High-velocity resistance training mitigates physiological and functional impairments in middle-aged and older adults with and without mobility-limitation.

The aim of the present study was to compare the neuromuscular, morphological, and functional responses to a high-velocity resistance training (HVRT) program between three cohorts: middle-aged adults (40-55 years, n = 18), healthy older adults (> 60 years, n = 18), and mobility-limited older adults (n = 8). Participants were tested before and after a 4-week control period and then assigned to a 12-week HVRT intervention. Investigated outcomes included ultrasound-derived muscle thickness and quality, maximal dynamic strength (1RM), maximal voluntary isometric contraction (MVIC), and muscle activation (sEMG), as well as muscle power and functional performance. After the intervention, quadriceps muscle thickness, 1RM, and sEMG improved in all three groups (all p < 0.05), whereas muscle quality improved only in middle-aged and older participants (p ≤ 0.001), and MVIC only in middle-aged and mobility-limited older adults (p < 0.05). With a few exceptions, peak power improved in all groups from 30-90% 1RM (p < 0.05) both when tested relative to pre-training or post-training 1RM workloads (all p < 0.05). Both mobility-limited older adults and older adults improved their short physical performance battery score (p < 0.05). Chair stand, stair climb, maximal gait speed, and timed up-and-go performance, on the other hand, improved in all three groups (p < 0.05), but no change was observed for habitual gait speed and 6-min walk test performance. Overall, our results demonstrate that a HVRT intervention can build a stronger foundation in middle-aged individuals so that they can better deal with age-related impairments at the same time that it can mitigate already present physiological and functional impairments in older adults with and without mobility-limitation.