A strain-gauge dynamometer for measuring the strength of muscle contraction and for re-educating muscles.
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Although nonoperative treatment is considered the standard of care for the treatment of Grade I and II acromioclavicular (AC) joint injuries, the treatment of Grade III injuries is controversial. There are as many methods of nonoperative treatment as there are for operative stabilization. Most of the literature represents Level IV evidence with very few Level II and III studies upon which to base decisions. A systematic review of the English-language literature was performed to determine if Grade III AC joint separations are best treated operatively or nonoperatively. Based on limited low-evidence, nonoperative treatment was deemed more appropriate than traditional nonoperative treatments because the results of the latter were not clearly better and were associated with higher complication rates, longer convalescence, and longer time away from work and sport.
OBJECTIVE: To determine the responsiveness to change of isokinetic dynamometry of the shoulder and to compare this responsiveness with outcome measures of pain and activity level. DESIGN: Responsiveness was evaluated as the change in outcome after intra-articular steroid injection in patients with capsulitis of the shoulder. Effect sizes of all outcome measures, quantified as standardized response means, were compared. Relationships between change scores of shoulder function and activities were assessed. SUBJECTS: Ten patients with unilateral capsulitis of the shoulder. MAIN OUTCOME MEASURES: Muscle strength and active range of motion were measured by isokinetic dynamometry. We then calculated involved/uninvolved ratios of the maximal peak torques of abduction, adduction, external and internal rotation, active range of motion of abduction and external rotation. In addition, pain was scored using the numeric rating scale (NRS-101) and activity level was scored using the Shoulder Disability Questionnaire. RESULTS: The standardized response mean of all outcome parameters was equal to or greater than 0.8, except for active range of motion of abduction. No significant differences between the standardized response means were found. There is a significant correlation between the change scores of NRS-101 and Shoulder Disability Questionnaire. No significant correlations were found between the change scores of NRS-101 and Shoulder Disability Questionnaire on the one hand, and involved/ uninvolved ratios of peak torques and active range of motion on the other. CONCLUSIONS: Responsiveness of all outcome measures is good. Parameters of isokinetic dynamometry may provide additional information as compared with the usual outcome measures of pain and functional level.
For many populations the ability to move efficiently is compromised by an impaired muscular functioning. Strength development is necessary to overcome the effects of gravity to maintain posture and generate movement responses for mobility. The strength and power capabilities of individuals with total blindness (n = 12) were compared to those with partial vision (n = 12) to evaluate effects of vision on performance. Results indicate that (1) no significant differences were apparent between total blindness and partial vision, (2) significant sex differences were evident in each group, and (3) better performance was apparent at lower velocities. It was concluded that physical performance in individuals with blindness and partial vision are equally deficient.
The purpose of this study was to examine properties and sex differences of the decreasing force during sustained isometric grip using various target forces, 50%, 75%, and 100% of maximal voluntary contraction (MVC), for 6 min. Participants were healthy, 15 men (height = 172.9 +/- 4.6 cm, body mass = 67.7 +/- 5.36 kg) and 15 women (height = 160.9 +/- 5.4 cm, body mass = 55.9 +/- 5.36 kg). The force decrease for target forces of 75% and 100% MVC was marked until 60 sec. from the onset of grip and then decreased gradually. On the other hand, the target force of 50% MVC was maintained for about 60 sec. and then decreased markedly until 100 sec. Differences in the decreasing force among target force levels was observed until 60 sec., and there were no significant differences of the time to decay to 20%, 30%, and 40% MVC. Namely, the time and force exertion reaching an almost steady state were considered to be almost the same at any target force. A sex difference on a parameter was found after 60 sec. or a decreasing force after 40% MVC, and women held it longer or higher than the men. However, the tendency was smaller in the latter phase of the steady state.
