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Results for “Muscle Strength Dynamometer”

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PubMed1996

Nature of age-related changes in muscle strength of the extremities of women.

Age-related changes in the muscle strength of the extremities of 123 women (20-79 years) were measured using a hand-held dynamometer. The isometric strength of three upper- and three lower-extremity muscle actions declined across ages. The magnitudes of strength decreases were a function of both the action and side tested. The earlier and steeper strength declines in actions of functional importance, e.g., knee extension, should alert those working with aging women of the potential importance of strengthening such muscle actions.

Adult↗

PubMedDate not supplied

Influence of active release technique on quadriceps inhibition and strength: a pilot study.

OBJECTIVE: To determine if Active Release Technique (ART) protocols could be used as an effective way to influence strength and muscle inhibition in the quadriceps muscles of athletes with anterior knee pain. DESIGN: Pilot clinical outcome study. METHODS: The sample consisted of 9 athletes (4 male athletes, 5 female athletes) who were identified as suffering from unilateral anterior knee pain. A Biodex dynamometer and the interpolated twitch technique were used to determine isometric strength and inhibition in the quadriceps muscles, respectively. The treatment intervention consisted of the Active Release Technique treatment protocols for anterior knee pain. The experimental leg and contralateral leg were tested pretreatment and posttreatment, and the experimental leg was tested a third time approximately 20 minutes posttreatment. RESULTS: Knee extensor moments were calculated by multiplying the moment arm by the forces measured by the Biodex dynamometer. Percentage of muscle inhibition was calculated by dividing the interpolated twitch torque (ITT) by the resting twitch torque (RTT), that is (ITT/RTT*100). A repeated measures analysis of variance (ANOVA) was used to compare pretreatment and posttreatment values for strength and muscle inhibition for the experimental and contralateral knees. The results showed no statistical significance. CONCLUSION: ART protocols did not reduce inhibition or increase strength in the quadriceps muscles of athletes with anterior knee pain. Further study is required.

Adult↗

PubMed2005

One-legged bicycling as an assessment tool for patients with stroke.

OBJECTIVE: To assess whether one-legged bicycling correlates with muscle strength and thereby could work as an outcome measure for persons with stroke. METHODS: The study comprised 29 men (age 35-65) with a first occurrence of stroke 6-35 months earlier. Each leg was evaluated separately. A ramp protocol was used (10 W/min), with continuous recording of the ventilatory uptake (Vo(2)) and heart rate. An isokinetic dynamometer was used to assess strength and endurance. Enzyme assays were performed on muscle biopsy samples. RESULTS: The peak isometric strength and isokinetic strength of the paretic leg correlated with the max. W on the bicycle. The oxidative enzyme citrate synthase correlated with the workload for both legs on the bicycle and lactate dehydrogenase correlated with peak isometric strength in both legs. CONCLUSIONS: The one-legged bicycle exercise test can be used to assess endurance in persons with a previous stroke as it correlates with dynamometer testing and muscle biopsies.

Adult↗

PubMed1989

Hamstring/quadriceps strength ratios in knees with medial collateral ligament insufficiency. Isokinetic and isometric results and their relation to patients' long-term recovery.

The purpose of this study was to investigate the peak torque and total work hamstring/quadriceps strength ratios (HQ-ratios) of 25 knees with medial collateral ligament (MCL) insufficiency and to find out the possible relation between different HQ-ratios and the long-term outcome of the patients. The isokinetic (speed 60 and 180 degrees/sec) and isometric muscle strengths were measured by a Cybex II dynamometer. Three standardized knee scoring scales were used to determine the subjective, clinical, and radiological outcome of the knees with MCL insufficiency. All tests showed great interpersonal variation in HQ-ratios even in the healthy knees (range from 23% to 183%). The average HQ-ratios between the uninjured and injured legs did not differ significantly from each other (range from 40% to 82%). The mean peak torques and total work of hamstrings as well as of quadriceps were slightly, but not significantly lower in the injured leg than on the uninjured side. The follow-up scores did not differ significantly between patient groups with low (less than or equal to 50%), optimal (50-80%), or high (greater than or equal to 80%) absolute HQ-ratios of the MCL insufficient knee. However, in every test the scores were significantly better for patients with an HQ-ratio difference of less than or equal to 15% between the injured and the uninjured side than for those with a clear difference (greater than 15%). The findings suggest that the HQ-ratio is a patient-specific parameter and that any general recommendation on its optimal value is difficult to give.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Effect of early mobilisation on grip strength, pinch strength and work of hand muscles in cases of closed diaphyseal fracture radius-ulna treated with dynamic compression plating.

