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Results for “Muscle Strength Dynamometer”

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PubMed2005

Relationships between structural and functional measures of nutritional status in a normally nourished population.

BACKGROUND AND AIMS: Both anthropometric and functional measurements have been used in nutritional assessment and monitoring. Hand dynamometry is a predictor of surgical outcome and peak expiratory flow rate has been used as an index of respiratory muscle function. This study aims to measure in normal subjects the relationship between anthropometric measurements, voluntary muscle strength by hand grip dynamometry and respiratory muscle function by peak expiratory flow rate. METHODS: Ninety-eight subjects (46 male, 52 female) with a mean age of 45.9 years were studied. Hand grip strength was measured in the dominant and non-dominant hands with a portable strain-gauge dynamometer. Peak expiratory flow rate was measured using a mini-Wright peak flow meter. Three readings were taken, each 1 min apart, and the average recorded. Midarm muscle circumference (MAMC) was derived from triceps skin fold thickness and midarm circumference (MAC) using standard anthropometric techniques. Statistical relationships were measured with Pearson's coefficient of correlation. RESULTS: In both sexes there was significant correlation between hand grip strength in the dominant and non-dominant hands and peak expiratory flow rate (P<0.001). In men, there was a positive correlation between MAMC, hand grip strength (P<0.001) and peak expiratory flow rate (P<0.001). In women muscle function correlated with height (P<0.001) but not MAMC (P>0.05). CONCLUSIONS: In normal subjects bedside tests of skeletal and respiratory muscle function correlated with each other in both sexes, and with muscle mass in men but not in women.

Adult↗

PubMed2005

[Poland syndrome (a case report)].

Poland syndrome is characterized with unilateral absence of pectoralis major muscle. Its incidence is one in 30000 live births. A 20 years old case with Poland syndrome is presented together with its clinical and laboratory features in this study. The case had anomaly of shortness of right hand fingers and syndactily between second and third fingers in addition to absence of right pectoralis muscle group. There was not another associated anomaly except aforementioned ones. Strength loss in abduction and adduction of right shoulder was detected with Cybex dynamometer. Furthermore decrease in predicted maximal inspiratory and expiratory pressures was detected.

Adult↗

PubMed2002

Muscle power increases after resistance training in growth-hormone-deficient adults.

PURPOSE: To measure the effects of a resistance training (RT) program over muscle function and body composition of adults with GH deficiency without replacement. METHODS: 11 GH-deficient patients (39 +/- 11 yr) were evaluated in four occasions (two pretraining and at 6 and 12-wk of training). We performed anthropometric measurements and physical tests. Muscle power was measured by a specific tensiometer (Fitro, Bratislava, Slovakia) in five different exercises: seated chest press, rear lat pull-down, knee extension, standing upright row, and triceps press down. Muscle endurance was assessed by maximum number of sit-ups and maximum static strength by measurement with a handgrip dynamometer. A 12-wk home-based RT program was individually prescribed and consisted of 13 exercises, performed each other day, using simple material. RESULTS: No significant differences occurred in body weight or limb circumferences ( > 0.05), although the sum of central skinfolds decreased with RT (111 +/- 9 vs 100 +/- 9 mm; < 0.05). RT induced significant gains in four of five exercises: rear lat pull-down (141 +/- 19 vs 198 +/- 20 W), standing upright row (134 +/- 22 vs 157 +/- 24 W), triceps press down (85 +/- 14 vs 123 +/- 21 W), and seated chest press (114 +/- 20 vs 143 +/- 21 W; < 0.05). Sit-up results also showed significant improvements, while handgrip did not ( > 0.05). CONCLUSION: GH-deficient adults without GH replacement may improve their maximum muscle power when submitted to an individualized, simple, and short home-based RT program. Considering that limb girths did not significantly change, the gains were most likely due to improvements in neuromuscular components.

Adult↗

PubMed1993

Impaired muscle strength in female adolescents and young adults surviving leukemia in childhood.

