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Results for “Muscle Strength”

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PubMed2000

Abdominal muscle strength in patients with tetraplegia.

The abdominal muscles are completely paralyzed after traumatic transection of the cervical cord. To assess the residual pressure-generating capacity of these muscles, we first measured the changes in gastric pressure (DeltaPga) during paired bilateral stimulation of the lower thoracic nerve roots in eight chronic patients with C5-C7 tetraplegia and eight matched unaffected subjects in the seated posture. Stimulations were applied with a 90-mm circular magnetic coil positioned at the level of T10 and connected to a Magstim 250 stimulator. During relaxation at FRC, DeltaPga during maximal stimulation averaged (mean +/- SE) 76.0 +/- 11.7 cm H(2)O in the control subjects, whereas in the patients it was only 29.9 +/- 3.7 cm H(2)O (p = 0.002). Stimulations were next applied during the course of a forced expiration. All patients consistently demonstrated an abrupt increase in esophageal pressure (22.7 +/- 4.5 cm H(2)O), and six of them also showed an increase in expiratory flow. The cumulative thickness of the four abdominal muscles, as measured with an ultrasound probe, was 34% smaller in the patients than in the control subjects and correlated positively with maximal DeltaPga. We conclude that in patients with tetraplegia, muscle atrophy causes a marked reduction in abdominal muscle strength. However, magnetic stimulation of the abdominal muscles elicits increases in intrathoracic pressure that are greater than those required to initiate dynamic airway compression; it might, therefore, improve the clearing of airway secretions.

Abdominal Muscles↗

PubMed1986

Quantifying human muscle strength, endurance and fatigue.

Physiologic methods have been developed to objectively quantify muscle strength, endurance, and fatigability. Isometric force and rectified/integrated electromyogram were simultaneously recorded during the three phases of a recording session: pre-fatigue, fatigue (1 min duration) and post-fatigue recovery (up to 10 min). Five parameters of muscle performance were computed: Maximum force (MF) exerted during isometric voluntary contraction (muscle strength); Force-time integral--area under force-time plot (endurance); Fatigue index (FI) (% reduction in MF); Neuromuscular efficiency (force/mV of EMG recruited), and Recovery time (RT). Normal values based on data from 20 normal subjects were determined for four muscles: index finger abductor, elbow flexors, knee extensors, and ankle dorsiflexors. Neuromuscular efficiency (NME) decreased significantly (20 to 70%) at the end of the fatigue phase; it generally increased to the pre-fatigue level in 2 to 10 min, during the recovery phase. The period needed to reach pre-fatigue level was referred to as RT. The elbow flexors had the highest mean FI (48%) and the longest RT (greater than 6 min); the ankle dorsiflexors had the lowest mean FI (34%) and the shortest RT (1.5 min). These methods have been used also to evaluate the effects of weight training in two patients with neuromuscular disorders.

Adolescent↗

PubMed2004

Validity and reliability of the measurement of the quardriceps femoris muscle strength with a hand-held dynamometer on the affected side in hemiplegic patients.

The purpose of this study was to investigate validity and reliability of measuring the quadriceps femoris muscle strength on the affected side in hemiplegic patients with a hand-held dynamometer(HHD) to prepare for a multi-center cooperative study. Measurements of the known weights(8.972 and 18.665 kg) with HHD were 8.98 +/- 0.00 kg and 18.57 +/- 0.00 kg, respectively, and measurements with HHD were almost consistent with those with KIN-COM (gold standard), because the Pearson's product-moment correlation coefficient was 0.99 (P < 0.001). There were significant differences in measurements of the quadriceps femoris muscle strength on the affected side in a hemiplegic patient between just anterior to the face of the ankle and 7 cm proximal to the ankle, and on a chair with or without a backrest (t-test, P < 0.05), but no significant difference was found between the 90 degrees and 60 degrees flexed position of the knee (t-test, 0.1 > P > 0.05). There were also no significant differences in muscle strength measured by three different examiners and on four trials, but significant differences were found among three patients (General Linear Model, P < 0.001). Therefore, by using the standardized measuring procedure, the HHD is reliable to measure strength of the quadriceps femoris muscle on the affected side in hemiplegic patients.

