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Exercise training (EX) and weight loss (WL) improve lower extremity physical function (LEPF) in older overweight women; however, effects on rate of torque development (RTD) are unknown. This study aimed to determine the effects of WL + EX or WL alone on RTD, and relatedly LEPF, in overweight older women. Leg strength was assessed using isokinetic dynamometry, and RTD was calculated (RTD200 = RTD at 200 ms, RTDPeak = peak RTD, T2P = time to 1st peak). LEPF was determined via clinical functional tasks. Women (n = 44, 69.1 ± 3.6 years, 30.6 ± 4.3 kg/m2) completed a 6-month trial in EX + WL or WL groups with similar weight loss (−9.8 ± 4.2%, p > .95). EX + WL had greater improvements in (a) most LEPF tasks (p 200, compared with WL (36% vs. −16%, p = .031); no other RTD parameters differed. Changes in RTD parameters and LEPF were not related (all p > .05). RTD is responsive to EX but is not associated with LEPF in older women.

Viscoelastic properties of striated muscle are often measured using length perturbation analysis and quantified as a complex modulus, whose elastic and viscous components reflect the energy-storage and energy-absorbing properties of the tissue, respectively. The energy stored as inertia is commonly ignored due to the small size of samples examined, typically 5% error at frequencies of 200 Hz and higher.

Obesity has become one of the most pressing public health issues of the 21st century and currently affects a substantial proportion of the older adult population. Although the cardiometabolic complications are well documented, research from the past 20 years has drawn attention to the detrimental effects of obesity on physical performance in older adults. Obesity-related declines in physical performance are due, in part, to compromised muscle strength and power. Recent evidence suggests there are a number of mechanisms potentially underlying reduced whole muscle function, including alterations in myofilament protein function and cellular contractile properties, and these may be related to morphological adaptations, such as shifts in fiber type composition and increased intramyocellular lipid content within skeletal muscle. To date, even less research has focused on how exercise and weight loss interventions for obese older adults affect these mechanisms. In light of this work, we provide an update on the current knowledge related to obesity and skeletal muscle contractile function and highlight a number of questions to address potential etiologic mechanisms as well as intervention strategies, which may help advance our understanding of how physical performance can be improved among obese older adults.

Skeletal muscle myopathies represent a common non-pulmonary manifestation of influenza infection, leading to reduced physical function and hospitalization in older adults. However, underlying mechanisms remain poorly understood. Our study examined the effects of influenza virus A pulmonary infection on contractile function at the cellular (single fiber) and molecular (myosin-actin interactions and myofilament properties) levels in soleus and extensor digitorum longus muscles of aged (20 months) C57BL/6 male mice that were healthy or flu-infected for 7 (7-days post-infection; 7-DPI) or 12 days (12-DPI). Cross-sectional area (CSA) of myosin heavy chain (MHC) IIA and IIB fibers was reduced at 12-DPI relative to 7-DPI and healthy. Maximal isometric force in MHC IIA fibers was also reduced at 12-DPI relative to 7-DPI and healthy, resulting in no change in specific force (maximal isometric force divided by CSA). In contrast, MHC IIB fibers produced greater isometric force and specific force at 7-DPI compared to 12-DPI or healthy. The increased specific force in MHC IIB fibers was likely due to greater myofilament lattice stiffness and/or an increased number or stiffness of strongly bound myosin-actin cross-bridges. At the molecular level, cross-bridge kinetics were slower in MHC IIA fibers with infection, while changes in MHC IIB fibers were largely absent. In both fiber types, greater myofilament lattice stiffness was positively related to specific force. This study provides novel evidence that cellular and molecular contractile function is impacted by influenza infection in a fiber type-specific manner, suggesting potential molecular mechanisms to help explain the impact of flu-induced myopathies.