BACKGROUND: With the improving cure rate in childhood malignancies, increasing interest has been focused on long-term survivors. To evaluate late sequelae of childhood leukemia, the muscle strength of 43 young female survivors was investigated and compared with that of 69 healthy age-matched women. The patients had been off therapy for 1 to 19 years. METHODS: The anthropometric characteristics measured were height and weight, and body mass index was calculated. The maximal isometric strengths for elbow flexion, knee extension, and hand grip were measured on a special dynamometer chair. Dynamic muscular endurance was measured by pushup and situp tests. RESULTS: The mean height of the patients was 6.5 cm shorter (P < 0.001) and their mean weight 4.8 kg lighter (P = 0.011) than that of the reference subjects. Muscle strength was in most tests poorer in the patients than in the reference subjects. The differences were statistically significant in elbow flexion and knee extension, and in both muscular endurance tests. There was an association between the maximal isometric strengths and the anthropometric characteristics. Even when allowance was made for the smaller size of the patients, however, they still had less muscle strength than the reference subjects. Of the various treatment modalities, radiation therapy to the cranial area and chemotherapy with L-asparaginase were independently associated with the lower muscle strength values. CONCLUSIONS: The muscle strength of female patients may be subnormal for many years after therapy for childhood leukemia. To compensate for these deficiencies, the possible benefits of prophylactic and individually planned exercise should be studied.

Acute Disease↗

PubMed1996

A biomechanical model of the lumbar spine during upright isometric flexion, extension, and lateral bending.

STUDY DESIGN: Task-specific and subject-specific lumbar trunk muscle function, muscle geometry, and vertebral density data were collected from 16 men. A biomechanical model was used to determine muscle strength and the compressive forces acting on the lumbar spine. OBJECTIVES: To develop an anatomic biomechanical model of the low back that could be used to derive task-specific muscle function parameters and to predict compressive forces acting on the low back. Several model-specific constraints were examined, including the notion of bilateral trunk muscle anatomic symmetry, the influence of muscle lines of action, and the use of density-derived vertebral strength for model validation. SUMMARY OF BACKGROUND DATA: Clinical and basic science investigators are currently using a battery of diverse biomechanical techniques to evaluate trunk muscle strength. Noteworthy is the large variability in muscle function parameters reported for different subjects and for different tasks. This information is used to calculate forces and moments acting on the low back, but limited data exist concerning the assessment of subject-specific, multiaxis, isometric trunk muscle functions. METHODS: A trunk dynamometer was used to measure maximum upright, isometric trunk moments in the sagittal (extension, flexion) and coronal (lateral flexion) planes. Task- and subject-specific trunk muscle strength or "gain" was determined from the measured trunk moments and magnetic resonance image-based muscle cross-sectional geometry. Model-predicted compressive forces obtained using muscle force and body force equilibrium equations were compared with density-derived estimates of compressive strength. RESULTS: Individual task-specific muscle gain values differed significantly between subjects and between each of the tasks they performed (extension > flexion > lateral flexion). Significant differences were found between left side and right side muscle areas, and the lines of action of the muscles deviated significantly from the vertical plane. Model-predicted lumbar compressive forces were 38% (lateral flexion) to 73% (extension) lower that the L3 vertebral compressive strength estimated from vertebral density. CONCLUSION: The present study suggests that biomechanical models of the low back should be based on task-specific and subject-specific muscle function and precise geometry. Vertebral strength estimates based upon vertebral density appear to be useful for validation of model force predictions.

Adult↗

PubMed2005

Quantification of the weakness and fatigue in thoracic outlet syndrome with isokinetic measurements.

OBJECTIVES: Patients with thoracic outlet syndrome (TOS) complain of many subjective symptoms that are difficult to measure and quantify. In this study we have tried to assess the weakness (muscle strength) and fatigue (endurance) of these patients with an objective measurement method, isokinetic muscle testing. METHODS: Twenty three TOS patients and 15 age matched healthy controls were enrolled in the study. Detailed histories of the patients were taken and the patients underwent complete physical examinations. Cervical radiographies, Doppler ultrasonography, electromyography, and isokinetic measurements were carried out. The isokinetic measurements were carried using the Biodex System 3 dynamometer during concentric shoulder flexions and extensions at velocities of 60 degrees /s, 180 degrees /s, and 240 degrees /s. RESULTS: Although the muscle strengths of both groups seemed to be similar, the fatigue ratios of TOS patients at 60 degrees /s and 180 degrees /s were found to be higher compared with those of healthy controls (p = 0.029, p = 0.007). CONCLUSIONS: TOS patients were found to have muscular performance similar to controls, but their upper extremities developed fatigue more easily than those of healthy individuals.