Hemiplegia↗

PubMedDate not supplied

Pulmonary muscle strength, pulmonary function tests, and dyspnea in women with major depression.

OBJECTIVE: To evaluate the subjective sensation of dyspnea compared with pulmonary function tests, pulmonary muscle strength, and chest expansion in depressed women and control subjects free of cardiorespiratory disease. METHODS: Thirty female patients with major depression (MD) and 30 age-matched female control subjects were included in the study. All subjects were assessed by pulmonary function tests (spirometry) and pulmonary muscle strength measurement (maximum inspiratory and expiratory pressures [MIP and MEP]) by mouth pressure meter (MPM). Chest expansion was measured, and body mass index (kg/m(2)) (BMI) was calculated. The Health Assessment Questionnaire (HAQ) was used to evaluate the activities of daily living, and a dyspnea score was used to determine dyspnea severity. RESULTS: There were no significant differences between groups regarding pulmonary function tests, pulmonary muscle strength, and chest expansion. HAQ scores were significantly lower in women, and dyspnea was higher with MD compared with controls (p < 0.05). BMI was also lower in depressed patients (p < 0.05). CONCLUSIONS: The subjective sensation of dyspnea is increased in women with MD in the presence of normal lung function and is associated with the level of anxiety rather than that of depression.

Adult↗

PubMed1995

Isometric muscle strength and muscular endurance in normal persons aged between 17 and 70 years.

Isometric muscle strength was measured in 63 women and 65 men, randomly selected, aged 17-70 years, using Penny & Giles' hand-held dynamometer. Eight muscle groups as well as the hand grip strength were tested bilaterally. The muscular endurance was measured as time to exhaustion in the abductors of the shoulder and the flexors of the hip. Reference values for muscle strength and muscular endurance are given in the age groups 17-18, 20-29, 30-39, 40-49, 50-59 and 60-70 years of age. The mean strength of females was about 65-70% of that of the men, but when the results were related to weight, the differences almost disappeared. Both men and women seem to have the greatest muscle strength at the age of about 17-18. The strength is rather constant up to the age of about 40 years, after which a discrete decline is seen up to about 60, from where the decline is more obvious. Muscular endurance showed great variability between individuals. However, no decrease in endurance was seen in older ages. For both sexes, lower reference limits of endurance, with the methods used, for arm abductors are suggested as being 3 minutes and for hip flexors, 90 seconds.

Adolescent↗

PubMedDate not supplied

Influence of noninvasive ventilation by BiPAP on exercise tolerance and respiratory muscle strength in chronic obstructive pulmonary disease patients (COPD).

This study aimed to assess the effect of BiPAP, by nasal mask, on exercise tolerance and respiratory muscle strength in patients with a clinical and spirometric diagnosis of moderate/severe COPD (FEV1 < 60% of predicted). Ten patients of 59.4+/-8.9 years old, with FEV1/FVC <70% of predicted level, were treated with 30 minutes of BiPAP (IPAP:10 and 15 cmH2O; EPAP:4 cmH2O), three days per week, during two months. Before and after the treatment, spirometry, inspiratory (MIP) and expiratory (MEP) muscle strength and the distance walked in six minutes (6MWT) were measured. We observed a significant increase (Wilcoxon, p<0.05) in the mean values of MIP (from -55+/-17 to -77+/-19, respectively), MEP (from 75+/-20 to 109+/-36, respectively) and walking distance (from 349+/-67 to 448+/-75). Based on these results, we concluded that BiPAP improves respiratory muscle strength and exercise tolerance in these COPD patients.

Aged↗

PubMed2006

Low-frequency electrical stimulation increases muscle strength and improves blood supply in patients with chronic heart failure.