AIMS: The purpose of the study was to objectively determine the effects of early mobilisation in terms of grip strength and work of hand muscles in cases of closed diaphyseal fracture radius - ulna treated with dynamic compression plating. SUBJECTS AND METHODS: Fifty normal subjects and Twenty-one patients, (Eleven patients treated with early active and resistive goal directed mobilisation and Ten control group) were assessed for pinch strength and grip strength on Pinch Dynamometer and Jamar Dynamometer and work of hand muscles on Ergograph. Standardised positions of the equipments and patients were maintained throughout the study. RESULTS: Results showed highly significant reduction in performance in patients treated with early mobilisation as compared to normal subjects in their first assessment (Fourth week post operatively). These patients showed significant improvement in successive assessments (sixth & eighth post operative week) on exercising in between these assessments. CONCLUSIONS: There are significant effects on grip strength and work of hand muscles in patients treated with that early active and resistive goal directed mobilisation.

Adult↗

PubMed2006

[Masticatory muscle activity during exertion of the back].

PURPOSE: The lower jaw is considered to be fixed during body exercise. However, its mechanism remains to be elucidated. The present study investigated masticatory muscle activity during of the back. METHODS: The subjects were 9 healthy dentulous patients. The maximum back strength of the patients was measured with a back-dynamometer. Muscle activities of the temporal, masseter and digastric muscles during exertion of the back and mastication of peanuts were measured. Muscle activities of the temporal and masseter muscle during maximum voluntary clenching and that of the digastric muscles during exertion of resistance against forced mouth opening were also measured, and maximum voluntary muscle activities were obtained. The relative percentage of each masticatory muscle against maximum voluntary activity was calculated from the data obtained, and muscle activities during exertion of the back, mastication of peanuts and maximum muscle activity were compared. RESULTS: Muscle activities of the temporal, masseter and digastric muscles during exertion of back muscles against maximum voluntary muscle activity were 32.1%, 26.4% and 97.4% respectively. Muscle activities of these muscles during mastication of peanuts against maximum voluntary muscle activity were 40.7%, 36.0% and 17.3% respectively. CONCLUSIONS: Muscle activities during exertion of the back were 30% in the temporal and masseter muscle, and approximately 100% in the digastric muscles. The result suggests that the digastric muscles play a key role in fixing the mandible in all masticatory muscles including jaw-opening and closing muscles. People exert back strength not only in sports but also in daily life. This study demonstrates the stronger involvement of the digastric muscles in fixation of the mandible during exercise than during strong clenching. The results are of interest in terms of mandibular position, occlusal contact and the load on the temporomandibular joint (TMJ) since there is no wide mouth opening.

Adult↗

PubMed1999

Test-retest reliabilty of isokinetic hip adductor and flexor muscle strength.

