Resumen de Acute and Delayed Effects of a Resistance Training Session Leading to Muscular Failure on Mechanical, Metabolic, and Perceptual Responses

Juan A. Párraga Montilla, Amador García Ramos, Adrián Castaño Zambudio, Fernando Capelo Ramirez, Jorge M. González Hernández, Yaiza Cordero Rodríguez, Pedro Jiménez Reyes

• This study explored the acute and delayed (24 and 48 hours after exercise) effects of a resistance training session leading to muscular failure. Eleven resistance-trained men completed a training session consisting on 3 sets of repetitions to failure during the back-squat exercise performed at the maximum possible speed with a load equivalent to a mean propulsive velocity (MPV) of 1 m[middle dot]s-1 ([almost equal to]60% of 1 repetition maximum). A number of mechanical (number of repetitions and starting MPV of the set, MPV achieved against the 1MPV load, countermovement jump [CMJ] height, and handgrip strength), metabolic (lactate, uric acid, and ammonia concentrations), and perceptual (OMNI-RES perceived exertion) variables were measured. The results revealed (a) a decrease of 38.7% in set 2 and 54.7% in set 3 of the number of repetitions performed compared with the first set (p < 0.05), (b) a reduction in the MPV of the repetitions and an increase in lactate concentration and OMNI-RES values with the succession of sets (p < 0.05), (c) comparable decrements in CMJ height after the 3 sets (25-32%), (d) a decrease in CMJ height (p < 0.05; 6.7-7.9%) and in the MPV attained against the 1MPV load (p < 0.05; 13-14%) after 24 and 48 hours of completing the training session, but no significant changes were observed in handgrip strength (p > 0.05; <2%), and (e) uric acid and ammonia concentrations above the basal levels (p < 0.05). The large decrements in mechanical performance together with the high metabolic stress discourage the frequent use of resistance training sessions leading to muscular failure.