Effects of Resistance Training, Interval Training, and Detraining on Functional Performance in Older Women: A Longitudinal Study.

Age-related declines in neuromuscular function and mobility increase the risk of frailty and functional dependence in older adults. Although resistance training (RT) is an effective exercise modality for improving functional capacity in older adults, the effects of combining RT with interval training (IT) particularly across repeated detraining periods, remain insufficiently explored. To examine the effects of sequential training interventions (RT alone and RT combined with IT) on functional performance in older women and to compare functional adaptations and losses across two 100-day detraining periods. Sixteen older women (≥60 years) completed a longitudinal protocol with five assessments: baseline, post-RT, post-first detraining, post-RT + IT, and post-second detraining. Outcomes included agility and dynamic balance, upper and lower body muscle endurance, gait speed, handgrip strength, and flexibility. RT induced significant improvements in agility and dynamic balance (+12.2%; p < .001), upper body (+35.4%; p < .001) and lower body (+24.6%; p < .001) muscle endurance, and gait speed (+8.2%; p = .004), whereas handgrip strength (p = .860) and flexibility (p = .683) remained unchanged. The first detraining period resulted in marked functional losses, particularly in agility and dynamic balance (-19.5%; d = 1.44) and lower body muscle endurance (-21.6%; d = -1.13). The RT + IT phase promoted partial functional recovery, notably in agility and dynamic balance (d = -0.59). The second detraining period showed attenuated losses, with minimal changes overall. RT and RT combined with IT improved functional capacity in older women; however, RT + IT was associated with greater retention of functional gains during detraining.