The Effects of Training Interventions on Interlimb Asymmetries: A Systematic Review With Meta-analysis

Interlimb asymmetries have been recently investigated in athletic populations. However, the effects of training interventions on interlimb asymmetries have been scarcely examined. Therefore, the aim of this study was to determine the effects of training interventions on changes in interlimb asymmetries from pre- to post-training. Furthermore, to examine the effects of training programs on intervention groups compared with control groups. A database search was completed (MEDLINE, CINAHL, and SPORTDiscus). Eight studies were then included in the meta-analysis. Results showed small reductions in interlimb asymmetries in single-leg broad jump (SLBJ) and change of direction (COD) speed from pre- to post-training interventions, whereas moderate effects were found in single-leg countermovement jump (SLCMJ) and SL lateral jump. When comparing the training interventions with the control groups, results showed small effects in favor of the training groups for reducing interlimb asymmetries in SLBJ and large effects in SLCMJ and COD speed. Thus, training interventions can evoke small to moderate reductions in interlimb asymmetries from pre- to post-training programs. Strength training performed unilaterally or bilaterally may elicit these reductions. Furthermore, training interventions showed larger effects compared with the control groups in reducing interlimb asymmetries. However, further research is needed.