Growth response to resistance exercise : influence of exercise device
The purpose of this study was to compare the growth response elicited by an acute bout of resistance exercise (RE) conducted on a traditional weight stack device (WS) and a flywheel device (FW). Eight recreationally trained males (25 ± 9 y, 77 ± 27 kg) performed 4 sets of 7 repetitions of bilateral knee extension on each exercise device separated by 7 days. Muscle biopsies were obtained from the vastus lateralis at rest and 4 hrs post-exercise to examine the expression of selected myogenic and proteolytic genes. RE increased (P < 0.05) mRNA expression of Myogenin (3.6 vs. 3.6 fold), and MyoD (2.2 vs. 2.0 fold) and decreased (P < 0.05) expression of Myostatin (1.4 vs. 1.5 fold) to a similar degree on both exercise devices. There was no change in the expression of Atrogin-1, MuRF-1 or MRF4 following RE on either device. The only device mediated difference in the expression of the selected genes was observed in Atrogin-1 which was lower following RE on the FW versus the WS device. The current data shows that in the initial hrs following RE, use of the FW is as effective as the traditional resistance training devices (WS) in promoting the induction of genes involved with muscle remodeling and growth.