Do muscle mass, muscle density, strength, and physical function similarly influence risk of hospitalization in older adults? Bed rest promotes reductions in walking speed, functional parameters, and aerobic fitness in older, healthy adults. Impact of Weight Loss on Physical Function with Changes in Strength, Muscle Mass, and Muscle Fat Infiltration in Overweight to Moderately Obese Older Adults: A Randomized Clinical Trial Handgrip strength does not represent an appropriate measure to evaluate changes in muscle strength during an exercise intervention program in frail older people. Effects of physical activity on strength and skeletal muscle fat infiltration in older adults: a randomized controlled trial. Muscle strength and physical performance as predictors of mortality, hospitalization, and disability in the oldest old. Efficacy of whey protein supplementation on resistance exercise-induced changes in lean mass, muscle strength, and physical function in mobility-limited older adults. The value of strength training for older adults. Changes in thigh muscle volume predict bone mineral density response to lifestyle therapy in frail, obese older adults Comparative associations of muscle mass and muscle strength with mortality in dialysis patients. Two-Year Whey Protein Supplementation Did Not Enhance Muscle Mass and Physical Function in Well-Nourished Healthy Older Postmenopausal Women. Whole-body vibration training increases muscle strength and mass in older women: a randomized-controlled trial. Nutrient-rich dairy proteins improve appendicular skeletal muscle mass and physical performance, and attenuate the loss of muscle strength in older men and women subjects: a single-blind randomized clinical trial Multicomponent Training Program with Weight-Bearing Exercises Elicits Favorable Bone Density, Muscle Strength, and Balance Adaptations in Older Women Knee strength maintained despite loss of lean body mass during weight loss in older obese adults with knee osteoarthritis. Clinical meaningfulness of the changes in muscle performance and physical function associated with testosterone administration in older men with mobility limitation. Muscle mass, muscle strength, and muscle fat infiltration as predictors of incident mobility limitations in well-functioning older persons. The effects of high- and moderate-resistance training on muscle function in the elderly. Early nutritional support and physiotherapy improved long-term self-sufficiency in acutely ill older patients. Associations between dietary nutrient intake and muscle mass and strength in community-dwelling older adults: the Tasmanian Older Adult Cohort Study. Changes in muscle mass, muscle strength, and power but not physical function are related to testosterone dose in healthy older men. Atrophy and impaired muscle protein synthesis during prolonged inactivity and stress. Effects of muscle strength training and megestrol acetate on strength, muscle mass, and function in frail older people.
OBJECTIVES To examine the association between strength , function , lean mass , muscle density , and risk of hospitalization . DESIGN Prospect i ve cohort study . SETTING Two U.S. clinical centers . PARTICIPANTS Adults aged 70 to 80 ( N=3,011 ) from the Health , Aging and Body Composition Study . MEASUREMENTS Measurements were of  grip strength , knee extension strength , lean mass , walking speed , and chair st and pace . Thigh computed tomography scans assessed muscle area and density ( a proxy for muscle fat infiltration ) . Hospitalizations were confirmed by local review of medical records . Negative binomial regression models estimated incident rate ratios ( IRRs ) of hospitalization for race- and sex-specific quartiles of each muscle and function parameter separately . Multivariate models adjusted for age , body mass index , health status , and coexisting medical conditions . RESULTS During an average 4.7 years of follow-up , 1,678 ( 55.7 % ) participants experienced one or more hospitalizations . Participants in the lowest quartile of muscle density were more likely to be subsequently hospitalized ( multivariate IRR=1.47 , 95 % confidence interval (CI)=1.24 - 1.73 ) than those in the highest quartile . Similarly , participants with the weakest grip strength were at greater risk of hospitalization ( multivariate IRR=1.52 , 95 % CI=1.30 - 1.78 , Q1 vs. Q4 ) . Comparable results were seen for knee strength , walking pace , and chair st and s pace . Lean mass and muscle area were not associated with risk of hospitalization . CONCLUSION Weak strength , poor function , and low muscle density , but not muscle size or lean mass , were associated with greater risk of hospitalization . Interventions to reduce the disease burden associated with sarcopenia should focus on increasing muscle strength and improving physical function rather than simply increasing lean mass CONTEXT The exact relationship between the bed rest-induced loss of skeletal muscle and reductions in muscle strength and physical performance in the older individuals is still unclear . OBJECTIVE We examined the effect of 10 days of bed rest on changes in regional body composition , muscle strength , and functional status , and the relationship between these variables in older individuals . DESIGN , PARTICIPANTS , AND INTERVENTION Regional body composition was measured using dual energy x-ray absorptiometry . We also determined changes in leg strength and several indices of functional status , including