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Results for “Muscle Strength Dynamometer”

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PubMed1990

[The effect of meniscectomy on the strength of the femoral quadriceps muscle after more than 3 years].

This paper investigates the strength of the quadriceps extensor femoris following partial meniscectomy by means of arthrotomy. Measurements were carried out on 30 patients using a velocity-controlled dynamometer. Follow-up ranged from three to twelve years. On clinical examination 17 patients revealed atrophy of the quadriceps, amounting to 1 cm in 12 patients and up to 2 cm in 5 patients. The average difference in muscular strength between the operated leg and the non-operated one totalled 11% in the cases of 1 cm atrophy and 19% in the 2 cm cases. Those patients who presented with no atrophy on the operated leg had an average loss of 4% in muscular strength, which is within the normal range. In addition, an interrelationship was established between measurements carried out at different angular velocities and the extent of quadriceps atrophy. The high percentage of patients showing a weakness of the quadriceps extensor femoris after a long follow-up period is most likely due to the severing of proprioceptors during surgery and to inadequate or lacking postoperative physiotherapy.

Adult↗

PubMed1993

Influence of isotonic, isometric and isokinetic muscle strength on bone mineral density of the spine and femur in young women.

Bone mineral density (BMD) is dependent on multiple influences including genetics, mechanical forces, hormonal changes and nutritional mechanisms. The mechanical forces are, in part, influenced by muscle strength. This study examined the relationships between BMD of the spine and femur with muscle strength. Eighty-one healthy, non-athletic women aged 20-30 years were the subjects in the study. BMD was measured by dual energy x-ray absorptiometry. Trunk strength was measured by a Wagner Dynamometer or a Cable Tensiometer and leg strength was measured with a Cybex II isokinetic dynamometer. Trunk, leg and hip strength was also measured using 1 RM (one repetition maximum). There were significant correlations between spine density and trunk extension (r = 0.40, P = 0.0001) and spine density and trunk flexion (r = 0.30, P = 0.0037). There were significant correlations between femoral neck density and knee extension (r = 0.40, P = 0.003) and femoral neck density and knee flexion (r = 0.24, P = 0.0240). Multiple regression analysis showed that amongst young adult females weight and trunk extensor muscle strength contributed about equally to spine density. Flexor muscle strength did not influence bone density.

Absorptiometry, Photon↗

PubMed1996

Relationship between baseline insulin-like growth factor-I (IGF-I) and femoral bone density in women aged over 70 years: potential implications for the prevention of age-related bone loss.

OBJECTIVE: To test the hypothesis that the decline in femoral bone mass associated with healthy aging is partially accounted for by deficiency of the growth hormone-insulin-like growth factor-I (IGF-I) axis. DESIGN: Cross-sectional study. STUDY PARTICIPANTS: A sample of 245 community-dwelling healthy women aged 70 and older. Exclusion criteria were diseases or medications known to affect the musculoskeletal system or the somatotrophic axis. MEASUREMENTS: Serum levels of IGF-I, calcitriol, and osteocalcin were determined by radioimmunoassay; serum calcidiol was measured by competitive binding assay, and serum parathyroid hormone (PTH) was assessed immunochemically. Urinary pyridinium crosslinks were measured by fluorescent detection after high-pressure liquid chromatography. Isometric and isokinetic quadriceps strength was evaluated using an isokinetic dynamometer. Bone density (BMD) was assessed by dual-energy X-ray absorptiometry at the proximal femur. Multiple regression was used to adjust for potential confounders. RESULTS: At the proximal femur, BMD declined by 0.59-0.84% per year. In addition to body mass index and muscle strength, serum IGF-I was found to be an independent predictor of BMD at all femoral sites. CONCLUSION: The data support the hypothesis that circulating IGF-I not only reflects the integrated growth hormone secretion but also has a direct role in the endocrine regulation of bone remodeling. The present findings support the need for further studies to assess the potential of IGF-I in attenuating age-related femoral bone loss.

Age Factors↗

PubMed1999

Strength assessment in postpolio syndrome: validity of a hand-held dynamometer in detecting change.

