Effect of Unilateral E‐Stim on Strength in a Contralateral Untrained Limb After Bilateral Strength Training

Abstract

Unilateral strength training or electrical stimulation increases strength in an untrained, contralateral limb. This cross education effect is similar to conventional training. We have shown reduced strength loss in a contralateral untrained limb with unilateral strength training after 4 weeks of bilateral leg extension training.MethodsIn a pre‐and post‐test design, 18 subjects, aged 18–35, not engaged in structured strength training for 3 months, were randomly assigned to a unilateral strength training (U), e‐stim training (E), or control group(C). All subjects underwent 4 weeks of bilateral leg extension training, then for 4 weeks, either stopped training, or trained the right limb with strength training or e‐stim. A pre‐training, 4 week post‐training and final unilateral 1 RM for leg extension was obtained.ResultsAfter 4 weeks of bilateral training, unilateral 1 RM strength significantly increased (left leg p=0.001; right leg p=0.000). However, during the final 4 weeks, all subjects lost strength in the trained and untrained limbs. The percent change in the untrained and trained limbs respectively were: Group E −4.23%; −1.20%; Group U −6.05%; −0.78% and Group C −8.47%; −6.55%.ConclusionAt these training loads, neither unilateral strength training or e‐stim had a significant effect on the trained or untrained limb, and therefore were unable to prevent strength loss in either limb.