Girard Olivier, Micallef Jean-Paul, Millet Gregoire P
UPRES-EA 3759, Faculty of Sports Sciences, Montpellier, France.
Med Sci Sports Exerc. 2005 Jun;37(6):1021-9.
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.
Thirty-two participants distributed in three groups (beginner, B; intermediate, I; 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 (I(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).
Pmax was similar in the three groups. The duration of Pre was longer (P < 0.05) in E than in B, whereas Con was shorter (P < 0.05). Vmax (169.4 +/- 11.3 vs 107.2 +/- 6.1 kmxh, P < 0.001), I(height) (149.2 +/- 2.7 vs 142.6 +/- 4.7% of standing height, P < 0.05), and Fz(max) (2.12 +/- 0.36 vs 1.68 +/- 0.33 of body weight, P < 0.01) 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 (79 +/- 17% of Con) than in other groups (B: 94 +/- 11% and I: 94 +/- 15%).
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.
本研究旨在调查不同水平网球运动员在强力发球时下肢活动的差异。
32名参与者分为三组（初学者，B组；中级，I组；精英，E组），进行反向纵跳以测量腿部力量（P(max)），并在测力平台上进行15次强力发球。同时采集来自六条腿部肌肉的肌电图信号以及横向、水平和垂直力（Fx、Fy和Fz）。分别通过视频分析和雷达测量球拍与球撞击时的高度（I(height)）和球的最大速度（V(max)）。发球的总时长分为四个阶段：准备阶段（Pre）、离心阶段（Ecc）、向心阶段（Con）和悬浮阶段（Sus）。
三组的Pmax相似。E组的Pre阶段持续时间比B组长（P < 0.05），而Con阶段则较短（P < 0.05）。E组的Vmax（169.4 +/- 11.3 vs 107.2 +/- 6.1 km/h，P < 0.001）、I(height)（站立高度的149.2 +/- 2.7 vs 142.6 +/- 4.7%，P < 0.05）和Fz(max)（体重的2.12 +/- 0.36 vs 1.68 +/- 0.33，P < 0.01）均高于B组。E组中I(height)与Fz(max)相关（r = 0.85，P < 0.001）。E组的肌电图峰值出现时间比其他组早（P < 0.05）（Con阶段的79 +/- 17%）（B组：94 +/- 11%，I组：94 +/- 15%）。
不同技能水平的网球运动员在发球时下肢的垂直力和协调性存在差异，但P(max)相同。这可能部分解释了发球效率的差异。
