The effects of pre-habilitative conditioning on unloading-induced adaptations in young and aged neuromuscular systems

► Aging alters morphology of the neuromuscular junction (NMJ). ► Both young and aged NMJs resisted remodeling following 2 weeks of muscle unloading. ► Aged muscle fibers are more sensitive to unloading-induced atrophy than the young ones. ► Only in aged muscle fibers did pre-habilitation attenuate unloading-induced atrophy. ► Only in aged muscle fibers did 2 weeks of endurance training increase fiber size.