The Hong Kong Journal of Sports Medicine and Sports

Volume XIV, May 2002
Abstract

EFFECTS OF UNILATERAL VOLUNTARY AND ELECTROMYOSTIMULATION TRAINING ON MUSCULAR STRENGTH OF THE CONTRALATERAL LIMB

SHI ZHOU, ANDREW OAKMAN & ALLAN DAVIE
School of Exercise Science & Sport Management
Southern Cross University, Australia

This study investigated the effects of unilateral electromyostimulation (EMS) versus voluntary isometric strength (VIM) training on knee extension strength of the contralateral limb, a phenomenon termed cross education, in previously untrained healthy young adults. Subjects in EMS (n=10) and VIM (n=10) groups trained with 40 voluntary or evoked isometric knee extensions, at an intensity of 65% of maximum voluntary contraction force (MVC), three sessions per week for four weeks. Before and after training, both legs were tested for MVC on an isokinetic dynamometer, at 0 deg.s-1 (isometric), 60 and 180 deg.s-1 velocities. The results showed that the EMS and VIM training induced similar strength improvement in the trained limb (P<0.05), as well as cross-education effects (EMS +21.1% and VIM +21.4% in the contralateral limb, both P<0.05) in isometric MVC, but no cross education was found in isokinetic performance. Analysis of integrated EMG showed a trend, but not statistically significant, of increase in the trained groups. No significant variation in knee extension strength, neither in EMG, was found in a control group (n=10). The mechanism of cross education in response to the EMS training, and the application significance of cross education in exercise rehabilitation are of the interests in further studies.


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