Laboratory of Instrumentation for Biomechanics, College of Physical Education, Campinas State University , Campinas, Brazil.
J Sports Sci Med. 2007 Jun 1;6(2):233-42. eCollection 2007.
Methods based on visual estimation still is the most widely used analysis of the distances that is covered by soccer players during matches, and most description available in the literature were obtained using such an approach. Recently, systems based on computer vision techniques have appeared and the very first results are available for comparisons. The aim of the present study was to analyse the distances covered by Brazilian soccer players and compare the results to the European players', both data measured by automatic tracking system. Four regular Brazilian First Division Championship matches between different teams were filmed. Applying a previously developed automatic tracking system (DVideo, Campinas, Brazil), the results of 55 outline players participated in the whole game (n = 55) are presented. The results of mean distances covered, standard deviations (s) and coefficient of variation (cv) after 90 minutes were 10,012 m, s = 1,024 m and cv = 10.2%, respectively. The results of three-way ANOVA according to playing positions, showed that the distances covered by external defender (10642 ± 663 m), central midfielders (10476 ± 702 m) and external midfielders (10598 ± 890 m) were greater than forwards (9612 ± 772 m) and forwards covered greater distances than central defenders (9029 ± 860 m). The greater distances were covered in standing, walking, or jogging, 5537 ± 263 m, followed by moderate-speed running, 1731 ± 399 m; low speed running, 1615 ± 351 m; high-speed running, 691 ± 190 m and sprinting, 437 ± 171 m. Mean distance covered in the first half was 5,173 m (s = 394 m, cv = 7.6%) highly significant greater (p < 0.001) than the mean value 4,808 m (s = 375 m, cv = 7.8%) in the second half. A minute-by-minute analysis revealed that after eight minutes of the second half, player performance has already decreased and this reduction is maintained throughout the second half. Key pointsA novel automatic tracking method was presented. No previous work was found in the literature reporting data of simultaneous trajectories of all soccer players obtained by an automatic tracking method.The study reveals 7% reduction in mean distance covered in the second half and moreover after eight minutes of the second half, player performance has already decreased and this reduction is maintained throughout the second half.
方法基于视觉估计仍然是最广泛使用的分析距离的足球运动员在比赛中覆盖,和最描述可在文献中获得使用这种方法。最近,基于计算机视觉技术的系统已经出现,第一个结果是可用的比较。本研究的目的是分析巴西足球运动员的距离覆盖和比较结果与欧洲球员的,都通过自动跟踪系统测量。四个常规巴西甲级联赛之间的不同球队的比赛被拍摄。应用一个预先开发的自动跟踪系统(DVideo,坎皮纳斯,巴西),结果 55 名轮廓球员参加了整场比赛(n = 55)提出的。结果平均距离覆盖,标准差(s)和变异系数(cv)后 90 分钟分别为 10012 米,s = 1024 米和 cv = 10.2%。根据演奏位置的三因素方差分析的结果表明,距离覆盖外部后卫(10642 ± 663 m),中场球员(10476 ± 702 m)和外部中场球员(10598 ± 890 m)大于前锋(9612 ± 772 m)和前锋比中央后卫覆盖更大的距离(9029 ± 860 m)。更大的距离是站着、走着或慢跑,5537 ± 263 m,其次是中等速度运行,1731 ± 399 m;低速运行,1615 ± 351 m;高速运行,691 ± 190 m 和冲刺,437 ± 171 m。上半场的平均距离为 5173 米(s = 394 m, cv = 7.6%)显著高于( p < 0.001)比下半场的平均值 4808 米(s = 375 m, cv = 7.8%)。一分钟的分析表明,八分钟后下半场,球员的表现已经下降,这种减少是保持整个下半场。关键点提出了一种新的自动跟踪方法。没有发现之前的工作在文献中报道数据的所有足球运动员的同时轨迹获得自动跟踪方法。研究表明平均距离覆盖的 7%减少在下半年,更重要的是八分钟后下半场,球员的表现已经下降,这种减少是保持整个下半场。
