Functional role of arm motion on gait stability and balance recovery.

我的研究计划的目标是确定运动学模式和潜在的神经肌肉控制机制涉及人类运动，并确定运动系统如何调节稳定性。同一水平的滑倒、绊倒和跌倒占工作场所发生的跌倒总数的65%，人工搬运重物被认为是一个主要的风险因素。手臂运动在步态稳定中起着重要作用，因为它调节着全身的动量。考虑到大多数步态分析和建模研究往往忽略了手臂摆动，其对步态稳定性的影响必须进一步研究。

The objectives of my research program are to determine the kinematic patterns and underlying neuromuscular control mechanisms involved in human locomotion and to identify how the locomotor system regulates stability. Same-level slips, trips and falls account for 65% of the overall falls occurring in the workplace and manual load handling is recognized as a major risk factor. Arm motion plays an important role in gait stability, as it regulates the whole-body momentum. Considering that most gait analyses and modeling studies tend to ignore arm swing, its impact on gait stability must be further investigated. Intentionally increasing arm movement has been shown to improve gait stability, as it could decrease the corrective torques around the hip of the stance leg. However, it is unknown whether vigorous arm activity could also contribute to gait stability and hasten gait adaptations during and when recovering from small perturbations such as asymmetric gait. During a trip-like perturbation, simulation showed that the arm motion could have a detrimental effect on gait stability in the first phase of the perturbation, while being beneficial to the recovery phase. Indeed during steady-state walking, restricting arm motion could increase trunk inertia and therefore improve its resistance to perturbations. It was also suggested that distinctive muscle activation patterns could enhance stability. However, neither hypothesis was verified and therefore, the effect of arm motion on muscle pattern adaptations and gait stability remains only partially understood. During the recovery phase of a trip-like perturbation, arm motion postpones the transfer of angular momentum to the trunk in the transverse plane, which results in a larger trunk rotation on the side of the non-tripped leg and increases the length of the recovery step. However, the impact of arm motion on muscle activation patterns in the leg and torso and how they contribute to gait stability when recovering from a large perturbation needs to be further explained and even more so during asymmetric gait. My research program will systematically determine the effect of arm motion on whole-body angular momentum, gait stability and muscular activation pattern adaptations under specific environmental conditions. Specifically, it will: Determine the effect of arm movement on muscle pattern adaptations and gait stability 1. During and after small perturbations. 2. During and after a trip-like perturbation in steady-state walking, and 3. During asymmetric gait. This work is critical to the development of comprehensive biomechanical models to reduce the occurrence of falls in the workplace and in providing insight for safety recommendations regarding manual handling of loads for workers navigating in unfamiliar, and precarious surroundings. It also has major impacts in the conception of exoskeletons for motor training programs.