Increased adiposity is associated with reduced skeletal muscle function in older adults, but the mechanisms underlying this relationship remain unclear. To explore whether skeletal muscle properties track with adiposity, whole-muscle, cellular, and molecular function were examined in relation to adiposity measured at various anatomical levels in healthy older (60–80 years) men and women. Although women had greater absolute and relative body and thigh fat than men, quadriceps muscle attenuation, an index of intramuscular lipid content, was similar between sexes. At the whole-muscle level, greater quadriceps attenuation was associated with reduced knee extensor function in women, but not men. In women, decreased myosin heavy chain I and IIA fiber-specific force was associated with higher intramuscular lipid content, which may be explained, in part, by the reduced myofilament lattice stiffness found in myosin heavy chain IIA fibers. Longer myosin attachment times in myosin heavy chain I fibers from men and women were associated with greater amounts of adipose tissue, suggesting that fat deposits lead to slower myosin–actin cross-bridge kinetics. Our results indicate greater quantities of adipose tissue alter myofilament properties and cross-bridge kinetics, which may partially explain the adiposity-induced decrements in single-fiber and whole-muscle function of older adults, especially women.

This study demonstrated the combination of black pepper and vegetable oil-based emulsion synergistically enhanced carotenoid bioavailability of raw vegetables in humans. In a randomized crossover design, healthy young adults consumed (1) vegetable salad (control), (2) salad with canola oil emulsion (COE), (3) salad with black pepper (BP), and (4) salad with canola oil emulsion and black pepper (COE + BP). COE + BP led to a higher AUC0-10h of total plasma carotenoids (p

As studies examining the hypertrophic effects of resistance training (RT) at the cellular level have produced inconsistent results, we performed a systematic review and meta-analysis to investigate muscle fiber size before and after a structured RT intervention in older adults. A random-effects model was used to calculate mean effect size (ES) and 95% confidence intervals (CI). Thirty-five studies were included (age range: 59.0–88.5 yr), and 44 and 30 effects were used to estimate RT impact on myosin heavy chain (MHC) I and II fiber size. RT produced moderate-to-large increases in MHC I (ES = +0.51, 95%CI +0.31 to +0.71; P < 0.001) and II (ES = +0.81, 95%CI +0.56 to +1.05; P < 0.001) fiber size, with men and women having a similar response. Age was negatively associated with change in muscle fiber size for both fiber types (MHC I: R2 = 0.11, β = −0.33, P = 0.002; MHC II: R2 = 0.10, β = −0.32, P = 0.04), indicating a less robust hypertrophic response as age increases in older adults. Unexpectedly, a higher training intensity (defined as percentage of one-repetition maximum) was associated with a smaller increase in MHC II fiber size ( R2 = 15.09%, β = −0.39, P = 0.01). Notably, MHC II fiber subtypes (IIA, IIX, IIAX) were examined less frequently, but RT improved their size. Overall, our findings indicate that RT induces cellular hypertrophy in older adults, although the effect is attenuated with increasing age. In addition, hypertrophy of MHC II fibers was reduced with higher training intensity, which may suggest a failure of muscle fibers to hypertrophy in response to high loads in older adults.

