans. DESIGN: Randomized, single-blind, placebo-controlled, crossover trial with two testing stages of 5 days duration separated by a washout period of more than 8 weeks. SETTING: University-based sports medicine center. PARTICIPANTS: Twenty volunteers equally representing untrained male and female subjects. INTERVENTIONS: 20 sets of 10 repetitions of single-leg eccentric knee extensions for 37 minutes with the Biodex dynamometer set at 30 degrees per second were performed on the first day of stage one and stage two to induce DOMS in the quadriceps muscle. Double layers of fabric, either Farabloc or placebo, were wrapped around the thigh of each participant during each stage for 5 days. MAIN OUTCOME MEASURES: Perception of muscle pain, as measured by a visual analog scale (VAS), and strength, as measured by knee extensor torque (EST) with the Biodex dynamometer, were evaluated at 0, 24, 48, 72, and 96 hours. Serum inflammatory markers of muscle damage, including malondialdehyde. creatine phosphokinase, myoglobin, leukocytes, and neutrophils, were assayed at 0, 2, 6, 24, and 48 hours. RESULTS: Repeated-measures analysis of variance was carried out for each of the seven variables to assess differences for fabric, order of treatment, time, and all combinations. Results of VAS and EST and levels of malondialdehyde, creatine phosphokinase, myoglobin, leukocytes, and neutrophils all showed a highly significant effect of Farabloc compared with placebo. This analysis shows that the order of Farabloc or placebo fabric use in stage I and 2 produces different results. This may be caused by a learning effect, but did not alter the overall influence of Farabloc. CONCLUSION: The data indicate that double layers of Farabloc fabric wrapped around the thigh reduces pain and strength loss and serum levels of malondialdehyde, creatine phosphokinase, myoglobin, leukocytes, and neutrophils when untrained human subjects are exposed to eccentric exercise to produce DOMS in the quadriceps. Farabloc shields high-frequency electromagnetic fields, although the results do not indicate how these changes are mediated. Further research is needed to determine the mechanism.

Adult↗
PubMed2003

Muscle fatigue induced by exercise simulating the work rate of competitive soccer.

Fatigue represents a reduction in the capability of muscle to generate force. The aim of the present study was to establish the effects of exercise that simulates the work rate of competitive soccer players on the strength of the knee extensors and knee flexors. Thirteen amateur soccer players (age 23.3+/-3.9 years, height 1.78+/-0.05 m, body mass 74.8+/-3.6 kg; mean+/-s) were tested during the 2000-2001 soccer season. Muscle strength of the quadriceps and hamstrings was measured on an isokinetic dynamometer. A 90 min soccer-specific intermittent exercise protocol, incorporating a 15 min half-time intermission, was developed to provide fatiguing exercise corresponding in work rate to a game of soccer. The exercise protocol, performed on a programmable motorized treadmill, consisted of the different intensities observed during soccer match-play (e.g. walking, jogging, running, sprinting). Muscle strength was assessed before exercise, at half-time and immediately after exercise. A repeated-measures analysis of variance showed significant reductions (P < 0.001) in peak torque for both the quadriceps and hamstrings at all angular velocities (concentric: 1.05, 2.09, 5.23 rad x s(-1); eccentric: 2.09 rad x s(-1)). The peak torque of the knee extensors (KE) and knee flexors (KF) was greater before exercise [KE: 232+/-37, 182+/-34, 129+/-27, 219+/-41 N x m at 1.05, 2.09 and 5.23 rad x s(-1) (concentric) and 2.09 rad x s(-1) (eccentric), respectively; KF: 126+/-20, 112+/-19, 101+/-16, 137+/-23 N x m] than at half-time (KE: 209+/-45, 177+/-35, 125+/-36, 214+/-43 N x m; KF: 114+/-31, 102+/-20, 92+/-15, 125+/-25 N x m) and greater at half-time than after exercise (KE: 196+/-43, 167+/-35, 118+/-24, 204+/-43 N x m; KF: 104+/-25, 95+/-21, 87+/-13, 114+/-27 N x m). For the hamstrings:quadriceps ratio, significant changes were found (P < 0.05) for both legs, the ratio being greater before than after exercise. For fast:slow speed and left:right ratios, no significant changes were found. We conclude that there is a progressive reduction in muscle strength that applies across a range of functional characteristics during exercise that mimics the work rate in soccer.

