Understanding the minimal dose of physical activity required to achieve improvement in physical functioning and reductions in disability risk is necessary to inform public health recommendations. To ...examine the effect of physical activity dose on changes in physical functioning and the onset of major mobility disability in The Lifestyle Interventions and Independence for Elders (LIFE) Study. We conducted a multicenter single masked randomized controlled trial that enrolled participants in 2010 and 2011 and followed them for an average of 2.6 years. 1,635 sedentary men and women aged 70-89 years who had functional limitations were randomized to a structured moderate intensity walking, resistance, and flexibility physical activity program or a health education program. Physical activity dose was assessed by 7-day accelerometry and self-report at baseline and 24 months. Outcomes included the 400 m walk gait speed, the Short Physical Performance Battery (SPPB), assessed at baseline, 6, 12, and 24 months, and onset of major mobility disability (objectively defined by loss of ability to walk 400 m in 15 min). When the physical activity arm or the entire sample were stratified by change in physical activity from baseline to 24 months, there was a dose-dependent increase in the change in gait speed and SPPB from baseline at 6, 12, and 24 months. In addition, the magnitude of change in physical activity over 24 months was related to the reduction in the onset of major mobility disability (overall P < 0.001) (highest versus the lowest quartile of physical activity change HR 0.23 ((95% CI:0.10-0.52) P = 0.001) in the physical activity arm. We observed a dose-dependent effect of objectively monitored physical activity on physical functioning and onset of major mobility disability. Relatively small increases (> 48 minutes per week) in regular physical activity participation had significant and clinically meaningful effects on these outcomes.
ClinicalsTrials.gov NCT00116194.
Evidence implicates the amount and location of fat in aging-related loss of muscle function; however, whether intramyocellular lipids affect muscle contractile capacity is unknown.
We compared both ...in vivo knee extensor muscle strength, power, and quality and in vitro mechanical properties of vastus lateralis single-muscle fibers between normal weight (NW) and obese older adults and determined the relationship between muscle lipid content (both intramuscular adipose tissue and intramyocellular lipids) and in vivo and in vitro muscle function in NW and obese individuals.
The obese group had a greater percentage of type-I fibers compared to the NW group. The cross-sectional area of type-I fibers was greater in obese compared to NW; however, maximal shortening velocity of type-I fibers in the obese was slower compared to NW. Type-I and type-IIa fibers from obese group produced lower specific force than that of type-I and type-IIa fibers from the NW group. Normalized power was also substantially lower (~50%) in type-I fibers from obese adults. The intramyocellular lipids data showed that total lipid droplet area, number of lipid droplets, and area fraction were about twofold greater in type-I fibers from the obese compared to the NW group. Interestingly, a significant inverse relationship between average number of lipid droplets and single-fiber unloaded shortening velocity, maximal velocity, and specific power was observed in obese participants. Additionally, muscle echointensity correlated with single-fiber specific force.
These data indicate that greater intramyocellular lipids are associated with slower myofiber contraction, force, and power development in obese older adults.
