Bilateral effects of six-week unilateral electromyostimulation or voluntary isometric training on dorsiflexion strength and muscle activation (Presentation)
Yu, JH, Zhou, S, Huang, LP, Liu, J & Cao LJ 2007, 'Bilateral effects of six-week unilateral electromyostimulation or voluntary isometric training on dorsiflexion strength and muscle activation', Australian Conference of Science and Medicine in Sport Program and Abstracts. Journal of Science and Medicine in Sport, vol. 10, no. 6 (supplement), p. 46, Adelaide, SA, 13-16 October.
This study aimed to investigate the bilateral effect of unilateral training on isometric dorsiflexion strength and capacity in muscle activation as detected using twitch interpolation technique. Thirty healthy male volunteers, aged 18-30 years, were randomly assigned into three groups (n=10 each): electromyostimulation (EMS), voluntary isometric contraction (VIM), and control (CON). The EMS and VIM groups trained the right leg, three sessions per week for six weeks. Each EMS session involved percutaneous stimulation on the tibialis anterior muscle at 50Hz, 50-100mA, with duties cycles of 5s on, 10s off, for 15-20min. The VIM session involved static dorsiflexion at 60-70%MVC, 8repetitions per set, for 3-5sets, with 1min resting intervals between sets. All groups were tested for muscular strength and muscle activation pre and post the training period. Repeated measures ANOVA with bonferroni adjustment detected significant (P＜0.05) increase in dorsiflexion MVC of both legs in both EMS (13.3% on the right side, 15.6% on the left) and VIM (15.3%, 14.8%), while CON showed no significant increase (2.5%%, -2.6%, respectively). The muscle activation was significantly improved bilaterally in the EMS group (P<0.05, right 13.5%, left 15.9%) but not in the VIM (P>0.05, 11.7%, 8.0%) nor in the CON (2.8%, 5.2%), respectively. The results indicated that unilateral electromyostimulation and voluntary isometric training significantly improved dorsiflexion strength not only in the exercised leg, but also in the contralateral limb. The results also indicated that the increased capacity in muscle activation was responsible for much of the improved strength, particularly for the EMS training.