BACKGROUND: This study was designed to evaluate the effects of low-frequency electrical stimulation (LFES) on muscle strength and blood flow in patients with advanced chronic heart failure (CHF). METHODS AND RESULTS: Patients with CHF (n=15; age 56.5 +/- 5.2 years; New York Heart Association III - IV; ejection fraction 18.7 +/- 3.3%) were examined before and after 6 weeks of LFES (10 Hz) of the quadriceps and calf muscles of both legs (1 h/day, 7 days/week). Dynamometry was performed weekly to determine maximal muscle strength (F(max); N) and isokinetic peak torque (PT(max); Nm); blood flow velocity (BFV) was measured at baseline and after 6 weeks of LFES using pulsed-wave Doppler velocimetry of the right femoral artery. Six weeks of LFES significantly increased F(max) (from 224.5 +/- 96.8 N to 340.0 +/- 99.4 N; p<0.001), and also PT(max) (from 94.5 +/- 41.5 Nm to 135.3 +/- 28.8 Nm; p<0.01). BFV in the femoral artery increased after 6 weeks from 35.7 +/- 15.4 cm/s to 48.2 +/- 18.1 cm/s (p<0.05); BFV values at rest before and after 6 weeks of LFES did not differ significantly. CONCLUSIONS: LFES may improve muscle strength and blood supply, and could be recommended for the treatment of patients with severe CHF.

Biomarkers↗

PubMed1998

Muscle strength and functional mobility in relation to lean body mass in free-living frail elderly women.

OBJECTIVES: (1) To describe body composition of the frail elderly, (2) To relate lean body mass to muscle strength and functional ability, and (3) To assess temporal stability of strength measures and index of functional ability. DESIGN: Cross-sectional study. SETTING: Community-dwelling. SUBJECTS: Thirty frail elderly women (81.5 +/- 7 y) recruited from residences or out-patient facilities. METHODS: Total body fat and fat-free mass (FFM) were determined using multi-frequency bioelectrical impedance analysis and predicted from anthropometry. Handgrip strength, biceps and quadriceps strength, functional capacities (Timed 'Up & Go') as well as self-perceived health and functional status were measured. Reliability was assessed using two separate observations made one week apart by the same examiner. RESULTS: Mean height, weight and body mass index were 1.52 +/- 0.04 m, 60.4 +/- 10.7 kg and 26.0 +/- 4.8 kg/m2 respectively. FFM (34.1 +/- 4.6 kg) was lower than previous reports for autonomous elderly females and associated with all measures of muscle strength (Pearson's r = 0.42-0.62, P < or = 0.02), but not with performance on the Timed 'Up & Go' or self-perceived health and functional status. Strength measures correlated significantly with different subscales of self-perceived functional capacities and were significantly lower among women with a low %FFM (n = 19) and those reporting pain (n = 11) as compared to other women. Excellent temporal stability for muscle and functional measures was observed (ICC = 0.80-0.90). CONCLUSIONS: Muscle strength was strongly related to FFM in free-living frail elderly women especially in the absence of pain.

Adipose Tissue↗

PubMed2002

Relationship of interleukin-6 and tumor necrosis factor-alpha with muscle mass and muscle strength in elderly men and women: the Health ABC Study.

BACKGROUND: A decline in muscle mass and muscle strength characterizes normal aging. As clinical and animal studies show a relationship between higher cytokine levels and low muscle mass, the aim of this study was to investigate whether markers of inflammation are associated with muscle mass and strength in well-functioning elderly persons. METHODS: We used baseline data (1997-1998) of the Health, Aging, and Body Composition (Health ABC) Study on 3075 black and white men and women aged 70-79 years. Midthigh muscle cross-sectional area (computed tomography), appendicular muscle mass (dual-energy x-ray absorptiometry), isokinetic knee extensor strength (KinCom), and isometric grip strength were measured. Plasma levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were assessed by enzyme-linked immunosorbent assay (ELISA). RESULTS: Higher cytokine levels were generally associated with lower muscle mass and lower muscle strength. The most consistent relationship across the gender and race groups was observed for IL-6 and grip strength: per SD increase in IL-6, grip strength was 1.1 to 2.4 kg lower (p <.05) after adjustment for age, clinic site, health status, medications, physical activity, smoking, height, and body fat. An overall measure of elevated cytokine level was created by combining the levels of IL-6 and TNF-alpha. With the exception of white men, elderly persons having high levels of IL-6 (>1.80 pg/ml) as well as high levels of TNF-alpha (>3.20 pg/ml) had a smaller muscle area, less appendicular muscle mass, a lower knee extensor strength, and a lower grip strength compared to those with low levels of both cytokines. CONCLUSIONS: Higher plasma concentrations of IL-6 and TNF-alpha are associated with lower muscle mass and lower muscle strength in well-functioning older men and women. Higher cytokine levels, as often observed in healthy older persons, may contribute to the loss of muscle mass and strength that accompanies aging.