walking speed . RESULTS Body weight , body mass index , and total and lower extremity lean mass decreased with bed rest . There were also significant reductions in knee extension one repetition maximum , isometric knee extension , knee extension 60 ° concentric , stair ascent time , stair ascent power , stair descent time , VO2 max , floor transfer test , 5-minute walk time , and chair st and . The overall change in total and lower extremity lean mass was also directly related to bed rest-induced reductions in one repetition maximum knee extension . CONCLUSIONS Bed rest promoted overall declines in muscle mass , muscle strength , and physical function in older individuals . The changes in lean tissue were closely correlated with the bed rest-induced decline of muscle strength Purpose . Evaluate the effects of weight loss on muscle mass and area , muscle fat infiltration , strength , and their association with physical function . Methods . Thirty-six overweight to moderately obese , sedentary older adults were r and omized into either a physical activity plus weight loss ( PA+WL ) or physical activity plus successful aging health education ( PA+SA ) program . Measurements included body composition by dual-energy X-ray absorptiometry , computerized tomography , knee extensor strength , and short physical performance battery ( SPPB ) . Results . At 6 months , PA+WL lost greater thigh fat and muscle area compared to PA+SA . PA+WL lost 12.4 % strength ; PA+SA lost 1.0 % . Muscle fat infiltration decreased significantly in PA+WL and PA+SA . Thigh fat area decreased 6-fold in comparison to lean area in PA+WL . Change in total SPPB score was strongly inversely correlated with change in fat but not with change in lean or strength . Conclusion . Weight loss result ed in additional improvements in function over exercise alone , primarily due to loss of body fat INTRODUCTION Although h and grip strength is considered a strong predictor of negative health outcomes , it is unclear whether h and grip strength represents a useful measure to evaluate changes in muscle strength following resistance-type exercise training in older people . We assessed whether measuring h and grip strength provides proper insight in the efficacy of resistance-type exercise training to increase muscle mass , strength , and physical performance in frail older people . METHODS Prefrail and frail older people ( ≥ 65 y ) were either conducting a 24-week resistance-type exercise training or no exercise training . Before , during , and after the intervention , h and grip strength ( JAMAR ) , lean body mass ( DXA ) , leg strength ( 1-RM ) , and physical performance ( SPPB ) were assessed . RESULTS H and grip strength correlated with appendicular lean mass ( r = 0.68 ; p < .001 ) and leg strength ( r = 0.67 ; p < .001 ) . After 24 weeks of whole body resistance-type exercise training , leg extension strength improved significantly better when compared with the control group ( 57 ± 2 - 78 ± 3 kg vs 57 ± 3 - 65 ± 3 kg : p < .001 ) . Moreover , physical performance improved significantly more in the exercise group ( 8.0 ± 0.4 - 9.3 ± 0.4 points ) when compared with the control group ( 8.3 ± 0.4 - 8.9 ± 0.4 points : p < .05 ) . These positive changes were not accompanied with any significant changes in h and grip strength ( 26.3 ± 1.2 - 27.6 ± 1.2 kg in the exercise group vs 26.6 ± 1.2 - 26.3 ± 1.3 kg in the control group : p = .71 ) . CONCLUSION Although h and grip strength strongly correlates with muscle mass and leg strength in frail older people , h and grip strength does not provide a valid means to evaluate the efficacy of exercise intervention programs to increase muscle mass or strength in an older population Considerable evidence suggests that the loss of strength and muscle mass appear to be inevitable consequences of aging . Moreover , aging is associated with an increase in body fat . This study examined whether increased physical activity could prevent or reverse the losses of strength and skeletal muscle mass as well as the gain in  fat in older adults . Eleven men and 31 women completed a r and omized trial consisting of either a physical activity ( PA ; n = 22 ) or successful aging health educational control ( SA ; n = 20 ) group . Isokinetic knee extensor strength and computed tomography-derived midthigh skeletal muscle and adipose tissue cross-sectional areas ( CSA ) were assessed at baseline and at 12 mo following r and omization .  Total body weight and muscle CSA decreased in both groups , but these losses were not different between groups . Strength adjusted for muscle mass decreased ( -20.1 + /- 9.3 % , P < 0.05 ) in SA . The loss of strength was completely prevented in PA ( + 2.5 + /- 8.3 % ) . In addition , there was a significant increase ( 18.4 + /- 6.0 % ) in muscle fat infiltration in SA , but this gain was nearly completely prevented in PA ( 2.3 + /- 5.7 % ) . In conclusion , regular physical activity prevents both the age-associated loss of muscle strength and increase in muscle fat infiltration in older adults with moderate functional limitations OBJECTIVES To evaluate the predictive value of muscle strength and physical performance in the oldest old for all-cause mortality ; hospitalization ; and the onset of disability , defined as a decline in activities of daily living ( ADLs ) , independent of muscle mass , inflammatory markers , and comorbidities . DESIGN A prospect i ve , observational , population -based follow-up study . SETTING Three well-circumscribed areas of Belgium . PARTICIPANTS Five hundred sixty participants aged 80 and older were followed for 33.5 months ( interquartile range 31.1 - 35.6 months ) . MEASUREMENTS  Grip strength , Short Physical Performance Battery ( SPPB ) score , and muscle mass  were measured at baseline ; ADLs at baseline and after 20 months ; and all-cause mortality and time to first hospitalization from inclusion onward . Kaplan-Meier curves and Cox proportional hazards models were calculated for all-cause mortality and hospitalization . Logistic regression analysis was used to determine predictors of decline in ADLs . RESULTS Kaplan-Meier curves showed significantly higher all-cause mortality and hospitalization in subjects in the lowest tertile of grip strength and SPPB score . The adjusted Cox proportional hazards model showed that participants with high grip strength or a high SPPB score had a lower risk of mortality and hospitalization , independent of muscle mass , inflammatory markers , and comorbidity . A relationship was found between SPPB score and decline in ADLs , independent of muscle mass , inflammation , and comorbidity . CONCLUSION In people aged 80 and older , physical performance is a strong predictor of mortality , hospitalization , and disability , and muscle strength is a strong predictor of mortality and hospitalization . All of these relationships were independent of muscle mass , inflammatory markers , and comorbidity BACKGROUND Whey protein supplementation may augment resistance exercise-induced increases in muscle strength and mass . Further studies are required to determine whether this effect extends to mobility-limited older adults . The objectives of the study were to compare the effects of whey protein concentrate ( WPC ) supplementation to an isocaloric control on changes in whole-body lean mass , mid-thigh muscle cross-sectional area , muscle strength , and stair-climbing performance in older mobility-limited adults in response to 6 months of resistance training ( RT ) . METHODS Eighty mobility-limited adults aged 70 - 85 years were r and omized to receive WPC ( 40g/day ) or an isocaloric control for 6 months . All participants also completed a progressive high-intensity RT intervention . Sample sizes were calculated based on the primary outcome of change in whole-body lean mass to give 80 % power for a 0.05-level , two-sided test . RESULTS Lean mass increased 1.3 % and 0.6 % in the WPC and control groups , respectively . Muscle cross-sectional area was increased 4.6 % and 2.9 % in the WPC and control groups , respectively , and muscle strength increased 16%-50 % in WPC and control groups . Stair-climbing performance also improved in both groups . However , there were no statistically significant differences in the change in any of these variables between groups . CONCLUSIONS These data suggest that WPC supplementation at this dose does not offer additional benefit to the effects of RT in mobility-limited older adults Health in older adults can best be measured in terms of functional status . Skeletal muscle strength has been reported to be a determinant of functional status in older individuals . Two major contributors to the decline in muscle function as a person ages are disuse and physical inactivity . Declining muscle function through a loss of muscular strength may decrease functional independence and mobility and increase the risk for falls and injuries , physical frailty , and disability .  Older individuals lacking an appropriate amount of muscular strength may not be able to perform various activities of daily living , which are important indicators of independence Summary We studied the relationships among strength , muscle mass , and bone mineral density ( BMD ) with lifestyle change . Lifestyle therapy consisted of exercise , diet , and diet plus exercise . Diet was by caloric restriction to induce and maintain a weight loss of 10 % from baseline body weight . Exercise attenuated weight loss-induced muscle and bone losses . Exercise improved strength despite muscle loss in patients on diet and exercise . Changes in strength did not correlate with changes in BMD . However , changes in thigh muscle volume correlated with , and predicted changes in hip BMD . Introduction Losses of hip BMD and lean body mass are major complications of lifestyle therapy in frail , obese older adults ; however , the contribution of mechanical strain loss from muscle loss is poorly defined . We determined the effect of changes in thigh muscle volume and muscle strength on BMD in frail , obese older adults undergoing lifestyle therapy aim ed at intentional weight loss with or without exercise . Methods One hundred seven obese older adults were r and omized to control , diet , exercise , and diet – exercise groups for 1 year . Thigh muscle volume was measured by magnetic resonance imaging , BMD by DXA , knee strength by dynamometry , total strength by one-repetition maximum ( 1-RM ) , and bone markers by immunoassay . Results Thigh muscle volume decreased in the diet group ( −6.2 ± 4.8 % ) and increased in the exercise group ( 2.7 ± 3.1 % ) , while it was not significantly different from the control in the diet – exercise group . Changes in hip BMD followed similar pattern as those in thigh muscle volume . Knee extension and flexion increased in the exercise group ( 23 ± 20 % ; 25 ± 19 % ) and diet – exercise group ( 20 ± 19 % ; 20.6 ± 27 % ) but were unchanged in the control