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PubMed2004

Muscle strength after resistance training is inversely correlated with baseline levels of soluble tumor necrosis factor receptors in the oldest old.

OBJECTIVES: To test the hypothesis that physical exercise induces an antiinflammatory response that is associated with reduced chronic activation of the tumor necrosis factor (TNF)-alpha system in frail elders and that the increase in muscle strength after resistance training is limited by systemic low-grade inflammation. DESIGN: A 12-week controlled resistance-training study. SETTING: Nursing homes in Copenhagen, Denmark. PARTICIPANTS: Twenty-one frail nursing home residents aged 86 to 95 completed the study. INTERVENTION: Ten participants were randomized to a program of resistance training of knee extensors and flexors three times a week for 12 weeks; the remaining 11 participants served as a control group who joined social activities supervised by an occupation therapist. MEASUREMENTS: Muscle strength, plasma levels of TNF-alpha, soluble TNF receptor (sTNFR)-1, and interleukin (IL)-6 were measured before and at the end of the intervention period. RESULTS: The training program improved muscle strength but did not affect plasma levels of TNF-alpha and sTNFR-I or IL-6. However, plasma levels of sTNFR-I at baseline were inversely correlated with the increase in muscle strength. CONCLUSION: Low-grade activation of the TNF system could limit the increase in muscle strength after resistance training in the oldest old. Furthermore, data suggest that the antiinflammatory response induced by 12 weeks of resistance training is not sufficient to reduce chronic activation of the TNF system, but the small sample size limited this interpretation.

Aged↗

PubMed1993

Influence of isotonic, isometric and isokinetic muscle strength on bone mineral density of the spine and femur in young women.

Bone mineral density (BMD) is dependent on multiple influences including genetics, mechanical forces, hormonal changes and nutritional mechanisms. The mechanical forces are, in part, influenced by muscle strength. This study examined the relationships between BMD of the spine and femur with muscle strength. Eighty-one healthy, non-athletic women aged 20-30 years were the subjects in the study. BMD was measured by dual energy x-ray absorptiometry. Trunk strength was measured by a Wagner Dynamometer or a Cable Tensiometer and leg strength was measured with a Cybex II isokinetic dynamometer. Trunk, leg and hip strength was also measured using 1 RM (one repetition maximum). There were significant correlations between spine density and trunk extension (r = 0.40, P = 0.0001) and spine density and trunk flexion (r = 0.30, P = 0.0037). There were significant correlations between femoral neck density and knee extension (r = 0.40, P = 0.003) and femoral neck density and knee flexion (r = 0.24, P = 0.0240). Multiple regression analysis showed that amongst young adult females weight and trunk extensor muscle strength contributed about equally to spine density. Flexor muscle strength did not influence bone density.

Absorptiometry, Photon↗

PubMed1993

Clenbuterol, a beta-adrenoceptor agonist, increases relative muscle strength in orthopaedic patients.

1. The sympathomimetic agent clenbuterol has a muscle-specific anabolic effect in normal and wasted muscles from animals. This trial was designed to examine the effect of the drug on the recovery of muscle strength and area after open medial meniscectomy. 2. A double-blind, completely randomized, placebo-controlled study was carried out on 20 healthy male patients. Muscle strength and cross-sectional area were determined before and after surgery. Patients were treated with drug or placebo for 4 weeks postoperatively and there was a 2 week washout period. 3. The results suggest that, in the operated leg, clenbuterol treatment is associated with a more rapid rehabilitation of strength in knee extensor muscles; in the unoperated leg, knee extensor strength increased above the initial values after 6 weeks (P = 0.01). However, in terms of absolute strength the differences were not significant between the two groups. 4. It is concluded that the data lend support to the proposition that clenbuterol has therapeutic potential in the treatment of muscle-wasting conditions.

Adult↗

PubMed2006

Knee muscle strength, gait performance, and perceived participation after stroke.