Adult↗
PubMed1999

Gender differences in muscle strength & endurance in young Indian adults.

Muscle strength was studied in 70 males and 53 females between the ages of 17-30 yr, using a handgrip dynamometer. In a subset group of 31 males and 20 females, muscle endurance during sustained isometric contraction was studied using a load cell based handgrip dynamometer coupled to a polygraph. The males had a significantly greater muscle mass and lower body fat as compared to the females. Males had close to twice the handgrip strength of females in absolute terms (P < 0.01) and this difference persisted after correction for forearm muscle area (P < 0.05). In contrast, the rate of decline of muscle strength during sustained isometric contraction was lower in females as compared to males (P < 0.05), suggestive of greater skeletal muscle endurance in females. Physical activity patterns were not a determinant of skeletal muscle function. These findings are consistent with gender specific muscle fibre characteristics reported in literature in other racial groups.

Adolescent↗
PubMedDate not supplied

Calf muscle area and strength changes after five weeks of horizontal bed rest.

Nine male volunteers participated in a 10 week metabolic study in which subjects underwent 5 weeks of ambulatory control and 5 weeks of complete horizontal bed rest. Bed rest is a model commonly used to simulate space flight. The changes in muscle area and strength of the calf dorsiflexors and plantar flexors were measured before and after bed rest using magnetic resonance imaging (MRI) and a Cybex II dynamometer. The muscle area of the plantar flexors (gastrocnemius and soleus) decreased 12%, whereas the muscle area of the dorsiflexors was not significantly decreased. The maximal muscle strength of the plantar flexors decreased 26%; the muscle strength of the dorsiflexors was not significantly decreased. These results, which demonstrate differential muscle atrophy and a larger loss in strength relative to muscle area, have important implications in the development of exercise counter-measures to be implemented during space flight. The results also have implications for patients who have severe orthopaedic disorders and must be bed rested for long periods of time, and for persons who are voluntarily inactive (a large number of the elderly).

Adult↗
PubMed1983

Thigh muscle strength in below-knee amputees.

The aim of this investigation has been to study the magnitude of the reduction of thigh muscle strength of below-knee amputees and to correlate the strength to the degree of atrophy and to the clinical function. Thirty-two below-knee amputees participated in examinations of the isometric and isokinetic knee extension and flexion strength using an isokinetic dynamometer (Cybex II). The atrophy was evaluated by measuring the mean muscle fibre area on muscle biopsies of the vastus lateralis and the cross-sectional area of the quadriceps and hamstring muscles measured with computed tomography. The isometric and isokinetic knee extension and flexion strength in the amputated leg with and without prosthesis was significantly lower than the strength in the non-amputated leg (p less than 0.01). Knee extension strength was significantly correlated to the mean muscle fibre area of the vastus lateralis. There was no correlation between strength and the cross-sectional area of the quadriceps muscles. There was, however, a significant correlation between the side differences (amputated leg versus non-amputated leg) in isometric knee extension and flexion strength and the side differences in cross-sectional areas. The reduction in isometric and isokinetic knee extension and flexion strength in the amputated leg both with and without prosthesis compared with the non-amputated leg was larger than the reduction in cross-sectional areas of the quadriceps and hamstring muscles and in muscle fibre areas of the vastus lateralis. This indicates that besides muscle atrophy changes in motor unit recruitment pattern may be of importance for the reduction in muscle strength. Isometric and isokinetic knee extension and flexion strength values in the amputated leg with prosthesis were significantly correlated to step length, maximal walking speed and circumference of the thigh. These results indicate that below-knee amputees with a better preserved thigh muscle strength have a good walking capacity.

