An exploratory study in relationship between biomechanical bilateral asymmetry and power output during the power clean

Biomechanical bilateral asymmetry can be significantly related to power production during the power clean. We investigated the relationship between bilateral asymmetry in ground reaction force (GRF) and lower extremity (hip, knee, and ankle) net joint torques (NJT) and whole-body power (WBP) during the power clean. Ten experienced weightlifters performed five trials of the power clean with 75% of one repetition maximum. Peak GRF and lower extremity NJT and WBP were extracted through a three-dimensional motion analysis. Differences in GRF and NJT asymmetries were extracted. Pearson correlation coefficients were obtained to observe the relationship between GRF and lower extremity NJT asymmetries and WBP during the power clean. A stepwise multiple regression analysis was conducted to identify the best predictor of WBP during the power clean with hip, knee, and ankle NJT asymmetries being the independent variables. Hip and ankle NJT asymmetries were characterized by significant negative correlations with WBP (r = −.38, p < .01). Hip and ankle NJT asymmetries also appeared to be significant predictors of WBP with up to 32% of the variance in WBP explained. In conclusion, it is suggested that power clean training programs needs to incorporate muscle balance training, particularly of the hip extensors and ankle plantarflexors, for performance and safety purposes.