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 non-dominant 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, F2,34 = 5.901) and in the dominant pelvis-trunk CRP during 76-100% of the acceleration phase (p = 0.016, F2,34 = 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.