and diet groups . Changes in thigh muscle volume correlated with changes in hip BMD ( r = 0.55 , P = < 0.001 ) and were an independent predictor of changes in hip BMD ( β = 0.12 , P = 0.03 ) in the multiple regression analyses after accounting for demographic factors and changes in weight and physical activity . There were no correlations between BMD changes and knee strength , 1-RM , and sclerostin changes . Conclusions Changes in thigh muscle volume predict hip BMD changes in obese older patients undergoing lifestyle therapy . The effect of exercise in attenuating thigh muscle loss when added to diet may in part account for the reduction in weight loss-induced bone loss in the diet – exercise group BACKGROUND AND OBJECTIVES Reduced muscle mass and strength are prevalent conditions in dialysis patients . However , muscle strength and muscle mass are not congruent ; muscle strength can diminish even though muscle mass is maintained or increased . This study addresses phenotype and mortality associations of these muscle dysfunction entities alone or in combination ( i.e. , concurrent loss of muscle mass and strength/mobility , here defined as sarcopenia ) . DESIGN , SETTING , PARTICIPANTS , & MEASUREMENTS This study included 330 incident dialysis patients ( 203 men , mean age 53±13 years , and mean GFR 7±2 ml/min per 1.73 m(2 ) ) recruited between 1994 and 2010 and followed prospect ively for up to 5 years . Low muscle mass ( by dual-energy x-ray absorptiometry appendicular mass index ) and low muscle strength ( by h and grip ) were defined against young reference population s according to the European Working Group on Sarcopenia in Older People . RESULTS Whereas 20 % of patients had sarcopenia , low muscle mass and low muscle strength alone were observed in a further 24 % and 15 % of patients , respectively . Old age , comorbidities , protein-energy wasting , physical inactivity , low albumin , and inflammation associated with low muscle strength , but not with low muscle mass ( multivariate ANOVA interactions ) . During follow-up , 95 patients ( 29 % ) died and both conditions associated with mortality as separate entities . When combined , individuals with low muscle mass alone were not at increased risk of mortality ( adjusted hazard ratio [ HR ] , 1.23 ; 95 % confidence interval [ 95 % CI ] , 0.56 to 2.67 ) . Individuals with low muscle strength were at increased risk , irrespective of their muscle stores being appropriate ( HR , 1.98 ; 95 % CI , 1.01 to 3.87 ) or low ( HR , 1.93 ; 95 % CI , 1.01 to 3.71 ) . CONCLUSIONS Low muscle strength was more strongly associated with aging , protein-energy wasting , physical inactivity , inflammation , and mortality than low muscle mass . Assessment of muscle functionality may provide additional diagnostic and prognostic information to muscle-mass evaluation BACKGROUND Protein may play a role in preventing muscle loss with aging . To our knowledge , there have been no long-term r and omized controlled trials to examine the effects of increased dietary protein intake on muscle health in community-dwelling older women . OBJECTIVE In this study , we evaluated the effects of whey protein supplementation on muscle mass and physical function in community-dwelling older Australian women . METHODS In this 2 y r and omized , double-blind , placebo-controlled trial , women aged 70 - 80 y ( mean 74.3 ± 2.7 y ) were r and omly assigned to either a high protein drink containing 30 g of whey protein ( n = 109 ) or a placebo drink containing 2.1 g protein ( n = 110 ) daily . Dual-energy X-ray absorptiometry appendicular skeletal muscle mass , upper arm and calf ( 38 % tibia ) muscle cross-sectional area , physical function including h and grip strength , lower limb muscle strength and Timed Up and Go test , and 24 h urinary nitrogen were measured at baseline , 1 y , and 2 y. RESULTS A total of 196 women with at least one follow-up measurement were included in this analysis . Baseline mean BMI was 26.7 ± 3.9 kg/m(2 ) and protein intake was 76 ± 17 g/d ( 1.1 ± 0.3 g · kg body weight(-1 ) · d(-1 ) ) . A mean increase in protein intake of ∼ 20 g/d in the protein group was confirmed by the estimates from 24 h urinary nitrogen . Over the 2 y in both groups there was a significant decrease in the upper arm ( mean ± SE : -5.59 ± 0.75 cm(2 ) ) and calf ( -0.77 ± 0.11 cm(2 ) ) muscle area , as well as h and grip strength ( -1.30 ± 0.3 kg ) ( all P < 0.05 ) , but appendicular skeletal muscle mass did not change significantly . There were no significant effects of the protein intervention on any of the muscle mass or physical function measures ( all P > 0.05 ) at 1 and 2 y. CONCLUSION This study showed that in protein-replete , healthy , ambulant , postmenopausal older women , 30 g/d of extra protein did not improve the maintenance of muscle mass or physical function despite evidence of deterioration in muscle measurements in the upper limb . This trial was registered at the Australian New Zeal and Clinical Trials Registry as ACTRN012607000163404 To determine whether 10 weeks of whole-body vibration ( WBV ) training has a significant effect on strength , muscle mass , muscle power , and mobility in older women , 26 subjects were r and omly assigned to a  WBV training group ( n=13 ; mean age 79 years ) and a control ( CON ) group ( n=13 ; mean age 76 years ) . Maximal voluntary isometric contraction ( MVIC ) increased 38.8 % in the WBV group , without changes in the CON group . Electromyographic