OBJECTIVES: To investigate the validity, the intraexaminer and interexaminer reproducibility, and the ability to detect change of a hand-held dynamometer (HHD) in strength measurements in former polio subjects. DESIGN: HHD measurement of knee extensor strength was compared with the criterion standard of a chair dynamometer measurement in 49 subjects. The "break" method was used for HHD measurements. Reproducibility was studied for six lower extremity muscle groups in 28 subjects. The measurements were performed by one experienced and one inexperienced examiner on two separate occasions, with an interval of 1 week. The examiners were blinded to each other's and to previous results. SETTING: University hospital. SUBJECTS: Volunteer sample of former polio subjects. RESULTS: For knee extension, the forces that could be measured with the HHD were limited to approximately 200N. Although the intraclass correlation coefficients were high (.75 to .98), the 95% limits of agreement between measurements showed large intervals for differences between two measurements (ratio intervals ranging from .76-1.52 to .52-2.77). The intraexaminer reproducibility for the experienced examiner was superior to that of the inexperienced examiner. The reproducibility of the inexperienced examiner showed systematic bias, with significantly higher strength values for the second session measurement of three muscle groups. CONCLUSION: The device has good validity in the lower force range. However, because the agreement between measurements was poor, it has limited ability to detect a change in muscle strength. Therefore, this method is unable to detect small changes in lower extremity muscle strength in former polio patients.

Clinical Competence↗

PubMed1998

Donor-site morbidity after pedicled or free TRAM flap surgery: a prospective and objective study.

The main disadvantage when the transverse rectus abdominis musculocutaneous (TRAM) flap is used for breast reconstruction is the potential for weakening of the abdominal wall. This prospective study was initiated to objectively evaluate abdominal muscle strength after pedicled and free TRAM flap breast reconstructions over time. Twenty-three patients with pedicled TRAM flaps and 19 patients with free TRAM flaps were included. A dynamic dynamometer system, KIN-COM, was used to measure maximal voluntary trunk flexor and extensor strength preoperatively and 6 and 12 months postoperatively. The patients' subjective opinions 1 year postoperatively were recorded by means of a questionnaire. A transient decrease in abdominal strength, in both groups, occurred at 6 months but was essentially regained at 12 months. The use of a pedicled or free TRAM flap did not influence postoperative abdominal strength per se. The balance between the abdominal strength and back strength remained in the free flap group but was altered postoperatively in the pedicled flap group; back strength was increased and remained so after 12 months. The difference between the two procedures is relatively small compared with individual variations, indicating that there are more important factors than the kind of surgery influencing the restoration of muscle strength. The questionnaire revealed a greater occurrence of abdominal wall bulging in the free flap group (82 percent) versus 48 percent in the pedicled flap group. No postoperative differences regarding exercise frequency or sensitivity of the abdominal wall were found between the pedicled and free TRAM flap groups.

Abdominal Muscles↗

PubMed1991

Quantitative cervical flexor strength in healthy subjects and in subjects with mechanical neck pain.

Although weakness of anterior cervical muscles is postulated to contribute to persistent neck pain in patients with mechanical neck pain, quantitation of weakness has never been reported. We compared anterior cervical muscle strength in 30 subjects with mechanical neck pain and in 30 asymptomatic control subjects. Testing was performed with the subject supine, chin retracted, and neck flexed. Assessment was made using a hand-held dynamometer with head held at the midline and with rotation left and right within a pain-free range. Analysis with Wilcoxon scores showed that patients with neck pain had significantly less (p less than .05) strength (N.Kg-1) in all three positions than controls (1.16 +/- 0.49 vs 1.71 +/- 0.42, sagittally; 1.01 +/- 0.52 vs 1.47 +/- 0.41, rotation left; .99 +/- 0.46 vs 1.43 +/- 0.43 rotation right; neck pain vs control, respectively.) This weakness and its role in persistent neck pain should be recognized. The efficiency and effect of cervical muscle strengthening in treatment of chronic neck pain should be further defined.

