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Results for “Muscle Strength Dynamometer”

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At least 37 records · Page 2Linked to original sources

PubMed2006

[Specific strength measurement of musculus abductor pollicis brevis in order to objectively evaluate muscle regeneration after carpal tunnel release surgery].

47 patients with a carpal tunnel syndrome were preoperatively examined not only by electrophysical studies (nerve velocity and distal motoric latency) and clinical tests (Phalen's sign, Tinel's sign) but also by measuring the strength of the M. abductor pollicis brevis with a specifically designed strength-testing unit. 30 patients agreed to participate in a voluntary postoperative examination. In the 45 degrees -measurement there was a relative strength loss of the injured hand's thumb of about 25 % in comparison with the healthy hand preoperatively. The postoperative strength disadvantage amounted to only 10 %. Measurement of the strength in the neutral zero method showed a relative strength loss of the injured hand's thumb of 8 % while postoperatively there was even a strength advantage of 9 % in comparison with the thumb of the healthy hand. Both methods showed a relevant and significant postoperative strength increase of the injured hand's thumb. We could prove a significant correlation (p = 0.03) of the neutral zero strength measurement and the distal motoric latency of the median nerve. Furthermore, we could show a trend for a correlation between the neutral zero strength measurement and the median motoric velocity. In conclusion, it can be said that the special strength measurement of the M. abductor pollicis brevis is an important parameter to objectively evaluate the motoric symptomatology in carpal tunnel syndrome patients.

Adult↗

PubMed2006

Effects of movement velocity and maximal concentric and eccentric actions on the bilateral deficit.

Department of Health, Physical Education, Recreation, and Dance at the University of Idaho. This study was performed to examine the effects of movement velocity and maximal concentric and eccentric actions on the bilateral deficit. Eighteen female participants performed maximal unilateral and bilateral knee extensions concentrically and eccentrically across six movement velocities (30, 60, 90, 120, 150, and 180 degrees/s). Repeated measures analyses of variance revealed significant differences (p < .025) between bilateral and summed unilateral contractions both concentrically and eccentrically at each velocity tested. Post hoc analyses revealed that the degree of bilateral deficit increased as movement velocity increased for concentric actions (e.g., 17-33% deficit, for 30 and 180 degrees/s, respectively), and an increasing trend was seen for eccentric actions (e.g., 18-25% deficit, for 30 and 180 degrees/s, respectively). These findings suggest that with increased velocity, a decreased or incomplete activation of fast twitch muscle fibers may have occurred in bilateral actions when compared to unilateral actions.

Adult↗

PubMed2006

Voluntary activation and central activation failure in the knee extensors in young women and men.

Quadriceps muscle weakness is common after knee injuries. This weakness is caused, in part, by reduced voluntary activation (VA) because of central activation failure (CAF). Superimposed electrical stimulation techniques are used to assess VA and to detect CAF. The aim of this study was to assess VA during knee extension in young healthy women and men, and to evaluate subjective discomfort from the electrical stimulation. The quadriceps muscle in six young healthy women (mean age 22 years) and six young healthy men (mean age 29 years) was stimulated during maximal voluntary contractions using a 100 Hz pulse train. Data were collected from two test sessions separated by 6-8 days and each session comprised of two trials. A visual analog scale for pain (VAS-pain) was used to evaluate subjective discomfort. Overall, young healthy, moderately active men and women did have the ability to fully activate their knee extensors isometrically, but they did not achieve full activation on every trial. In those trials where a CAF was detected, the degree was small (mean less than 2%), and did not vary between the two test sessions. Subjective discomfort was generally moderate and tolerable (mean VAS-pain score 35 mm). These results will assist the clinical assessment of muscle weakness following a knee injury and facilitate the design and evaluation of appropriate rehabilitation interventions.

Adult↗

PubMed2006

Knee-flexion torque and morphology of the semitendinosus after ACL reconstruction.

