SEARCH · PubMed Health

Results for “Muscle Strength”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 847 records · Page 47Linked to original sources

PubMed1988

Trunk muscle strength in athletes.

Maximal voluntary strength of the trunk muscles was measured in 57 male elite athletes (soccer players, wrestlers, tennis players, and gymnasts), 14 female elite gymnasts, and in a normal group of 87 conscripts. Mean ages in the different groups ranged from 18-22 yr. An isokinetic (constant velocity) technique was used to record maximal torque produced by trunk and hip muscles during flexion, extension, and lateral flexion over the range of motion. The constant angular velocities used were 15 deg.s-1 and 30 deg.s-1, respectively. Isometric strength was measured in a straight body position (0 deg. of flexion). The measurements were made with the subjects in a horizontal position with the pivot point at the hip and at the lumbar (L2-L3) level. All male athlete groups showed higher peak torque values than the normals. The differences were largest in hip extension and trunk flexion. The male gymnasts also showed significantly higher peak values in hip flexion as compared to all other categories. There was no difference in strength per kg body weight between female gymnasts and untrained males, except in trunk extension. The position for peak torque occurred earlier in the movements for the athletes, especially for the gymnasts in extension movements and for the tennis players in flexion movements. In isometric contractions essentially the same strength differences were present as in the slow isokinetic contractions. In lateral flexion wrestlers and tennis players showed significantly higher strength in movements toward the nondominant side. Thus, differences were present between the athletes and the normals, some of which appeared to be sport specific and related to long-term systematic training.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Residual lung volume and ventilatory muscle strength changes following maximal and submaximal exercise.

In order to evaluate a mechanism which may be responsible for the often observed acute increase in residual lung volume (RV) following exercise, 12 non-smoking males (20-30 yrs) performed two bouts of exercise on separate days; one to maximal heart rate (HRmax) and one to 85% of HRmax for 20 min. Prior to exercise and at 5, 15, 30, 60 and 120 min post-exercise, the following parameters were measured: RV, forced vital capacity (FVC), forced expiratory volume (FEV1.0), forced expiratory flow (FEF75-85), maximal expiratory pressure (PEmax), and maximal inspiratory pressure (PImax). Significant (p < 0.05) increases occurred in RV at 5, 15 and 30 min following maximal exercise and at 5 and 30 min after submaximal exercise. Changes in RV between the two exercise bouts were generally greater (p < 0.05) for maximal exercise. Accompanying the increases in RV were significant (p < 0.05) decreases in PEmax and decreases in FVC, while FEV1.0 and FEF75-85 remained generally unchanged or were slightly elevated. The data suggest that decreases in expiratory muscle strength due to fatigue may in part be responsible for increases in RV.

Adult↗

PubMed1994

Respiratory muscle strength in the elderly. Correlates and reference values. Cardiovascular Health Study Research Group.

Maximal inspiratory pressure (MIP) was assessed in 4,443 ambulatory participants of the Cardiovascular Health Study, 65 yr of age and older, sampled from four communities. Maximal expiratory pressure (MEP) was also measured in 790 participants from a single clinic. Positive predictors of MIP included male sex, FVC, handgrip strength, and higher levels of lean body mass (or low bioelectric resistance). Negative predictors were age, current smoking, self-reported fair to poor general health, and waist size. Both participant and technician learning effects were noted, but there was no independent effect of race, hypertension, cardiovascular disease, or diabetes. A healthy subgroup was identified by excluding current smokers, those with fair to poor general health, or an FEV1 less than 65% of predicted. Mean values determined from the healthy group were 57/116 cm H2O (MIP/MEP) for women, and 83/174 for men. Lower limits of the normal range (fifth percentiles) were 45 to 60% of the mean predicted values. The reference equations derived from this group of healthy 65 to 85-yr-olds may be used by pulmonary function laboratories and respiratory therapists who evaluate the respiratory muscle strength of elderly patients.

Aged↗

PubMed2003

Relation between isokinetic muscle strength and functional capacity in recreational athletes with chondromalacia patellae.