activity of the vastus medialis ( VM ) , the vastus lateralis , and the biceps femoris ( BF ) did not change in either group . Thigh muscle cross-sectional area increased significantly after training in VM ( 8.7 % ) and BF ( 15.5 % ) . Muscle power at 20 % , 40 % , and 60 % MVIC decreased from pre-test to post-test in the CON group ; however , WBV training prevented the decrease in the WBV group . Consequently , mobility , measured by the Timed Up and Go test , increased significantly after training ( 9.0 % ) only in the WBV group . Ten weeks of lower limb WBV training in older women produces a significant increase in muscle strength induced by thigh muscle hypertrophy , with no change in muscle power . The adaptations to WBV found in the present study may be of use in counteracting the loss of muscle strength and mobility associated with age-induced sarcopenia Background At present , it is unknown whether the use of nutrient-rich dairy proteins improves the markers of sarcopenia syndrome . Therefore , our proposal was to investigate whether adding 210 g of ricotta cheese daily would improve skeletal muscle mass , h and grip strength , and physical performance in non-sarcopenic older subjects . Subjects and methods This was a single-blind r and omized clinical trial that included two homogeneous , r and omized groups of men and women over 60 years of age . Participants in the intervention group were asked to consume their habitual diet but add 210 g of ricotta cheese ( IG/HD + RCH ) , while the control group was instructed to consume only their habitual diet ( CG/HD ) . Basal and 12-week follow-up measurements included appendicular skeletal muscle mass ( ASMM ) by dual-energy X-ray absorptiometry , h and grip strength by a h and held dynamometer , and physical performance using the short physical performance battery ( SPPB ) and the stair-climb power test ( SCPT ) . The main outcomes were relative changes in ASMM , strength , SPPB , and SCPT . Results ASMM increased in the IG/HD + RCH ( 0.6±3.5 kg ) , but decreased in the CG/HD ( −1.0±2.6 ) . The relative change between groups was statistically significant ( P=0.009 ) . The relative change in strength in both groups was negative , but the loss of muscle strength was more pronounced in CG/HD , though in this regard statistical analysis found only a tendency ( P=0.07 ) . The relative change in the balance-test scores was positive for the IG/HD + RCH , while in the CG/HD it was negative , as those individuals had poorer balance . In this case , the relative change between groups did reach statistical significance . Conclusion The addition of 210 g of ricotta cheese improves ASMM and balance-test scores , while attenuating the loss of muscle strength . These results suggest that adding ricotta cheese to the habitual diet is a promising dietetic strategy that may improve the markers of sarcopenia in subjects without a pronounced loss of ASMM or sarcopenia Physical exercise is advised as a preventive and therapeutic strategy against aging-induced bone weakness . In this study we examined the effects of 8-month multicomponent training with weight-bearing exercises on different risk factors of falling , including muscle strength , balance , agility , and bone mineral density ( BMD ) in older women . Participants were r and omly assigned to either an exercise-training group ( ET , n = 30 ) or a control group ( CON , n = 30 ) . Twenty-seven subjects in the ET group and 22 in the CON group completed the study . Training was performed twice a week and was design ed to load bones with intermittent and multidirectional compressive forces and to improve physical function . Outcome measures included lumbar spine and proximal femoral BMD ( by dual X-ray absorptiometry ) , muscle strength , balance , h and grip strength , walking performance , fat mass , and anthropometric data . Potential confounding variables included dietary intake , accelerometer-based physical activity , and molecularly defined lactase nonpersistence . After 8 months , the ET group decreased percent fat mass and improved h and grip strength , postural sway , strength on knee flexion at 180 ° /s , and BMD at the femoral neck ( + 2.8 % ) . Both groups decreased waist circumference and improved dynamic balance , chair st and performance , strength on knee extension for the right leg at 180 ° /s , and knee flexion for both legs at 60 ° /s . No associations were found between lactase nonpersistence and BMD changes . Data suggest that 8 months of moderate-impact weight-bearing and multicomponent exercises reduces the potential risk factors for falls and related fractures in older women BACKGROUND The effects of weight loss on muscle function in older adults have not been well studied . This study determined the effects of a 6-month weight-loss intervention on muscle strength and quality in older obese adults with knee osteoarthritis . METHODS Participants were r and omized to a weight loss ( WL ) ( n = 44 , 70 + /- 6 years ) or weight stable ( WS ) ( n = 43 , 69 + /- 6 years ) group . The WL intervention consisted of weekly educational meetings , a meal replacement diet , and a three-session-per-week structured exercise program to achieve 10%-12 % weight loss . The WS intervention included bimonthly group meetings and newsletters .  