Obesity negatively affects lower extremity physical function (LEPF) in older adults. Exercise and a higher protein diet are both known to positively and independently affect body composition, muscle strength, and LEPF during weight loss; however, their potential interactive effects have not been well characterized in older women. PURPOSE The aim of this study was to determine the relative efficacy of a higher protein diet with or without exercise to improve body composition, muscle strength, and LEPF in older inactive overweight/obese women after weight loss. METHODS Postmenopausal women (body mass index = 31.1 ± 5.1 kg·m, 69.2 ± 3.6 yr) completed a 6-month weight loss program after randomization to three groups (n = 72 randomized; 15% dropout): 1) higher protein diet (PRO, ~30% energy from protein; n = 20), 2) PRO plus exercise (PRO + EX; n = 19), or 3) a conventional protein control diet plus EX (CON + EX, ~18% energy from protein; n = 22). EX was supervised, multicomponent (aerobic, muscle strengthening, balance, and flexibility), and three sessions per week. Body composition was measured via dual-energy x-ray absorptiometry, leg strength by isokinetic dynamometry, and LEPF via 6-min walk, 8-ft up and go, and 30-s chair stand tests. RESULTS Changes in weight (-7.5 ± 4.1 kg; -9.2% ± 4.8%), fat mass, and leg lean mass did not differ among groups (all P > 0.50). Despite weight loss, muscle strength improved in the exercise groups (PRO + EX and CON + EX) but it declined in the PRO group (P = 0.008). For all LEPF measures, the PRO group had attenuated improvements compared with both PRO + EX and CON + EX (all P < 0.01). CONCLUSION Exercise during weight loss is critical to preserve strength and enhance LEPF; however, a higher protein diet does not appear to influence body composition, muscle strength, or LEPF changes when combined with multicomponent exercise.

The purpose of this study was to examine the relative contributions of changes in muscle quality and body composition to changes in lower-extremity physical function (LEPF) following a 6-month exercise and weight loss intervention in overweight and obese older women. Thirty-eight overweight and obese (BMI = 30.0 ± 4.4 kg/m2) older (age = 69.3 ± 4.1 y) women completed 6 months of multicomponent exercise (cardiorespiratory, resistance, balance and flexibility training) and weight loss (hypocaloric diet that reduced energy intake by ~500 kcal/d). Body composition was measured via dual-energy X-ray absorptiometry and muscle quality (N-m/kg) was defined as maximal concentric isokinetic knee torque divided by upper-leg lean mass. The standardized scores of four objective measures of physical function were summed to yield a composite LEPF Z-score. At 6 months, there were significant reductions in body weight (−9.6 ± 3.5%, p

Evidence suggests that ectopic fat deposition interferes with skeletal muscle structure and function, but few studies have examined underlying morphological and contractile properties at the single fiber level. Healthy older (65-75 y) men (n=9) and women (n=9) underwent dynamometry for assessment of knee extensor maximal torque, water-fat magnetic resonance imaging to quantify quadriceps muscle cross-sectional area (CSA) and fat fraction (FF), and vastus lateralis biopsies to determine morphology and function of type I and II muscle fibers. Despite similar body mass indices (24.4±1.3 vs. 24.6±0.5 kg∙m2, p=0.93) and daily moderate-to-vigorous physical activity (46±7 vs. 41±9 min∙d-1, p=0.67), women had greater FF (9.0±0.3 [range: 7.6-10.6] vs. 7.9±0.4 [6.0-9.7] %, p=0.04) than men, indicating increased adipose tissue deposition in skeletal muscle. Women also had smaller quadriceps CSA (39.8±1.8 vs. 57.9±1.3 cm2, p=0.01), specific torque (1.5±0.1 vs. 1.9±0.1 Nm∙cm-2, p=0.01) and type II fiber CSA (3,943±312 [2,350-5,140] vs. 5,352±384 [3,560-6,590] µm2, p=0.01) than men. Type I CSA did not differ by sex (4,918±228 [3,740-5,600] vs. 5,630±440 [3,640-7,670] µm2, p=0.19). In older women, FF was inversely associated with single fiber CSA in type I (r= -0.81, p=0.02) and II (r= -0.76, p=0.03) fibers, and tended to be associated with slower myosin-actin cross-bridge kinetics (longer myosin attachment time) in type I fibers (r=0.65, p=0.08). These relationships were not observed in men. Overall, healthy older women have greater intramuscular fat than men, which may contribute to sex-specific effects on knee extensor specific torque through differences in muscle fiber size and cross-bridge kinetics.