PURPOSE: The present study aimed to clarify the relationship between deficits in knee-flexion torque and morphological changes in the semitendinosus muscle-tendon complex after harvesting the semitendinosus tendon for anterior cruciate ligament (ACL) reconstruction. METHODS: Isometric knee-flexion torque at 45 and 90 degrees of knee flexion was measured in limbs of 23 patients (22 +/- 4 yr) who underwent unilateral ACL reconstruction (12-43 months postoperation) using ipsilateral semitendinosus tendon. Magnetic resonance imaging scans were used to calculate the muscle volume and the muscle length of the semitendinosus and to confirm the presence of the regenerated semitendinosus tendon. RESULTS: The percentage of the knee-flexion torque of the ACL-reconstructed limb compared with that of the contralateral limb was lower at 90 degrees than at 45 degrees . The regeneration of the semitendinosus tendon-like structure was confirmed in 21 of the 23 patients. However, muscle volume and muscle length of the semitendinosus in the ACL-reconstructed limb were significantly smaller compared with in the contralateral limb. CONCLUSION: Deficits in knee-flexion torque at deep knee flexion were associated with the atrophy and shortening of the semitendinosus after harvesting the semitendinosus tendon for ACL reconstruction.

Adult↗

PubMed2006

The relationship between maximal repetition performance and muscle fiber type as estimated by noninvasive technique in the quadriceps of untrained women.

The purpose of this investigation was to establish a relationship between the number of repetitions an individual can complete at a predetermined load and their percentage of type II muscle fibers in their quadriceps. Subjects included 22 untrained women between the ages of 18 and 35. Day 1 consisted of noninvasive anthropologic testing, 1 repetition maximum (1RM) testing, and recording repetition performance at 70% 1RM. Day 2 consisted of isokinetic dynamometry to determine muscle fiber composition. Results were obtained and analyzed using the Pearson product correlation coefficient (r). The results demonstrated a fair-to-moderate relationship (Pearson r = -0.48, p = 0.02) that individuals with greater percentages of type II muscle fibers performed fewer repetitions at 70% 1RM. The results of this study demonstrate that muscle fiber type composition is an important variable to consider when designing training or rehabilitation programs.

Adolescent↗

PubMed2006

Hand-held dynamometry: adoption 1900-2005.

The purpose of this brief report is to describe the adoption of hand-held dynamometry, a procedure for documenting muscle strength. Between the early 1900s and the end of 2005, 478 research articles were published that documented use of hand-held dynamometry. The adoption of the procedure for research is consistent with the S-shaped curve described by Rogers. The extent to which hand-held dynamometry is used in clinical practice remains to be delineated.

Equipment Design↗

PubMed2006

Contribution of muscular strength in cardiorespiratory fitness tests.

AIM: Reports from laboratory-based studies have revealed a relationship between resistance training and endurance performance in both trained and untrained individuals. The purpose of the present study was to investigate the contribution of lower extremity muscular strength levels in performing cardiorespiratory fitness tests in laboratory, as well as field-based settings. METHODS: Within 2 weeks 38 healthy males (age 21.6+/-2.5 years, body mass index--BMI--24.4+/-2.2) performed three maximal oxygen uptake (VO(2max)) assessments using the 20 m multistage shuttle run test (MSR), the 20 m square shuttle run test (SSR), and a maximal treadmill test (MT) to exhaustion. Data were also obtained from knee flexion and extension isokinetic dynamometry at 60 degrees xs(-1). RESULTS: MSR performance correlated with the peak torque generated from both legs at r=0.63 (P<0.001). The equivalent for SSR was significant at r=0.44 (P<0.05), while MT demonstrated a non-significant positive correlation coefficient (r=0.34, P>0.05). Stepwise regression analyses revealed that the inclusion of leg strength parameters increased the coefficient of determination by 9% (P<0.001) and 4% (P<0.05) in the MSR and SSR, respectively. The MT model was not significantly associated with any of the isokinetic indices studied. CONCLUSIONS: Although moderately significant, the present coefficients suggest that performance in the present field-based cardiorespiratory fitness tasks is affected to a certain extent by lower extremity muscular strength. The latter also demonstrates a positive relationship with laboratory-based performance.

