Statistical results for stride time.

Step width is a parameter that determines the size of the base of support (BOS) during gait. Further, it is related to the control of center of mass (COM) and trunk movements and gait speed. The current study aimed to validate the effect of conditioning using combined step width (narrow and wide) and gait speed (normal [4.5 km/h] and slow [2.2 km/h]) on the segmental control of the head, thorax, and pelvis with respect to the BOS. The behavior of the head, thorax, and pelvis of 17 healthy adult participants were measured during treadmill walking using a three-dimensional motion analysis system. If the step width was narrow, the whole body segment with a high contribution to COM under narrow BOS conditions was more likely to have a high variability. However, the mediolateral direction behavior was small. On the contrary, if the step width was wide, the whole body segment with a high contribution to COM under wide BOS conditions was more likely to have a low variability. Nevertheless, the mediolateral direction behavior was large. Regarding the intersegmental association, particularly if the step width was narrow and the gait speed was normal, the head showed highly controlled movements with minimal displacement and increased fine-tuning. The thorax displayed significant importance in maintaining trunk stability, operating within a larger range of mediolateral displacement compared to the head and pelvis, under three conditions, except if the step width was narrow and the gait speed was normal. The study underscores the significant impact of both step width and gait speed on the control and stability of high-mass body segments during gait. It suggests that narrow step widths necessitate advanced control strategies, while wide step widths promote simpler, compensatory mechanisms, especially relevant in clinical contexts.

步宽（step width）是决定步态期间支撑基底（base of support, BOS）尺寸的参数。此外，该参数与重心（center of mass, COM）、躯干运动及步态速度的调控密切相关。本研究旨在验证采用联合步宽（宽窄两种）与步态速度（正常[4.5 km/h]、慢速[2.2 km/h]）的训练方案，对以支撑基底（BOS）为参照的头部、胸廓及骨盆节段运动调控的影响。研究采用三维运动分析系统（three-dimensional motion analysis system），对17名健康成年受试者在跑步机行走时的头部、胸廓及骨盆运动状态进行了采集。当采用窄步宽时，在窄支撑基底（BOS）条件下对重心（COM）贡献度较高的全身节段，其运动变异性往往更高，但中外侧方向（mediolateral direction）的运动幅度较小。反之，当采用宽步宽时，在宽支撑基底（BOS）条件下对重心（COM）贡献度较高的全身节段，其运动变异性往往更低，但中外侧方向的运动幅度更大。就节段间关联（intersegmental association）而言，尤其是当步宽较窄且步态速度正常时，头部的运动调控精度极高，位移幅度极小且微调机制更为显著。在除“窄步宽+正常步态速度”之外的三种实验条件下，胸廓相较于头部与骨盆，其中外侧位移范围更大，在维持躯干稳定性方面发挥着关键作用。本研究证实，步宽与步态速度均会对步态过程中高体重身体节段的运动调控与稳定性产生显著影响。研究结果表明，窄步宽需要更为精细的调控策略，而宽步宽则会触发更为简单的代偿机制，这一发现尤其适用于临床场景。