OBJECTIVE: To determine the test-retest reliability of eccentric hip flexor and adductor peak torque and endurance using a Cybex Norm isokinetic dynamometer and to evaluate muscle soreness after exercise as a result of the testing procedure. DESIGN: Prospective test-retest reliability study. PARTICIPANTS: A total of 19 male volunteers (21-43 years old). INTERVENTION: Tests included hip flexor and adductor peak torque strength measured at 60 degrees/s (concentric and eccentric) and endurance measurements (total work done over 20 continuous concentric/eccentric contractions at 150 degrees/s). Subjects were tested on three occasions at 1-week intervals. MAIN OUTCOME MEASURES: Repeated measures analysis of variance was performed for all dependent variables including the subject's dominant and nondominant side among the three test sessions. Intraclass correlation coefficients (ICCs) were calculated to compare the data between sessions. In addition, simple linear regression analysis was completed to determine the relationship between session measurements for all measures with ICC > 0.75. RESULTS: The main findings of this study are that eccentric peak hip adductor torque was reliably measured on a Cybex Norm isokinetic dynamometer using a continuous eccentric/ concentric cycle protocol at a speed of 60 degrees/s (ICC > 0.84). Peak concentric adductor torque and peak eccentric and concentric hip flexor torque were less reliable using the same protocol (ICC < 0.67). Endurance measurements, using total work done over 20 repetitions, were not reliable for hip flexor and adductor muscle groups using a continuous eccentric/concentric cycle protocol at a speed of 150 degrees/s (ICC < 0.55). Posttest muscle soreness was found to be of significant concern with such a protocol. CONCLUSION: The results from this test-retest reliability study confirm the reliability of eccentric peak hip adductor torque measurements for use clinically and in future research. In addition, the need to assess posttest muscle soreness after isokinetic muscle testing is confirmed.

Adult↗

PubMed1997

Generation II knee bracing for severe medial compartment osteoarthritis of the knee.

OBJECTIVE: To investigate the clinical efficacy of the Generation II (G II) knee brace, a newly developed knee orthosis, on patients experiencing severe medial compartment osteoarthritis (OA) of the knee. DESIGN: Case series. SETTING: A national medical and pharmaceutical hospital in Japan. PATIENTS: Twenty primary OA subjects (excluding those with secondary OA), all older than 55 years of age and experiencing only knee joint problems, were selected according to their ability to walk more than 500 meters independent of support. These patients had arthritis in both knees and no less than one half of normal joint space remaining as revealed by roentgenogram studies. The more severely affected side was selected for bracing. INTERVENTIONS: For 12 months, each patient wore a G II knee brace on the affected knee on a daily basis, removing it only at night. To evaluate the effects of G II OA brace alone, additional use of new oral drugs or any other treatment was prohibited from 1 month before application of the G II OA brace and throughout the trial period. MAIN OUTCOME MEASURES: Clinical efficacy was evaluated using the Japan Orthopaedic Association's knee scoring system. X-ray evaluation was performed with patients standing on one leg. A dynamometer was used to evaluate isokinetic quadriceps muscle strength. The center of gravity was measured using an X-Y recording. Clinical evaluation was performed every 2 months thereafter. Final evaluation was at 12 months. RESULTS: Nineteen of the 20 patients answered that they experienced significant pain relief. Knee pain scores on walking increased from 18.0 to 21.5 and on ascending and descending stairs increased from 12.8 to 15.8. The femorotibial angle decreased in 12 of the patients, and the mean angle decreased from 185.1 degrees before application to 183.7 degrees with the brace on at the final observation period. In addition, isokinetic quadriceps muscle strength increased from an average of 36.8 Nm to 42.8 Nm for all patients. In 17 patients, quadriceps muscle strength increased, while it decreased in 2 and remained the same in 1. Finally, lateral movement of the center of gravity decreased compared with before G II application in all patients. CONCLUSION: G II bracing is a beneficial treatment for severe medial OA of the knee.

Aged↗

PubMed2003

Creatine supplementation in Huntington's disease: a placebo-controlled pilot trial.

OBJECTIVE: To evaluate the effect of creatine (Cr) supplementation (5 g/day) in Huntington's disease (HD). METHODS: A 1-year double-blind placebo-controlled study was performed in 41 patients with HD (stage I through III). At baseline and after 6 and 12 months, the functional, neuromuscular, and cognitive status of the patients was assessed by a test battery that consisted of 1) the Unified Huntington's Disease Rating Scale (UHDRS), 2) an exercise test on an isokinetic dynamometer to assess strength of the elbow flexor muscles, 3) a maximal exercise test on a bicycle ergometer to evaluate cardiorespiratory fitness, and 4) a test to assess bimanual coordination ability. Following the baseline measurements, the subjects were assigned to either a creatine (n = 26) or a placebo group (n = 15). RESULTS: Scores on the functional checklist of the UHDRS (p < 0.05), maximal static torque (p < 0.05), and peak oxygen uptake (p < 0.05) decreased from the start to the end of the study, independent of the treatment received. Cognitive functioning, bimanual coordination ability, and general motor function (total motor scale, UHDRS) did not change from baseline to 1 year in either group. CONCLUSION: One year of Cr intake, at a rate that can improve muscle functional capacity in healthy subjects and patients with neuromuscular disease (5 g/day), did not improve functional, neuromuscular, and cognitive status in patients with stage I to III HD.

