Effect of intense strength training on walking speed, standing balance, and sit-to-stand performance in older adults

Muscle size and strength decrease with aging, and resultant muscle weakness has been implicated in increased risk of falls in older adults, falls which have large economic and functional costs. Most studies examining the effect of exercise on risk of failing have utilized multifaceted exercise interventions. The purpose of this randomized, controlled study was to determine if an 8-week, 3-day per week intense (75% of 1 repetition maximum) strength training program, in the absence of aerobic or flexibility training, could improve postural stability in 24 subjects aged 61–87 (Mean = 72, SD = 6.3). Eleven strength training-naive subjects performed two sets of 10 repetitions for six different lower body exercises. Post-intervention strength was significantly better (p \u3c .017) in all training subjects across all exercises, and no injuries were reported as a result of either training or 1RM testing. After controlling for pre-intervention differences, repeated measure ANCOVAS found a significant difference between experimental and non-intervention control subjects for post-intervention maximal walking speed (F(1, 19) = 5.03, p \u3c .05). There were no significant between-group differences for 1-leg blind balance time or 5-repetition sit-to-stand performance (F(1,19) = .082; F(1,19) = .068, respectively, p \u3e .05). These findings suggest that strength training alone does not enhance standing balance or sit-to-stand performance in active, community-living older adults, but may improve maximal walking speed. The data also reinforce the notion that intense strength training is a safe and effective way to increase muscle strength.