Pelvis-Trunk coordination strategies differ a cross preparatory court movement distances during the tennis forehand

Objectives. To examine the effects of on-court movement distances on pelvis-trunk coordination during forehand strokes. Methods. Eighteen male college tennis athletes participated in this study. They performed forehand stroke task at three different preparatory court movement distances (minimum, medium and maximum movement distances). A one-way repeated-measures ANOVA with Statistical Parametric Mapping was used to determine differences in pelvis-trunk coordination in the transverse plane across the three movement distances, and Pearson's correlation analysis was used to determine the relationships between each of the four pelvis-trunk coordination features on the dominant and nondominant side and racket speed. Results. Significant differences were observed for different movement distances in the non-dominant pelvis-trunk continuous relative phase (CRP) during 23-41% of the acceleration phase (p = 0:016, F_2,34 = 5.901) and in the dominant pelvis-trunk CRP during 76-100% of the acceleration phase (p = 0:016, F_2,34 = 5.946). For the minimum distance, significant correlations with racket speed were found in the mean CRP (r = -0:889, p = 0:001) and peak CRP (r = -0:488, p = 0:04) for the non- dominant side, and the mean CRP (r = -0:478, p = 0:045) for the dominant side. Regarding medium distances, significant correlations with racket speed were observed for the non-dominant side in the mean CRP (r = -0:493;p = 0:037), peak CRP (r = -0:628;p = 0:005), and maximum positive CRP slope (r = 0:477;p = 0:046). For the dominant side, significant correlations with racket speed were noted for peak CRP (r =0:551;p=0:018) and maximum positive CRP slope (r =0:514;p=0:029). At the maximum distance, significant correlations with racket speed were identified for the dominant side in the maximum positive CRP slope (r =0:580;p=0:012) and maximum negative CRP slope (r =0:566;p=0:014); however, there was no significant difference in racket speed at impact when approaching from different distances. Conclusion. These findings underscore the role of pelvis-trunk coordination in enhancing racket speed, particularly under varying task constraints. Coaches and players should focus on developing adaptable coordination strategies for optimizing performance across different movement distances.