Adult↗

PubMedDate not supplied

The effect of diagnostic and operative arthroscopy and open meniscectomy on muscle strength in the thigh.

In this study we measured the effect on the muscle strength in the thigh in connection with diagnostic arthroscopy with central approach, arthroscopy with arthroscopic operation of bucket-handle ruptures, flap tears, total arthroscopic meniscectomy, and open meniscectomy. Thirty-seven patients were tested preoperatively and 1, 4 and 8 weeks postoperatively with a Cybex II isokinetic dynamometer. The extensor muscles of the knee joint were most affected. The flexor muscles were generally recovered in all groups within a month. Diagnostic arthroscopy and arthroscopic operations for bucket-handle ruptures showed no significant effect on the thigh muscle torque. With the other arthroscopic operations there was a 40% decrease of quadriceps function 1 week after operation. After 8 weeks normal function returned. Open meniscectomy had a much more negative effect on the quadriceps muscle with a decrease of about 70% after 1 week. After 8 weeks, the rehabilitation was still not complete.

Adolescent↗

PubMed2005

Bone properties and muscle strength of young haemophilia patients.

PURPOSE: To evaluate bone properties, muscle strength and the relationship between the two, in young (7.0-17.7 years) haemophilia patients (h) and healthy boys (c). SUBJECTS: Twenty-seven boys with severe haemophilia and 33 healthy boys, of similar age, body mass, height, (mean +/- sd for h and c, respectively: 11.2 +/- 3.2 vs. 11.4 +/- 2.9 years, 42.6 +/- 16.6 vs. 41.6 +/- 17.3 kg, 145 +/- 18 vs. 146 +/- 17 cm) and pubertal stage according to secondary sex characteristics, volunteered for the study. all subjects were physically inactive (as determined by questionnaire). METHODS: Subjects performed isokinetic elbow and knee extension and flexion tests at two angular velocities (biodex system ii dynamometer). Bone properties were evaluated by qualitative ultrasound (sunlight omnisense), at the distal radius and tibial mid-shaft. H subjects received prophylactic factor viii treatment within the 24 h preceding testing. No test was performed in the presence of haemorrhage. RESULTS: Muscle strength was consistently higher in c compared with h, especially in the lower limbs (e.g. knee extension: 1.80 +/- 0.44 vs 1.48 +/- 0.53 N x m x kg(-1) body mass, respectively, p = 0.01). No differences were observed in tibial or radial speed of sound between groups. Correlations between muscle strength and bone properties were observed only in the lower limbs and only in c (r = 0.37-0.48). CONCLUSION: Muscle strength, especially lower limbs' strength, was lower in haemophilia patients compared with a matched, similarly inactive population of healthy boys. Nevertheless, at this age range, this relative weakness is not associated with inferior bone properties.

Adolescent↗

PubMedDate not supplied

Fate of the psoas muscle after open reduction for developmental dislocation of the hip (DDH).

We evaluated the anatomic and functional consequences of psoas lengthening during operative intervention for developmental dislocation of the hip (DDH). Possible anatomic changes were assessed by magnetic resonance imaging (MRI), and functional assessment included strength determination by an isokinetic dynamometer and gait analysis. Six girls and one boy, ranging in age from 15 to 20 months, had operative reduction of a unilateral DDH. One closed and six open reductions (three anteromedial and three anterolateral approaches) were performed. Follow-up ranged from 4 years 0 months to 9 years 2 months. The cross-sectional area determined by MRI of the lengthened psoas muscles was markedly reduced for all of the six open-reduction patients (three moderate and three severe). Atrophy of the iliacus muscle also was apparent by MRI in five of the six open-reduction patients. Maximum flexion torque, as determined by the isokinetic dynamometer, was diminished on the DDH side for the three patients whose hips were reduced open through the anteromedial approach. Average hip-flexion torque over the entire range of motion was decreased for both anteromedial and anterolateral groups on the operated-on side. Lengthening of the psoas tendon during open reduction of a DDH is associated with considerable atrophy of the psoas muscle.

Atrophy↗

PubMedDate not supplied

Reliability and validity of the DynEx dynamometer.