Stretch activation (SA) is a delayed increase in force following a rapid muscle length increase. SA is best known for its role in asynchronous insect flight muscle, where it has replaced calcium’s typical role of modulating muscle force levels during a contraction cycle. SA also occurs in mammalian skeletal muscle but has previously been thought to be too low in magnitude, relative to calcium-activated (CA) force, to be a significant contributor to force generation during locomotion. To test this supposition, we compared SA and CA force at different Piconcentrations (0–16 mM) in skinned mouse soleus (slow-twitch) and extensor digitorum longus (EDL; fast-twitch) muscle fibers. CA isometric force decreased similarly in both muscles with increasing Pi, as expected. SA force decreased with Piin EDL (40%), leaving the SA to CA force ratio relatively constant across Piconcentrations (17–25%). In contrast, SA force increased in soleus (42%), causing a quadrupling of the SA to CA force ratio, from 11% at 0 mM Pito 43% at 16 mM Pi, showing that SA is a significant force modulator in slow-twitch mammalian fibers. This modulation would be most prominent during prolonged muscle use, which increases Piconcentration and impairs calcium cycling. Based upon our previous Drosophila myosin isoform studies and this work, we propose that in slow-twitch fibers a rapid stretch in the presence of Pireverses myosin’s power stroke, enabling quick rebinding to actin and enhanced force production, while in fast-twitch fibers, stretch and Picause myosin to detach from actin.

The mechanisms responsible for the loss in muscle power and increased fatigability with ageing are unresolved. We show that the contractile mechanics of fibres from the vastus lateralis of old men were well-preserved compared to those of young men, but the selective loss of fast myosin heavy chain II muscle was strongly associated with age-related decrements in whole-muscle strength and power. We reveal that the combination of acidosis (HThe present study aimed to identify the mechanisms responsible for the loss in muscle power and increased fatigability with ageing by integrating measures of whole-muscle function with single fibre contractile mechanics. After adjusting for the 22% smaller muscle mass in old (73-89 years, n = 6) compared to young men (20-29 years, n = 6), isometric torque and power output of the knee extensors were, respectively, 38% and 53% lower with age. Fatigability was ∼2.7-fold greater with age and strongly associated with reductions in the electrically-evoked contractile properties. To test whether cross-bridge mechanisms could explain age-related decrements in knee extensor function, we exposed myofibres (n = 254) from the vastus lateralis to conditions mimicking quiescent muscle and fatiguing levels of acidosis (H

OBJECTIVE The aim of this study was to examine the association between asymmetry in leg extension power (LP) and lower-extremity physical function (LEF) in community-dwelling older women. METHODS Older women (n = 94, 74.0 ± 5.5 y) were assessed for unilateral LP (watts) using the Nottingham power rig, and absolute and relative (%ASYM) differences in LP between the dominant and nondominant legs were calculated. LEF was assessed via the 6-minute walk, 8-foot up-and-go and 30-second chair stand, and a composite measure of LEF was calculated by summing z scores of each test. In addition, body composition was measured via dual-energy x-ray absorptiometry and moderate-intensity physical activity was assessed via questionnaire. RESULTS The absolute difference in LP between the dominant and nondominant legs was 10.2 ± 9.0 watts, which translated to a %ASYM of 11.3% ± 10.5% (P < 0.01). %ASYM had bivariate associations with all individual measures of LEF (r range = -0.22 to -0.34, all P < 0.05). Using multivariate linear regression, %ASYM was an independent predictor of a composite LEF z score (standardized β= -0.18, P < 0.05) after adjustment for age, comorbidities, physical activity, relative adiposity, and total leg power. Analysis of covariance indicated that women with low asymmetry had a significantly better LEF z score than those with high asymmetry (0.60 vs -0.13, P = 0.04). CONCLUSIONS These findings indicate that a greater magnitude of asymmetry in LP is associated with poorer LEF in older women. Research is needed to determine whether interventions that correct asymmetries in lower-body muscle power confer functional benefits in older women.

