Moderate-intensity resistance exercise alters skeletal muscle molecular and cellular structure and function in inactive older adults with knee osteoarthritis.

摘要: High-intensity resistance exercise (REX) training increases physical capacity, in part, by improving muscle cell size and function. Moderate-intensity REX, which is more feasible for many older adults with disease and/or disability, also function, but the mechanisms underlying such improvements are not understood. Therefore, we measured skeletal structure function from molecular to tissue level response 14 wk of moderate-intensity REX physically inactive knee osteoarthritis (n = 17; 70 ± 1 yr). Although increased quadriceps cross-sectional area (CSA), average single-fiber CSA was unchanged because reciprocal changes myosin heavy chain (MHC) I IIA fibers. Intermyofibrillar mitochondrial content men, women, no subsarcolemmal mitochondria either sex. whole contractile performance similarly men women. In contrast, adaptations single-muscle fiber force production per (i.e., tension) velocity varied between women a type-dependent manner, being explained at differential myosin-actin cross-bridge kinetics mechanics MHC protein expression. Our results notable compared studies high-intensity they show that effects on size/structure myofilament absent or modest. Moreover, our data highlight unique sex-specific due cellular subcellular structural functional changes.NEW & NOTEWORTHY causes levels adult osteoarthritis. However, these responses were minimal training. Thus adjuncts need be developed correct deficits root impaired this mobility-limited population.