Adult↗
PubMedDate not supplied

Intrarater and interrater reliability of three isometric dynamometers in assessing shoulder strength.

The purpose of this study was to evaluate the reliability of three separate isometric strength testing devices. Seventeen (10 female, 7 male) adult volunteers with no known shoulder dysfunction participated. Each subject's internal rotation, external rotation and abduction strength was measured with the Nicholas Manual Muscle Tester (MMT), Biodex Isokinetic Dynamometer, and Isobex 2.0. Two investigators administered the test to each subject with each device. Data were analyzed with intraclass correlation coefficients (ICCs). Ranges of the intrarater intraclass correlation coefficient (3,1) values for each muscle group with each device for both testers were as follows: Nicholas MMT = .84 to .97, Biodex = .97 to .99, and Isobex 2.0 = .95 to .98. Ranges of interrater intraclass correlation coefficient values for each device and muscle group were as follows: Nicholas MMT = .79 to .94, Biodex = .93 to .96, and Isobex 2.0 = .90 to .97. Time to complete testing was shortest for Nicholas MMT, followed by Isobex 2.0, then Biodex. Measurements taken on the same day by the same therapist appear to be highly reliable for all three devices. Measurements taken over a 3-day period by two therapists appear to be highly reliable for all devices and muscle groups with the exception of Nicholas MMT abduction (.79), which was moderately reliable.

Adult↗
PubMed1996

Site-specific bone mass differences of the lower extremities in 17-year-Old ice hockey players.

The purpose of the present study was to evaluate bone mass in the pelvis and lower extremities in young ice hockey players, and especially to investigate whether any differences are related to the type and magnitude of weight-bearing loading and muscle stress. The ice hockey group consisted of 22 boys (mean age 16.9 +/- 0.3) from three different ice hockey teams training for about 9 hours/week (mean 9.3 +/- 2.0, range 6-15). The reference group consisted of 22 boys (age 16.8 +/- 0.3) not training for more than 4 hours per week (mean 1.5 +/- 1.5, range 0-4). The groups were matched according to age, pubertal stage, weight, and height. Areal bone mineral density (BMD) was measured in total body, head, pelvis, ala ossis ilii, femoral neck, trochanter, femur diaphysis, and tibia diaphysis using dual energy X-ray absorptiometry. Isokinetic muscle strength of the quadriceps and hamstrings muscles was measured using an isokinetic dynamometer. BMDs of the total body, femoral neck, trochanter, and pelvis, but not of the head, ala ossis ilii, femur diaphysis, and tibia diaphysis, were found to be significantly higher (P < 0.05) in the ice hockey group. Muscle strength of the quadriceps muscles was also found to be significantly higher among the ice hockey players, but this greater muscle strength did not predict any BMD site significantly. However, in the reference group, there was a general strong relationship between muscle strength and BMD. This study has demonstrated significantly higher BMD in adolescent ice hockey players than in referents on a low or moderate level of physical activity. The differences seem to be site-specific and may be related to the type and magnitude of loading acting on each site, during off-season training and preferentially during ice hockey. The nonsignificant differences in BMD of the tibia and femur diaphyses may reflect that the compressive forces acting on these sites during ice hockey are not of sufficient magnitude to influence BMD. High muscle stress in itself, without weight-bearing loading, acting on the ala ossis ilii in adolescent boys does not seem to increase BMD, and an increased muscle strength does not predict BMD in highly trained adolescent boys.

Adolescent↗
PubMed1993

Muscle strength and history of heavy manual work among elderly trained women and randomly chosen sample population.

The association between a history of heavy work and muscle strength was studied among 51 physically active women aged 66-85 years trained in sports and 41 women aged 70-81 years selected randomly from the population register. Maximal isometric muscle strength of hand grip, arm flexion, leg extension and trunk flexion and extension were measured using specially constructed dynamometers. The capacity of the abdominal muscles was evaluated by means of a sit-up test. The study included an interview dealing with the subjects' histories of heavy manual employment. The mean histories of heavy work for the trained and untrained women were 24 and 36 years, respectively. The trained women showed significantly greater maximal isometric muscle strength and abdominal muscle capacity than the untrained women. Among the trained women there was no correlation between the amount of heavy work and muscle performance. Among the untrained women the amount of heavy work correlated positively with maximal isometric trunk extension strength. The results would suggest that among elderly women, whether physically active or not, a history of heavy work has no systematic association with muscle strength.