Resistance training (RT) has been investigated as a potential intervention strategy for improving muscle function, but the effects on lower-extremity muscle power in middle-aged and older adults have not been systematically reviewed. The aim of this meta-analysis is to provide a quantitative estimate of the effect of RT on lower-extremity muscle power in middle-aged and older adults and to examine independent moderators of this relationship. Randomized controlled trials that examined the effects of RT on either leg press (LP) or knee extension (KE) muscle power in adults aged ≥50 years were included. Data were aggregated with meta-analytic techniques, and multi-level modeling was used to adjust for nesting effects. A total of 52 effects from 12 randomized controlled trials were analyzed with a random-effects model to estimate the effect of RT on lower-extremity muscle power. A multiple-regression analysis was conducted to examine independent moderators of the mean effect. The adjusted aggregated results from all studies indicate that RT has a small-to-moderate effect on lower-extremity muscle power (Hedges’ d = 0.34, 95 % confidence interval [CI] 0.25–0.43), which translated to 54.90 watts (95 % CI 40.37–69.43). Meta-regression analyses indicated that high-velocity RT was superior to traditional RT (Δ = 0.62 vs. 0.20, respectively) for increasing lower-extremity muscle power. In addition, training volume significantly moderated the effect of RT on muscle power. The findings from this meta-analysis indicate that RT is an efficacious intervention strategy for improving LP and KE muscle power in adults aged ≥50 years. Training mode and volume independently moderate the effect of RT on lower-extremity muscle power, and should be considered when prescribing RT exercise for middle-aged and older adults.

OBJECTIVE Greater muscle strength and power are associated with better physical function in middle-aged and older women. The aim of the present study was to determine whether accelerometer-measured physical activity was associated with muscle strength and power in middle-aged postmenopausal women. METHODS Postmenopausal women (N = 60; mean [SD] age, 58.9 [3.9] y) were assessed for physical activity (step count and moderate to vigorous physical activity [MVPA]) via accelerometer, for body composition via dual-energy x-ray absorptiometry, for concentric isokinetic knee torque at 60°/s and 180°/s using isokinetic dynamometry, and for leg extensor power with the Nottingham power rig. RESULTS In linear regression analysis, daily step count was independently associated with isokinetic knee torque at 60°/s (standardized β = 0.32, P = 0.01), isokinetic knee torque at 180°/s (standardized β = 0.32, P = 0.01), and total leg extensor power (β = 0.36, P = 0.01) after adjustment for covariates. Daily MVPA had similar associations with isokinetic knee torque at 60°/s (β = 0.38, P

Eating behaviors (cognitive restraint, flexible and rigid restraint, disinhibition, hunger) have been associated with obesity and weight loss success in middle-aged individuals, but little is known about these relationships in older adults. This study examined relationships between eating behaviors and weight loss in overweight/obese older women (n = 61; 69 ± 3.6 years; body mass index = 31.1 ± 5.0 kg/m

A classic unresolved issue in human integrative physiology involves the role of exercise intensity, duration and volume in regulating skeletal muscle adaptations to training. We employed counterweighted single-leg cycling as a unique within-subject model to investigate the role of exercise intensity in promoting training-induced increases in skeletal muscle mitochondrial content. Six sessions of high-intensity interval training performed over 2 weeks elicited greater increases in citrate synthase maximal activity and mitochondrial respiration compared to moderate-intensity continuous training matched for total work and session duration. These data suggest that exercise intensity, and/or the pattern of contraction, is an important determinant of exercise-induced skeletal muscle remodelling in humans.We employed counterweighted single-leg cycling as a unique model to investigate the role of exercise intensity in human skeletal muscle remodelling. Ten young active men performed unilateral graded-exercise tests to measure single-leg V̇O2, peak and peak power (W

The aging process leads to adverse changes in body composition (increases in fat mass and decreases in skeletal muscle mass), declines in physical function (PF), and ultimately increased risk for disability and loss of independence. Specific components of body composition or muscle capacity (strength and power) may be useful in predicting PF; however, findings have been mixed regarding the most salient predictor of PF. The development of a conceptual model potentially aids in understanding the interrelated factors contributing to PF with the factors of interest being physical activity, body composition, and muscle capacity. This article also highlights sex differences in these domains. Finally, factors known to affect PF, such as sleep, depression, fatigue, and self-efficacy, are discussed. Development of a comprehensive conceptual model is needed to better characterize the most salient factors contributing to PF and to subsequently inform the development of interventions to reduce physical disability in older adults.

