Spaulding National Running Center, Cambridge, MA, USA.
Department of Physical Therapy, Springfield College, Springfield, MA, USA.
J Sports Sci. 2021 Jun;39(11):1302-1311. doi: 10.1080/02640414.2020.1868089. Epub 2021 Feb 17.
Exertion may alter running mechanics and increase injury risk. Effects of exertion following gait-retraining are unknown.
To determine how exertion effects load rates, footstrike, and cadence in runners following a transition to forefoot strike (FFS) or increased cadence (CAD) gait-retraining.
33 (9 M, 24 F) healthy rearfoot strike runners were randomized into CAD or FFS groups. All runners received strengthening exercises and gait-retraining. 3D kinetic and kinematic motion analysis with instrumented treadmill at self-selected speed was performed at baseline & 1-week post-intervention, including an exerted run. Exertion was ≥17 on Borg's Rating of Perceived Exertion scale voluntary termination of running.
Within group comparisons between fresh and exerted running: Cadence not affected in either group. Foot angle at contact became less plantarflexed in FFS (-2.2°, ±0.4) and was unchanged in CAD. Both groups increased vertical average load rate (FFS +16.9%, CAD +13.6%). CAD increased vertical stiffness (+8.6 kN/m). FFS reduced ankle excursion (1.8). (p ≤ 0.05 for all values listed).
Both FFS and CAD exhibited increased load rates with exertion. Variables that may have increased load rates were different for each group. CAD runners had increased vertical stiffness while FFS runners had reduced plantarflexion at contact and reduced ankle dorsiflexion excursion.
运动可能会改变跑步的力学机制并增加受伤的风险。步态再训练后运动对负荷率、足跟着地和步频的影响尚不清楚。
确定在过渡到前足着地（FFS）或增加步频（CAD）步态再训练后，运动如何影响跑步者的负荷率、足跟着地和步频。
33 名（9 名男性，24 名女性）健康的后足着地跑步者随机分为 CAD 或 FFS 组。所有跑步者均接受强化锻炼和步态再训练。在自我选择的速度下，使用带有仪器的跑步机进行三维运动分析，包括在基线和干预后 1 周进行的剧烈运动。剧烈运动是指在 Borg 主观用力感知等级量表上达到 17 级，即自愿停止跑步。
在新鲜运动和剧烈运动之间进行组内比较：在任何一组中，步频均不受影响。FFS 组的接触时足角跖屈角度减小（-2.2°，±0.4°），而 CAD 组则保持不变。两组的垂直平均负荷率均增加（FFS 增加 16.9%，CAD 增加 13.6%）。CAD 增加了垂直刚度（+8.6 kN/m）。FFS 减少了踝关节活动度（1.8）。（列出的所有值均为 p≤0.05）。
FFS 和 CAD 在剧烈运动时均表现出增加的负荷率。每个组增加负荷率的变量不同。CAD 跑步者的垂直刚度增加，而 FFS 跑步者的接触时跖屈角度减小，踝关节背屈活动度减小。
