Department of Sport, Health Sciences and Social Work, Oxford Brookes University, Oxford OX23 0BP, UK.
Department of Sport, Health Sciences and Social Work, Oxford Brookes University, Oxford OX23 0BP, UK.
J Biomech. 2019 Dec 3;97:109377. doi: 10.1016/j.jbiomech.2019.109377. Epub 2019 Oct 4.
This study aimed to investigate effects of walking direction and speed on gait complexity, symmetry and variability as indicators of neural control mechanisms, and if a period of backward walking has acute effects on forward walking. Twenty-two young adults attended 2 visits. In each visit participants walked forwards at preferred walking speed (PWS) for 3-minutes (pre) followed by 5-minutes walking each at 80%, 100% and 120% of PWS of either forward or backward walking then a further 3-minutes walking forward at PWS (post). The order of walking speed in each visit was randomised and walking direction of each visit was randomised. An inertial measurement unit was placed over L5 vertebra to record tri-axial accelerations. From the trunk accelerations multiscale entropy, harmonic ratio and stride time variability were calculated to measure complexity, symmetry and variability for each walk. Complexity increased with increasing walking speed for all axes in forward and backward walking, and backward walking was less complex than forward walking. Stride time variability was also greater in backward than forward walking. Anterio-posterior and medio-lateral complexity increased following forward and backward walking but there was no difference between forward and backward walking post effects. No effects were found for harmonic ratio. These results suggest during backward walking trunk motion is rigidly controlled but central pattern generators responsible for temporal gait patterns are less refined for backward walking. However, in both directions complexity increased as speed increased suggesting additional constraint of trunk motion, normally characterised by reduced complexity, is not applied as speed increases.
本研究旨在探讨行走方向和速度对步态复杂性、对称性和可变性的影响，这些指标可作为神经控制机制的指标，以及是否有一段时间的后退行走对前进行走有急性影响。22 名年轻成年人参加了 2 次访问。在每次访问中，参与者以其自身的惯用行走速度（PWS）向前行走 3 分钟（预），然后以 80%、100%和 120%的 PWS 向前或向后行走 5 分钟，然后再以 PWS 向前行走 3 分钟（后）。每次访问中的行走速度顺序是随机的，每次访问的行走方向也是随机的。在 L5 椎骨上放置一个惯性测量单元来记录三轴加速度。从躯干加速度中，计算多尺度熵、谐波比和步长时间变异性，以测量每个行走的复杂性、对称性和可变性。在前进和后退行走中，所有轴的行走速度增加都会增加复杂性，后退行走比前进行走更复杂。后退行走的步长时间变异性也大于前进行走。前进和后退行走后，前-后和中-侧复杂性增加，但前进和后退行走后效果之间没有差异。谐波比没有发现效果。这些结果表明，在后退行走中，躯干运动受到严格控制，但负责时间步态模式的中枢模式发生器对于后退行走的精细程度较低。然而，在两个方向上，随着速度的增加，复杂性都增加了，这表明通常以降低复杂性为特征的躯干运动的额外约束在速度增加时并没有施加。