OBJECTIVES: To investigate the effects of isokinetic exercise on pain and functional test scores of recreational athletes with chondromalacia patellae (CMP) and to examine the correlation between isokinetic parameters and functional tests or pain score. METHODS: The functional ability of 30 recreational athletes with unilateral CMP was evaluated using six different tests. Pain scores were assessed during daily activities before and after the treatment protocol. Isokinetic exercise sessions were carried out at angular velocities of 60 degrees /s (25-90 degrees range of flexion) and 180 degrees /s (full range). These sessions were repeated three times a week for six weeks. RESULTS: Quadriceps and hamstring peak torque, total work, and endurance ratios had improved significantly after the treatment, as did the functional parameters and pain scores. There was a poor correlation between the extensor endurance ratio and one leg standing test. A moderate correlation between the visual analogue scale and the extensor endurance ratio or flexion endurance ratio was also found. CONCLUSIONS: The isokinetic exercise programme used in this study had a positive effect on muscle strength, pain score, and functional ability of knees with CMP. The improvement in the functional capacity did not correlate with the isokinetic parameters.

Adult↗

PubMed2005

Muscle strength and weight-bearing symmetry relate to sit-to-stand performance in individuals with stroke.

This study investigated the relationship of lower extremity joint torques and weight-bearing symmetry to sit-to-stand (STS) performance in individuals with chronic stroke. A motion analysis system and two force plates measured STS duration and weight-bearing symmetry (determined by ground reaction forces) during three self-paced and three fast-paced conditions. An isokinetic dynamometer measured maximum concentric joint torques of the paretic and non-paretic ankle, knee, and hip, which were normalized by body mass. Pearson correlations indicated that (a) paretic ankle dorsiflexion and knee extension torques related to the duration of the self-paced STS condition (r = -0.450, -0.716, respectively), (b) paretic ankle dorsiflexion, plantar flexion, and knee extension torques related to the duration of the fast-paced STS condition (r = -0.466, -0.616, -0.736, respectively), and (c) greater weight-bearing symmetry related to faster STS performance for both self-paced and fast-paced STS conditions (r = -0.565, -0.564, respectively) (P < 0.05). This evidence suggests that paretic muscle strength and the ability to load the paretic limb are important factors underlying the ability to rise from a chair in individuals with chronic stroke.

Aged↗

PubMed2005

Association between 25-hydroxy vitamin D levels, physical activity, muscle strength and fractures in the prospective population-based OPRA Study of Elderly Women.

Vitamin D supplements have been used to prevent fractures. The effect may be mediated through increased bone mass, but also through reduced falling propensity. The aim of this study was to evaluate the association between 25-hydroxy vitamin D levels (25OHD), fall-associated variables (including tests of functional performance), and fracture in ambulatory women. At baseline 25OHD was measured in 986 women. Fall-associated variables were investigated at baseline. Fractures were recorded during a 3-year follow-up. Four percent of the women had 25OHD levels below 20 ng/ml (50 nmol/l), and 26% had 25OHD levels below 30 ng/ml (75 nmol/l). 25OHD correlated with gait speed (r =0.17, P <0.001), the Romberg balance test (r =0.14, P <0.001), self-estimated activity level (r =0.15, P <0.001), and thigh muscle strength (r =0.08, P =0.02). During the 3-year follow-up, 119 out of the 986 women sustained at least one fracture. The Cox proportional hazard ratio (HR) (95% confidence interval) for sustaining a fracture during the follow-up was 2.04 (1.04-4.04) for the group of women with 25OHD below 20 ng/ml, in which 9 out of 43 women sustained a fracture. Thirty-two of the 256 women with 25OHD levels below 30 ng/ml sustained a fracture during the follow-up, with a non-significant HR of 1.07 (1.07-1.61). This cohort of elderly, ambulatory women had a high mean 25OHD. A low 25OHD was associated with inferior physical activity level, gait speed and balance. A 25OHD level below 30 ng/ml was not associated with an increased risk of fractures in this study. However, a subgroup of women with 25OHD levels below 20 ng/ml had a tendency to an increased risk of fractures, which may be associated with an inferior physical activity and postural stability.

Accidental Falls↗

PubMed2026

Effects of blood flow restriction training combined with plyometric training on lower limb muscle strength and motor unit recruitment in basketball players: An experimental study.

