Functional and molecular responses to concurrent exercise of the arm extensors

Abstract: Aim  As most concurrent exercise studies to date have focused on lower limb muscles, this study explored the acute response to concurrent exercise of the arm extensors. Specifically, the effects of a preceding bout of aerobic exercise on the subsequent molecular and functional response to resistance exercise was explored. Method  Eleven men performed unilateral consecutive bouts of arm extensor aerobic exercise (~40 min) and resistance exercise (4 sets of 7 reps) interspersed by 15 min recovery. The contralateral arm performed resistance exercise only. Peak concentric power was assessed during the resistance exercise bout. Muscle biopsies were taken from the m. triceps brachii of each arm immediately before, 15 minutes and 3 h after the resistance exercise bout. Muscle samples were assessed for gene expression of markers involved in regulating protein turnover. Results  There was no difference in mean concentric peak power in AE + RE vs. RE limb. Gene expression of MuRF-1, atrogin-1, and PGC-1a were significantly greater in AE + RE compared to RE (arm x time interactions P < 0.05). Myostatin expression generally decreased in both AE + RE and RE (main effect of time P < 0.05). Conclusions Inconclusive results suggest that aerobic exercise does not alter power output during subsequent resistance exercise. Aerobic exercise, performed prior to resistance exercise, alters the expression of markers involved in muscle remodelling processes and anabolic signalling in the arm extensors compared to resistance exercise alone.