Body composition and knee extensor strength were measured at baseline and after intervention . RESULTS The WL group decreased body weight , lean body mass , fat mass , and percent body fat ( p < .001 for all ) . Concentric extension strength increased 25 % in WL ( p > .05 ) , whereas eccentric extension decreased 6 % in WS ( p = .028 ) . Concentric muscle quality ( strength per kg body weight or lean body mass ) increased in WL ( p < .05 ) , whereas eccentric muscle quality decreased in WS ( p < .05 ) . Changes in lean body mass and fat mass were inversely associated with changes in most muscle strength and quality measures ( p < .05 ) . Men and women did not differ in response to the intervention in knee strength outcomes . CONCLUSIONS Hypocaloric dieting in combination with exercise training had beneficial effects on muscle strength/ quality , despite loss of lean body mass in this sample of older men and women . Greater fat loss was associated with greater gains in muscle strength and quality . More studies are needed regarding the mechanisms by which loss of fat mass increases muscle strength and quality CONTEXT Testosterone in Older Men with Mobility Limitations Trial determined the effects of testosterone on muscle performance and physical function in older men with mobility limitation . Trial 's Data and Safety Monitoring Board recommended enrollment cessation due to increased frequency of adverse events in testosterone arm . The changes in muscle performance and physical function were evaluated in relation to participant 's perception of change . METHODS Men aged 65 years and older , with mobility limitation , total testosterone 100 - 350 ng/dL , or free testosterone less than 50 pg/mL , were r and omized to placebo or 10 g testosterone gel daily for 6 months . Primary outcome was leg-press strength . Secondary outcomes included chest-press strength , stair-climb , 40-m walk , muscle mass , physical activity , self-reported function , and fatigue . Proportions of participants exceeding minimally important difference in study arms were compared . RESULTS Of 209 r and omized participants , 165 had follow-up efficacy measures . Mean ( SD ) age was 74 ( 5.4 ) years and short physical performance battery score 7.7 ( 1.4 ) .  Testosterone arm exhibited greater improvements in leg-press strength , chest-press strength and power , and loaded stair-climb than placebo . Compared with placebo , significantly greater proportion of men receiving testosterone improved their leg-press and chest-press strengths ( 43 % vs 18 % , p = .01 ) and stair-climbing power ( 28 % vs 10 % , p = .03 ) more than minimally important difference . Increases in leg-press strength and stair-climbing power were associated with changes in testosterone levels and muscle mass . Physical activity , walking speed , self-reported function , and fatigue did not change . CONCLUSIONS Testosterone administration in older men with mobility limitation was associated with patient-important improvements in muscle strength and stair-climbing power . Improvements in muscle strength and only some physical function measures should be weighed against the risk of adverse events in this population BACKGROUND Lower muscle mass has been correlated with poor physical function ; however , no studies have examined this relationship prospect ively . This study aims to investigate whether low muscle mass , low muscle strength , and greater fat infiltration into the muscle predict incident mobility limitation . METHODS Our study cohort included 3075 well-functioning black and white men and women aged 70 - 79 years participating in the Health , Aging , and Body Composition study . Participants were followed for 2.5 years . Muscle cross-sectional area and muscle tissue attenuation ( a measure of fat infiltration ) were measured by computed tomography at the mid-thigh , and knee extensor strength by using a KinCom dynamometer .  Incident mobility limitation was defined as two consecutive self-reports of any difficulty walking one-quarter mile or climbing 10 steps . RESULTS Mobility limitations were developed by 22.3 % of the men and by 31.8 % of the women . Cox 's proportional hazards models , adjusting for demographic , lifestyle , and health factors , showed a hazard ratio of 1.90 [ 95 % confidence interval ( CI ) , 1.27 - 2.84 ] in men and 1.68 ( 95 % CI , 1.23 - 2.31 ) in women for the lowest compared to the highest quartile of muscle area ( p < .01 for trend ) . Results for muscle strength were 2.02 ( 95 % CI , 1.39 - 2.94 ) and 1.91 ( 95 % CI , 1.41 - 2.58 ) , p < .001 trend , and for muscle attenuation were 1.91 ( 95 % CI , 1.31 - 2.83 ) and 1.68 ( 95 % CI , 1.20 - 2.35 ) , p < .01 for trend . When included in one model , only muscle attenuation and muscle strength independently predicted mobility limitation ( p < .05 ) . Among men and women , associations were similar for blacks and whites . CONCLUSION Lower muscle mass ( smaller cross-sectional thigh muscle area ) , greater fat infiltration into the muscle , and lower knee extensor muscle strength are associated with increased risk of mobility loss in older men and women . The association between low muscle mass and functional decline seems to be a function of underlying muscle strength The purpose of this study was to investigate the effects of a 12-week resistance-training program on muscle strength and mass in older adults . Thirty-three inactive participants ( 60 - 74 years old ) were assigned to 1 of 3 groups : high-resistance training ( HT ) , moderate-resistance training ( MT ) , and control . After the training period , both HT and MT significantly increased 1-RM body