a State University of Londrina, Sport Sciences Department , Londrina , Brazil.
J Sports Sci. 2013;31(14):1568-77. doi: 10.1080/02640414.2013.789920. Epub 2013 Apr 30.
The purposes of this study were to characterise the total space covered and the distances between players within teams over ten Brazilian First Division Championship matches. Filmed recordings, combined with a tracking system, were used to obtain the trajectories of the players (n = 277), before and after half-time. The team surface area (the area of the convex hull formed by the positions of the players) and spread (the Frobenius norm of the distance-between-player matrix) were calculated as functions of time. A Fast Fourier Transform (FFT) was applied to each time series. The median frequency was then calculated. The results of the surface area time series median frequencies for the first half (0.63 ± 0.10 cycles · min⁻¹) were significantly greater (P < 0.01) than the second-half values (0.47 ± 0.14 cycles · min⁻¹). Similarly, the spread variable median frequencies for the first half (0.60 ± 0.14 cycles · min⁻¹) were significantly greater (P < 0.01) than the second-half values (0.46 ± 0.16 cycles · min⁻¹). The median frequencies allowed the characterisation of the time series oscillations that represent the speed at which players distribute and then compact their team formation during a match. This analysis can provide insights that allow coaches to better control the team organisation on the pitch.
本研究的目的是描述十场巴西甲级联赛比赛中球队的总覆盖面积和球员之间的距离。通过拍摄记录并结合跟踪系统，获取球员（n=277）在上下半场前后的运动轨迹。团队表面积（由球员位置形成的凸壳面积）和扩散（球员间距离矩阵的 Frobenius 范数）作为时间的函数进行计算。对每个时间序列进行快速傅里叶变换（FFT）。然后计算中值频率。上半场表面积时间序列中值频率（0.63 ± 0.10 个周期·min⁻¹）显著大于（P < 0.01）下半场值（0.47 ± 0.14 个周期·min⁻¹）。同样，上半场扩散变量中值频率（0.60 ± 0.14 个周期·min⁻¹）显著大于（P < 0.01）下半场值（0.46 ± 0.16 个周期·min⁻¹）。中值频率可以对代表球员在比赛中分配和压缩球队阵型的速度的时间序列振荡进行特征化。这种分析可以为教练提供更好地控制球场上球队组织的见解。
