Department of Kinesiology, University of Maryland, College Park, MD.
Neuroscience & Cognitive Science Program, University of Maryland, College Park, MD.
Med Sci Sports Exerc. 2019 Jun;51(6):1178-1185. doi: 10.1249/MSS.0000000000001888.
As running speed increases there are concomitant changes in loads associated with tibial stress fracture risk. Runners often include multiple speeds in their training, but the effect of speed distribution on load accumulation is unknown. We studied how running at different proportions of speed within a given running distance affects the cumulative loading of the vertical average loading rate, cumulative peak absolute tibial free moment, and cumulative peak axial tibial load. These loads were compared between two proportions of speed: running all distance at normal self-selected speed, and running the same distance at a combination of slow/fast speeds with the same average speed as normal. Also, the contributions of slow and fast running to the combined condition were compared.
Forty-three recreational runners (age, 18-49 yr; 29 female, 14 male) ran around a 50-m indoor track for three laps each at self-selected slow, normal, and fast speeds. Per-step peak loads and cumulative loads per kilometer were calculated at each speed and for each speed distribution, respectively.
Only cumulative vertical average loading rate was lower at normal speed compared with the slow/fast speed combination. The contribution of fast speed running to cumulative tibial load was less than the contribution of slow speed running.
Running at a combination of slow and fast speeds, rather than a single moderate speed, increased cumulative vertical average loading rate but not cumulative tibial load or free moment. Fast running can be included in a training program without necessarily increasing the cumulative load. Total distance and average speed may not be sufficient information to estimate cumulative load from running training.
随着跑步速度的增加，与胫骨应力性骨折风险相关的负荷也会发生相应的变化。跑步者经常在训练中包含多种速度，但速度分布对负荷积累的影响尚不清楚。我们研究了在给定跑步距离内以不同速度比例跑步如何影响垂直平均加载率的累积加载、累积峰值绝对胫骨自由力矩和累积峰值轴向胫骨载荷。将这三种负荷在两种速度比例之间进行比较：以正常的自选择速度跑完所有距离，以及以相同的平均速度将相同的距离组合以慢/快速度跑完。此外，还比较了慢跑和快跑在组合条件下的贡献。
43 名休闲跑步者（年龄 18-49 岁；29 名女性，14 名男性）分别以自选择的慢、正常和快速度在 50 米室内跑道上跑三圈。在每个速度和每个速度分布下分别计算了每步的峰值负荷和每公里的累积负荷。
仅正常速度下的垂直平均加载率低于慢/快速度组合。与慢速度跑步相比，快速跑步对累积胫骨负荷的贡献较小。
与单一中等速度相比，以慢和快速度的组合进行跑步会增加垂直平均加载率，但不会增加累积胫骨负荷或自由力矩。快速跑步可以包含在训练计划中，而不必增加累积负荷。总距离和平均速度可能不足以根据跑步训练来估计累积负荷。