During the period 1978-1984, 38 patients aged 23-55 years were treated for patellofemoral pain by the Maquet procedure. The mean postoperative observation time was 5(3-9) years. Thirty-three of the 38 patients were available for follow-up including functional and activity scoring, clinical examination, and Cybex II dynamometer muscle-strength measurement. Ten patients improved, 17 were unchanged, and 6 were worse. Characteristic for the improved group was Grades III and IV chondromalacia - mainly involving the lateral facet - whereas the group with no improvement or deterioration exhibited a low-grade chondromalacia, chiefly affecting the medial patellar facet.
OBJECTIVE: To determine the anthropometric parameters and the isometric muscle strength in a working population sample in China, and to investigate the relationship between muscle strength and individual attributes, such as age, gender, height and weight. METHODS: The study population consisted of 146 male and 47 female people including workers, administrators and college students. Four types of muscle strength, i.e., handgrip, arm lift, shoulder lift, and torso pull, were measured. RESULTS: Left handgrip, right handgrip, arm lift, shoulder lift and torso pull of male workers were (42.07 +/- 7.20), (43.92 +/- 7.14), (26.79 +/- 4.64), (33.79 +/- 6.88), (88.56 +/- 17.98) kg, respectively while those of female workers were (21.29 +/- 5.09), (23.26 +/- 5.47), (13.29 +/- 3.37), (18.52 +/- 4.01), (41.06 +/- 12.04) kg, respectively. The female's strength was about 50% lower than the male's. The strength in the 40 approximately years old group was higher than that in other age groups. There were significant positive correlation between the gender and the isometric strength as well as between the body weight and the isometric strength. If the body weight served as the corrected parameter, there was no significant difference in the handgrip among the groups (P < 0.05), but the torso pull of male workers > college students > administrators. All relative muscle strengths except the torso pull were similar for all age groups. CONCLUSION: The body weight as the independent variable can be used for establishing the predictive equation of the muscle strength. Calculation of the relative muscle strength can relieve the interference of the body weight for the muscle strength.
AIM: The purpose of this study was to compare the exertion and electromyography (EMG) properties during the developmental phase (DFmax) in static explosive grip (SEG), rapid submaximal exertion grip, namely fake SEG exertion (FAKE), and SEG in a muscle fatigue state. METHODS: Thirty healthy males and females performed the SEG and FAKE exertions (50% and 75% of peak value as a target value). Then, they performed sustained repeated rhythmic grip for 6 min (30 times x min(-1)), and SEG after 1-min, 4-min, and 7-min (SEG after the exertion). EMG was measured concurrently to compare with the muscle activation property during each grip exertion. Eight force-time parameters evaluating the DFmax in addition to the peak value were selected. RESULTS: The peak value significantly decreased, and the mean power spectrum density shifted to the low-wave in SEG after the exertion as compared with before. Therefore, SEG after the exertion was judged to be a muscle fatigue state. In addition, because the frequency properties in each exertion differed, the muscle activation properties during their DFmaxs were considered to differ. From the comparison between SEG before and after the exertion and FAKE, it is suggested that the time of reaching the peak value and the relative muscle strength when reaching an inflection point are not useful as parameters to evaluate the explosive muscle function during SEG. CONCLUSIONS: The maximal increasing volume during the DFmax and integrated area until 0.25 and 0.5 s could discriminate a difference of the DFmaxs according to each exertion and they are useful parameters.
The hallmark of progression in patients with amyotrophic lateral sclerosis (ALS) is the development of progressive weakness and muscular wasting. Strength testing has been used to monitor the course of the disease and to test the efficacy of new drugs. This paper review the methods used to quantify the weakness and compare their accuracy and reproducibility.
This retrospective study was undertaken to determine the test-retest reliability of hand-held dynamometer strength testing for 18 extremity muscle groups. To assess reliability, I compared three dynamometer strength scores recorded for each muscle group on the strength score forms of 30 neurologically involved patients, using the Pearson product-moment correlation and a one-way analysis of variance (ANOVA) for repeated measures. All correlations were significant (p less than .01); the median and modal correlations were all .97 or .98. The ANOVA revealed significant differences in repeated dynamometer test scores only for hip and shoulder abduction. The results suggest that hand-held dynamometry can be a reliable assessment technique when practiced by a single experienced tester.