Purpose To (1) determine whether standard clinical muscle fatty infiltration and atrophy assessment techniques using a single image slice for patients with a rotator cuff tear (RCT) are correlated ...with 3-dimensional measures in older individuals (60+ years) and (2) to determine whether age-associated changes to muscle morphology and strength are compounded by an RCT. Methods Twenty older individuals were studied: 10 with an RCT of the supraspinatus (5 men and 5 women) and 10 matched controls. Clinical imaging assessments (Goutallier and Fuchs scores and cross-sectional area ratio) were performed for participants with RCTs. Three-dimensional measurements of rotator cuff muscle and fat tissues were obtained for all participants using magnetic resonance imaging (MRI). Isometric joint moment was measured at the shoulder. Results There were no significant associations between single-image assessments and 3-dimensional measurements of fatty infiltration for the supraspinatus and infraspinatus muscles. Compared with controls, participants with RCTs had significantly increased percentages of fatty infiltration for each rotator cuff muscle (all P ≤ .023); reduced whole muscle volume for the supraspinatus, infraspinatus, and subscapularis muscles (all P ≤ .038); and reduced fat-free muscle volume for the supraspinatus, infraspinatus, and subscapularis muscles (all P ≤ .027). Only the teres minor ( P = .017) fatty infiltration volume was significantly greater for participants with RCTs. Adduction, flexion, and external rotation strength (all P ≤ .021) were significantly reduced for participants with RCTs, and muscle volume was a significant predictor of strength for all comparisons. Conclusions Clinical scores using a single image slice do not represent 3-dimensional muscle measurements. Efficient methods are needed to more effectively capture 3-dimensional information for clinical applications. Participants with RCTs had increased fatty infiltration percentages that were likely driven by muscle atrophy rather than increased fat volume. The significant association of muscle volume with strength production suggests that treatments to preserve muscle volume should be pursued for older patients with RCTs. Level of Evidence Level II, diagnostic study, with development of diagnostic criteria on the basis of consecutive patients with universally applied reference gold standard.
Background: Resistance training (RT) improves muscle strength and overall physical function in older adults. RT may be particularly important in the obese elderly who have compromised muscle ...function. Whether caloric restriction (CR) acts synergistically with RT to enhance function is unknown. Objective: As the primary goal of the Improving Muscle for Functional Independence Trial (I’M FIT), we determined the effects of adding CR for weight loss on muscle and physical function responses to RT in older overweight and obese adults. Design: I’M FIT was a 5-mo trial in 126 older (65–79 y) overweight and obese men and women who were randomly assigned to a progressive, 3-d/wk, moderate-intensity RT intervention with a weight-loss intervention (RT+CR) or without a weight-loss intervention (RT). The primary outcome was maximal knee extensor strength; secondary outcomes were muscle power and quality, overall physical function, and total body and thigh compositions. Results: Body mass decreased in the RT+CR group but not in the RT group. Fat mass, percentage of fat, and all thigh fat volumes decreased in both groups, but only the RT+CR group lost lean mass. Adjusted postintervention body- and thigh-composition measures were all lower with RT+CR except intermuscular adipose tissue (IMAT). Knee strength, power, and quality and the 4-m gait speed increased similarly in both groups. Adjusted postintervention means for a 400-m walk time and self-reported disability were better with RT+CR with no group differences in other functional measures, including knee strength. Participants with a lower percentage of fat and IMAT at baseline exhibited a greater improvement in the 400-m walk and knee strength and power. Conclusions: RT improved body composition (including reducing IMAT) and muscle strength and physical function in obese elderly, but those with higher initial adiposity experienced less improvement. The addition of CR during RT improves mobility and does not compromise other functional adaptations to RT. These findings support the incorporation of RT into obesity treatments for this population regardless of whether CR is part of the treatment. This trial was registered at clinicaltrials.gov as NCT01049698.
Little is known about the effect of exercise modality during a dietary weight loss program on muscle size and quality, as measured by computed tomography (CT). Even less is known about how CT-derived ...changes in muscle track with changes in volumetric bone mineral density (vBMD) and bone strength.
Older adults (66 ± 5 years, 64 % women) were randomized to 18-months of diet-induced weight loss (WL), WL with aerobic training (WL + AT), or WL with resistance training (WL + RT). CT-derived muscle area, radio-attenuation and intermuscular fat percentage at the trunk and mid-thigh were determined at baseline (n = 55) and 18-month follow-up (n = 22–34), and changes were adjusted for sex, baseline value, and weight lost. Lumbar spine and hip vBMD and finite element-derived bone strength were also measured.
After adjustment for the weight lost, muscle area losses at the trunk were −7.82 cm2 −12.30, −3.35 for WL, −7.72 cm2 −11.36, −4.07 for WL + AT, and −5.14 cm2 −8.65, −1.63 for WL + RT (p < 0.001 for group differences). At the mid-thigh, decreases were −6.20 cm2 −10.39, −2.02 for WL, −7.84 cm2 −11.19, −4.48 for WL + AT, and −0.60 cm2 −4.14, 2.94 for WL + RT; this difference between WL + AT and WL + RT was significant in post-hoc testing (p = 0.01). Change in trunk muscle radio-attenuation was positively associated with change in lumbar bone strength (r = 0.41, p = 0.04).
