Bonnaerens Senne, Fiers Pieter, Galle Samuel, Derie Rud, Aerts Peter, Frederick Edward, Kaneko Yasunori, Derave Wim, De Clercq Dirk, Segers Veerle
Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium.
Department of Biology, University of Antwerp, Antwerp, Belgium.
BMJ Open Sport Exerc Med. 2021 Mar 3;7(1):e000996. doi: 10.1136/bmjsem-2020-000996. eCollection 2021.
Recreational runners show a large interindividual variation in spatiotemporal characteristics. This research focused on slow runners and intended: (1) to document the variance in duty factor (DF) between runners in a real-life running setting and (2) examine whether the interindividual variation in DF and stride frequency (SF) relates to differences in external loading parameters between runners.
Spatiotemporal characteristics of 23 slow runners (ie, <2.6 m/s) were determined during a 5.2 km running event. To relate the interindividual variation in DF and SF to differences in external forces between runners (maximal vertical ground reaction force (FzMax), peak braking force (PBF) and vertical instantaneous loading rate (VILR)), 14 of them were invited to the lab. They ran at 1.9 m/s on a treadmill while ground reaction forces were recorded. A multiple linear regression analysis was conducted to investigate the effect of DF and SF on external force measures.
DF between slow runners varied from 42.50% to 56.49% in a recreational running event. DF was found to be a significant predictor of FzMax (R²=0.755) and PBF (R²=0.430). SF only improved the model for PBF, but to a smaller extent than DF (R² change=0.191). For VILR, neither DF nor SF were significant predictors.
External forces are lower in recreational runners that run with higher DFs and slightly lower SFs. These findings may be important for injury prevention purposes, especially directed to recreational runners that are more prone to overuse injuries.
休闲跑者在时空特征上存在较大的个体差异。本研究聚焦于慢跑者，旨在：（1）记录现实跑步环境中跑者之间的负荷系数（DF）差异；（2）研究DF和步频（SF）的个体差异是否与跑者之间的外部负荷参数差异相关。
在一场5.2公里的跑步赛事中，测定了23名慢跑者（即速度<2.6米/秒）的时空特征。为了将DF和SF的个体差异与跑者之间的外力差异（最大垂直地面反作用力（FzMax）、峰值制动力（PBF）和垂直瞬时负荷率（VILR））联系起来，邀请了其中14人到实验室。他们在跑步机上以1.9米/秒的速度跑步，同时记录地面反作用力。进行多元线性回归分析，以研究DF和SF对外力测量的影响。
在休闲跑步赛事中，慢跑者之间的DF在42.50%至56.49%之间变化。发现DF是FzMax（R²=0.755）和PBF（R²=0.430）的显著预测因子。SF仅改善了PBF的模型，但改善程度小于DF（R²变化=0.191）。对于VILR，DF和SF均不是显著的预测因子。
负荷系数较高且步频略低的休闲跑者的外力较小。这些发现对于预防损伤可能很重要，尤其是针对更容易发生过度使用损伤的休闲跑者。
