Influence of jump-landing direction on dynamic postural stability and hamstring-to-quadriceps co-activation ratio

This study investigated the effect of jump landing direction and leg dominance on the Dynamic Postural Stability Index (DPSI) and the importance of the hamstring-to-quadriceps (H/Q) co-activation ratio. Fifteen female sports players performed unilateral jump landing, for the dominant (DL) and the non-dominant (NDL) legs in anterior (AJL), lateral (LJL), and vertical directions (DJL). The results indicated that the DPSI was higher in DJL compared to LJL and AJL. Besides, the DPSI score during DJL was higher in NDL indicating lower stabilization capacity associated with a lower H/Q co-activation ratio. A significant correlation was found between H/Q co-activation ratio and DPSI in the DL during AJL (r = -0.57). Current results suggest that DJL was more appropriate to evaluate dynamic postural stability since it highlights limb asymmetry. In addition, H/Q co-activation appears to play an essential role in the effectiveness of ground reaction force stabilization during jump landing.

Automated summary

This study investigated the effects of jump landing direction and leg dominance on the Dynamic Postural Stability Index (DPSI). The results showed that the DPSI was higher in vertical jump landing compared to lateral and anterior jump landing. Furthermore, the DPSI score during vertical jump landing was higher in the non-dominant leg, indicating lower stabilization capacity associated with a lower hamstring-to-quadriceps (H/Q) co-activation ratio. A significant correlation was also found between H/Q co-activation ratio and DPSI during anterior jump landing in the dominant leg.