To investigate the impact of body mass index (BMI) (normal weight, overweight, obese) on the relationship between muscle quality (MQ) and physical function in community-dwelling older women.Cross-sectional study.University research laboratory.Community-dwelling older women (n = 94, 73.6 ± 5.4 y) stratified by BMI (normal weight: 20.0-24.9 kg/m2; overweight: 25.0-29.9 kg/m2; obese: ≥ 30.0 kg/m2).Body mass index using height and weight, leg extension power via the Nottingham power rig, body composition using dual-energy X-ray absorptiometry, and physical function (6-minute walk, 8-foot up-and-go, 30-second chair stand). Muscle quality was defined as leg power (watts) normalized for lower-body mineral-free lean mass (kg).Following adjustments for covariates, muscle quality was significantly higher in women of normal BMI compared to overweight (10.0 ± 0.4 vs. 8.7 ± 0.4 watts/kg, p = 0.03). Muscle quality was a significant predictor of performance on the 6-minute walk and 8-foot up-and-go in normal and overweight women (all p0.05) and performance on the 30-second chair stand in normal and obese women (both p0.05). Body mass index did not significantly impact the association between MQ and physical function (all p0.05).Muscle quality varies by BMI, yet the relationship to physical function is not significantly different across BMI groups. The results imply that interventions that increase MQ in older women may improve physical function, regardless of BMI.

The population of older adults in the United States is steadily growing and identifying factors that contribute to healthy aging is a public health priority. Changes in body composition are a hallmark of the aging process and have been implicated in the loss of physical function among older adults. In particular, age-related declines in muscle strength and power occur at a faster rate than the loss of muscle mass (sarcopenia), and this suggests a decrease in muscle quality of older adults. Muscle quality has traditionally been defined as muscle function (strength or power) per unit of muscle size (mass or cross-sectional area) and a growing body of literature suggests that lower body muscle quality may be critical for maintaining functional independence with age. However, the literature regarding the definition of muscle quality and its relationship with health outcomes in older adults has not been adequately reviewed. Thus, the aim of this report is to highlight the contemporary literature regarding age-related changes in muscle quality and its relationship with health outcomes in community-dwelling older adults.

Skeletal muscle power is a salient determinant of physical function in older adults, but its relationship with habitual physical activity has not been well-characterized. The aim of this study was to examine the association between moderate-intensity physical activity and lower-extremity muscle power in community-dwelling older women. Older women (n = 96, mean age = 73.9 ± 5.6 years, mean body mass index = 26.5 ± 4.7 kg/m(2)) underwent assessments for body composition via dual-energy X-ray absorptiometry and lower-extremity muscle power (watts) using the Nottingham power rig. The Community Health Activities Model Program for Seniors questionnaire was used to estimate weekly caloric expenditure in moderate-intensity physical activity (kcals/wk). Linear regression indicated that moderate-intensity physical activity was independently related to muscle power (standardized β = 0.20, p = .03), and this relationship remained following adjustment for covariates. Analysis of covariance revealed that women in the highest tertile of volume of physical activity had significantly greater muscle power than those with the lowest volume (199.0 vs. 170.7 watts, p