Cognition↗

PubMed2004

Normalizing expressions of strength in elite rugby league players.

Physical strength has often been expressed per kilogram of body mass. Research suggests that strength increases in proportion to a body mass raised to a power between 0.6 and 0.7 rather than the ratio held exponent of 1. The current study was designed to identify differences in the strength of elite-level rugby league players and to identify whether ratio (per kg(-1)) expressions would penalize heavier subjects. Fifty-four elite rugby league players were recruited to the study during the preseason. Subjects were classified according to their highest playing level. Players performed 3 maximal lifts, using a dynamometer, to determine leg strength. Body mass and muscle mass estimations were also recorded. Results showed that absolute expressions of strength revealed differences by playing level (p < 0.05). These differences were removed when a ratio scaling technique was applied (p > 0.05). Mass and muscle mass exponents of 0.62 and 0.63 were derived and applied to the strength data. Differences in strength by playing level were reestablished following this adjustment (p < 0.05). These findings emphasize that ratio (per kg(-1)) expressions, despite being commonly used, can penalize heavier athletes and mask differences in performance. Coaches and sports scientists should reconsider using the ratio expression due to its potential for error when describing physical strength.

Adolescent↗

PubMed2006

Validity and reproducibility of hand-held dynamometry in children aged 4-11 years.

OBJECTIVE: To evaluate validity and reproducibility of hand-held dynamometry in 11 different muscle groups in children. DESIGN AND PATIENTS: Maximum isometric muscle strength was measured with a calibrated hand-held dynamometer in 61 patients aged 4-11 years who had been referred to our specialist centre in the past 3 years because of suspected myopathy. All the patients had had muscle biopsy. METHODS: Validity was assessed by the power to discriminate between patients with and without myopathy, using logistic regression analysis and receiver operating characteristic analysis and sensitivity and specificity at a specifically chosen cut-off point. Reproducibility was evaluated by test-retest reliability in a stratified random sample of 40 patients who returned for re-measurements, using the intraclass correlation coefficient and the standard error of measurement. RESULTS: In the patients, areas under the receiver operating characteristic curve ranged from 0.66 to 0.88. At a specifically chosen cut-off point, sensitivity varied from 73% to 87%, while specificity varied from 54% to 80%. Intraclass correlation coefficients ranged from 0.73 to 0.91. The standard error of measurement ranged from 3.3 N to 12.2 N. CONCLUSION: Performance of hand-held dynamometry varied widely in the 11 muscle groups. Highest performance was observed in the elbow flexors. Test-retest reliability of the mean value of 2 efforts was generally higher than the maximum value.

Child↗

PubMed1994

Effects of 10 and 20 days bed rest on leg muscle mass and strength in young subjects.

Sedentary voluntary students were exposed to 10 (n = 8) and 20 (n = 14) days bed rest to study effects of prolonged bed rest on isometric strength of knee extension and flexion, total leg strength, right hand grip and elbow flexion using different dynamometers. Further, muscle mass of right leg and arm was measured by dual energy X-ray absorptiometry, and cross sectional area of right thigh by X-ray computed tomography before and after bed rest and after 4 or 8 weeks of recovery. After 10 days bed rest, these variables tended to decrease except for the muscle mass of right arm which increased. After 20 days of bed rest, a similar trend was observed, but at a statistically significant level of p < 0.05. However, no correlation was observed between the decrease in knee extensor strength and cross sectional area of the thigh. Nor was a correlation observed between the sum total of isometric strength of the leg and the total muscle mass measured. The 24h urinary excretion of N2 and creatinine was not changed through the experiments. During recovery, the variables measured had reached the initial levels after 4 or 8 weeks. These changes were not affected by mild supine exercise training. The results suggest that isometric muscle strength was decreased in non-antigravity muscles as well as antigravity muscles by prolonged bed rest, but the rate of changes did not correlate to the corresponding changes in muscle mass. The decreases in maximum voluntary strength are probably not only due to the decrease in muscle mass but also due to reductions of neuromuscular function.