OBJECTIVE: Previous studies have shown that plyometric training (PT) improves neuromuscular function and explosive power but not maximal strength. Blood flow restriction training (BFR) combined with low-intensity resistance training (RT) increases muscle mass and strength. This study investigated the effects of PT, and BFR combined with PT on lower-limb muscle function. METHODS: Twenty elite basketball players were randomly assigned to two groups: PT-alone group (PT, n = 10) and BFR combine with PT group (PT-BFR, n = 10). All participants underwent bodyweight-based plyometric training three times per week for eight weeks. Peak torque values for hip and knee flexion and extension, as well as root mean square (RMS) values derived from electromyography, were measured before and after the intervention. RESULTS: After the 8-week intervention, both groups showed significant improvements in knee flexion and extension peak torque at 180°/s (all p < 0.01). Between-group comparisons revealed greater gains in the PT-BFR group for hip extension and flexion at 60°/s (p = 0.036-0.002; ηp2 = 0.225-0.233). RMS of the rectus femoris increased significantly more in the PT-BFR group than in the PT group (right: p = 0.004, ηp2 = 0.385; left: p = 0.020, ηp2 = 0.266), whereas no significant changes were observed in the gastrocnemius, tibialis anterior, or biceps femoris (all p > 0.05). CMJ height also improved more in the PT-BFR group, with a significant group × time interaction (p = 0.042, ηp2 = 0.210). CONCLUSION: Both training protocols enhanced bilateral lower-limb strength, with notable gains in the non-dominant leg; however, the magnitude did not differ substantially between groups. In contrast, compared with PT alone, BFR combined with PT produced superior enhancements in lower-limb muscle strength and neuromuscular recruitment. These findings suggest that when PT is employed to improve explosive power, it may be effectively combined with BFR to further augment muscular strength.

Humans↗

PubMed1999

An approach to estimating bone and joint loads and muscle strength in living subjects and skeletal remains.

Skeletal physiology that clarified after 1990 shows that bone modeling normally makes a bone strong enough to keep its loads from causing strains above a "modeling threshold". That arrangement adapts bone strength to the largest loads on a bone, which are usually brief and infrequent. Accordingly, in bone adapted chiefly to uniaxial compression loads, the modeling threshold's value and the cross-sectional amount of that bone could suggest the size of those loads. Bone loaded in that way does support the articular surfaces of synovial joints as their "supporting bone", so its amount could suggest the size of the loads it had adapted to, and therefore the loads on the joint that it supports. During growth a joint's size is proportional, directly but not linearly, to the size of its total loads, so that its size at skeletal maturity could be an index of those loads at that time. Joints cannot decrease in size. Yet throughout life their supporting bone can decrease or increase in strength and "mass" to adapt to changes in a joint's loads. Thus, an adult joint's size could suggest the size of the loads it adapted to by skeletal maturity, while the cross-sectional amount of its supporting bone at any later age could reveal the size of those loads at that later age, and thus suggest any change in those loads that might have occurred after skeletal maturity. Since the bone modeling threshold, and the relationships between bone strain, stress, and unit loads are now known, it is possible with this procedure to estimate the total loads on joints, and how body weight and muscle strength contribute to those loads in both living subjects and skeletal remains. To make a reliable technology of the idea involves some problems which this paper identifies and suggests how to resolve. Am. J. Hum. Biol. 11:437-455, 1999. Copyright 1999 Wiley-Liss, Inc.

Journal Article↗

PubMed2002

Relation between walking speed and muscle strength is affected by somatosensory loss in multiple sclerosis.

OBJECTIVE: To evaluate the correlation between gait speed and strength in multiple sclerosis (MS) with particular regard to patients presenting with proprioceptive loss. METHODS: Gait evaluation and isokinetic testing of muscular function were performed in 20 patients with unaided gait (expanded disability status scale < 6). Patients were separated into two groups in relation to the occurrence of somatosensory involvement: pyramidal group (8 patients) and sensory-pyramidal group (12 patients). Ten healthy subjects of similar age, sex, and height constituted a control group to evaluate gait parameters. RESULTS: In the whole patient group, gait speed was reduced and strongly related to hamstring peak torque but not with quadriceps peak torque. The gait speed and peak torques of quadriceps and hamstrings were similar in both groups of patients. However, in the patients with proprioceptive loss there was both a strong correlation between gait speed and hamstring torque and a significant correlation with quadriceps torque. In the pyramidal group there was poor or no correlation. CONCLUSION: In patients with undifferentiated MS there is some correlation between gait speed and muscle strength. In the case of sensory loss, a higher contribution of both flexor and extensors of the lower limbs was observed, suggesting that muscular compensation occurred in this situation to maintain gait speed. These results are relevant to assess rehabilitation modalities in MS.