Adult↗

PubMed1990

Isokinetic dynamometry.

Quantitative muscle performance assessments require standardized protocols and logical explication of raw scores, regardless of technique used. A very expensive dynamometer is not a substitute for competent personnel carrying out strength assessments, and well-thought-out interpretations of the data.

Adult↗

PubMed1998

Comparison of three methods to assess muscular strength in individuals with spinal cord injury.

The aim of the project was to compare three methods for measuring muscle strength in individuals with SCI: the manual muscle test (MMT), the hand-held myometry and the isokinetic dynamometry (Cybex). Thirty-eight (38) subjects, 31 men and seven women (age range = 14-63; lesion from C5 to L3) were included in this project. Muscle strength assessment of upper limbs was performed at admittance and discharge using MMT and myometry for the left and right side, and using Cybex dynamometer for the stronger side. The testing sessions were at least a day apart and performed by a single evaluator (trained physiotherapist). Significant and non-significant differences of myometry mean strength values were observed between consecutive levels of MMT. However, the range of myometry scores within each MMT grade led to significant overlaps between two adjacent MMT grades of each muscle group. Variables correlations were observed between the strength values measured by MMT and myometry with paraplegia (0.26 < or = r < or = 0.67) and tetraplegia (0.50 < or = r < or = 0.95). Similar results were observed when compared MMT and Cybex with the stronger side. Moderate to strong correlations were observed between the strength values measured by myometry and Cybex with paraplegia (0.70 < or = r < or = 0.90) and tetraplegia (0.57 < or = r < or = 0.96). These results suggest that the MMT method does not seem to be sufficiently sensitive to assess muscle strength, at least for grade 4 and higher and to detect small or moderate increases of strength over the course of rehabilitation. Since outcome measures is an important issue in rehabilitation, objective measurements of strength should be used in clinical settings. Considering cost and assessment time, the myometry technique seems to be highly valuable.

Adolescent↗

PubMed1996

Stump length as related to atrophy and strength of the thigh muscles in trans-tibial amputees.

Stump length and the thigh muscles strength of the amputated limb are among the major factors influencing outcome of prosthetic rehabilitation of trans-tibial amputees. In the present study the authors evaluated and compared the strength of quadriceps and hamstrings muscles of both limbs in trans-tibial amputees, as measured by means of an electrical dynamometer. The obtained results showed that the thigh muscles of the sound limbs are significantly stronger than those of the amputated limbs (p < 0.01). The results obtained for amputees with shorter stumps were compared with those with longer stumps. In the group of amputees (n = 9) with a stump shorter than 15.1 cm, values of peak torque (in isokinetic contraction) and maximal average torque (in isometric contraction) were significantly (p < 0.5) weaker when compared to those (n = 9) with a stump longer than 15.1 cm. The results obtained for amputees with a higher rate of thigh muscle atrophy were compared to those with lesser atrophy. In the group of amputees where muscle atrophy was accompanied by decrease in thigh girth of over 5.9 cm, muscles strength did not significantly decrease (p < 0.5) as compared to amputees where thigh girth decrease was less than 5.9 cm. It is concluded that atrophy of the thigh muscles of trans-tibial amputees is accompanied with a significant decrease in strength. In amputees with a short stump, the short lever action provided by the stump interferes with the ability of the thigh muscles to control the prosthesis efficiently during daily activities such as standing and walking.

Activities of Daily Living↗

PubMed1987

Voluntary strength and muscle characteristics in untrained men and women and male bodybuilders.