Absorptiometry, Photon↗

PubMed1997

Comfortable and maximum walking speed of adults aged 20-79 years: reference values and determinants.

OBJECTIVES: to establish reference values for both comfortable and maximum gait speed and to describe the reliability of the gait speed measures and the correlation of selected variables with them. DESIGN: descriptive and cross-sectional. METHODS: subjects were 230 healthy volunteers. Gait was timed over a 7.62 m expanse of floor. Actual and height normalized speed were determined. Lower extremity muscle strength was measured with a hand-held dynamometer. RESULTS: mean comfortable gait speed ranged from 127.2 cm/s for women in their seventies to 146.2 cm/s for men in their forties. Mean maximum gait speed ranged from 174.9 cm/s for women in their seventies to 253.3 cm/s for men in their twenties. Both gait speed measures were reliable (coefficients > or = 0.903) and correlated significantly with age (r > or = -0.210), height (r > or = 0.220) and the strengths of four measured lower extremity muscle actions (r = 0.190-0.500). The muscle action strengths most strongly correlated with gait speed were nondominant hip abduction (comfortable speed) and knee extension (maximum speed). CONCLUSIONS: these normative values should give clinicians a reference against which patient performance can be compared in a variety of settings. Gait speed can be expected to be reduced in individuals of greater age and of lesser height and lower extremity muscle strength.

Adult↗

PubMed1975

[The development of strength in the masticatory muscles and its sensory control].

By means of inductive dynamometers the absolute force of mastication as well as factors influencing that force are studied. In addition to the mechanical effects resulting from the lower jaw's acting as lever arm, the pulp, especially its coronal portion, showed a dominating influence on the extent of the developed adduction force.

Dental Pulp↗

PubMed2005

[Effect of physical training on postural control of elderly].

BACKGROUND: Preservation of balance in the elderly is fundamental to maintaining functional independence. Balance impairments have a tremendous impact on health care costs and quality of life. Fall prevention programs are an important health strategy, consequently there is a general need to develop effective and practical exercise programs that improve balance in the elderly. OBJECTIVE: To explore whether stability can be improved through exercise in inactive old subjects and to determine whether specific balance training proves to be more beneficial to retaining balance than strength training. METHODS: A randomized controlled study was conducted with 42 healthy elderly individuals. They were randomly allocated to three groups: Balance training (BT), Isometric training (IT) and Control (CG) received no intervention; each group consisted of 14 members. "Static" and "dynamic" postural stability were evaluated for seven postural conditions in upright standing before and immediately after 3 months of intervention using a force platform, and an isokinetic dynamometer used to determine whether the training improved muscle strength. RESULTS: The BT group significantly improved their forward-backward stability limits (maximal body lean) post intervention compared with other groups. Plantar and dorsiflexion isometric strength remained the same in all groups. No significant improvement was found in COP based measures in upright standing in all study groups, apart from the BT group that significantly improved parameters in performance with eyes open and during standing on a foam. BT subjects improved their self-confidence post intervention in 64.2%, while IT subjects improved in only 35.7%. CONCLUSIONS: Balance exercises appear to improve balance in the elderly, especially extending the boundaries of their stability a more dynamic component of balance. However it remains to be determined whether the lack of difference between groups in COP measures in upright standing ("static balance") was due to the short period of intervention, small sample size, unchallenged exercise regime or due to the inability of elderly individuals to improve their sway in upright standing.