OBJECTIVE: To assess the relation between knee muscle strength, gait performance, and perceived participation in subjects with chronic mild to moderate poststroke hemiparesis. DESIGN: Descriptive analysis of convenience sample. SETTING: University hospital. PARTICIPANTS: Fifty men and women (mean age, 58+/-6.4y) 6 to 46 months poststroke. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Isokinetic concentric knee extension and flexion strength was measured at 60 degrees /s. Gait performance was assessed by Timed Up & Go, comfortable and fast gait speed, stair climbing ascend and descend, and 6-minute walk test. Perceived participation was assessed with the Stroke Impact Scale. RESULTS: There was a significant correlation (P < .01) between knee muscle strength and gait performance for the paretic but not for the nonparetic lower limb. Strength for the paretic limb explained 34% to 50% of the variance in gait performance; the addition of strength for the nonparetic limb explained at most a further 11% of the variance in gait performance. There was a significant correlation (P < .01) between gait performance and perceived participation; gait performance explained 28% to 40% of the variance in perceived participation. CONCLUSIONS: Knee muscle strength is a moderate to strong predictor of walking ability in individuals with chronic mild to moderate poststroke hemiparesis. Walking ability influences perceived participation, but the strengths of the relations indicate that other factors are also important.

Aged↗

PubMed2000

Treatment of vitamin D deficiency in patients with metastatic prostate cancer may improve bone pain and muscle strength.

PURPOSE: We performed a phase II study to determine whether pain associated with prostate cancer bone metastasis would respond to vitamin D replacement and parameters of muscle strength would be improved by vitamin D replacement therapy. MATERIALS AND METHODS: After a 4-week placebo period, eligible patients received orally 2,000 units vitamin D daily for 12 weeks. Pain questionnaires and measurements of muscle strength were competed at study enrollment and every 4 weeks thereafter. Serum calcium and vitamin D were measured at each clinic visit. RESULTS: A total of 16 patients with advanced hormone refractory prostate cancer were enrolled in this phase II study, of whom 7 (44%) had decreased baseline vitamin D. With vitamin D treatment, 4 patients (25%) had improvement in pain scores and 6 (37%) had improvement in muscle strength measurements. Improvement in pain scores correlated with improvement in subjective symptoms but did not result in a significant decrease in regular scheduled analgesic requirements. CONCLUSIONS: Vitamin D deficiency develops in a significant percent of patients with advanced hormone refractory prostate cancer. Supplementation with vitamin D may be a useful adjunct for improving pain, muscle strength and quality of life in this patient population.

Aged↗

PubMed2004

Trunk muscle strength and disability level of low back pain in collegiate wrestlers.

INTRODUCTION/PURPOSE: Low back pain (LBP) is a frequent injury in athletes. This study examined the relationship between isokinetic trunk muscle strength and the functional disability level of chronic LBP. We particularly focused on the existence of radiological abnormalities (RA) in the lumbar region. METHODS: Subjects were 53 collegiate wrestlers. Trunk extensor and flexor muscle strength was measured at three angular velocities (60, 90, and 120degrees x s(-1)). The examined parameters for trunk muscle strength were peak torque, work, average torque, and average power. The disability level of LBP was estimated by using two questionnaires. Based on the RA evaluation with x-ray and MRI, all 53 wrestlers were assigned to two groups as the RA group (N = 35, 66%) and the non-RA group (N = 18, 34%). Correlations between trunk muscle strength and the disability level of LBP in each group were analyzed with Spearman's rank test. RESULTS: Without considering the disability level, there were 14 subjects with LBP (40%) in the RA group and 8 (44%) in the non-RA. Significantly correlated parameters with the disability level of LBP could be observed only when the subjects were restricted to the non-RA group. The correlated parameters with the two questionnaires were peak torque at 120degrees x s(-1), work at 60degrees x s(-1) and 90degrees x s(-1), and average torque at 90degrees x s(-1) and 120degrees x s(-1). There were no significantly correlated parameters in the RA group. None of the trunk flexor parameters were significantly correlated with the disability level of LBP. CONCLUSION: The relatively low strength of trunk extensors may be one of the factors related to nonspecific chronic low back pain in collegiate wrestlers.