Abstract The purpose of the study was to examine the reliability and validity of the digital DynEx dynamometer. Grip strength testing was conducted on 100 healthy subjects (aged 20-40 years) using both the Jamar and DynEx dynamometers in the second handle position. The data were analyzed for test-retest reliability and concurrent validity using the intraclass correlation coefficient. A repeated-measures analysis of covariance was conducted to reveal differences in grip strength between instruments. In addition, measurement error was calculated with known weights. The DynEx dynamometer was found to have high test-retest reliability both with human subjects ( r = 0.9864) and with known weights suspended from the dynamometer's handle ( r = 0.9999). The DynEx dynamometers had a smaller measurement error (1.63%) than the Jamar dynamometers (7.74%). Although significant differences were found between grip scores obtained on the Jamar and the DynEx (F = 6.222; p = 0.014), the concurrent validity between the two instruments was excellent ( r > 0.98). The results of this study indicate that clinicians can use the DynEx dynamometer at the second handle position knowing that it is reliable, valid, and comparable to the second handle position of the Jamar dynamometer.

Adult↗

PubMed2004

Sports massage after eccentric exercise.

BACKGROUND: The use of sports massage is very common in the athletic community. However, only a few studies have shown any therapeutic effect of massage. HYPOTHESIS: Sports massage can improve the recovery after eccentric exercise. STUDY DESIGN: Prospective randomized clinical trial. METHODS: Sixteen subjects performed 300 maximal eccentric contractions of the quadriceps muscle bilaterally. Massage was given to 1 leg, whereas the other leg served as a control. Subjects were treated once daily for 3 days. Maximal strength was tested on a Kin-Com dynamometer, and functional tests were based on 1-leg long jumps. Pain was evaluated using a visual analog scale. RESULTS: There was a marked loss of strength and function of the quadriceps directly after exercise and on the third day after exercise. The massage treatment did not affect the level or duration of pain or the loss of strength or function following exercise. CONCLUSION: Sports massage could not improve the recovery after eccentric exercise.

Adult↗

PubMed2002

Isokinetic evaluation of the knee in patients with rheumatoid arthritis.

OBJECTIVES: Rheumatoid arthritis is a chronic inflammatory disease with a clinical picture of arthritis, muscle hypotrophy, loss of range of motion, loss of strength and disability. The objective of this study was to evaluate knees of patients with rheumatoid arthritis using an isokinetic dynamometer. METHODS: Fifty patients with a diagnosis of rheumatoid arthritis and 50 control subjects were evaluated using an isokinetic dynamometer (Cybex 6.000) regarding the following parameters: peak torque, peak torque angle, power, total work, peak torque acceleration time, set total work, torque acceleration energy ('explosion') and endurance. Comparisons between rheumatoid arthritis and the control group, left side versus right side, flexors and extensors and the proportion between flexors and extensors were made. The subjects were also evaluated through the Health Assessment Questionnaire, visual and analogical scale of pain, EPM-ROM and goniometry of the knee. RESULTS: The results showed that patients with rheumatoid arthritis have less strength than the control group (P < 0.05); the extensors are stronger than the flexors (P < 0.05); no significant differences between the right and the left knee for rheumatoid arthritis and the control group were observed and the proportion between flexors and extensors is the same in both groups. We concluded that regarding the isokinetic parameters, the knees of subjects with rheumatoid arthritis are different from normal knees with decreased strength parameters, maintaining the proportion between flexors and extensors with a global loss of strength in the segment, excluding the high speeds in some of the parameters.

Adult↗

PubMedDate not supplied

The strength characteristics of internal and external rotator muscles in professional baseball pitchers.

