Trewartha Grant, Casanova Remy, Wilson Cassie
Sport and Exercise Science, School for Health, University of Bath, Bath, UK.
J Sports Sci. 2008 Jun;26(8):845-54. doi: 10.1080/02640410701885629.
To characterize rugby union lineout throwing technique, three experienced male rugby players performed throwing trials under varying conditions of distance and trajectory. Motion analysis permitted the recovery of joint centre coordinates at 120 Hz and the construction of a three-dimensional linked segment model for calculation of joint angle and centre of mass time histories. All participants exhibited greater accuracy at shorter throwing distances, although the accuracy decrement was less in players of higher standard. Participants demonstrated different alterations in technique when performing throws of longer distances, either showing increased magnitudes of upper-body joint angle velocities (less accurate thrower) or lower-body joint velocities (more accurate thrower). The most elite thrower exhibited greater consistency in timing of peak joint angle velocities, with an overall standard deviation of 0.008 s compared with 0.027 s for the least accurate thrower. Data from participants of lesser ability suggest that changes are made to both magnitudes and timing of joint kinematics, which leads to increased variability in performance. The implications for players and coaches include the need to develop core strength to permit limited changes to the timing and magnitude of upper-body joint actions while allowing sufficient end-point velocity to be imparted on the ball.
为了描述英式橄榄球争边球投掷技术的特点，三名经验丰富的男性橄榄球运动员在不同的距离和轨迹条件下进行了投掷试验。运动分析能够以120赫兹的频率获取关节中心坐标，并构建三维链接段模型，以计算关节角度和质心随时间的变化情况。所有参与者在较短投掷距离时表现出更高的准确性，不过高水平运动员的准确性下降幅度较小。在进行更远距离投掷时，参与者展示出不同的技术变化，要么是上身关节角速度幅度增加（准确性较低的投掷者），要么是下身关节速度增加（准确性较高的投掷者）。最优秀的投掷者在关节角速度峰值的时间上表现出更高的一致性，总体标准差为0.008秒，而准确性最低的投掷者为0.027秒。能力较弱的参与者的数据表明，关节运动学的幅度和时间都发生了变化，这导致了表现的变异性增加。对运动员和教练的启示包括需要发展核心力量，以便在上身关节动作的时间和幅度上进行有限的改变，同时使球获得足够的端点速度。