Aged↗

PubMed2000

Muscle strength and electromyogram in boys and girls followed through puberty.

The main purpose of this study was to investigate the changes in anthropometric measures and muscle strength that occur during puberty in children from the age of 11 to 16 years. Special attention was paid to possible gender- and muscle action-type-specific alterations in torque/velocity and EMG/velocity characteristics. Sixteen children participated in the study (9 boys and 7 girls). Eccentric and concentric muscle strength was measured on an isokinetic dynamometer at angular velocities of 45, 90 and 180 degrees x s(-1). Simultaneously, a surface electromyogram (EMG) was recorded from the quadriceps muscle. At the age of 11, the boys and girls exhibited equal anthropometric measures and strength performance. In both genders, body measures and muscle strength increased significantly during the 5-year period, with larger increases being recorded for the boys. In addition, the boys increased selectively their eccentric torque per body mass, indicating an action-type-specific change in muscle quality. The general shape of the torque/velocity relationship exhibited an adult-like pattern both before and after puberty, and did not differ between genders. Both pre- and postpuberty, myoelectric activity was generally lower during eccentric than concentric actions, the highest values occurring for both genders in the concentric 180 degrees x s(-1) test. Ratios of eccentric to concentric torque per EMG, which reflect electromechanical efficiency, showed no significant changes with age. A significant velocity- and gender-specific change in electromechanical efficiency was observed at the highest speed at postpuberty, where the ratio for the girls was higher than for the boys.

Adolescent↗

PubMed1991

Interrelationships of trunk and extremity muscle strengths and body awareness following unilateral brain lesions.

From 11 hemiparetic adults measurements of muscle strength of lateral trunk flexion and of extremities of paretic side were intercorrelated. Their varied magnitudes and correlations with body awareness suggested strengths of trunk and extremities are not exclusive and that decreased muscle strength is more likely for patients with decreased body awareness. Possible explanations are considered.

Adult↗

PubMed2000

Early recovery of isometric shoulder muscle strength after open acromioplasty in stage II impingement syndrome.

The recovery of shoulder muscle strength after open acromioplasty was evaluated in 48 patients (27 male, 21 female, mean age 44.3 years) who had undergone open acromioplasty because of stage II impingement syndrome. The isometric strengths of flexion, abduction and external rotation were measured before the operation and at 3, 6 and 12 months postoperatively. The mean preoperative flexion strength of the involved shoulder was 72.6% of that of the uninvolved shoulder, and this increased to 77.1% by 3 months post operation, to 88.3% at 6 and to 88.3% at 12 months. Corresponding abduction strengths were 68.4%, 80.4%, 88.7% and 91.0% and the external rotation strengths were 75.1%, 77.4%, 95.1% and 93.5%, respectively. These recoveries were markedly improved when the cases with poor subjective results at 1 year were not considered. The low preoperative strengths were more pronounced in women than in men, but recovery was better in women. It is concluded that shoulder muscle strengths recover to near normal in 1 year after open acromioplasty.

Acromion↗

PubMed1998

Decreased muscle strength in patients with alcoholic liver cirrhosis in relation to nutritional status, alcohol abstinence, liver function, and neuropathy.