Adolescent↗

PubMed1998

Isometric muscle strength in alcoholic and nonalcoholic liver-transplantation candidates.

Intensity of isometric muscle contractions was measured in alcoholic subjects with cirrhosis (N = 42), nonalcoholic subjects with cirrhosis (N = 33), and normal controls (N = 31). Muscle strength and endurance were comparable in the alcoholic and nonalcoholic cirrhotic subjects for all variables. Both cirrhotic groups were inferior to normal controls for all variables. The quantity x frequency (Q x F) index reported for the period during peak alcohol consumption correlated with 6 muscle-force variables, accounting for 9-20% of the variance. Alcoholic and nonalcoholic cirrhotic subjects did not differ in Quality of Life Inventory (QOLI) scales. Significant correlations, however, were found for the alcoholic cirrhotic subjects but not for the nonalcoholic cirrhotic subjects between quality-of-life indices and muscle strength and endurance. Muscle weakness is thus differentially associated with quality of life in alcoholic cirrhotic subjects as compared with nonalcoholic subjects with cirrhosis even though level of strength and endurance in the two groups is comparable.

Adult↗

PubMed2006

Impaired muscle strength is associated with fractures in hemodialysis patients.

INTRODUCTION: Fractures are extremely common among hemodialysis (HD) patients. METHODS: To assess if bone mineral density (BMD) and/or tests of muscle strength were associated with fractures, we studied 37 men and 15 women, 50 years and older, on HD for at least 1 year. We excluded subjects with prior renal transplants and women taking hormone replacement therapy. We inquired about low-trauma fractures since starting dialysis. Subjects underwent BMD testing with a Lunar DPX-L densitometer. Tests of muscle strength included: timed up and go (TUG), 6-min walk, functional reach, and grip strength. Lateral and thoracic radiographs of the spine were obtained and reviewed for prevalent vertebral fractures. We used logistic regression to examine associations between fracture (prevalent vertebral, self-reported low trauma since starting dialysis and/or both) and BMD, and fracture and muscle-strength tests. Analyses were adjusted for age, weight, and gender. RESULTS: Mean age was 66+/-9.0 years, mean weight was 72.9+/-15.2 kg, and most (35 of 52) participants were Caucasian. Average duration of dialysis was 40.2 (interquartile range: 24-61.2) months. The most common cause of renal failure was diabetes (16 subjects). There were no differences by gender or fracture. Of the 52 subjects, 27 had either a vertebral fracture or low trauma fracture. There was no association between fractures, hip or spine BMD, or grip strength. In contrast, greater functional reach [odds ratio (OR) per standard deviation (SD) increase: 0.29; 95% CI: 0.13-0.69), quicker TUG (OR per SD decrease: 0.14; 95% CI: 0.11-0.23), and a greater distance walked in 6 min (OR per SD increase: 0.10; 95% CI: 0.03-0.36) were all associated with a reduced risk of fracture. CONCLUSIONS: Impaired neuromuscular function is associated with fracture in hemodialysis patients.

Absorptiometry, Photon↗

PubMed2001

Comparison of short-term versus long-term epidural analgesia after limited thoracotomy with special reference to pain score, pulmonary function, and respiratory muscle strength.