Adolescent↗

PubMed2006

Implications for using H-max/M-max ratio in H-reflex parameters for elderly subjects compared with young subjects.

The H-max/M-max ratio has long been used to understand motoneuron excitability induced by the Ia fibers. However, we contend that when comparing young and elderly subjects, this measurement can be controversial. We compared the modulation of the soleus H-max and M-max at five different muscle lengths between elderly and young subjects. The young subjects demonstrated a significant modulation of both H-max and M-max between dorsiflexion (DF) and plantarflexion (PF) positions. In contrast, the elderly subjects demonstrated no difference in H-max and M-max between DF and PF positions. However, it was more interesting to note that those elderly subjects who had similar H-max/M-max ratios to the young subjects at 0 deg showed identical modulation of H-max and M-max to that of the young In this paper, we discuss that H-reflex comparisons between young and elderly subjects may be confounded by the initial H-max/M-max ratio. This finding has implications for both the statistical analysis of this data as well as the theoretical interpretation of H-reflex measurements.

Adult↗

PubMedDate not supplied

Influence of different stimuli on electromyographic variables of the biceps brachii.

The objective of this study was to assess the influence of different stimuli on the muscular response of 30 young sedentary male and female subjects. A conditioning module with A/D 16/32 signals of 12 bits (LYNX), with band-pass filter of 10-500 Hz and sampling frequency of 1000 Hz was used. A bipolar active surface electrode (LYNX), a load cell (MM-100 KRATOS) and a pressure cuff were also used. The volunteers were submitted to four conditions: Without stimulus (WS), auditive stimulus (AS), visual stimulus (VS), and auditive + visual stimuli (AVS). Matlab 6.5.1 software was used to process the signals for analyzing RMS and median frequency (MF), as well as muscular force (F) and cuff pressure (P). Statistical analysis consisted of the Wilcoxon and Mann-Whitney test with a critical level of 5%. As to RMS, females presented a significant increase in all types of stimuli compared to WS. As to MF there was no significant difference between the different groups for either sex. P in both sexes presented a significant increase when submitted to VS and AVS. F was higher for AVS in males and for any of the stimuli in females when compared to WS. In all the variables analyzed, males presented significantly higher values than females for all types of stimuli.

Acoustic Stimulation↗

PubMed1984

Measuring muscle strength.

A dynamometer that can be held in the hand and that was designed to measure muscle strength in a simple way in the range 2-5 of the MRC scale, was tested in order to establish to what extent differences in results can be attributed to the observer, the subject and replication. Observers learned the technique quickly and their results agreed with each other to a considerable extent. The subjects showed a small learning effect in three of the four muscles tested. Normal muscle strength was measured in one hundred 18-year-old men.

Adult↗

PubMed2006

Synergists activation pattern of the quadriceps muscle differs when performing sustained isometric contractions with different EMG biofeedback.

The aims of the present study were to examine (1) endurance time and (2) activation pattern of vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) muscles during fatiguing isometric knee extensions performed with different EMG biofeedbacks. Thirteen men (27 +/- 5 year) volunteered to participate in three experimental sessions. Each session involved a submaximal isometric contraction held until failure at an EMG level corresponding to 40% maximal voluntary contraction torque (MVC), with visual EMG biofeedback provided for either (1) RF muscle (RF task), (2) VL and VM muscles (Vasti task) or (3) the sum of the VL, VM and RF muscles (Quadriceps task). EMG activity of VL, VM and RF muscles was recorded during each of the three tasks and further analyzed. Time to task failures and MVC loss (P < 0.001) after exercises were similar (P > 0.05) between the three sessions (182 s and approximately 28%, respectively) (P > 0.05). Moreover, the magnitude of central and peripheral fatigue was not different at failure of the three tasks. Activation pattern was similar for knee extensors at the beginning of each task (P > 0.05). However, RF EMG activity decreased (P < 0.05) during the Vasti and the Quadriceps tasks (from approximately 33 to approximately 25% maximal EMG), whereas vasti EMG activity remained constant during the RF task ( approximately 41% maximal EMG). These findings suggest that (1) task failure occurs when sustaining a submaximal level of EMG activity for as long as possible and (2) CNS is not able to differentiate descending drive to the different heads of the quadriceps at the beginning of a sustained contraction, despite a different activation pattern for the bi-articular RF muscle compared to the mono-articular vasti muscles during fatigue.

