Atack Alexandra, Trewartha Grant, Bezodis Neil E
a School of Sport, Health and Applied Science , St Mary's University , Twickenham , UK.
b Department for Health , University of Bath , Bath , UK.
Sports Biomech. 2019 Oct;18(5):457-469. doi: 10.1080/14763141.2018.1433714. Epub 2018 Apr 9.
The appropriate determination of performance outcome is critical when appraising a performer's technique. Previous studies of rugby place kicking technique have typically assessed performance based on ball velocity, but this is not the sole requirement. Therefore, a mathematical model of rugby place kick ball flight was developed to yield a single measure more representative of true performance. The model, which requires only initial ball flight kinematics, was calibrated and validated using empirical place kick data, and found to predict ball position with a mean error of 4.0% after 22 m of ball flight. The model was then applied to the performances of 33 place kickers. The predicted maximum distance, a single performance measure which accounted for initial ball velocity magnitude and direction, and spin, was determined using the model and was compared against ball velocity magnitude. A moderate association in the rank-order of the kicks between these two measures ( = 0.52) revealed that the relative success of the kicks would be assessed differently with each measure. The developed model provides a representative measure of place kick performance that is understandable for coaches, and can be used to predict changes in performance outcome under different ball launch or environmental conditions.
在评估运动员的技术时，正确确定表现结果至关重要。先前对橄榄球定位踢技术的研究通常基于球速来评估表现，但这并非唯一要求。因此，开发了一个橄榄球定位踢球飞行的数学模型，以得出一个更能代表真实表现的单一指标。该模型仅需初始球飞行运动学数据，通过实证定位踢数据进行校准和验证，发现在球飞行22米后预测球位置的平均误差为4.0%。然后将该模型应用于33名定位踢球者的表现。使用该模型确定预测的最大距离，这是一个考虑了初始球速大小、方向和旋转的单一表现指标，并将其与球速大小进行比较。这两个指标在踢球排名顺序上的中度相关性（=0.52）表明，每种指标对踢球相对成功率的评估会有所不同。所开发的模型为定位踢表现提供了一个教练易于理解的代表性指标，可用于预测在不同的球发射或环境条件下表现结果的变化。
