Samenvatting

Objectives: The strategy for dynamic postural stability might be different for male and female players. Additionally, dynamic and challenging tasks are recommended to measure differences in postural stability between injured and non-injured players. Therefore, the dynamic stability index (DSI) was developed which measures the ability of a player to maintain static balance after a dynamic task. The first aim of this study was to evaluate DSI differences between males and females for different jump directions. The second aim was to examine both preseason DSI differences between players with and without a history of ankle sprain, and between players with and without an ankle sprain during the subsequent season.Design: Prospective cohort design. Setting: Laboratory. Participants: 47 male (22.9 ± 3.9 y, 193.5 ± 7.9 cm, 87.1 ± 10.6) and 19 female (21.5 ± 2.9 y, 175.9 ± 7.3 cm, 69.0 ± 11.7 kg) sub-elite and elite basketball, volleyball and korfball players. Main outcome measures: Ankle sprain history was collected using a general injury history questionnaire. DSI on a single-leg hop-stabilization task measured preseason were calculated by using force plates and a Matlab program. Ankle sprains were reported during subsequent season. Results: Male players demonstrated larger DSI than female players on forward medial/lateral stability index (MLSI) (0.037± 0.007 vs 0.029 ± 0.005) and vertical stability index (VSI) (0.369 ± 0.056 vs 0.319 ± 0.034) (p < 0.001), diagonal VSI (0.363 ± 0.046 vs 0.311 ± 0.033) (p < 0.001), and lateral anterior/posterior stability index (APSI) (0.062 ± 0.015 vs 0.047 ± 0.011) and VSI (0.350 ± 0.054 vs 0.294 ± 0.037) (p < 0.001). Forward (0.384 ± 0.055 vs 0.335 ± 0.033), diagonal (0.379 ± 0.046 vs 0.328 ± 0.032) and lateral (0.368 ± 0.053 vs 0.313 ± 0.035) dynamic postural stability indices (DPSI) were larger for males (p < 0.001). No significant differences were found between players with and without a previous ankle sprain nor between players with and without an ankle sprain during subsequent season.