Wikstrom Erik A, Hass Chris J
Biodynamics Research Laboratory, Department of Kinesiology, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, United States.
Clin Biomech (Bristol). 2012 Jul;27(6):619-24. doi: 10.1016/j.clinbiomech.2012.01.001. Epub 2012 Jan 27.
Chronic ankle instability is a common occurrence after an ankle sprain. Yet, some people (copers) possess a mechanism that limits recurrent injury and disability. During gait termination, those with chronic ankle instability exhibit altered feed-forward and feedback control but little is known about alterations in copers. Therefore, the purpose of this investigation was to determine the biomechanical control alterations present in controls, copers, and those with chronic ankle instability during planned and unplanned gait termination.
Twenty subjects with chronic ankle instability, 20 copers, and 20 uninjured controls completed planned and unplanned gait termination tasks. Unplanned gait termination required subjects to stop, when cued, during randomly selected trials. Planned gait termination required intended stopping. A total of 10 trials were recorded for each condition. Normalized propulsive and braking force magnitudes and dynamic postural stability indices were calculated and compared among the groups.
Normalized maximum braking forces were significantly higher in the chronic ankle instability group (Mean: 2.82 SD: 0.93N/kg), relative to copers (Mean: 2.59 SD: 0.84N/kg) and controls (Mean: 2.51 SD: 0.78N/kg). Similarly, the antero-posterior postural stability index revealed higher scores in the chronic ankle instability group (Mean: 0.15 SD: 0.03) compared to the coper (Mean: 0.14 SD: 0.02) and control group (Mean: 0.14 SD: 0.02). Copers did not differ from controls.
The findings suggest that the ability of copers to terminate gait in a manner similar to uninjured controls may represent part of the underlying mechanism that limits recurrent injury and disability in copers.
慢性踝关节不稳是踝关节扭伤后常见的情况。然而，有些人（适应者）拥有一种限制反复受伤和残疾的机制。在步态终止过程中，患有慢性踝关节不稳的人表现出前馈和反馈控制的改变，但对于适应者的改变知之甚少。因此，本研究的目的是确定在有计划和无计划的步态终止过程中，对照组、适应者和患有慢性踝关节不稳的人存在的生物力学控制改变。
20名患有慢性踝关节不稳的受试者、20名适应者和20名未受伤的对照组完成了有计划和无计划的步态终止任务。无计划的步态终止要求受试者在随机选择的试验中接到提示时停止。有计划的步态终止要求有意停止。每种情况共记录10次试验。计算并比较各组的标准化推进力和制动力大小以及动态姿势稳定性指数。
相对于适应者（平均值：2.59，标准差：0.84N/kg）和对照组（平均值：2.51，标准差：0.78N/kg），慢性踝关节不稳组的标准化最大制动力显著更高（平均值：2.82，标准差：0.93N/kg）。同样，与适应者（平均值：0.14，标准差：0.02）和对照组（平均值：0.14，标准差：0.02）相比，慢性踝关节不稳组的前后姿势稳定性指数得分更高（平均值：0.15，标准差：0.03）。适应者与对照组没有差异。
研究结果表明，适应者以类似于未受伤对照组的方式终止步态的能力可能是限制适应者反复受伤和残疾的潜在机制的一部分。