Sarcopenia is associated with substantial health and economic consequences and is emerging as a major public health problem in the older population. The effects of sarcopenia may increase the risk for adverse health outcomes in older adults, and strategies need to be developed to maintain healthy aging. Although several intervention strategies have been proposed, resistance training (RT) has been suggested as the most effective stimulus for optimizing improvements in physical function and body composition with age. Although RT has been established as a safe and efficacious intervention for the prevention and treatment of sarcopenia, very few older adults regularly participate in RT programs. Community-based RT programs may be a feasible strategy because of their accessibility, cost-effectiveness, and lower-intensity training stimuli. However, the effects of these interventions on health outcomes in older adults have not been adequately reviewed. This report will describe the health effects associated with sarcopenia and summarize the major findings from community-based RT interventions on different health outcomes in older adults. Finally, it is suggested that all older adults who demonstrate the ability to safely participate in RT comply with the guidelines recommended by the American College of Sports Medicine.

Endurance athletes commonly ingest caffeine as a means to enhance training intensity and competitive performance. A widely-used source of caffeine is coffee, however conflicting evidence exists regarding the efficacy of coffee in improving endurance performance. In this context, the aims of this evidence-based review were threefold: 1) to evaluate the effects of preexercise coffee on endurance performance, 2) to evaluate the effects of coffee on perceived exertion during endurance performance, and 3) to translate the research into usable information for athletes to make an informed decision regarding the intake of caffeine via coffee as a potential ergogenic aid. Searches of three major databases were performed using terms caffeine and coffee, or coffee-caffeine, and endurance, or aerobic. Included studies (n = 9) evaluated the effects of caffeinated coffee on human subjects, provided the caffeine dose administered, administered caffeine ≥ 45 min before testing, and included a measure of endurance performance (e.g., time trial). Significant improvements in endurance performance were observed in five of nine studies, which were on average 24.2% over controls for time to exhaustion trials, and 3.1% for time to completion trials. Three of six studies found that coffee reduced perceived exertion during performance measures significantly more than control conditions (p < .05). Based on the reviewed studies there is moderate evidence supporting the use of coffee as an ergogenic aid to improve performance in endurance cycling and running. Coffee providing 3–8.1 mg/kg (1.36–3.68 mg/lb) of caffeine may be used as a safe alternative to anhydrous caffeine to improve endurance performance.

To examine the effects of diet education (DE) plus light resistance training (RT) on coronary heart disease risk (CHD) factors, specifically dietary quality, blood lipid and C-Reactive protein (CRP) concentrations in overweight and obese older adults in a community setting.Community outreach intervention with a quasi-experimental design.A total of 96 subjects, 16 males and 80 females, aged 69.2 ± 6.2 years, community-dwelling, and from one of four senior centers in Rhode Island.Subjects participated in 30 minutes of DE (once per week) and ~80 minutes of RT (two separate sessions per week) for eight weeks. The DE sessions were led by a registered dietitian.Anthropometrics (height, weight, waist circumference, hip circumference, and body composition), clinical (blood pressure), biochemical (lipid profile, glucose, and CRP concentrations), and diet quality measured by the Dietary Screening Tool (DST).A significant change was seen in DST risk categories from baseline to post-intervention, χ² (2)=20.43, p0.01. Significant differences were seen in triacylglycerol (p=0.028) as well as in systolic and diastolic blood pressures, weight, waist circumference, hip circumference, percent body fat, fat mass, and body mass index (all p0.05).This intervention effectively decreased CHD risk in overweight and obese older adults. Future research is needed to examine the effects of longer DE plus RT interventions with greater weight loss on the lipid profile and CRP concentrations in overweight and obese older adults at risk for CHD.

