Characterising change of direction performance in elite team sport athletes using jump data and key positions of the turn

Changing direction effectively is critical to team sports performance. Understanding the biomechanics that underpin change of direction (COD) may be valuable to the practitioner. Twenty-four elite level field hockey players volunteered for this study. They were analysed performing a 20m shuttle (20S) with a 180-degree turn. This time was analysed alongside the change of direction deficit (CODD) and the pacing strategy approaching the turn (PS). Absolute and relative kinetic measures were analysed during countermovement jumps using force plates and correlations were calculated between these measures and the COD scores. Kinematic analysis was performed using video cameras and analysed using Kinovea software. Magnitude based inferences were calculated to examine possible relationships between movements of the knee, ankle and torso during the brake step, plant step and propulsive step of the turn. Jump height and concentric kinetic variables showed significant negative correlations with 20S time (p<0.05). Eccentric variables showed greater negative correlations with PS and CODD. Subjects that performed better at all COD measures displayed less knee flexion during the plant step of the turn. Subjects that performed better in the CODD and PS displayed a straighter leg during the propulsive step out of the turn. This study concluded that different movement patterns may be beneficial for COD compared to linear sprinting. It also concluded that maintaining a straight plant leg was beneficial to COD performance. Eccentric strength and power seemed to be the most beneficial improving isolated COD and limiting the PS. This may help the practitioner prescribe training interventions.