Adult↗

PubMed2006

High-altitude exposure reduces inspiratory muscle strength.

It was the aim of the study to assess the maximal pressure generated by the inspiratory muscles (MIP) during exposure to different levels of altitude (i.e., hypobaric hypoxia). Eight lowlanders (2 females and 6 males), aged 27 - 46 years, participated in the study. After being evaluated at sea level, the subjects spent seven days at altitudes of more than 3000 metres. On the first day, they rode in a cable car from 1200 to 3200 metres and performed the first test after 45 - 60 minutes rest; they then walked for two hours to a mountain refuge at 3600 metres, where they spent three nights (days 2 - 3); on day 4, they walked for four hours over a glacier to reach Capanna Regina Margherita (4559 m), where they spent days 5 - 7. MIP, flow-volume curve and SpO (2) % were measured at each altitude, and acute mountain sickness (Lake Louise score) was recorded. Increasing altitude led to a significant decrease in resting SpO (2) % (from 98 % to 80 %) and MIP (from 134 to 111 cmH (2)O) (baseline to day 4: p < 0.05); there was an improvement in SpO (2) % and a slight increase in MIP during the subsequent days at the same altitude. Expiratory (but not inspiratory) flows increased, and forced vital capacity and FEF (75) decreased at higher altitudes. We conclude that exposure to high altitude hypoxia reduces the strength of the respiratory muscles, as demonstrated by the reduction in MIP and the lack of an increase in peak inspiratory flows. This reduction is more marked during the first days of exposure to the same altitude, and tends to recover during the acclimatisation process.

Adult↗

PubMed2002

A double-blind, placebo-controlled, randomized clinical trial of recombinant human chorionic gonadotropin on muscle strength and physical function and activity in older men with partial age-related androgen deficiency.

Despite partial androgen deficiency, the safety and efficacy of androgen therapy in older men remains controversial because controlled studies of testosterone have given equivocal results. Human chorionic gonadotropin (hCG) can be conveniently and infrequently self-administered, and it increases not only circulating testosterone but also estradiol and other testicular steroids. We evaluated the efficacy and safety of 3 months of treatment with sc recombinant hCG (r-hCG, Ovidrel) on muscle mass, strength, mobility, and physical activity in ambulant, community-dwelling men more than 60 yr old having partial androgen deficiency (testosterone < or = 15 nmol/liter, twice). Forty eligible men (mean age, 67 yr; range, 60-85 yr) were randomized to receive r-hCG (5000 IU, 250 microg) or placebo by twice weekly sc self-injection and were studied before treatment, monthly during treatment, and 1 month after treatment. All completed the study, and treatment groups were well matched. r-hCG significantly increased body weight (approximately 1 kg; P < 0.05) and lean body mass ( approximately 2 kg; P < 0.001) and reduced fat mass (approximately 1 kg, P < 0.05). However, anthropometric measures of skinfold thickness (biceps, triceps, subscapular, suprailiac) and circumferences (midarm, waist, hip, and midthigh), including the waist-hip ratio, did not change significantly. Shoulder and knee strength (peak torque), as measured by isokinetic and isometric dynamometry, was not significantly increased, nor was physical activity (accelerometry and Physical Activity Scale for Elderly self-report) or gait and balance (modified Guralnik and Frailty and Injuries: Cooperative Studies of Intervention Techniques performance batteries) altered. Total and free testosterone and estradiol were markedly (150%; P < 0.001) and stably increased, whereas LH, FSH, and urea were significantly decreased. Testis volume was significantly decreased (approximately 5 ml; P < 0.05). There were no significant changes in hemoglobin, osteocalcin, or prostate-specific antigen, and the International Prostate Symptom Score did not change. Three men developed nipple tenderness that did not progress to gynecomastia. We conclude that 3 months of treatment with twice weekly r-hCG demonstrates sustained androgenic effects on hormones and muscle mass but has no effect on muscle strength or physical functioning.