OBJECTIVE This study aims to determine the sex-specific relationships of physical activity, body composition, and muscle quality with lower-extremity physical function in older men and women. METHODS Seventy-nine community-dwelling men (n = 39; mean [SD] age, 76.1 [6.2] y; mean [SD] body mass index, 27.3 [3.8] kg/m(2)) and women (n = 40; mean [SD] age, 75.8 [5.5] y; mean [SD] body mass index, 27.0 [3.8] kg/m(2)) were assessed for physical activity via questionnaire, body composition via dual-energy x-ray absorptiometry scanning, leg extension power using the Nottingham power rig, and muscle quality (W/kg; the ratio of leg extension power [W] to lower-body mineral-free lean mass [kg]). A composite measure of physical function was obtained by summing Z scores from the 6-minute walk, 8-ft up-and-go test, and 30-second chair-stand test. RESULTS As expected, men had significantly greater levels of physical activity, lower adiposity, greater lean mass, higher leg extension power, and greater muscle quality compared with women (all P < 0.05). In linear regression analyses, muscle quality and physical activity were the strongest predictors of lower-extremity physical function in men and independently explained 42% and 29% of the variance, respectively. In women, muscle quality (16%) and percent body fat (12%) were independent predictors after adjustment for covariates. CONCLUSIONS Muscle quality is the strongest predictor of lower-extremity physical function in men and women, but sex impacts the importance of physical activity and adiposity. These findings suggest that older men and women may benefit from different intervention strategies for preventing physical disability and also highlight the importance of weight management for older women to preserve physical function.

The aim of this study was to examine the relative contributions of physical activity, adiposity, lean mass and muscle quality to lower-extremity physical function (LEPF) in older women.Cross-sectional analysis at a university research laboratory.Community-dwelling older women (n=96, 73.9 ± 5.6 years, BMI=26.5 ± 4.7 kg/m(2)) were assessed for body composition via dual-energy X-ray absorptiometry, leg extension power using the Nottingham power rig, muscle quality (W/kg) as the ratio of leg extension power (W) to lower-body mineral free lean mass (kg) and moderate-intensity physical activity via questionnaire. A composite measure of LEPF was calculated by summing Z-scores of the 6-min walk, 8-foot up-and-go and 30-s chair stand tests.Muscle quality and physical activity were associated with all measures of LEPF (all p0.01). Relative adiposity was related to the 6-min walk and 30-s chair stand (both p0.01); lower-body mineral-free lean mass was not related to any measure of LEPF (p0.05). Hierarchical linear regression analyses revealed that muscle quality (standardized β=0.47, p0.01) and relative adiposity (β=-0.33, p0.01) were the strongest independent predictors of composite LEPF Z-score explaining 24% and 17% of the variance, respectively.Muscle quality and relative adiposity are the strongest independent predictors of LEPF in older women. These findings suggest that maintaining muscle quality, especially relative to adiposity, may be a critical target for interventions to prevent declines in physical function in older women.

Background:Community-based interventions that incorporate resistance training (RT) and dietary changes have not been extensively studied in overweight and obese older adults. The purpose of this investigation was to determine the effects of a community-based RT and dietary intervention on physical function and body composition in overweight and obese older adults.Methods:Ninety-five overweight and obese (BMI = 33.4 ± 4.0 kg/m2) older adults aged 55–80 years completed an 8-week RT and dietary intervention at 4 Rhode Island senior centers. Participants performed RT twice-weekly using resistance tubing, dumbbells, and ankle weights. Participants also attended 1 weekly dietary counseling session on a modified Dietary Approaches to Stop Hypertension diet. Outcome measurements included anthropometrics, body composition, and physical function.Results:There were small changes in body mass (–1.0 ± 1.8 kg, P < .001), waist circumference (–5.2 ± 3.8 cm, P < .001), and percent body fat (–0.5 ± 1.4%, P < .001). In addition, significant improvements were observed in knee extensor torque (+7.9 ± 19.1 N-m, P < .001), handgrip strength (+1.2 ± 2.5 kg, P < .001), and 8-foot up-and-go test time (–0.56 ± 0.89 s, P < .001).Conclusion:Community-based RT and dietary modifications can improve body composition, muscle strength, and physical function in overweight and obese older adults. Future investigations should determine if this intervention is effective for long-term changes.