To determine the optimal duration of epidural analgesia (EA) after lung cancer surgery, a retrospective analysis was conducted to compare chest pain, pulmonary function, and respiratory muscle strength between patients given EA until postoperative day (POD) 3 and those given EA until POD 8. Each group comprised 25 lung cancer patients who underwent a lobectomy under anterior limited thoracotomy and given continuous thoracic EA using morphine until POD 3 (POD3-EA group) or POD 8 (POD8-EA group). The two groups were matched by sex and age. Postoperative pain from PODs 1 to 12 was evaluated by the pain score and analgesic requirements. The pulmonary function and respiratory muscle strength were measured on POD 7. The POD3-EA group did not experience any increase in pain after withdrawal, but the POD8-EA group did show a significant increase in pain the day after withdrawal (P < 0.05). The pain scores on PODs 8 and 9 in the POD8-EA group were significantly higher than those in the POD3-EA group (P < 0.05). There was no significant difference in pulmonary function and respiratory muscle strength on POD 7 between the two groups. Although the postoperative thoracic EA did not affect pulmonary function and respiratory muscle strength, prolonged thoracic EA after a limited thoracotomy significantly increased the pain after withdrawal, thus negatively affecting postoperative pain control.

Aged↗

PubMed1985

Age-related differences in knee muscle strength in normal women.

This study provides normal baselines of knee muscle strength for women up to 86 years of age. Knee muscle strength (torque) was measured during maximum isometric and dynamic (isokinetic) contractions in 72 normal healthy women in three age groups between 20 and 86 years. Strength of the oldest group ranged from 56 to 78% of that in the youngest group, depending on knee joint position. Strength values were greater for isometric contractions than for isokinetic contractions (performed at 36 degrees per second) and were approximately twice as great for the extensor as for the flexor muscles. For both muscle groups, the torque generated with the knee in 30 degrees of flexion was usually lower than that generated with the knee at the 45- or 60-degree position. Despite the significant deficit found in the strength of the oldest group, it is likely that this relative weakness would not be detected on routine clinical examination using manual muscle testing.

Adult↗

PubMed2006

ACE ID genotype and the muscle strength and size response to unilateral resistance training.

PURPOSE: To examine associations among the angiotensin I-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism and the response to a 12-wk (2 d.wk) unilateral, upper-arm resistance training (RT) program in the trained (T, nondominant) and untrained (UT, dominant) arms. METHODS: Subjects were 631 (mean+/-SEM, 24.2+/-0.2 yr) white (80%) men (42%) and women (58%). The ACE ID genotype was in Hardy-Weinberg equilibrium with frequencies of 23.1, 46.1, and 30.8% for ACE II, ID, and DD, respectively (chi=1.688, P=0.430). Maximum voluntary contraction (MVC) and one-repetition maximum (1RM) assessed peak elbow flexor muscle strength. Magnetic resonance imaging measured biceps muscle cross-sectional area (CSA). Multiple variable and repeated-measures ANCOVA tested whether muscle strength and size differed at baseline and pre- to post-RT among T and UT and ACE ID genotype. RESULTS: Baseline muscle strength and size were greater in UT than T (P<0.001) and did not differ among ACE ID genotype in either arm (P >or= 0.05). In T, MVC increases were greater for ACE II/ID (22%) than DD (17%) (P<0.05), whereas 1RM (51%) and CSA (19%) gains were not different among ACE ID genotype pre- to post-RT (P >or= 0.05). In UT, MVC increased among ACE II/ID (7%) (P<0.001) but was similar among ACE DD (2%) pre- to post-RT (P >or= 0.05). In UT, 1RM (11%) and CSA (2%) increases were greater for ACE DD/ID than ACE II (1RM, 7%; CSA, -0.1%) (P<0.05). ACE ID genotype explained approximately 1% of the MVC response to RT in T and approximately 2% of MVC, 2% of 1RM, and 4% of CSA response in UT (P<0.05). CONCLUSION: ACE ID genotype is associated with the contralateral effects of unilateral RT, perhaps more so than with the muscle strength and size adaptations that result from RT.

Adult↗

PubMed2005

Thigh muscle strength and endurance in patients with COPD compared with healthy controls.