Aged↗

PubMed2003

Development of a dynamometer for measuring the isometric force of the pelvic floor musculature.

AIMS: The aim of this study was to design and develop a dynamometer providing a direct measurement of pelvic floor muscle (PFM) strength. MATERIALS AND METHODS: Two pairs of strain gauges were mounted on the moveable branch of a dynamometric speculum allowing measurements at different vaginal apertures. Linearity, repeatability, independence of the site of application of the resultant force to the lower branch of the speculum and hysteresis were tested by means of in vitro calibration studies. RESULTS: The linearity proved excellent over a range of 0-15 N with regression coefficients close to unity between imposed loads and voltage outputs. The slopes and intercepts of the regression lines were not significantly different between repeated sessions, indicating the high reliability of these in vitro measurements. The slopes and intercepts of the calibrations, using the same repertoire of loads imposed at three locations on the moving branch of the dynamometer, were not significantly different, confirming that the force measurement is independent of the site of the force application. Hysteresis was considered to be minimal. CONCLUSIONS: This study demonstrates that the dynamometer provides reliable measurements. The new device thus appears to have conceptual and measuring advantages over conventional methods and seems to be a very promising instrument for measuring pelvic floor strength.

Calibration↗

PubMed1997

Two years of growth hormone (GH) treatment increase isometric and isokinetic muscle strength in GH-deficient adults.

GH deficiency in adults is associated with reduced muscle mass and muscle strength. The objective of this trial was to follow the effect of 2 yr of GH treatment in GH-deficient adults on muscle performance in relation to a reference population. Knee extensor and flexor strengths for isometric and isokinetic concentric muscle strength were measured using a Kin-Com dynamometer. Hand-grip strength was measured in both hands. The fatigue index was calculated as the percent reduction in peak torque at 50 repeated isokinetic knee extensions. Superimposed, single twitch electrical stimulation was performed. The GH-deficient subjects had lower isometric knee extensor, knee flexor, and hand-grip strength than the reference population. Two years of GH treatment increased and normalized the mean isometric knee extensor and flexor strengths. The concentric knee flexor and extensor strength at an angular velocity of pi rad/s increased, as did the concentric knee flexor strength at an angular velocity of pi/3 rad/s. The increase in muscle strength was more marked in younger patients and in patients with lower initial muscle strength than predicted. Quadriceps endurance decreased, whereas the effect of superimposing single twitches on isometric contraction and hand-grip strength was unaffected by the GH treatment. Two years of GH therapy in GH-deficient adults increased and normalized isokinetic and isometric muscle strength studied in proximal muscle groups. Hand-grip strength and the degree of lack of maximal motor unit activation on voluntary isometric knee extensor force did not change. The dynamic local muscle fatigue index decreased.

Adult↗

PubMed1997

Muscle strength in rheumatoid elbow: quantitative measurement and comparison to Larsen's X-ray grade.

Accurate assessment of elbow function is important to determine the total ability of the arm. The purpose of this study was to clarify the relationship between isometric muscle strength of the elbows of patients with rheumatoid arthritis (RA) and Larsen's X-ray evaluation. Fifty-six elbows of 45 RA patients aged 47 to 77 years (mean age, 63 years) were tested. Muscle strength was measured with an isometric torque-cell dynamometer. Test-retest reliability of the dynamometer was proven by measuring 12 elbows of 6 healthy young men. In RA patients, elbow flexion and extension strength decreased in proportion to increases in the severity of Larsen's grades from Grade 1 to 4. However, Grade 5 elbows had greater muscle strength than those in Grade 4. Forearm pronation and supination strength also decreased in proportion to increases in the severity of Larsen's grades from Grade 1 to 5. This quantitative study made it clear that the muscle strength of RA patients' elbows almost completely correlates to X-ray finding according to the grade of Larsen's evaluation based on X-rays. With regard to muscle strength of postoperative elbows, both flexion strength and supination strength after total elbow replacement (TER) were about two times greater than before TER, and after synovectomy it was as great as those in non-operative RA patients of Grade 2.

Adult↗