To study motor function quantitatively in alcoholic liver cirrhosis muscle strength, liver function, peripheral nerve function, and nutrition were assessed in 24 patients. Isokinetic strength of flexion and extension at elbow, wrist, hip, knee, and ankle and of shoulder abduction and adduction was evaluated and compared with findings in 24 matched healthy subjects. Degree of liver disease was assessed with the Child-Pugh score and the galactose elimination capacity (GEC). Nutritional status was evaluated with an estimation of lean body mass (LBM) from 24-hour urinary creatinine excretions. Peripheral nerve function was evaluated with neurological symptom and disability scores, nerve conduction studies, and quantitative sensory tests summed to obtain a neuropathy rank-sum score (NRSS) for each patient. Combined muscle strength at hip, knee, ankle, shoulder, elbow, and wrist were weakened with 34% (P < .005), 35% (P < .001), 35% (P < .01), 34% (P < .01), 29% (P < .01), and 29% (P < .02), respectively. The median Child-Pugh score was 7 (range, 5-12), and the median duration of alcohol abstinence was 90 days (range, 5-960 days). After multiple linear regression analysis including LBM, Child-Pugh score, GEC, duration of alcohol abstinence, and NRSS, only LBM was correlated to the strength at the knee (r=.79; P < .0001) and at the ankle (r=.63; P < .01). It is concluded that muscle strength is weakened substantially in alcoholic patients with liver cirrhosis and that weakness is related to the severity of malnutrition but not to the severity of liver disease, duration of alcohol abstinence, or neuropathy.

Adult↗

PubMed2003

Is there any difference in measurement of pelvic floor muscle strength in supine and standing position?

BACKGROUND: Traditionally, pelvic floor muscle function and strength have been measured in a supine position. However, stress urinary incontinence most often occurs in an upright position, and an important clinical question is whether measurement of pelvic floor muscle strength in the supine position reflects strength in standing. The purpose of the present study was to investigate whether there is a significant and clinical difference in pelvic floor muscle strength measurement in supine and standing position. METHODS: Eighteen women, mean age 43.4 years (range 31-64 years), with symptoms of stress and mixed incontinence attending a pelvic floor muscle-training program participated in the study. Measurement of pelvic floor muscle strength was conducted with a fiberoptic microtip transducer connected to a balloon catheter inserted into the vagina (Camtech AS, Sandvika, Norway). Measurement of resting pressure, maximum squeeze pressure, and holding period in seconds, were assessed in random order in supine and standing position. RESULTS: The mean difference between supine and standing resting pressure was 8.6 cmH2O (95% CI 4.9-12.3), p < 0.001, between supine and standing maximum strength 0.3 cmH2O (95% CI - 4.0 to 3.4), p = 0.884, and between supine and standing holding period 0.9 s (95% CI - 3.3 to 1.4), p = 0.409. CONCLUSION: Vaginal resting pressure was significantly higher in the standing compared to the supine position. Neither maximal strength nor holding time was different when comparing the two positions. Measurement of vaginal squeeze pressure is easier to perform and standardize in the supine compared to the standing position, and seems to reflect pelvic floor muscle strength in the standing position.

Adult↗

PubMed1985

Relationship of muscle strength for knee extension to walking capacity in patients with spastic hemiparesis.

Muscle strength for knee extension, both isokinetic and isometric, and walking capacity, maximum velocity and walking rate, were examined in 11 post-stroke hemiparetic patients. The degree of spasticity of the affected lower extremity was not related to the isokinetic and isometric torques, or to the walking capacity. Although both the isokinetic and isometric torques decreased on the affected side compared to the non-affected side, the rate of decrease was remarkable in isokinetic torque at fast velocities. The walking capacity was well correlated with isokinetic torque of the affected side at fast velocities but not isometric torques. These results suggest that reduction of muscle strength at rapid movements is an essential feature of spastic paresis and is primary cause of motor disabilities such as impaired locomotor function.

Adult↗

PubMed1976

Measurements of muscle strength and performance in children with normal and diseased muscle.

