Mo Shiwei, Chow Daniel H K
Department of Health and Physical Education, The Education University of Hong Kong, 10 Lo Ping Road, Tai Po, New Terries, Hong Kong Special Administrative Region.
Department of Health and Physical Education, The Education University of Hong Kong, 10 Lo Ping Road, Tai Po, New Terries, Hong Kong Special Administrative Region.
Gait Posture. 2018 Jul;64:7-11. doi: 10.1016/j.gaitpost.2018.05.021. Epub 2018 May 19.
Motor control, related to running performance and running related injuries, is affected by progression of fatigue during a prolonged run. Distance runners are usually recommended to train at or slightly above anaerobic threshold (AT) speed for improving performance. However, running at AT speed may result in accelerated fatigue. It is not clear how one adapts running gait pattern during a prolonged run at AT speed and if there are differences between runners with different training experience.
To compare characteristics of stride-to-stride variability and complexity during a prolonged run at AT speed between novice runners (NR) and experienced runners (ER).
Both NR (n = 17) and ER (n = 17) performed a treadmill run for 31 min at his/her AT speed. Stride interval dynamics was obtained throughout the run with the middle 30 min equally divided into six time intervals (denoted as T1, T2, T3, T4, T5 and T6). Mean, coefficient of variation (CV) and scaling exponent alpha of stride intervals were calculated for each interval of each group.
This study revealed mean stride interval significantly increased with running time in a non-linear trend (p<0.001). The stride interval variability (CV) maintained relatively constant for NR (p = 0.22) and changed nonlinearly for ER (p = 0.023) throughout the run. Alpha was significantly different between groups at T2, T5 and T6, and nonlinearly changed with running time for both groups with slight differences.
These findings provided insights into how the motor control system adapts to progression of fatigue and evidences that long-term training enhances motor control. Although both ER and NR could regulate gait complexity to maintain AT speed throughout the prolonged run, ER also regulated stride interval variability to achieve the goal.
运动控制与跑步表现及跑步相关损伤有关，在长时间跑步过程中会受到疲劳进展的影响。通常建议长跑运动员以无氧阈（AT）速度或略高于该速度进行训练以提高成绩。然而，以AT速度跑步可能会导致疲劳加速。目前尚不清楚在以AT速度进行的长时间跑步过程中，人们如何调整跑步步态模式，以及不同训练经验的跑步者之间是否存在差异。
比较新手跑步者（NR）和有经验的跑步者（ER）在以AT速度进行长时间跑步过程中步幅间变异性和复杂性的特征。
NR组（n = 17）和ER组（n = 17）均在跑步机上以其AT速度跑31分钟。在整个跑步过程中获取步幅间隔动态数据，将中间30分钟等分为六个时间间隔（记为T1、T2、T3、T4、T5和T6）。计算每组每个间隔的步幅间隔平均值、变异系数（CV）和标度指数α。
本研究表明，步幅间隔平均值随跑步时间呈非线性趋势显著增加（p<0.001）。在整个跑步过程中，NR组的步幅间隔变异性（CV）保持相对恒定（p = 0.22），而ER组则呈非线性变化（p = 0.023）。两组在T2、T5和T6时α存在显著差异，且两组均随跑步时间呈非线性变化，略有差异。
这些发现为运动控制系统如何适应疲劳进展提供了见解，并证明长期训练可增强运动控制。尽管ER组和NR组在长时间跑步过程中都能调节步态复杂性以维持AT速度，但ER组还调节了步幅间隔变异性以实现这一目标。