OBJECTIVE: To evaluate the retest reliability and quantify the degree of measurement error when measuring isometric muscle strength with a hand-held dynamometer for people with chronic obstructive pulmonary disease (COPD). DESIGN: Retest reliability of hand-held dynamometry for 4 muscle groups was assessed on 2 occasions separated by a 2-week interval. SETTING: Community rehabilitation center. PARTICIPANTS: Eight men and 4 women (mean age +/- standard deviation, 71.4+/-10.3y) with moderately severe COPD (percentage of predicted forced expiratory volume in 1 second, 41.5%+/-17.7%). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Muscle strength (in kilograms). Statistical analysis was conducted by calculating intraclass correlation coefficients and 95% confidence intervals for both group and individual scores. RESULTS: All reliability coefficients were greater than .79. Muscle strength would need to increase by between 4% and 18% in groups of people with COPD and between 34% and 58% in a person with COPD to be 95% confident of detecting real changes. CONCLUSIONS: Hand-held dynamometry is suitable for monitoring change in muscle strength and testing hypotheses for groups of people with COPD. However, hand-held dynamometry is not likely to detect changes in muscle strength for a person with COPD.
An isokinetic dynamometer was used to measure plantar flexion muscle strength at 60 degrees/s and 200 degrees/s in 10 healthy young men (mean age 25 years). Muscle and tendon stiffnesses were determined on the dynamometer by the use of electrical stimulation and passive stretch (200 degrees/s). Differences in jumping heights between squat and counter-movement jumps were calculated from flight times. The number of heel-rises performed until exhaustion, standing on one leg, were counted. Stepwise regression analysis showed that differences in jumping height increased with lower muscle strength and with higher muscle and tendon stiffnesses, indicating that elastic components may be of more importance in persons with lower muscle strength. The number of heel-rises was negatively dependant on tendon stiffness, indicating that increased stiffness may enhance the development of fatigue.
Numerous neurological diseases are accompanied by atrophy of the intrinsic muscles of the hand. Muscle strength testing of these muscles is frequently used for clinical decision making. Traditionally, these strength measurements have focused on manual muscle testing (MMT) or on grip and pinch strength dynamometry. We have developed a hand-held dynamometer, the Rotterdam Intrinsic Hand Myometer (RIHM), to measure this intrinsic muscle strength. The RIHM was designed such that it can measure a wide range of muscle groups, such as the abduction and adduction strength of the little finger and index finger, the opposition, palmar abduction (anteposition) and opposition strength of the thumb, and intrinsic muscles of the fingers combined in the intrinsic plus position. We found that the reliability of RIHM measurements in nerve injury patients was comparable to grip and pinch strength measurements and is appropriate to study the functional recovery of the intrinsic muscles of the hand in isolation. We have applied the RIHM in a recent study on the long-term outcome of muscle strength in patients with ulnar and median nerve injuries and found that while recovery of grip and pinch strength was relatively good, recovery of the ulnar nerve innervated muscles measured with the RIHM was poor. This poor recovery could not be detected with manual muscle strength testing or with grip and pinch dynamometry. We conclude that the RIHM provides an accurate clinical assessment of the muscle strength of the intrinsic hand muscles that adds valuable information to MMT and grip and pinch dynamometry.
The knee extension force of 50 patients was investigated using traditional manual muscle testing and hand-held dynamometry. The relationship between manual muscle test word scores and dynamometer force scores was determined using Kendall tau, as was the relationship between manual muscle test percentage scores and dynamometer scores expressed as a percentage of "normal." Percentage scores were also compared to determine if a significant difference existed. Manual muscle test scores and dynamometer test scores were significantly correlated (p less than .001). Percentage manual muscle test and dynamometer test scores were significantly different (p less than .001). These results suggest that the two procedures measure the same variable-strength. Manual muscle test percentage scores of knee extension may, however, overestimate the extent to which a patient is "normal."