Adult↗

PubMed2006

Repeatability of electromyography and force measurements of the neck muscles in adolescents with and without headache.

BACKGROUND: Reliable measurements are needed to study the dysfunction of the neck muscles. The aim of this study was to determine the intra-tester repeatability of EMG and isometric force measurements of the neck muscles in adolescents with headache and headache-free controls. METHODS: A group of 30 adolescents with migraine-type headache, 29 with tension-type headache, and 30 headache-free controls were recruited. Maximal isometric neck muscle force with simultaneous recording of surface EMG from the cervical erector spinae and the sternocleidomastoideus muscles was measured twice during one day. FINDINGS: For all groups, intra-class correlation coefficients (ICC) and coefficients of variation (CV) showed acceptable repeatability of all measurements. (Force measurements: ICC 0.98-0.99, CV 0.7-3.7%; EMG measurements: ICC 0.95-0.99, CV 4.9-10.1%.) On the individual level, variation between the consecutive measurements was found to be low in all groups. INTERPRETATION: The present EMG and force measurements of neck muscles indicate acceptable intra-tester repeatability in adolescents. The repeatability was comparable in migraine- and tension-type headache and headache-free groups. The EMG and the force measurements offer the possibility to investigate neck muscle dysfunction in adolescent headache.

Adolescent↗

PubMedDate not supplied

Evaluation of neck muscle strength with a modified sphygmomanometer dynamometer: reliability and validity.

OBJECTIVE: Determine test-retest reliability, normative data and clinical validity of isometric muscle strength testing in the neck with a modified sphygmomanometer dynamometer (MSD). DESIGN: Analytic survey. Paired trials of various muscle strength tests were conducted on convenience samples of normal subjects and consecutive samples of symptomatic subjects. SETTING: Outpatient chiropractic research clinic. PATIENTS/SUBJECTS: For study 2, 40 normal male subjects, average age 25 +/- 2 yr, were studied for reliability and normative data. For study 3, 24 symptomatic patients, 12 males and 12 females, average age 39 +/- 7 yr, were studied, 8 with "whiplash"-type injuries (average duration 22.5 wk) and 16 with nontraumatic chronic neck pain (average duration 110 wk). INTERVENTION: No therapeutic intervention is reported. MAIN OUTCOME MEASURE: Pressure levels generated by subjects against a modified sphygmomanometer-type dynamometer as measured in kilopascals. RESULTS: Study 1. Repeated paired trials of a standardized weight column (20 lbs) produced a coefficient of variation of 0.84% and virtually no difference between the means of the first vs. second trials. Study 2. High test-retest correlation coefficients were found for all ranges of motion (.79-.97). Right-to-left asymmetry in rotation and lateral flexion was within 6-8%. The flexion/extension ratio was .57:1, indicating that in normal subjects, flexion was approximately 40% lower than extension. Lower cutoffs were established as the mean--1 SD as follows (in kPa): flexion--3300, extension--5800, rotation--5200 and lateral flexion--6200. Coefficients of variation ranged from 25 to 29%. Study 3. Differences between paired trials were analyzed by intraclass coefficients, which were very high (.95-.99), and by percentages, which ranged from 4 to 10.4%, with an average of 7%, indicating a high degree of test-retest consistency. The mean values for all symptomatic subjects for flexion, extension, right rotation and right lateral bending were all well below the normal cutoff values as found in study 2. The flexion/extension ratio for whiplash subjects was 0.25:1.00, which is half of that of normal subjects. CONCLUSIONS: The MSD has been found to be a reliable instrument for the evaluation of isometric muscle strength in the neck in normal and symptomatic subjects. Normative values for absolute test levels, bilateral symmetry and flexion/extension ratios have been determined. A symptomatic group demonstrated significant deviations from these norms in the form of reduced strength levels and reduced flexion/extension ratios, while still maintaining very high levels of test-retest consistency and bilateral symmetry. The MSD appears very promising in the evaluation of neck-injured patients.

