The effects of strength and power training on single-step balance recovery in older adults: a preliminary study

Abstract

Derek N Pamukoff,1 Eric C Haakonssen,1 Joseph A Zaccaria,1 Michael L Madigan,2 Michael E Miller,3 Anthony P Marsh1 1Department of Health and Exercise Science, Wake Forest University, Winston-Salem, NC, USA; 2Department of Engineering Science and Mechanics, Center for Gerontology, Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Blacksburg, VA, USA; 3Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC USA Abstract: Improving muscle strength and power may mitigate the effects of sarcopenia, but it is unknown if this improves an older adult's ability to recover from a large postural perturbation. Forward tripping is prevalent in older adults and lateral falls are important due to risk of hip fracture. We used a forward and a lateral single-step balance recovery task to examine the effects of strength training (ST) or power (PT) training on single-step balance recovery in older adults. Twenty older adults (70.8±4.4 years, eleven male) were randomly assigned to either a 6-week (three times/week) lower extremity ST or PT intervention. Maximum forward (FLeanmax) and lateral (LLeanmax) lean angle and strength and power in knee extension and leg press were assessed at baseline and follow-up. Fifteen participants completed the study (ST =7, PT =8). Least squares means (95% CI) for ΔFLeanmax (ST: +4.1° [0.7, 7.5]; PT: +0.6° [–2.5, 3.8]) and ΔLLeanmax (ST: +2.2° [0.4, 4.1]; PT: +2.6° [0.9, 4.4]) indicated no differences between groups following training. In exploratory post hoc analyses collapsed by group, ΔFLeanmax was +2.4° (0.1, 4.7) and ΔLLeanmax was +2.4° (1.2, 3.6). These improvements on the balance recovery tasks ranged from ~15%–30%. The results of this preliminary study suggest that resistance training may improve balance recovery performance, and that, in this small sample, PT did not lead to larger improvements in single-step balance recovery compared to ST. Keywords: resistance exercise, falls, muscle strength, muscle power, exercise intervention, randomized tria