The purpose of this study was to establish a data base regarding the isokinetic muscular performance characteristics of the external/internal rotator muscles of professional baseball pitchers. One hundred fifty healthy professional baseball pitchers were evaluated by use of a Biodex isokinetic dynamometer. The subjects tested had a mean age of 23.4 years and a mean body weight of 199 pounds. Isokinetic tests were performed concentrically at 180 and 300 deg/sec for both the throwing and nonthrowing shoulders. Testing procedures regarding positioning and stabilization followed established guidelines. The testing protocol and actual test repetitions were standardized for each subject. Statistical analysis was performed using the Pearson Product Moment Correlation and paired t-tests. Determination of the correlation coefficient was made at the P < 0.05 level of significance. Test results for bilateral comparison of mean peak torque for the throwing and nonthrowing shoulders indicated no statistically significant difference between the internal rotators at both test speeds, or for the external rotators at 300 deg/sec. There was a significant statistical difference at the 180 deg/sec test speed for the external rotators. The external/internal rotator strength ratio indicated a 65% ratio at 180 deg/sec and a 61% ratio at 300 deg/sec. Data were also collected for mean peak torque/body weight ratios of the throwing shoulder to establish a data base in professional throwers. This study offers clinical relevance in establishing a muscle performance profile for the professional thrower. This data base can therefore be used as criteria that should be met before an injured pitcher can be returned to throwing at the professional baseball level.

Adolescent↗

PubMed2001

Associations of isokinetic knee extensor and flexor strength with steroid use and walking ability in women with rheumatoid arthritis.

Seventy-five women with rheumatoid arthritis according to the 1987 criteria of the American Rheumatism Association were examined. Mean age was 61.9 +/- 12.5 years, mean disease duration 14 years. Sixty-three were or had been on steroids (median cumulative prednisolone dose 2.5 g). Maximal voluntary knee extensor and flexor strength (Nm) was assessed at 30 degrees/s by an isokinetic dynamometer. Walking ability was expressed as walking and stair-climbing time (s). Markers of disease activity included number of swollen and tender joints, pain as recorded by the patients on a visual analogue scale (VAS), and disability as scored by the Stanford Health Assessment Questionnaire (HAQ). Muscle strength, walking time (50 m) and stair-climbing time were reduced on average by 30%, and increased by 28% and 54% (p<0.0001), respectively, compared to 67 age-, weight- and height-matched healthy women. Associations between muscle strength and cumulative or current steroid dose were not found after correction for age and disease duration. Significant linear correlations were found between knee extensor strength and walking time (r =-0.78, p<0.0001) and stair-climbing time (r = -0.76, p<0.0001). Similar correlations were found for flexor strength. The correlations remained significant (Rpartial ranging from -0.64 to -0.69, p<0.0001) in multiple regression analyses adjusting for age, height, weight, disease duration, number of swollen and tender joints, and VAS and HAQ scores. In conclusion, negative effects of steroids on muscle strength were not demonstrated. Leg muscle strength is an important and independent determinator of walking ability in RA.

Aged↗

PubMed1991

Strength recovery and muscle activation of the knee extensor and flexor muscles after arthroscopic meniscectomy. A pilot study.

Maximal isokinetic strength and electromyographic activity of the operated leg were measured preoperatively and one, two, three, and eight weeks postoperatively after a partial medial meniscectomy by arthroscopy in a group of ten patients. Strength deficits, measured with a Kin-Com dynamometer using a static preloading protocol, were found in comparison with a group of matched healthy subjects preoperatively and three and eight weeks postoperatively in the knee extensors. These deficits were related to previously unreported modifications in the shape of the moment-angle curves and a tendency to lower activation levels of the vastus medialis (VM) but not the vastus lateralis or rectus femoris muscles. No deficits were found in the knee flexors preoperatively or three and eight weeks postoperatively, but the medial hamstrings activation level was lower for movements at 30 degrees per second. During flexion movements, the percentage of coactivation of the antagonist VM was significantly greater than healthy values at 30 degrees and 180 degrees per second. These results clearly indicate that neuromuscular recovery is not complete when return to work is advocated three to four weeks postoperatively. Such findings suggest the need for a rehabilitation program to promote recovery of the knee muscles in workers with a physically demanding occupation.

Adult↗

PubMed1990

Effects of age and regular exercise on muscle strength and endurance.