Adult↗

PubMed1988

A new dynamometer measuring concentric and eccentric muscle strength in accelerated, decelerated, or isokinetic movements. Validity and reproducibility.

A new computerized dynamometer (the SPARK System) is described. The system can measure concentric and eccentric muscle strength (torque) during linear or nonlinear acceleration or deceleration, isokinetic movements up to 400 degrees.s-1, and isometric torque. Studies were performed to assess: I. validity and reproducibility of torque measurements; II. control of lever arm position; III. control of different velocity patterns; IV. control of velocity during subject testing; and, V. intra-individual reproducibility. No significant difference was found between torque values computed by the system and known torque values (p greater than 0.05). No difference was present between programmed and external measurement of the lever arm position. Accelerating, decelerating and isokinetic velocity patterns were highly reproducible, with differences in elapsed time among 10 trials being never greater than 0.001 s. Velocity during concentric and eccentric isokinetic quadriceps contractions at 30 degrees.s-1, 120 degrees.s-1 and 270 degrees.s-1 never varied by more than 3 degrees.s-1 among subjects (N = 21). Over three days of testing, the overall error for concentric and eccentric quadriceps contraction peak torque values for 5 angular velocities between 30 degrees.s-1 and 270 degrees.s-1 ranged from 5.8% to 9.0% and 5.8% to 9.6% respectively (N = 25). The results indicate that the SPARK System provides valid and reproducible torque measurements and strict control of velocity. In addition, the intra-individual error is in accordance with those reported for other similar devices.

Adult↗

PubMed2006

Electrical stimulation in cerebral palsy: a randomized controlled trial.

A randomized placebo-controlled trial was carried out to investigate the efficacy of neuromuscular electrical stimulation (NMES) and threshold electrical stimulation (TES) in strengthening the quadriceps muscles of both legs in children with cerebral palsy (CP). Sixty children (38 males, 22 females; mean age 11y [SD 3y 6mo]; age range 5-16y) were randomized to one of the following groups: NMES (n=18), TES (n=20), or placebo (n=22). Clinical presentations were diplegia (n=55), quadriplegia (n=1), dystonia (n=1), ataxia (n=1), and non-classifiable CP (n=2). Thirty-four children walked unaided, 17 used posterior walkers, six used crutches, and the remaining three used sticks for mobility. Peak torque of the left and right quadriceps muscles, gross motor function, and impact of disability were assessed at baseline and end of treatment (16wks), and at a 6-week follow-up visit. No statistically significant difference was demonstrated between NMES or TES versus placebo for strength or function. Statistically significant differences were observed between NMES and TES versus placebo for impact of disability at the end of treatment, but only between TES and placebo at the 6-week follow-up. In conclusion, further evidence is required to show whether NMES and/or TES may be useful as an adjunct to therapy in ambulatory children with diplegia who find resistive strengthening programmes difficult.

Adolescent↗

PubMed1995

Testosterone administration to elderly men increases skeletal muscle strength and protein synthesis.

Aging men develop a significant loss of muscle strength that occurs in conjunction with a decline in serum testosterone concentrations. We investigated the effects of testosterone administration to six healthy men [67 +/- 2 (SE) yr] on skeletal muscle protein synthesis, strength, and the intramuscular insulin-like growth factor I (IGF-I) system. Elderly men with serum testosterone concentrations of 480 ng/dl or less were given testosterone injections for 4 wk to produce serum concentrations equal to those of younger men. During testosterone administration muscle strength (isokinetic dynamometer) increased in both right and left hamstring and quadricep muscles as did the fractional synthetic rate of muscle protein (stable-isotope infusion). Ribonuclease protection assays done on total RNA from muscle showed that testosterone administration increased mRNA concentrations of IGF-I and decreased mRNA concentrations of insulin-like growth factor binding protein-4. We conclude that increasing testosterone concentrations in elderly men increases skeletal muscle protein synthesis and strength. This increase may be mediated by stimulation of the intramuscular IGF-I system.