strength , the peak torque of knee extensors and flexors , and the midthigh cross-sectional area of the total muscle . In addition , both HT and MT significantly decreased the abdominal circumference . HT was more effective in increasing 1-RM strength , muscle mass , and peak knee-flexor torque than was MT . These data suggest that muscle strength and mass can be improved in the elderly with both high- and moderate-intensity resistance training , but high-resistance training can lead to greater strength gains and hypertrophy than can moderate-resistance training OBJECTIVE An acute disease is regularly associated with inflammation , decreased food intake , and low physical activity ; the consequence is loss of muscle mass . However , the restoration of muscle tissue is problematic , especially in older patients . Loss of muscle mass leads to further decrease of physical activity which leads , together with recurring disease , to the progressive muscle mass loss accompanied by loss of self-sufficiency . Early nutrition support and physical activity could reverse this situation . Therefore , the aim of this study was to determine whether an active approach based on early nutritional therapy and exercise would influence the development of sarcopenia and impaired self-sufficiency during acute illness . METHODS Two hundred patients > 78 y were admitted to a hospital internal medicine department and participated in a prospect i ve , r and omized controlled study . The patients were r and omized to a control group receiving st and ard treatment ( n = 100 ) or to an intervention group ( n = 100 ) . The intervention consisted of nutritional supplements ( 600 kcal , 20 g/d protein ) added to a st and ard diet and a simultaneous intensive rehabilitation program . The tolerance of supplements and their influence on spontaneous food intake , self-sufficiency , muscle strength , and body composition were evaluated during the study period . The patients were then regularly monitored for 1 y post-discharge . RESULTS The provision of nutritional supplements together with early rehabilitation led to increased total energy and protein intake while the intake of st and ard hospital food was not reduced . The loss of lean body mass and a decrease in self-sufficiency were apparent at discharge from the hospital and 3 mo thereafter in the control group . Nutritional supplementation and the rehabilitation program in the study group prevented these alterations . A positive effect of nutritional intervention and exercise during the hospital stay was apparent at 6 mo post-discharge . CONCLUSIONS The early nutritional intervention together with early rehabilitation preserves muscle mass and independence in ill older patients hospitalized because of acute disease OBJECTIVES To describe associations between dietary nutrient intake and progression of sarcopenia , the age-related loss of muscle mass and strength . DESIGN Prospect i ve cohort study of community-dwelling older adults . SETTING Southern Tasmania , Australia . PARTICIPANTS Seven hundred forty noninstitutionalized older adults ( 50 % female ; mean age 62 ± 7 ) r and omly sample d from electoral rolls .  MEASUREMENTS Dietary nutrient intake  was examined at baseline and follow-up ( 2.6 ± 0.4 years later ) using The Cancer Council Victoria 's Food Frequency Question naire ( FFQ ) . Appendicular lean mass ( aLM ) was assessed using dual X-ray absorptiometry and muscle strength of the knee extensors using a dynamometer . RESULTS Failing to meet the recommended dietary intake for protein was associated with significantly lower aLM at baseline ( -0.81 kg , 95 % confidence interval ( CI ) = -1.54 to -0.08 ) and follow-up ( -0.79 kg , 95%CI = -1.42 to -0.17 ) . Energy-adjusted protein intake was a positive predictor of change in aLM over 2.6 years ( β = 0.10 , P = .003 ) . Energy-adjusted intake of iron ( β = 0.07 , P = .02 ) , magnesium ( β = 0.07 , P=.02 ) , phosphorus ( β = 0.07 , P = .047 ) , and zinc ( β = 0.08 , P = .02 ) were positive predictors of change in aLM , whereas retinol ( β = -0.09 , P = .005 ) was a negative predictor of change in aLM after adjustment for protein intake . No significant associations were observed between nutrient intake and muscle strength . CONCLUSION Protein and several other dietary nutrients are associated with muscle mass and rate of muscle loss ( but not strength ) in older adults , suggesting that multiple dietary components may ameliorate the progression of sarcopenia OBJECTIVES To examine the effect of grade d doses of testosterone on physical function and muscle performance in healthy , older men . DESIGN R and omized , double-blind , placebo-controlled clinical trial . SETTING General clinical research center . PARTICIPANTS Community-dwelling healthy men aged 60 to 75 ( N=44 ) . INTERVENTION Monthly treatment with a gonadotropin-releasing hormone agonist plus 25 , 50 , 125 , or 300 mg/wk of intramuscular injections of testosterone enanthate for 20 weeks . MEASUREMENTS Skeletal muscle mass ( SMM ) was estimated using dual-energy X-ray absorptiometry . Leg press strength was measured by one repetition maximum , leg power by Nottingham Leg Rig , and muscle fatigability by repetitions to failure in the leg press exercise .  