The Effects of Unilateral versus Bilateral Resistance Training on Bilateral Deficit, Unilateral and Bilateral Strength Adaptation among Trained Men

Abstract

This study aimed to examine the effects of unilateral versus bilateral resistance training and bilateral deficit on unilateral and bilateral strength adaptation among trained men. Thirty recreationally active, resistance trained men were recruited and were divided into three groups; i) unilateral (n=10), ii) bilateral (n=10) and iii) control (n=10). Chest press and biceps curl strength tests were conducted unilaterally and bilaterally before and after six weeks of training intervention. Unilateral bicep curl and chest press training was given to the unilateral group while the bilateral group was asked to undergo bilateral bicep curl and chest press training. 1RM bicep curl and chest press tests were measured unilateral and bilateral strength and bilateral deficit before and after the intervention. The intervention period were six weeks. Mixed design (ANOVA) was used to compare strength during pre- and post-test in groups while MANOVA was used to compare the changes in percentage during pre and post-test between groups. Results showed a significant difference in the test of unilateral strength within groups. Both unilateral and bilateral training groups managed to improve both unilateral and bilateral strength significantly in both exercises but there was a decrease in unilateral and bilateral strength within control group. On the other hand, all the three groups showed no bilateral deficit for bicep curl and chest press test. The findings also revealed that there was a significant difference in the percentage changes between groups. The unilateral group showed a greater change in percentage the in unilateral strength compared to the control group but no significant difference with the bilateral group. While, the bilateral group showed a greater percentage change in bilateral strength compared with the unilateral and control group. In conclusion, this study showed that both of these unilateral and bilateral exercises can increase muscle strength in trained men. However, the unilateral and bilateral strength adaptation is specific to the training performed especially for multi-joint and complex exercise.