Eight untrained women (F), 13 untrained men (M), and 11 male bodybuilders (BB) did maximal elbow flexions on an isokinetic dynamometer at velocities of 30, 120, 180, 240, and 300 degrees/s, from which impact torque (IT), peak torque (PT), and work (W) were measured. Biceps and total flexor cross-sectional area (CSA) were measured by computerized tomographic scanning. Muscle fiber area, fiber composition, and collagen volume density were determined from single needle biopsies of biceps brachii. Biceps fiber number was estimated as the ratio of biceps CSA (corrected for connective tissue) to mean fiber area. PT and W decreased at higher velocities in M and BB but not in F; consequently, the correlation between CSA and PT and W was lower at 300 degrees/s (r = 0.58, 0.60) than 30 degrees/s (r = 0.80, 0.79). The ratio of PT to flexor CSA was similar in all groups at 30 degrees/s, whereas F had greater ratios than M and BB at the remaining velocities. F had greater W/CSA ratios than M and BB at all velocities. IT increased at higher velocities in all groups; the increase was greater in F and M than in BB. In contrast to PT and W, the correlation between IT and CSA was greater at 300 degrees/s (r = 0.67) than 30 degrees/s (r = 0.58), and there were no differences among groups in the IT/CSA ratios. Flexor CSA correlated negatively with the ratio of IT, PT, and W to CSA. Muscle fiber composition failed to correlate with any measure of strength. M and BB had greater biceps area, fiber number, and fiber area than F.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2002

Electromyographic assessment of back muscle weakness and muscle composition: reliability and validity issues.

OBJECTIVE: To assess the reliability and construct validity of various electromyographic indices developed to assess back muscle weakness and muscle fiber composition. DESIGN: A prospective study with repeated measures performed on 3 days along with comparisons of groups presenting different back strength and/or back muscle fiber composition. SETTING: A biomechanics laboratory within a rehabilitation center. PARTICIPANTS: Forty male volunteers (20 healthy, 20 with chronic low back pain) were assessed on 3 different days to assess reliability and to make group comparisons. Thirteen healthy women were also assessed once to obtain a third group with known lower strength and different back muscle fiber composition. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Surface electromyography was recorded for 4 pairs of homologous back muscles while the subjects performed, on a dynamometer, static trunk extension efforts. Electromyographic parameters were computed to assess muscle weakness and muscle fiber composition. The reliability of the data collected across the 3 sessions and comparisons between groups were determined. RESULTS: Electromyographic parameters generally showed good to excellent reliability, but were insensitive to differences in back muscle strength and did not appear to be related to muscle composition. Some trends were observed in the electromyographic parameters across the force levels, but the large interindividual variability impeded statistical comparisons. CONCLUSIONS: The assessment of muscle weakness and muscle fiber composition through electromyographic analysis does not appear feasible, at least on an individual basis, for the muscles of the back.

Adult↗

PubMed2002

A gender-related difference in the contribution of the knee musculature to sagittal-plane shear stiffness in subjects with similar knee laxity.

BACKGROUND: Women's susceptibility to injuries involving the anterior cruciate ligament remains unexplained. Volitional contraction of the knee musculature is known to increase the resistance of the knee to shear deformation, raising the possibility that muscles play a part in protecting the anterior cruciate ligament during hazardous activities. We therefore tested the hypothesis that a volitional co-contraction of the knee muscles increases the sagittal-plane shear stiffness (or resistance to anterior tibial translation) of the knee more in men than in women. METHODS: Twenty-three volunteers (ten men and thirteen women; mean age, 24.7 +/- 5.4 years), all with anterior tibial translation of 6 mm, agreed to participate in the study. Each subject underwent a subjective evaluation of knee function and activity level, an arthrometric measurement of passive anterior tibial translation, and an isokinetic dynamometer strength test at 60 degrees/sec. A dynamic stress test was then performed to measure anterior tibial translation while simultaneously monitoring lower-extremity muscle response. RESULTS: Maximum co-contraction of the knee musculature significantly decreased mean anterior tibial translation in both men and women (from 7.8 mm to 2.2 mm in men and from 6.5 mm to 3.1 mm in women). The corresponding percentage increase in shear stiffness of the knee was significantly greater (p = 0.003) in men (379%) than in women (212%). CONCLUSIONS: The results suggested that women have a diminished potential for muscular protection of passive structures of the knee in anterior tibial translation. CLINICAL RELEVANCE: Maximal muscular protection of the anterior cruciate ligament in women may be less than that in men. This may be one factor explaining why more women than men are apt to sustain injuries to the anterior cruciate ligament.

Adult↗

PubMed2006

Bilateral isokinetic peak torque of quadriceps and hamstring muscles in professional soccer players with dominance on one or both two sides.