Twenty male and 20 female non-professional tennis players were classified into two different age groups (n = 10 per group): young active men (30.4 +/- 3.3 years), young active women (27.5 +/- 4.3 years), elderly active men (64.4 +/- 3.7 years), and elderly active women (65.3 +/- 4.5 years). These individuals were matched (n = 10 per group) according to sex, age, height and mass to sedentary individuals of the same socio-economical background: young sedentary men (29.2 +/- 3.4 years), young sedentary women (25.6 +/- 4.4 years), elderly sedentary men (65.2 +/- 3.2 years) and elderly sedentary women (65.6 +/- 4.4 years). An isokinetic dynamometer was used to measure the strength of the knee extensors and flexors (two separate occasions) and the endurance of the extensors. Vastus lateralis electromyogram (EMG) was measured concomitantly. Significant sex, age and exercise effects (P less than 0.001) were observed for peak torque of both muscle groups. The effect of age on extensor strength was more pronounced at high speeds where men were also able to generate larger relative torques than women. No age or sex effects were noted for muscle endurance. However, muscles of active individuals demonstrated a greater resistance to fatigue than those of sedentary individuals. In conclusion, men were found to be stronger than women, age was associated with a decrease in muscle strength, but not of muscle endurance, and tennis players were stronger and had muscles that were more resistant to fatigue than their sedentary pairs in both age groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1980

A back and lift test.

In addition to the standard medical examination, a back and lift test has been introduced in the hiring of new employees. 100 men have been tested to date. Only people with no history of back trouble were tested. Body height and weight were measured and the isometric capacity of the back extensors and the strength of abdominal musculature were measured with a Darcus dynamometer. A series of lifts with gradually increasing weight were performed in order to find the subject's 'acceptable weight'. The correlation coefficients for these different test variables was consistently poor, and thus it is not possible to predict a person's true lifting capacity from knowledge of muscle strength, height and body weight. The subjects stood upon a force plate during the lifts, which recorded the vertical and horizontal forces, and the force of inertia exerted by the subject during the lift could be calculated. The activity in the back extensors, rectus abdominis and external oblique muscle was recorded. The flexibility of the lumbar spine was calculated.

Journal Article↗

PubMed2002

Hip muscle strength and muscle cross sectional area in men with and without hip osteoarthritis.

OBJECTIVE: To study the hip muscle strength and cross sectional area (CSA) in men with hip osteoarthritis (OA) compared to age and sex matched healthy controls. METHODS: Based on the American College of Rheumatology criteria regarding classification of hip OA, 27 men (aged 47-64 yrs) with unilateral or bilateral hip OA and 30 age matched randomly selected healthy male controls were studied. The maximal isometric hip abductor, adductor, flexor, and extensor strength (Nm) at 0 degree of hip flexion in the supine position was determined with a dynamometer. The isokinetic hip flexion and extension strength (peak torque, Nm) was determined using angular velocities of 60 degrees /s and 120 degrees /s. The subjective severity of hip pain was rated by visual analog scale prior to the muscle strength test. CSA of the pelvic and thigh muscles was measured from magnetic resonance images. RESULTS: The reliability of intraclass correlation coefficients for repeated measures of muscle strength varied from 0.70 to 0.94 in controls and from 0.84 to 0.98 in subjects with OA. Hip isometric adductor and abductor strength was 25% and 31% lower (p < 0.001) in OA subjects than in controls, respectively. The hip isometric and isokinetic flexion strength was 18-22% lower (p < 0.01) in OA subjects than in controls, but extension strength did not differ between groups. In OA subjects, the hip flexion and extension isometric and isokinetic strength values were 13-22% lower (p < 0.05) on the more deteriorated side compared to the better side. CSA of the pelvic and thigh muscles did not differ between the groups. However, in OA subjects, the CSA of the pelvic and thigh muscles was 6-13% less (p < 0.05 to < 0.001) on the more severely affected hip compared to the better hip. CONCLUSION: Men with hip OA have significantly lower abduction, adduction, and flexion muscle strength than controls. The decrease of muscle size and hip pain may contribute to the decrease of muscle strength in hip OA. Other possible underlying causes of the muscle weakness need to be studied.

Anatomy, Cross-Sectional↗