The aim of this study was to evaluate thigh muscle strength and endurance in patients with COPD compared with healthy controls. Forty-two patients (26 women; 16 men) with moderate to severe COPD and 53 (29 women; 24 men) age-matched healthy controls participated in the study. The subjects were tested for maximum voluntary contractions (MVC), endurance and fatigue of the thigh muscles on an isokinetic dynamometer (KinCom). Endurance was expressed as the number of attained repetitions of knee extension and muscle fatigue as a fatigue index (FI). MVC in knee extension was 17% lower in female patients (P=0.017) but no difference was found in male patients (P=0.56) compared to controls. MVC in knee flexion was lower both in female (51%) (P<0.001) and male patients (40%) (P<0.001) compared to controls. Both female and male patients had significantly lower muscle endurance compared to controls. Female patients had a higher FI (22.5%) than female controls (10%) (P=0.001) while no difference was found regarding FI between male patients (15%) and male controls (10%) (P=0.103). The level of self-reported everyday physical activity did not differ between groups. The results showed impaired skeletal muscle function in COPD, except for MVC in knee extension in male patients. Female patients seemed to be more prone to decrease in thigh muscle function. More focus on improving muscle strength and muscle endurance should be considered when designing pulmonary rehabilitation programs. Patients with preserved level of physical activity can be included in exercise programs and gender-related differences should be taken into account.

Activities of Daily Living↗

PubMed2003

Muscle strength, power and adaptations to resistance training in older people.

Muscle strength and, to a greater extent, power inexorably decline with ageing. Quantitative loss of muscle mass, referred to as "sarcopenia", is the most important factor underlying this phenomenon. However, qualitative changes of muscle fibres and tendons, such as selective atrophy of fast-twitch fibres and reduced tendon stiffness, and neural changes, such as lower activation of the agonist muscles and higher coactivation of the antagonist muscles, also account for the age-related decline in muscle function. The selective atrophy of fast-twitch fibres has been ascribed to the progressive loss of motoneurons in the spinal cord with initial denervation of fast-twitch fibres, which is often accompanied by reinnervation of these fibres by axonal sprouting from adjacent slow-twitch motor units (MUs). In addition, single fibres of older muscles containing myosin heavy chains of both type I and II show lower tension and shortening velocity with respect to the fibres of young muscles. Changes in central activation capacity are still controversial. At the peripheral level, the rate of decline in parameters of the surface-electromyogram power spectrum and in the action-potential conduction velocity has been shown to be lower in older muscle. Therefore, the older muscle seems to be more resistant to isometric fatigue (fatigue-paradox), which can be ascribed to the selective atrophy of fast-twitch fibres, slowing in the contractile properties and lower MU firing rates. Finally, specific training programmes can dramatically improve the muscle strength, power and functional abilities of older individuals, which will be examined in the second part of this review.

Adaptation, Physiological↗

PubMed2000

Reexamining the sarcopenia hypothesis. Muscle mass versus muscle strength. Health, Aging, and Body Composition Study Research Group.

The association of muscle mass and muscle strength with lower-extremity performance, as measured by timed repeated chair stands, was investigated using preliminary data from 3,075 Black and White participants (70-79 years old) in the Health, Aging, and Body Composition Study. Leg muscle mass (LM) was measured by dual-energy X-ray absorptiometry (Hologic QDR 4500). The maximal isokinetic torque of the leg extensors (LS) was measured at 60 degrees/s using a Kin-Com isokinetic dynamometer. Men were stronger, had greater LM, and better performance than women. As expected, low LS was associated with poorer performance after adjusting for race, study site, and body fat. Low LM was associated with poorer performance in men and women, with a potential threshold effect in women only. When LS and LM were modeled simultaneously, only LS remained independently associated with performance. In conclusion, muscle strength, but not muscle mass, is independently associated with lower-extremity performance.

Absorptiometry, Photon↗

PubMed1985

Muscle strength and anthropometric indices in elderly men and women.

Muscle strength, overlying skinfold thickness and calculated muscle area for the triceps surae muscle of the calf and the biceps brachii of the upper arm are described in 184 subjects (100 female, 84 male) aged between 65 and 90 years. The group comprised mobile volunteers, living independently, from a large group-practice. Health screening was minimal. Relationships between anthropometric and strength variables are explored and compared with other studies. This was apparently a well-nourished group. Muscle strengths and areas were low compared to younger subjects. Strength in relationship to area was variable, lower than in the younger subjects and also lower in the females than the males. Strength of the calf compared to body weight fell below unity in some cases.

