Effects of foot orientation on serve velocity and accuracy in tennis

The tennis serve is a technically complex biomechanical process where ball velocity serves as a primary determinant of competitive success and point dominance. This study examined how foot orientation (X, Y, and Z axes) and service side (Deuce and Ad court) influence serve velocity and accuracy in competitive players (N = 60; 30 male, 30 female). Participants performed serves in each condition using a randomized design to determine the biomechanical efficiency of varying stances. Velocity was recorded via radar technology, and accuracy was assessed based on target box success rates. In the Deuce court, foot orientation significantly affected velocity, revealing a distinct hierarchy where the Z-axis (diagonal) produced higher speeds than the Y-axis (net post) or X-axis (baseline) orientations. Conversely, no significant differences occurred in the Ad court (p > .05), suggesting side-specific motor stabilization. ANOVA results showed that accuracy remained consistent across axes (\chi^2(2) = 0.968, p = .616) and sides (p = .738), confirming the Z-axis velocity advantage induced no speed-accuracy trade-off. These findings highlight the asymmetrical nature of serve kinematics, suggesting that optimizing foot orientation toward the Z-axis in the Deuce court enhances mechanical efficiency and speed without compromising precision.