Stair climbing , 6-meter and 400-meter walking speed , and a timed-up- and -go ( TUG ) test were used to assess physical function . RESULTS Significant testosterone dose- and concentration-dependent increases were observed in SMM ( P<.001 ) and maximal strength ( P=.001 ) but not muscle fatigability . Leg power also increased dose-dependently ( P=.048 ) . In contrast , changes in self-selected normal and fast walking speed over 6 or 400 meters , stair climbing power , and time for the TUG were not significantly related to testosterone dose , testosterone concentrations , or changes in muscle strength or power , or SMM . CONCLUSION Testosterone administration was associated with dose-dependent increases in SMM , leg strength , and power but did not improve muscle fatigability or physical function . The observation that physical function scores did not improve linearly with strength suggests that these high-functioning older men were already in the asymptotic region of the curve describing the relationship between physical function and strength CONTEXT We recently demonstrated that 28-d bed rest in healthy volunteers results in a moderate loss of lean leg mass and strength . OBJECTIVE The objective of this study was to quantify changes in muscle protein kinetics , body composition , and strength during a clinical bed rest model reflecting both physical inactivity and the hormonal stress response to injury or illness . DESIGN Muscle protein kinetics were calculated during a primed , continuous infusion ( 0.08 micromol/kg.min ) of 13C6-phenylalanine on d 1 and 28 of bed rest . SETTING The setting for this study was the General Clinical Research Center at the University of Texas Medical Branch . PARTICIPANTS Participants were healthy male volunteers ( n = 6 , 28 + /- 2 yr , 84 + /- 4 kg , 178 + /- 3 cm ) . INTERVENTION During bed rest , hydrocortisone sodium succinate was administered iv ( d 1 and 28 ) and orally ( d 2 - 27 ) to reproduce plasma cortisol concentrations consistent with trauma or illness ( approximately 22 microg/dl ) . MAIN OUTCOME MEASURES We hypothesized that inactivity and hypercortisolemia would reduce lean muscle mass , leg extension strength , and muscle protein synthesis .  RESULTS Volunteers experienced a 28.4 + /- 4.4 % loss of leg extension strength ( P = 0.012 ) and a 3-fold greater loss of lean leg mass ( 1.4 + /- 0.1 kg ) ( P = 0.004 ) compared with our previous bed rest-only model . Net protein catabolism was primarily due to a reduction in muscle protein synthesis [ fractional synthesis rate , 0.081 + /- 0.004 ( d 1 ) vs. 0.054 + /- 0.007%/h ( d 28 ) ; P = 0.023 ] . There was no change in muscle protein breakdown . CONCLUSION Prolonged inactivity and hypercortisolemia represents a persistent catabolic stimulus that exacerbates strength and lean muscle loss via a chronic reduction in muscle protein synthesis OBJECTIVES To determine the independent and combined effects of progressive resistance muscle strength training ( PRMST ) and megestrol acetate ( MA ) on strength , muscle mass , and function in older recuperative care patients . DESIGN Double-blind , r and omized , controlled intervention using a two-by-two factorial design and conducted between 1999 and 2001 . SETTING University-affiliated Department of Veterans Affairs hospital . PARTICIPANTS Twenty-nine patients ( mean age 79.4 + /- 7.4 , 90 % white ) aged 65 and older and had recent functional decline . INTERVENTIONS After r and omization to one of four treatment groups ( low-resistance exercises plus 800 mg per day of MA or a placebo or high-intensity PRMST plus 800 mg/d of MA or placebo ) , subjects received training and the drug or placebo for 12 weeks . MEASUREMENTS Change in muscle strength , mid-thigh muscle area , and aggregate functional performance score as assessed using analysis of covariance . RESULTS Five subjects withdrew from the study before its completion . Based on intent-to-treat analyses , subjects who received high-intensity PRMST and placebo experienced the greatest strength gains . The addition of MA was associated with worse outcomes than with high-intensity exercise training alone , especially with regard to the leg exercises . Post hoc analysis demonstrated that subjects who received high-intensity PRMST and placebo experienced significantly greater percentage increases in leg strength than subjects in either of the MA treatment groups ( P<.05 for each comparison ) . There was also a significant negative effect of MA on physical function . In general , subjects who received MA experienced a deterioration in aggregate physical function scores , whereas the remaining subjects improved ( -0.80+/-0.40 vs 0.48+/-0.41 , P=.04 ) . There was not a significant interaction between exercise and MA for any outcome . CONCLUSION High-intensity PRMST is a safe and well-tolerated exercise regimen for frail elderly patients . The addition of MA appears to blunt the beneficial effects of PRMST , result ing in less muscle strength and functional performance gains
In conclusion , decrease in muscle strength and muscle mass in older patients is dependent on the type of admission .
HIGHLIGHTSPhysical inactivity during hospitalization is associated with detrimental outcome .Muscle strength and muscle mass decreased in electively admitted older patients .Muscle strength and muscle mass did not change in acutely admitted older patients
ABSTRACT Hospitalization may induce a decrease of muscle strength and muscle mass in older patients due to physical inactivity , malnutrition and diseases , negatively affecting health outcome .
We aim ed to examine the literature on change in muscle strength and muscle mass in older patients during hospitalization .