Institute of Sport Sciences, University of Lausanne, 1015, Lausanne, Switzerland.
Research and Development Department, Volodalen Swiss Sport Lab, 1860, Aigle, Switzerland.
Sci Rep. 2022 Jul 29;12(1):13061. doi: 10.1038/s41598-022-17274-0.
Runners were classified using their duty factor (DF) and using their foot-strike pattern (FSP; rearfoot, midfoot, or forefoot strikers), determined from their foot-strike angle (FSA). High and low DF runners showed different FSPs but DF was assumed to not only reflect what happens at initial contact with the ground (more global than FSP/FSA). Hence, FSP and DF groups should not necessarily be constituted by the same runners. However, the relation between FSP and DF groups has never been investigated, leading to the aim of this study. One hundred runners ran at 9, 11, and 13 km/h. Force data (1000 Hz) and whole-body kinematics (200 Hz) were acquired by an instrumented treadmill and optoelectronic system and were used to classify runners according to their FSA and DF. Weak correlations were obtained between FSA and DF values and a sensitivity of 50% was reported between FSP and DF groups, i.e., only one in two runners was attributed to the DF group supposedly corresponding to the FSP group. Therefore, 'local' FSP/FSA and DF do not represent similar running pattern information when investigated at the individual level and DF should be preferred to FSP/FSA when evaluating the global running pattern of a runner.
跑步者根据其足着地角度（foot-strike angle，FSA）被分为使用其功角（duty factor，DF）和足着地模式（foot-strike pattern，FSP；后足、中足或前足着地者）的跑步者。高 DF 和低 DF 跑步者表现出不同的 FSP，但 DF 不仅反映了与地面初始接触时的情况（比 FSP/FSA 更全面）。因此，FSP 和 DF 组不一定由相同的跑步者组成。然而，FSP 和 DF 组之间的关系从未被研究过，这导致了本研究的目的。100 名跑步者以 9、11 和 13km/h 的速度跑步。力数据（1000Hz）和全身运动学（200Hz）由仪器化跑步机和光电系统采集，并用于根据 FSA 和 DF 对跑步者进行分类。FSA 和 DF 值之间存在弱相关性，并且在 FSP 和 DF 组之间报告了 50%的敏感性，即只有一半的跑步者被归因于 DF 组，而该组据称与 FSP 组相对应。因此，在个体水平上研究时，“局部”FSP/FSA 和 DF 并不代表相似的跑步模式信息，并且在评估跑步者的整体跑步模式时，应优先使用 DF 而不是 FSP/FSA。