AIM: Dominance of one leg may cause asymmetry between the contralateral muscle groups and develop predisposition for injury to the leg with the weaker muscle strength. The purpose of this study was to examine the strength balance in the extensor and flexor muscle groups, as well as the hamstring to quadriceps (H/Q) ratios of both legs in professional soccer players with dominance on one or both legs. METHODS: Forty-two professional soccer players of the first Greek division participated in this study. Participants were divided into 3 groups according to their leg use during training sessions and matches. Fifteen players comprised the first group with dominance to the right leg, 12 players formed the second group with dominance to the left leg, and 15 players consisted the third group with dominance to both the right and left legs. Maximum voluntary concentric torque of the hamstring and quadriceps muscles of both legs was assessed using a Norm isokinetic dynamometer at angular velocities of 12 degrees, 60 degrees, 180 degrees and 300 degrees/s. RESULTS: No significant differences in the strength balance found between the groups. The isokinetic variables comparing the right and left body side in each group, with dominance on one or both legs, did not differ. No differences were recorded in the H/Q between the right and left legs for any of the subject groups. CONCLUSIONS: There is no evidence of muscle imbalances in extensor and flexor muscle groups and H/Q ratios between the right and left legs in professional soccer players with dominance on one or both legs. The training sessions and matches appear to have imposed strength balance for the right and left body sides of professional soccer players.

Adult↗

PubMed2003

The relationship between muscle cross-sectional area and strength in various isokinetic movements among soccer players.

The aim of the present study was to examine the relationships between muscle cross-sectional area (CSA) and muscular strength in terms of knee extension and flexion, hip extension and flexion, and hip abduction and adduction among well-trained soccer players. Fourteen university soccer players participated in the study, who had previously been divided into two groups based on ability (Group A: above-average ability; Group B: average ability). Maximal isokinetic and concentric muscular strength was measured in knee extension/flexion, hip extension/flexion and hip abduction/adduction using an isokinetic dynamometer at 1.57 and 4.19 rad x s(-1) (3.14 rad x s(-1)) in both the dominant and non-dominant leg. The CSAs of the thigh, gluteus muscles and iliopsoas muscles were calculated based on magnetic resonance imaging. There was no significant difference between the two groups in muscle CSA and isokinetic strength. Although there were some statistically significant differences between the dominant and non-dominant leg in terms of CSA and strength (P < 0.05-0.01), these were small and negligible. Apart from a non-significant relationship between the CSAs of the adductor muscles and hip adductor strength (r < 0.26, N.S.), the CSA of the other muscle groups correlated with maximal isokinetic strength (r = 0.38-0.64, P < 0.05). These results suggest that no difference in muscle characteristics (in terms of muscle CSA and strength) was apparent among well-trained soccer players, even between the dominant and non-dominant leg. There is also a case that the anatomical function of a single (or group of) muscle(s) may not be reflected by the strength-CSA relationship depending on the movements (such as hip adduction-adductor muscle CSA). Thus, further studies are required to develop methods to assess neuromuscular function in relation to muscle morphology among soccer players.

Adult↗

PubMed2006

Gender influence on fatigability of back muscles during intermittent isometric contractions: a study of neuromuscular activation patterns.

BACKGROUND: Gender difference in the fatigability of muscles can be attributed to muscle mass (or strength) and associated level of vascular occlusion, substrate utilization, muscle composition, and neuromuscular activation patterns. The purpose of this study was to assess the role of neuromuscular activation patterns to explain gender differences in back muscle fatigability during intermittent isometric tasks. METHODS: Sixteen males and 15 females performed maximal voluntary contractions (Strength) and a fatigue test to exhaustion (fatigue criterion=time to exhaustion), while standing in a static dynamometer measuring L5/S1 extension moment. The fatigue test consisted of repetitions of an 8-s cycle (1.5 s ramp to reach 40% of maximal voluntary contraction +5s plateau at 40% of maximal voluntary contraction +1.5s rest). Surface electromyography signals were collected bilaterally from 4 back muscles (multifidus at the L5 level, iliocostalis lumborum at L3, and longissimus at L1 and T10). FINDINGS: Males were stronger (P<0.05) than females (316, SD 82>196, SD 25 Nm) but showed significantly shorter time-to-exhaustion values (7.1, SD 5.2<13.0, SD 6.1 min.), the latter result being corroborated by electromyographic indices of fatigue. However, the gender effect on time to exhaustion disappeared when accounting for Strength, thus supporting the muscle mass hypothesis. Among the various electromyographic indices computed to assess neuromuscular activation patterns, the amount of alternating activity between homolateral and between contralateral muscles showed a gender effect (females>males). INTERPRETATION: These results support the muscle mass hypothesis as well as the neuromuscular activation hypothesis to explain gender differences in back muscle fatigability.

