Pacing during an ultramarathon running event in hilly terrain

Purpose. The dynamics of speed selection as a function of distance, or pacing, are used in recreational, competitive, and scientific research situations as an indirect measure of the psycho-physiological status of an individual. The purpose of this study was to determine pacing on level, uphill and downhill sections of participants in a long (~173 km) ultramarathon performed on trails in hilly terrain. Methods. Fifteen ultramarathon runners competed in a ~173 km event (five finished at ~103 km) carrying a Global-Positioning System (GPS) device. Using the GPS data, we determined the speed, relative to average total speed, in level (LEV), uphill (UH) and downhill (DH) gradient categories as a function of total distance, as well as the correlation between overall performance and speed variability, speed loss, and total time stopped. Results. There were no significant differences in normality, variances or means in the relative speed in 173-km and 103-km participants. Relative speed decreased in LEV, UH and DH. The main component of speed loss occurred between 5% and 50% of the event distance in LEV, and between 5% and 95% in UH and DH. There were no significant correlations between overall performance and speed loss, the variability of speed, or total time stopped. Conclusions. Positive pacing was observed at all gradients, with the main component of speed loss occurring earlier (mixed pacing) in LEV compared to UH and DH. A speed reserve (increased speed in the last section) was observed in LEV and UH. The decrease in speed and variability of speed were more important in LEV and DH than in UH. The absence of a significant correlation between overall performance and descriptors of pacing is novel and indicates that pacing in ultramarathons in trails and hilly terrain differs to other types of running events.

1. 研究目的
作为距离函数的速度选择动态变化（即配速（pacing）），在休闲跑步、竞技赛事及科研场景中常被用作评估个体心理生理状态的间接指标。本研究旨在针对丘陵地形越野赛道上举办的长距离（约173公里）超级马拉松赛事，分析参赛选手在平路、上坡及下坡路段的配速特征。
2. 研究方法
本研究共招募15名参与约173公里超级马拉松赛事的选手，其中5名选手仅完成约103公里的赛程，所有选手均佩戴全球定位系统（GPS）设备。基于采集到的GPS数据，本研究按总赛程距离，计算了平路（LEV）、上坡（UH）及下坡（DH）坡度类别下相对于总平均速度的相对速度，并分析了整体完赛表现与速度变异性、速度损耗及总停跑时长之间的相关性。
3. 研究结果
173公里完赛选手与103公里完赛选手的相对速度在正态性、方差及均值上均无显著差异。平路、上坡及下坡路段的相对速度均呈下降趋势。速度损耗的主要阶段在平路路段为赛事总距离的5%~50%，在上坡及下坡路段则为5%~95%。整体完赛表现与速度损耗、速度变异性及总停跑时长之间均无显著相关性。
4. 研究结论
所有坡度路段均呈现正配速（positive pacing）特征；相较于上坡与下坡路段，平路路段的速度损耗主要阶段出现更早，且呈现混合配速模式。平路及上坡路段存在速度储备现象（即赛程最后阶段速度提升）。平路与下坡路段的速度下降幅度及速度变异性降幅均大于上坡路段。整体完赛表现与配速特征指标间无显著相关性，这一发现具有创新性，表明丘陵地形越野超级马拉松的配速模式与其他类型跑步赛事存在差异。