Aged↗

PubMedDate not supplied

Association of muscle strength with maximum walking speed in disabled older women.

Our aim was to study the association of lower limb strength with maximum walking speed in disabled older women and to try to detect the reserve capacity threshold for maximum walking speed and the minimum strength required for walking at a speed of 1.22 m x s(-1), which is required in crossing signaled intersections. The data are from the baseline of Women's Health and Aging Study, a population-based study on causes and course of disability. Altogether, 1,002 disabled women participated in the tests, which took place at their homes. Maximum isometric hip flexion and knee extension forces were measured on both sides using a handheld dynamometer. For analytic purposes, knee extension torque/body mass ratio (KET/BM) was calculated. Maximum walking speed was measured with a stopwatch during a 4-m walk. KET/BM had a significant effect on walking speed after controlling for number of chronic conditions, balance, use of walking aid, joint pain, age, and body height and mass. A total of 42.3% of the variation in maximum walking speed was explained by these variables. The cumulative percentage distribution of KET/BM of those able to attain a maximum walking speed of 1.22 m x s(-1) (n = 148) was flat to the level of 1.1 N x m x kg(-1), after which it turned upward, indicating that the probability of attaining 1.22 m x s(-1) started to increase after that level. By using segmented linear regression analysis, 2.3 N x m x kg(-1) was found to be the cutoff point beyond which an increase in KET/BM did not correspond to an increase in maximum walking speed. Muscle strength was positively but not linearly associated with maximum walking speed. Strength testing may help to identify people close to functional thresholds and, thus, at risk of impaired walking, who would benefit most from strengthening exercises.

Activities of Daily Living↗

PubMed1994

Gender differences in muscle strength after 20 days bed rest.

In the previous studies, when Bed rest (BR) was prolonged over 2 weeks, muscle mass and strength began progressively to become reduced. There are many publications investigating the changes in skeletal muscles during inactivity. However it is still unclear whether the changing degrees of muscle mass and strength not only in antigravity muscles but also in non-antigravity muscles differ between males and females. So, the purpose of this study is to investigate gender difference in the effect of 20 days of BR (BR 20) on regional muscle mass and strength of the arm and leg.

Absorptiometry, Photon↗

PubMed2006

Effect of muscle wrapping on model estimates of neck muscle strength.

Of the computational models of the cervical spine reported in the literature, not one takes into account the changes in muscle paths due to the underlying vertebrae. Instead, all model the individual muscle paths as straight-line segments. The major aim of this study was to quantify the changes in muscle moment arm, muscle force and joint moment due to muscle wrapping in the cervical spine. Five muscles in a straight-line model of the cervical spine were wrapped around underlying vertebrae, and the results obtained from this model were compared against the original. The two models were then validated against experimental and computational data. Results show that muscle wrapping has a significant effect on muscle moment arms and therefore joint moments and should not be neglected.

Cervical Vertebrae↗

PubMed1998

Association of muscle strength and electrophysiological measures of reinnervation in diabetic neuropathy.

Motor function was assessed in 34 non-insulin-dependent and 19 insulin-dependent diabetic patients with macroelectromyography and isokinetic dynamometry. Fiber density (FD) and the amplitude of the macro motor unit potential (macro MUP) of the anterior tibial and lateral vastus muscles were obtained and maximal isokinetic strength of the ankle and knee extensors were determined. All patients underwent standardized clinical examination including a neurological disability score (NDS), quantitative sensory examination, and conventional motor nerve conduction studies. The amplitude of the macro MUP and FD of the anterior tibial muscle were increased in neuropathic patients without weakness (P < 0.05) and further increased in neuropathic patients with weakness (P < 0.05). The NDS was related to the FD and the amplitude of the macro MUP for the anterior tibial and lateral vastus muscle [r=0.55-0.75 (P < 0.005)]. Muscle strength of ankle and knee extensors correlated with the FD [r=-0.69 (P < 0.0001) and r=-0.58 (P< 0.001), respectively] and with the amplitude of the macro MUP of the two muscles [r=-0.63 (P < 0.0001) and r=-0.37 (P < 0.05), respectively]. Our findings support the hypothesis that loss of muscle strength in diabetic patients is due to incomplete reinnervation following axonal loss.