A study has been made of two simple means of measuring muscle power in children with normal and diseased muscle. In one the length of time that the leg and the head could be held at 45 degrees above the horizontal was measured with the child supine. In the second, measurements were made of the isometric strength of six muscle groups with the newly developed Hammersmith Myometer. In the timed performance tests only 5 (8%) of a group of 61 children known to have muscle disease achieved the minimum expected values for their ages. Myometer readings of the isometric power of the children with muscle disease also have values which were below those of a comparable group of normal children. The reproducibility of muscle strength measurements in young children has been shown to be good, whereas the timed performance tests, though able to differentiate normal children from children with muscle disease, did not show sufficient reporducibility for this test to be recommended for sequential measurements.

Adolescent↗

PubMed1991

Comparison of muscle strength and bone mineral density in healthy postmenopausal women. A cross-sectional population study.

In this cross-sectional population study with 78 healthy 0.5-5 years postmenopausal, 49-55 year old females a significant simple linear correlation between lumbar spine LII-LIV bone mineral density and adjacent back extensor and flexor isometric muscle strength was found. With the stepwise multiple linear regression analyses the most significant predictors for lumbar spine LII-LIV and femoral neck bone mineral density were weight (partial R2) (R2 = 0.197, p = 0.0001; R2 = 0.157, p = 0.0009) and age (R2 = 0.056, p = 0.0205; R2 = 0.036, p = 0.0708). Height and isometric muscle strength and endurance of muscles were not significant predictors. Weight and age were the most significant predictors also for isometric muscle strength. The mobility of spine, body fat content and anaerobic threshold had no correlation on bone mineral density.

Absorptiometry, Photon↗

PubMed2001

Respiratory muscle strength and ventilatory failure in amyotrophic lateral sclerosis.

Although ventilatory failure is the most common cause of death in amyotrophic lateral sclerosis (ALS) and measurement of respiratory muscle strength (RMS) has been shown to have prognostic value, no single test of strength can predict the presence of hypercapnia reliably. RMS was measured in 81 ALS patients to evaluate the relationship between tests of RMS and the presence of ventilatory failure, defined as a carbon dioxide tension > or = 6 kPa. We studied the predictive value of vital capacity (VC), static inspiratory and expiratory mouth pressures (MIP, MEP), maximal sniff oesophageal (sniff P(oes)), transdiaphragmatic (sniff P(di)) and nasal (SNP) pressure, cough gastric (cough P(gas)) pressure and transdiaphragmatic pressure after bilateral cervical magnetic phrenic nerve stimulation (CMS P(di)) to identify the risk of ventilatory failure in the whole group and in subgroups of patients with and without significant bulbar involvement. For patients without significant bulbar involvement, sniff P(di) had greatest predictive power [odds ratio (OR) 57] with specificity, sensitivity and positive and negative predictive values (PPV, NPV) of 87, 90, 74 and 95%, respectively Of the less invasive tests, per cent predicted SNP had greater overall predictive power (OR 25, specificity 85%, sensitivity 81%) than per cent predicted VC (9, 89%, 53%) and per cent predicted MIP (6, 83%, 55%). No test had significant predictive power for the presence of hypercapnia when used to measure RMS in a subgroup of patients with significant bulbar weakness. Thirty-five patients underwent polysomnography. CMS P(di), sniff P(di) and per cent predicted SNP were significantly correlated with the apnoea/hypopnoea index (AHI) (P = 0.035, 0.042 and 0.026, respectively). The correlations between AHI and per cent predicted MIP and VC were less strong (both non-significant). In ALS patients without significant bulbar involvement, novel tests of RMS have greater predictive power than conventional tests to predict hypercapnia. In particular, the non-invasive SNP is more sensitive than VC and MIP, suggesting that it could usefully be included in tests of respiratory muscle strength in ALS and will be helpful in assessing the risk of ventilatory failure. In patients with significant bulbar involvement, tests of respiratory muscle strength do not predict hypercapnia. Sleep-disordered breathing is correlated with RMS and the novel tests of RMS having the strongest relationship with the degree of sleep disturbance.

Adult↗