Gait & Motion Analysis Laboratory, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region.
Department of Orthopaedics & Traumatology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
Hum Mov Sci. 2020 Jun;71:102600. doi: 10.1016/j.humov.2020.102600. Epub 2020 Mar 12.
The mechanisms and underlying causes of bilateral asymmetry among healthy runners of different levels remain unclear. This cross-sectional laboratory study aimed to investigate the effects of running speed and running experience or competitive level on bilateral symmetry during running. Eleven competitive runners, 9 recreational runners and 11 novice runners were recruited in this study. They ran on an instrumented treadmill for 3 min at each of 5 fixed speeds (8, 9, 10, 11 and 12 km/h) in a randomized order. Bilateral asymmetry was evaluated and quantified using symmetry index (SI) of temporal and kinetic parameters. Overall, SI ranged between 0.8% for stride time and 21.4% for vertical average loading rate. Significant speed effects were observed on SI of flight time (p = .012), which was significantly higher at 8 km/h than that of the other 4 speeds (p = .023, 0.005, 0.023 and 0.028, respectively). Group-by-speed interactions were detected on SI in time to peak vertical ground reaction force (p = .032) and vertical average loading rate (p = .002). The competitive runners presented linear reduction in the SI with increasing speed from 8 to 12 km/h (R > 0.94); for the recreational runners, SI changed nonlinearly and presented a roughly U-shaped trend across speeds (R > 0.88); and for the novice runners, changes of SI across speed were inconsistent and dependent on parameters of interest (R > 0.64). Bilateral asymmetry was affected by both running speed and runners' running experience or competitive level. The competitive runners were found to run with a more symmetrical manner with a greater running speed, the recreational runners demonstrated the most symmetrical pattern at the critical speed, whereas the novice runners showed inconsistent trends.
不同水平健康跑者双侧对称性的机制和根本原因尚不清楚。本横断面实验室研究旨在探讨跑步速度和跑步经验或竞技水平对跑步时双侧对称性的影响。本研究招募了 11 名竞技跑者、9 名休闲跑者和 11 名新手跑者。他们在仪器化跑步机上以 5 种固定速度（8、9、10、11 和 12km/h）中的每一种速度随机跑 3 分钟。使用时间和动力学参数的对称指数（SI）评估和量化双侧对称性。总的来说，SI 范围从步长时间的 0.8%到垂直平均加载率的 21.4%。在飞行时间的 SI 上观察到显著的速度效应（p=0.012），在 8km/h 时显著高于其他 4 种速度（p=0.023、0.005、0.023 和 0.028）。在时间到达峰值垂直地面反作用力和垂直平均加载率的 SI 上检测到组-速度交互作用（p=0.032 和 p=0.002）。竞技跑者在 8 至 12km/h 的速度范围内，SI 呈线性降低（R>0.94）；休闲跑者的 SI 变化是非线性的，且在速度范围内呈现大致 U 形趋势（R>0.88）；新手跑者的 SI 变化在速度范围内不一致且取决于关注的参数（R>0.64）。双侧对称性受跑步速度和跑者跑步经验或竞技水平的影响。发现竞技跑者随着跑步速度的增加，以更对称的方式跑步，休闲跑者在临界速度下表现出最对称的模式，而新手跑者表现出不一致的趋势。
