Randomized, four-arm, dose-response clinical trial to optimize resistance exercise training for older adults with age-related muscle atrophy

Abstract

Purpose The myriad consequences of age-related muscle atrophy include reduced muscular strength, power, and mobility; increased risk of falls, disability, and metabolic disease; and compromised immune function. At its root, aging muscle atrophy results from a loss of myofibers and atrophy of the remaining type II myofibers. The purpose of this trial (NCT02442479) was to titrate the dose of resistance training (RT) in older adults in an effort to maximize muscle regrowth and gains in muscle function. Methods A randomized, four-arm efficacy trial in which four, distinct exercise prescriptions varying in intensity, frequency, and contraction mode/rate were evaluated: (1) high-resistance concentric-eccentric training (H) 3 d/wk (HHH); (2) H training 2 d/wk (HH); (3) 3 d/wk mixed model consisting of H training 2 d/wk separated by 1 bout of low-resistance, high-velocity, concentric only (L) training (HLH); and (4) 2 d/wk mixed model consisting of H training 1 d/wk and L training 1 d/wk (HL). Sixty-four randomized subjects (65.5 ± 3.6y) completed the trial. All participants completed the same 4 wk of pre-training consisting of 3 d/wk followed by 30 wk of randomized RT. Results The HLH prescription maximized gains in thigh muscle mass (TMM, primary outcome) and total body lean mass. HLH also showed the greatest gains in knee extension maximum isometric strength, and reduced cardiorespiratory demand during steady-state walking. HHH was the only prescription that led to increased muscle expression of pro-inflammatory cytokine receptors and this was associated with a lesser gain in TMM and total body lean mass compared to HLH. The HL prescription induced minimal muscle regrowth and generally lesser gains in muscle performance vs. the other prescriptions. Major Conclusions The HLH prescription offers distinct advantages over the other doses, while the HL program is subpar. Although limited by a relatively small sample size, we conclude from this randomized dose-response trial that older adults benefit greatly from 2 d/wk high-intensity RT, and may further benefit from inserting an additional weekly bout of low-load, explosive RT. Trial Registration ClinicalTrials.gov NCT02442479

Metformin blunts muscle hypertrophy in response to progressive resistance exercise training in older adults: A randomized, double‐blind, placebo‐controlled, multicenter trial: The MASTERS trial

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Effects of aging and Parkinson’s disease on motor unit remodeling: influence of resistance exercise training

“…To provide reference values of type I myofiber grouping data for non-exercisetrained young adults (YA; 26 Ϯ 4 yr; n ϭ 27, 12 women, 15 men) and age-matched non-PD older adults (OA; 66 Ϯ 4 yr; n ϭ 91; 41 women, 50 men), we included previously published data (21). For all other measures, we compared PD to YA and OA performance data and available remaining muscle tissue samples from two previously published RT trials (2,48).…”

Regulation of microRNAs in Satellite Cell Renewal, Muscle Function, Sarcopenia and the Role of Exercise

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