Adult↗

PubMed2003

The effects of a neuromuscular electrical stimulation home program on impairments and functional skills of a child with spastic diplegic cerebral palsy: a case report.

PURPOSE: To examine the effects of neuromuscular electrical stimulation (NMES) on impairments and functional skills of a 13-year-old child with spastic diplegic cerebral palsy (CP). METHODS: NMES was administered to the right quadriceps muscles every other day for six weeks. Pre- and posttesting included assessment of strength using a hand-held dynamometer, spasticity using a KinCom isokinetic dynamometer, gait spatiotemporal parameters using GAITRite, and functional motor performance with the use of the Pediatric Evaluation of Disability Inventory (PEDI). RESULTS: After intervention, right quadriceps strength increased from 16.3 +/- 3.06 to 41.7 +/- 4.2 Newtons. Right hamstring spasticity decreased at three tested velocities. In the untreated left lower extremity, strength remained unchanged but spasticity increased. The PEDI showed development of new skills, including the ability to climb stairs with less assistance. CONCLUSION: These findings indicate that NMES was an effective therapeutic technique to improve strength and motor function of a child with spastic diplegic CP.

Journal Article↗

PubMed1990

Relationships of body size, segmental dimensions, and ponderal equivalents to muscular strength in high-strength and low-strength subjects.

There are conflicting results in prior studies concerning the relationships among body size, muscle size, and muscular strength. The purpose of the present study was to evaluate how body size, body shape, and segmental dimensions related to individual differences in muscular strength. Subjects were tested on four dynamic measures of strength and then classified into one of two groups as high strength (HS; N = 21) and low strength (LS; N = 21). Individual differences in strength were then related to body composition and segmental anthropometry. Strength was assessed during high-resistance, low-velocity standing squat and supine bench press with an isokinetic dynamometer, and during seated bench press and knee extension with a hydraulic resistance dynamometer. Anthropometry and body composition included 11 girths, six fatfolds, predicted fat-free mass (FFM), thigh and upper arm volume, muscle + bone cross-sectional area (CSA), and the Behnke Ponderal Somatogram (PSom) body profiling system. There was a 21.3% difference in strength between HS and LS (p less than 0.05), but no significant differences in age, stature, and fatfolds. MANOVA revealed that seven of 11 girth components of PSom were larger for HS (p less than 0.05). The correlations between strength vs body mass, FFM, thigh and upper arm volume, and CSA and fatfolds in HS and LS ranged from r = -0.52 to 0.56 (r = -0.70 to 0.70 when corrected for restriction of range). We conclude that individual differences in muscular strength are poorly related to various measures of body size and segmental body dimensions.

Adult↗

PubMed1994

Comparison of a hand-held and fixed dynamometer in measuring strength of patients with neuromuscular disease.

While numerous studies report acceptable reliability of hand-held dynamometers, very little information is available on factors affecting measurements and comparisons with other force measurement systems. A hand-held dynamometer was compared to a fixed dynamometer to determine if the two systems of force measurement yielded comparable results. Twenty-one patients with neuromuscular disease were measured for maximal isometric strength of 12 muscle groups with both force measurement systems using standardized positioning and stabilization procedures. Only one of the 12 muscle groups tested demonstrated significantly different force measurements between the two systems. Good association was found between both systems in force measurements, with Pearson correlation coefficients ranging from .76 to .90. We conclude that a hand-held dynamometer and a fixed dynamometer yield comparable results in patients with neuromuscular disease, provided that testing is limited to muscle groups producing relatively low forces.

Adult↗