AIMS: Fatigue is a common complaint in diabetic patients during periods of hyperglycaemia. To test whether muscle performance is reduced during acute hyperglycaemia, diabetic patients were studied whilst performing maximal isokinetic and isometric contractions. METHODS: In this double-blind placebo controlled study, maximal isometric and isokinetic muscle strength was determined in seven Type 1 diabetic patients during normo- and hyperglycaemia using a hyperglycaemic clamp technique. On two separate days, maximal muscle strength of the knee extensors was determined quantitatively using a dynamometer. On both days, muscle strength was determined before a constant blood glucose level was obtained and after the blood glucose level had been kept constant at either 5 or 16 mmol/l for 3 h. Percentage of change from baseline at the two glycaemic levels were calculated and compared. In addition, the changes from baseline at these glycaemic levels were related to glucose turnover. RESULTS: Following hyperglycaemia, a significant decrease in maximal isometric muscle strength was found as compared with normoglycaemia (86 vs. 104% of the initial level) (P = 0.018). In contrast, no alteration of maximal isokinetic muscle strength was found comparing normo- and hyperglycaemia (96 and 95%) (P = 0.74). Changes in muscle strength were not significantly related to either basal or hyperglycaemic glucose turnover. CONCLUSIONS: A few hours of hyperglycaemia in Type 1 diabetic patients leads to a reduction of isometric muscle performance, whereas isokinetic muscle strength is unchanged. The reduction in muscle strength could play a role in the development of fatigue and is related more closely to ambient glucose concentrations than to systemic glucose availability.
In forty-four female patients with primary fibromyalgia, muscle function was related to clinical parameters such as age, height, number of tenderpoints, subjective scores of physical capacity and number of subjective symptoms. Muscle function was determined as the dynamic muscle strength measured with an isokinetic dynamometer. Muscle function was found to be low in primary fibromyalgia patients with pronounced muscle tenderness compared to matched controls. Furthermore the reduction in muscle function increased with increasing number of tenderpoints and subjective symptoms. In primary fibromyalgia patients correlations between muscle strength and age/height were either not present or were weaker than in the control subjects. It is concluded that voluntary dynamic muscle strength is a useful parameter for measuring disease impact in primary fibromyalgia patients.
A standard procedure for measurements of calf muscle strength with an isokinetic dynamometer is presented. The method is based on recordings in supine position, with a straight knee joint and a firm fixation of the foot in a new device. The reproducibility was studied by a test-retest procedure in ten testing subjects. The methodological error varied between 5 and 10% and the coefficient of reliability varied between 0.94 and 0.98. The coefficient of variation when measuring one testing subject at ten different occasions was smaller at isokinetic than at isometric measurements.
Leg compliance is "causally related with greater susceptibility" to orthostatic stress. Since peak O2 uptake (peak VO2) and muscle strength may be related to leg compliance, we examined the relationships between leg compliance and factors related to muscle size and physical fitness. Ten healthy men, 25-52 yr, underwent tests for determination of vascular compliance of the calf (Whitney mercury strain gauge), peak VO2 (Bruce treadmill), calf muscle strength (Cybex isokinetic dynamometer), body composition (densitometry), and anthropometric measurements of the calf. Cross-sectional areas (CSA) of muscle, fat, and bone in the calf were determined by computed tomography scans. Leg compliance was not significantly correlated with any variables associated with physical fitness per se (peak VO2, calf strength, age, body weight, or composition). Leg compliance correlated with calf CSA (r = -0.72, P less than 0.02) and calculated calf volume (r = -0.67, P less than 0.03). The most dominant contributing factor to the determination of leg compliance was CSA of calf muscle (r = -0.60, P less than 0.06), whereas fat and bone were poor predictors (r = -0.11 and 0.07, respectively). We suggest that leg compliance is less when there is a large muscle mass providing structural support to limit expansion of the veins. This relationship is independent of aerobic and/or strength fitness level of the individual.