Aged↗

PubMed2004

Anemia is associated with disability and decreased physical performance and muscle strength in the elderly.

OBJECTIVES: To examine the association between anemia and disability, physical performance, and muscle strength in older persons. DESIGN: Cross-sectional. SETTING: Community-dwelling older persons in the Chianti area in Italy. PARTICIPANTS: A total of 1,156 persons aged 65 and older participating in the InChianti Study ("Invecchiare in Chianti," i.e., Aging in the Chianti Area). MEASUREMENTS: Anemia was defined according to World Health Organization criteria as a hemoglobin concentration below 12 g/dL in women and below 13 g/dL in men. Disability in six basic and eight instrumental activities of daily living was assessed. Physical performance was assessed using the short physical performance battery (4-m walk, balance, and chair stands), which yields a summary performance score ranging from 0 to 12 (high). Muscle strength was determined using knee extensor and handgrip strength assessments. RESULTS: Overall, 11.1% of the men and 11.5% of the women had anemia. After adjustment for age, sex, body mass index, Mini-Mental State Examination score, creatinine level, and presence of various comorbid conditions, anemic persons had more disabilities (1.71 vs 1.04, P=.002) and poorer performance (8.8 vs 9.6, P=.003) than persons without anemia. Anemic persons also had significantly lower knee extensor strength (14.1 vs 15.2 kg, P=.02) and lower handgrip strength (25.3 vs 27.1 kg, P=.04) than persons without anemia. Further adjustment for inflammatory markers (interleukin-6, C-reactive protein, tumor necrosis factor-alpha) did not change these associations. CONCLUSION: Anemia is associated with disability, poorer physical performance, and lower muscle strength. Further research should explore whether treating anemia has a beneficial effect on the functional status of older persons.

Activities of Daily Living↗

PubMed2003

The effect of posterolateral reconstruction on range of motion and muscle strength in total hip arthroplasty.

Posterolateral reconstruction of the posterior capsule, piriformis tendon, and external rotators in total hip arthroplasty improves the stability of the hip joint. This study was performed to evaluate the effect of this reconstruction on range of motion (ROM) and circumferential muscle strength. We selected 58 limbs of 29 patients. Posterolateral reconstruction was performed in 13 patients (reconstruction group). Posterolateral reconstruction was not performed in 16 patients (nonreconstruction group). No significant differences were seen in preoperative and postoperative ROM between the 2 groups. The reconstruction group had significantly higher abduction muscle strength (P<.0001) and external rotation muscle strength (P<.01) than the nonreconstruction group. Posterolateral reconstruction may be effective in promoting the recovery of abduction and external rotator muscle strength, and it can improve joint stability without limiting ROM.

Aged↗

PubMed2004

Objective triceps muscle strength measurement using computerized adaptation.

In our centre the non-availability computerized exercise machines limits the objective monitoring of strength rehabilitation. We undertook this research programme to objectively measure triceps muscle strength by interfacing NORSK-Gym machine with accelerometer and positional transducers to a computer. This data was tabulated and processed using Microsoft Excel. The positional transducer was first calibrated and it showed an excellent Pearson Correlation Coefficients against a standard metric reading (r = 0.9999). Peak Force was used as a test parameter for isotonic triceps muscle strength measurements. The criterion-referenced validity was established as the peak forces measured using the accelerometer and positional transducer demonstrated identical Peak Forces (r = 0.94). Analysis of our mean Peak Force measurements using non-biological force as well as the intra-individual reproducibility demonstrated excellent Pearson Correlation Coefficients (r) = 0.982-0.998 and 0.929-0.972 respectively. This computerized adaptation of the NORSK-Gym machine produced an objective, valid and reproducible triceps muscle strength measurement.

Adaptation, Physiological↗