WL + RT better preserved muscle area and improved muscle quality more consistently than WL + AT or WL alone. More research is needed to characterize the associations between muscle and bone quality in older adults undertaking weight loss interventions.
•WL+RT better preserved muscle area more consistently than WL+AT or WL alone.•Exercise, either RT or AT, may be able to preserve muscle quality in direct comparison to WL alone.•There could be a positive association between muscle and bone quality changes.•Comprehensive research is needed to understand the link between changes in muscle and bone quality.
Background
Physical activity (PA) reduces the rate of mobility disability, compared with health education (HE), in at risk older adults. It is important to understand aspects of performance ...contributing to this benefit.
Objective
To evaluate intervention effects on tertiary physical performance outcomes.
Design
The Lifestyle Interventions and Independence for Elders (LIFE) was a multi‐centered, single‐blind randomized trial of older adults.
Setting
Eight field centers throughout the United States.
Participants
1635 adults aged 78.9 ± 5.2 years, 67.2% women at risk for mobility disability (Short Physical Performance Battery SPPB <10).
Interventions
Moderate PA including walking, resistance and balance training compared with HE consisting of topics relevant to older adults.
Outcomes
Grip strength, SPPB score and its components (balance, 4 m gait speed, and chair‐stands), as well as 400 m walking speed.
Results
Total SPPB score was higher in PA versus HE across all follow‐up times (overall P = .04) as was the chair‐stand component (overall P < .001). No intervention effects were observed for balance (overall P = .12), 4 m gait speed (overall P = .78), or grip strength (overall P = .62). However, 400 m walking speed was faster in PA versus HE group (overall P =<.001). In separate models, 29% of the rate reduction of major mobility disability in the PA versus HE group was explained by change in SPPB score, while 39% was explained by change in the chair stand component.
Conclusion
Lower extremity performance (SPPB) was significantly higher in the PA compared with HE group. Changes in chair‐stand score explained a considerable portion of the effect of PA on the reduction of major mobility disability–consistent with the idea that preserving muscle strength/power may be important for the prevention of major mobility disability.
Abstract Rotator cuff tears (RCT) in older individuals may compound age-associated physiological changes and impact their ability to perform daily functional tasks. Our objective was to quantify ...thoracohumeral kinematics for functional tasks in 18 older adults (mean age=63.3±2.2), and compare findings from nine with a RCT to nine matched controls. Motion capture was used to record kinematics for 7 tasks (axilla wash, forward reach, functional pull, hair comb, perineal care, upward reach to 90°, upward reach to 105°) spanning the upper limb workspace. Maximum and minimum joint angles and motion excursion for the three thoracohumeral degrees of freedom (elevation plane, elevation, axial rotation) were identified for each task and compared between groups. The RCT group used greater minimum elevation angles for axilla wash and functional pull ( p ≤0.0124) and a smaller motion excursion for functional pull ( p =0.0032) compared to the control group. The RCT group also used a more internally rotated maximum axial rotation angle than controls for functional reach, functional pull, hair comb, and upward reach to 105° ( p ≤0.0494). The most differences between groups were observed for axial rotation, with the RCT group using greater internal rotation to complete functional tasks, and significant differences between groups were identified for all three thoracohumeral degrees of freedom for functional pull. We conclude that older adults with RCT used more internal rotation to perform functional tasks than controls. The kinematic differences identified in this study may have consequences for progression of shoulder damage and further functional impairment in older adults with RCT.
Objectives
To investigate the heterogeneity of clinically meaningful levels of gait speed relative to self‐reported mobility disability (SR‐MD).
Design
Five longitudinal studies with older adults in ...different health states (onset of acute event, presence of chronic condition, sedentary, community living) were used to explore the relationship between gait speed and SR‐MD.
