Experimental Gerontology · Feb 14, 2020

Age-related neuromuscular fatigue and recovery after cycling: Measurements in isometric and dynamic modes

By Krüger RL, Aboodarda SJ, Jaimes LM et al.

Studies have suggested that older individuals are more fatigable than young adults when power loss, measured during single-joint contractions, is considered the fatigue index; however, age-related differences in fatigue considering power measurements during multi-joint movements (e.g., cycling) have not been fully elucidated yet. This study examined age-related differences in dynamic and isometric measures of fatigue in response to three cycling exercises. Ten young (27 ± 4 years) and ten old (74 ± 4 years) men performed exercises on different days, 30-s Wingate, 10-min at severe-intensity, and 90-min at moderate-intensity. Dynamic measures-maximal power, torque, and velocity-were assessed after cycling and during recovery (1-8 min post-exercise) through 7-s cycling sprints and isometric force and fatigue etiology (central and peripheral components) through isometric contractions. There were no age-related differences in the relative reduction of dynamic and isometric measures following the Wingate and moderate-intensity tasks. Maximal power, isometric force, and indices of peripheral function (e.g., high-frequency doublet) decreased more in young compared with older individuals after the severe-intensity exercise (all p < .05). The only observed age-related difference in the recovery of NM fatigue was a slower recovery of power and torque from 1 to 8 min (p < .05) and at 4 min (p = .015), respectively, in younger males after the Wingate. Age-related fatigue and recovery depend on the fatiguing exercise intensity and duration and on the fatigue assessment mode. This study provides novel information on age-related neuromuscular fatigue responses to multi-joint dynamic exercises performed at different intensities and durations.

doi.org/10.1016/j.exger.2020.110877Open access, accepted manuscriptPubMed 32068090Mechanisms