Aged↗

PubMedDate not supplied

Factors predicting dynamic balance and quality of life in home-dwelling elderly women.

BACKGROUND: Proper balance seems to be a critical factor in terms of fall prevention among the elderly. OBJECTIVE: The purpose of this cross-sectional study was to examine factors that are associated with dynamic balance and health-related quality of life in home-dwelling elderly women. METHODS: One hundred and fifty-three healthy postmenopausal women (mean age: 72 years, height: 159 cm, weight: 72 kg) were examined. General health and physical activity were assessed by a questionnaire. Quality of life was measured using a health-related quality of life questionnaire (Rand 36-Item Health Survey 1.0). Dynamic balance (agility) was tested by a figure-of-eight running test. Static balance (postural sway) was tested on an unstable platform. Maximal isometric strength of the leg extensors was measured with a leg press dynamometer. Dynamic muscle strength of lower limbs was tested by measuring ground reaction forces with a force platform during common daily activities (sit-to-stand and step-on-a-stair tests). RESULTS: Concerning physical activity, 33% of the subjects reported brisk exercise (walking, Nordic walking, cross-country skiing, swimming and aquatic exercises) at least twice a week, and 22% some kind of brisk activity once a week in addition to lighter physical exercise. The remaining 45% did not exercise regularly and were classified as sedentary. The correlations of step-on-a-stair and sit-to-stand ground reaction forces, and leg extensor strength to dynamic balance were from -0.32 to -0.43 (the better the strength, the better the balance). In the regression analysis with backward elimination, step-on-a-stair and sit-to-stand ground reaction forces, and leg extensor strength, age, brisk physical activity, number of diseases and dynamic postural stability explained 42% of the variance in the dynamic balance. Similarly, dynamic balance (figure-of-eight running time), number of diseases and walking more than 3 km per day explained 14% of the variance in the quality of life score. Of these, figure-of-eight running time was the strongest predictor of the quality of life score, explaining 9% of its variance. CONCLUSION: This study emphasizes the concept that in home-dwelling elderly women good muscle strength in lower limbs is crucial for proper body balance and that dynamic balance is an independent predictor of a standardized quality of life estimate. The results provide important and useful information when planning meaningful contents for studies related to fall prevention and quality of life and interventions in elderly women.

Accidental Falls↗

PubMed2004

Assessment of muscle strength and motor fatigue with a knee dynamometer in subjects with multiple sclerosis: a new fatigue index.

OBJECTIVE: To measure muscle strength and motor fatigue with a knee dynamometer and to assess the intra-rater reliability of measurements for maximal isometric extensor and flexor torques and the reliability of a new fatigue index (FI) in patients with mild to moderate multiple sclerosis (MS). DESIGN: Repeated assessments with one-week intervals. SETTING: The Masku Neurological Rehabilitation Centre, Masku, and the Social Insurance Institution, Research Department, Turku, Finland. SUBJECTS: Twenty-eight MS patients. OUTCOME MEASURES: Maximal isometric torque during 5 s and fatigue of knee flexors and extensors during isometric contractions of 30 s were assessed. A new FI was established and compared with the two previously used indices (FI1 and FI2). All three indices are based on the calculated area under the force versus time curve (AUFC), with FI1 using the 30-s recording time in its entirety and F2 omitting the initial 5 s in the calculation. In the new fatigue index (FI3), the time point of maximum (TPM) torque achieved by the subject is used as the starting point in the calculation. The patient's subjective fatigue was measured by Fatigue Severity Scale (FSS). RESULTS: The intraclass correlation coefficient (ICC) was 0.97 in maximal isometric torque measurements. FI3 showed good intra-rater reliability (ICC =0.68-0.86). None of the fatigue indices correlated with FSS. CONCLUSIONS: Maximal isometric torque and motor fatigue of knee flexor and extensor muscles can be reliably measured using a knee dynamometer in MS patients. The new FI proved to be a reliable model for MS patients.

Adult↗