Hanley Brian, Merlino Stéphane, Bissas Athanassios
Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom.
International Relations and Development Department, World Athletics, Monte Carlo, Monaco.
Front Sports Act Living. 2022 Apr 14;4:834813. doi: 10.3389/fspor.2022.834813. eCollection 2022.
The 800 m race challenges the aerobic and anaerobic energy systems, and athletes adopt a technique that allows for running efficiency as well as sprinting speeds. The aim of this novel study was to compare important kinematic variables between the two laps of the 2017 IAAF World Championships women's final. Video data (150 Hz) were collected of all eight finalists on both laps at a distance approximately 50 m from the finish line along the home straight. Running speed, step length, cadence, temporal variables, sagittal plane joint angles, and shank angle at initial contact were measured. Running speed was faster on lap 2 ( = 0.008) because of large increases in cadence ( = 0.012). These higher cadences resulted in large decreases in contact times ( = 0.031) and in flight times ( = 0.016) on lap 2. Greater knee flexion and ankle plantarflexion ( ≤ 0.039) at initial contact on lap 2 seemed partly responsible for shorter swing times ( = 0.016), and which accompanied a decrease in shank angle at initial contact from lap 1 (7°) to a more vertical position on lap 2 (4°) ( = 0.008). Coaches should note that the need for higher cadence, horizontal impulse production during shorter contact times, and the adoption of forefoot striking require strength and neural system training to allow for athletes to increase cadence during the sprint finish. Increasing cadence (and not step length) was the driving factor for faster finishing speeds in the women's 800 m.
800米比赛对有氧和无氧能量系统都构成挑战，运动员采用一种既能保证跑步效率又能实现冲刺速度的技术。这项新研究的目的是比较2017年国际田联世界锦标赛女子800米决赛两圈之间的重要运动学变量。在终点线前约50米处沿着主直道收集了所有八名决赛选手两圈的视频数据（150赫兹）。测量了跑步速度、步长、步频、时间变量、矢状面关节角度以及初始触地时的小腿角度。由于步频大幅增加（P = 0.012），第二圈的跑步速度更快（P = 0.008）。这些更高的步频导致第二圈的触地时间大幅减少（P = 0.031）和腾空时间减少（P = 0.016）。第二圈初始触地时更大的膝关节屈曲和踝关节跖屈（P≤0.039）似乎部分导致了摆动时间缩短（P = 0.016），并且伴随着初始触地时小腿角度从第一圈的7°减小到第二圈更垂直的位置4°（P = 0.008）。教练们应该注意，在较短的触地时间内需要更高的步频、产生水平冲量以及采用前脚掌着地，这需要力量和神经系统训练，以使运动员在冲刺阶段能够提高步频。增加步频（而非步长）是女子800米比赛中更快完成速度的驱动因素。