Aged↗
PubMed1995

Training-induced changes in muscle architecture and specific tension.

Five men underwent unilateral resistance training of elbow extensor (triceps brachii) muscles for 16 weeks. Before and after training, muscle layer thickness and fascicle angles of the long head of the triceps muscle were measured in vivo using B-mode ultrasound, and fascicle lengths were estimated. Series anatomical cross-sectional areas (ACSA) of the triceps brachii muscle were measured by magnetic resonance imaging, from which muscle volume (Vm) was determined and physiological cross-sectional area (PCSA) was calculated. Elbow extension strength (isometric; concentric and eccentric at 30, 90 and 180 degrees.s-1) was measured using an isokinetic dynamometer to determine specific tension. Muscle volumes, ACSA, PCSA, muscle layer thickness and fascicle angles increased after training and their relative changes were similar, while muscle and fascicle length did not change. Muscle strength increased at all velocities; however, specific tension decreased after training. Increase in fascicle angles, which would be the result of increased Vm and PCSA, would seem to imply the occurrence of changes in muscle architecture. This might have given a negative effect on the force-generating properties of the muscles.

Adult↗
PubMed1999

Physical performance in individuals with late effects of polio.

The aim of this study was to evaluate physical performance in individuals with late effects of polio; specifically, to evaluate the effects of reduced muscle strength in the lower limbs. Thirty-two individuals seen at the polio clinic at Sahlgrenska University Hospital, Göteborg, Sweden, participated in the study. Each subject performed a bicycle exercise test in which peak oxygen uptake and anaerobic threshold were determined. Muscle strength in the quadriceps and the hamstrings were measured on an isokinetic dynamometer. Reductions in peak workload, peak oxygen uptake and predicted heart rate were seen. The anaerobic threshold was within or slightly lower than normal limits in relation to predicted maximal oxygen uptake, indicating that the cardio-respiratory system was not limiting performance. The muscle testing demonstrated a significantly lower ability to perform muscle actions compared with individuals from a reference group, and strong correlations were found between muscle strength peak VO2 and peak workload, respectively. Adjusted peripheral muscle endurance training might improve the work capacity in those individuals with weak leg muscles and low oxygen uptake, while individuals with relatively good muscle strength would improve their aerobic fitness in a general fitness program.

Adult↗
PubMed1995

The quantitative measurements of hip isometric muscle torques in Chinese young adults--a preliminary report.

A standard procedure for measurement of hip muscle strength (maximal isometric torque) with the Cybex 340 isokinetic dynamometer is presented. Twenty-two healthy males aged 30-40 years (average 34.3 years) were tested on hip flexors, extensors and abductors; in which the factors as sex, age, dominant side and testing session were all eliminated. The test was redone two weeks later on the same 10 males to evaluate its reproducibility. The results disclosed the maximal isometric torque of the hip flexors was stronger than that of extensors and abductors in both sides hips. The comparison between two sides hips showed only the abductors of right side hip significantly stronger than that of left side (P = 0.0259). The tests between the two different periods were quite compatible. The results have clinical implications for objective assessment of preoperative and postoperative hip strengths in patients with hip arthropathy and thus giving a reasonable guidance for physiotherapeutic management.

Adult↗
PubMed1998

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

OBJECT: The goal of this investigation was to quantify changes in hamstring muscle spasticity and strength in children with cerebral palsy (CP) as a function of their having undergone a selective dorsal rhizotomy. METHODS: 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 the 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. CONCLUSIONS: The results of spasticity testing in the present investigation agreed with those of 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.

Adolescent↗