Lower-limb activity during the power serve in tennis: Effects of performance level

Purpose: The aim of the present study was to investigate the differences in lower-limb activity during the tennis power serve between players of different performance levels. Methods: Thirty-two participants distributed in three groups (beginner, 13; intermediate, 1; elite, E) performed countermovement jumps to measure leg power (P-max) and 15 power serves from a force platform. Lateral, horizontal, and vertical forces (Fx, Fy, and Fz) were sampled simultaneously with EMG signals from six leg muscles. Racquet-ball impact height and maximum velocity of the ball (V-max) were measured with video analysis and radar, respectively. The total duration of the serve was fractioned into four phases: preparation (Pre), eccentric (Ecc), concentric (Con), and suspension (Sus). Results: P-max was similar in the three groups. The duration of Pre was longer (P < 0.05) in E than in 13, whereas Con was shorter (P < 0.05). V-max (169.4 +/- 11.3 vs 107 +/-.2 6.1 km(.)h(-1), P < 0.00 1), I-height (149.2 +/- 2.7 vs 142.6 +/- 4.7% of standing height, P < 0.05), and Fz(max) (2.12 +/- 1 0.36 vs 1.68 +/- 0.33 of body weight, P < 0.0 1) were higher in E than in B. I-height was correlated (r = 0.85, P < 0.001) with Fz(max) in E. Peaks EMG Occurred earlier (P < 0.05) in E (7 < 17% of Con) than in other groups (13: 94 +/- 11% and 1: 94 +/- 15%). Conclusion: The vertical forces and coordination in lower extremities during the tennis serve were different between players of different skill levels but with the same P-max. This may partly explain the differences in serve efficiency.