Adult↗

PubMed1988

Muscle strength following anaesthesia with atracurium and pancuronium.

Postoperative recovery from muscle weakness was investigated by handgrip strength after general anaesthesia using short- and long-acting muscle relaxants. Handgrip strength was measured on four occasions, preoperatively, before and after premedication, and postoperatively, both as soon as the patient could sustain a five-second headlift and one hour later. Twenty patients received either atracurium 0.6 mg/kg or pancuronium 0.1 mg/kg as part of a general anaesthetic technique with neostigmine reversal. Compared with their initial preoperative hand strengths, the two relaxant groups showed only an insignificant decrease in grip strength to 92% after premedication. Postoperatively when a five-second headlift was achieved, the patients in both groups were weak. The group given atracurium had a mean of 60% of their initial grip strength and those given pancuronium had a mean of 44%. This difference in strength was statistically significant from the initial level and from each other. However, there was no difference between the groups in the time interval from administering reversal to achieving a sustained headlift. One hour later in both groups grip strength was much better, within 80% of that seen after premedication in most patients, and no significant difference in grip strength was seen between the groups. This study demonstrates that patients who receive relaxant anaesthesia have substantial muscle weakness in the recovery phase. When neostigmine reversal is used, pancuronium appears to have a similar return of voluntary muscle power to that seen with atracurium. The marked difference in elimination kinetics of these two relaxants seems to be of little importance when neostigmine reversal is used.

Adult↗

PubMed2006

Deficit in human muscle strength with cast immobilization: contribution of inorganic phosphate.

Metabolic factors have been proposed to explain strength deficits observed in skeletal muscle with immobilization that are not completely accounted for by changes in muscle cross-sectional area (CSA) and neural adaptations. The aim of this study was to quantify changes in the resting inorganic phosphate (Pi) concentration from the medial gastrocnemius muscle during immobilization, reloading and rehabilitation. Additionally, we assessed the contributions of CSA, muscle activation and Pi concentration to plantar flexor torque during rehabilitation following immobilization. Eight persons with a surgically stabilized ankle fracture participated. Subjects were immobilized for 6-8 weeks and subsequently participated in 10 weeks of rehabilitation. Localized (31)P-Magnetic resonance spectroscopy, magnetic resonance imaging, isometric torque and activation testing were performed on the immobilized and uninvolved limbs. At 6 weeks of immobilization, significant differences were noted between the immobilized and uninvolved limbs for the Pi concentration and the Pi/PCr ratio (P < 0.05). From 6 weeks of immobilization to 3-5 days of reloading, the increase in Pi concentration (15%, P = 0.26) and Pi/PCr (20%, P = 0.29) was not significant. During rehabilitation, the relative contributions of CSA, muscle activation and Pi concentration to plantarflexor torque were 32, 44 and 40%, respectively. Together, CSA, muscle activation and Pi concentration accounted for 76% of the variance in torque (P < 0.01). In summary, our findings suggest that immobilization, independent of reloading, leads to a significant increase in the resting Pi concentration of human skeletal muscle. Additionally, alterations in resting Pi concentration may contribute to strength deficits with immobilization not accounted for by changes in muscle CSA or neural adaptations.

Adult↗

PubMed1990

Postoperative muscle strength.

This study investigates the role of motivation in voluntary strength measurements during the postoperative period. Thirty patients underwent surgery which was deemed minor, intermediate or major in severity. Before operation and on the 4th postoperative day measurement of grip strength, maximal voluntary and maximal tetanic (stimulated) contraction of adductor pollicis and assessment of mood were recorded. These investigations were also repeated on the 7th postoperative day in those who had major surgery. No patient had postoperative complications. Minor surgery had no influence on any of the values. Those who underwent major surgery showed significant reductions in grip strength, maximal voluntary contraction and mood; however, maximal tetanic contraction was unaffected. The results in the intermediate group were similar to the major group, although mood depression was less marked. Real strength of a hand muscle appears to be unaltered even by major surgery, but voluntary muscle force is decreased by intermediate and major surgery, and correlates with the patient's subjective state of well-being.

Adult↗