Subscribed Content High-power resistance exercise induces MAPK phosphorylation in weightlifting trained men

摘要

Power is critical to muscle performance, specifically in athletic populations. Mitogen-activated protein kinasen(MAPK) pathways (extracellular signal-regulated protein kinase (ERK 1/2), p38, and c-Jun NH2-terminal kinase (JNK)) arenintracellular signal transduction mechanisms that partially regulate exercise-induced skeletal muscle alterations. These pathwaysnare highly responsive to exercise, but their reaction to high power, multi-joint resistance exercise is yet to be examined.nNine weightlifting-trained men performed 15 sets of three repetitions of a dynamic clean pull exercise at 85% of their onenrepetition maximum. Vastus lateralis biopsies were obtained prior to (pre) and after the 8th (mid) and 15th set (post) of exercise.nThree subjects returned to serve as non-exercising controls for a similar sequence of biopsies (CON). The ratio ofnphosphorylated MAPK to total MAPK increased significantly for p38 (3.0 fold, p < 0.05) and JNK (2.4 fold, p < 0.05) bynthe mid biopsy. ERK 1/2 phosphorylation followed a similar trend (2.3 fold) (p = 0.052). The ratio of phosphorylation tontotal MAPK did not differ from mid to post biopsy. None of the pathways were phosphorylated above resting in the CONncondition (p > 0.05), and thus the biopsy procedure itself did not account for the entire increase in MAPK phosphorylationnduring EX. These data indicate MAPK pathways are activated early and remain elevated throughout the duration of highnpower resistance exercise. These findings help describe the mechanisms partially responsible for chronic adaptations in responsento high intensity, high power resistance training in humans.