Large Heterogeneity In The Responsiveness To Resistance-type Exercise Training In The Older Population

Abstract

Ageing is associated with a decline in skeletal muscle mass, strength, and physical function. Resistance-type exercise is an effective interventional strategy to increase skeletal muscle mass and strength, however the adaptive response to exercise is remarkably heterogeneous. As small subsets of individual subjects sometimes show no increase or even a decline in muscle mass, it has been suggested that some older individuals may be unresponsive to the benefits of exercise. PURPOSE: To examine the heterogeneity in resistance-type exercise training induced changes in lean body mass (LBM), strength, and physical function in a large sample of older men and women. METHODS: Older subjects (>65 y) were selected to participate in 3 (n = 110) to 6 (n = 85) months of supervised resistance-type exercise training. Changes in LBM (DXA), leg strength (1-RM on leg press and leg extension), and physical function (chair rise-time) were assessed at baseline, and after 3 and 6 months of resistance-type training. RESULTS: LBM increased by 0.7±0.1 kg at 3 months, with individual data ranging from -3.8 to 5.4 kg. By 6 months, LBM increased by 1.1±0.2 kg, with individual data ranging from -1.8 to 9.2 kg. Leg press and leg extension strength increased by 33±2 and 20±1 kg at 3 months, with individual data ranging from -36 to 87 and -22 to 56 kg. At 6 months, leg strength had increased by 50±3 and 29±2 kg on the leg press and leg extension, with individual data ranging from -28 to 145 kg and -19 to 60 kg, respectively. Chair rise-time decreased by 1.3±0.4 s at 3 months, with individual data ranging from -12.5 to 21.6 s. At 6 months, chair rise-time had decreased by 2.3±0.4 s, with individual data ranging from -23 to 10.5 s. CONCLUSIONS: A large heterogeneity exists in the adaptive response to prolonged resistance-type exercise training in the older population. However, non-responsiveness was not apparent in any subject, as positive changes on one or more outcome measures (LBM, strength and physical function) were evident in all subjects. Furthermore, the magnitude of responsiveness was impacted by the duration of training, with more positive responders at 6 vs 3 months. We conclude that there are no non-responders to the benefits of resistance-type exercise training. Resistance-type exercise should be prescribed to support healthy aging in the elderly population.