The Influence of Optimal Handheld Load on the Technical Ability to Apply Ground Reaction Forces during Horizontal Jumping in Female Netball Players.

Handheld load has been reported to enhance horizontal jump performance, however little is known about its influence on ground reaction forces (GRF), especially in female athletes. This study investigated the effects of individualized optimal handheld loading on the technical and physical ability to apply GRF during horizontal jumping in female netball players. Maximal effort, single standing, horizontal jumps were performed by 13 female netballers. Participants performed the jumps under 2 conditions: 1) unloaded, and 2) loaded. Eccentric mean horizontal GRF significantly increased with loading (p<0.05; Effect Size [ES]= 0.74). The ratio of horizontal-to-total GRF significantly increased (p<0.05; ES=0.57), however resultant GRF did not, suggesting that the technical ability to apply force in the direction of intended movement may be of greater importance than the magnitude of force applied. Jump distance also increased from 188.2±16.1 cm to 196.4±13.6 cm (p<0.01; ES=0.55) with handheld load. In conclusion, individualized optimal handheld loading improved single horizontal jump performance in this population of athletes; most likely through various mechanisms that allowed for increased eccentric horizontal GRFs and the technical ability of force application. Findings could have practical implications for the strength and conditioning coach, trainer and athlete.