Neuromuscular adaptations after 12 weeks of light‐ vs. heavy‐load power‐oriented resistance training in older adults

This study aimed to determine the specific adaptations provoked by power‐oriented resistance training using light (LL‐PT, 40% 1‐RM) vs. heavy (HL‐PT, 80% 1‐RM) loads in older adults. Using a randomized within‐subject study design, 45 older adults (>65 years) completed an 8‐week control period (CTR) followed by 12 weeks of unilateral LL‐PT vs. HL‐PT on a leg press. The 1‐RM, theoretical force at zero velocity (F0), maximal unloaded velocity (V0), and maximal muscle power (Pmax) were determined through a force‐velocity relationship test. Isometrically, the rate of force development (RFD) and the corresponding muscle excitation of the knee extensor muscles were assessed. In addition, muscle cross‐sectional area (CSA) and architecture of two quadriceps muscles were determined. Changes after CTR, LL‐PT and HL‐PT were compared using linear mixed models. HL‐PT provoked greater improvements in 1‐RM and F0 (effect size (ES) = 0.55‒0.68; p