Setting
Lifestyle Interventions and Independence for Elders Pilot (LIFE‐P), LIFE, Trial of Angiotensin‐Converting Enzyme Inhibition and Novel Cardiovascular Risk Factors (TRAIN), Baltimore Hip Fracture Study (BHS2), Invecchiare in Chianti (InCHIANTI).
Participants
Individuals aged 65 and older (N=3,540): sedentary, community dwelling (LIFE‐P/LIFE), with hip fracture (BHS2), random population‐based sample (InCHIANTI), high cardiovascular risk (TRAIN).
Measurements
Usual‐pace gait speed across 3 to 4 m and SR‐MD, defined as inability to walk approximately 1 block or climb 1 flight of stairs.
Results
The mean gait speed of participants without SR‐MD was greater than 1.0 m/s in InCHIANTI and TRAIN, 0.79 m/s in LIFE‐P/LIFE, and 0.46 m/sec in BHS2. Of individuals with SR‐MD, mean gait speed was 0.08 m/s slower in LIFE‐P/LIFE, 0.19 m/s slower in TRAIN, 0.22 m/s slower in BHS2, and 0.36 m/s slower in InCHIANTI. The optimal gait speed cutpoint for minimizing SR‐MD misclassification rates ranged from 0.3 m/s in BHS2 to 1.0 m/s in TRAIN. In longitudinal analyses, development of SR‐MD was dependent on initial gait speed and change in gait speed (p<.001).
Conclusion
The relationship between absolute levels of gait speed and SR‐MD may be context specific, and there may be variations between populations. Across diverse clinical populations, clinical interpretations of how change in usual pace gait speed relates to development of SR‐MD depend on where on the gait speed continuum change occurs.
PURPOSEThe prevalence of metabolic syndrome (MetS) is greatest in older obese adults, and effective evidence-based treatment strategies are lacking. This study determined the efficacy of adding ...caloric restriction (CR) for weight loss to resistance training (RT) on MetS and its individual components in older overweight and obese adults.
METHODSWe performed a 5-month randomized controlled trial in 126 older (65–79 yr) overweight and obese (body mass index = 27–35 kg·m) men and women who were assigned to a progressive 3-d·wk moderate-intensity RT with (RT + CR) or without caloric restriction (RT). MetS components, according to the National Cholesterol Education Program Adult Treatment Panel III, were determined before and immediately after the interventions.
RESULTSBody mass decreased in RT + CR (−5.67% loss of initial mass) but was unchanged in RT (−0.15%). Compared with RT, RT + CR resulted in reduced VLDL cholesterol, triglycerides, and systolic and diastolic blood pressures (P between 0.000 and 0.013). The RT group showed no significant within-group changes in MetS criteria. Abdominal obesity, hypertension, the number of metabolic abnormalities and the presence of MetS significantly decreased with RT + CR. There were significant group differences for abdominal obesity, hypertension, and number of metabolic abnormalities.
CONCLUSIONRT + CR is an effective strategy for improving some of the metabolic abnormalities associated with MetS among older overweight and obese adults.
Studies in humans and animal models provide compelling evidence for age-related skeletal muscle denervation, which may contribute to muscle fiber atrophy and loss. Skeletal muscle denervation seems ...relentless; however, long-term, high-intensity physical activity appears to promote muscle reinnervation. Whether 5-month resistance training (RT) enhances skeletal muscle innervation in obese older adults is unknown. This study found that neural cell-adhesion molecule, NCAM+ muscle area decreased with RT and was inversely correlated with muscle strength. NCAM1 and RUNX1 gene transcripts significantly decreased with the intervention. Type I and type II fiber grouping in the vastus lateralis did not change significantly but increases in leg press and knee extensor strength inversely correlated with type I, but not with type II, fiber grouping. RT did not modify the total number of satellite cells, their number per area, or the number associated with specific fiber subtypes or innervated/denervated fibers. Our results suggest that RT has a beneficial impact on skeletal innervation, even when started late in life by sedentary obese older adults.
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