Leg ability factors in tennis players.

We investigated the effects of leg stiffness on running speed, jump height and leg power in 13 male 2(nd)- and 3(rd)-series ranked tennis players (23 ± 3 years old, 73.2 ± 8.4 kg, 1.81 ± 0.06 m). Leg stiffness and jump height were assessed using jumping and hopping tests. Mean running speeds over 20 m and 40 m (speed₂₀ and speed₄₀, respectively) were determined from a sprint test. Theoretical maximal leg power (P(maxth)) was extrapolated from a force-velocity test performed on a cycle ergometer. Leg stiffness averaged 478.7 ± 181.7 N.m⁻¹.kg⁻¹ (34,808 ± 12,573 N.m⁻¹. It was significantly correlated to speed₂₀ and counter movement jump height (r=0.60, P=0.028 and r=0.58, P=0.0407, respectively). There were also significant correlations between P (maxth) and counter-movement jump height (r=0.59, P=0.0335) and between P(maxth) and speed₄₀ (r=0.58, P=0.0393). This study characterizes leg stiffness in tennis players and brings new information concerning the way it is related to several other muscular biomechanical parameters.