Miller Christopher A, Peters Brian T, Brady Rachel R, Richards Jason R, Ploutz-Snyder Robert J, Mulavara Ajitkumar P, Bloomberg Jacob J
NASA Lyndon B. Johnson Space Center, Wyle Integrated Science and Engineering Group, TX 77058, USA.
Aviat Space Environ Med. 2010 Oct;81(10):919-28. doi: 10.3357/asem.2680.2010.
Astronauts exhibit sensorimotor changes upon return from long-duration spaceflight that can result in altered gait kinematics and possibly an increased risk of tripping. Toe trajectory during locomotion is a precise motor control task involving both legs, thus providing a composite metric of locomotor control. The purpose of this study was to determine whether astronauts are at an increased risk of tripping after their return from long-duration spaceflight. This was accomplished by assessing the pre- to postflight changes in toe clearance during treadmill walking.
Ten crewmembers walked on a treadmill while performing a visual-acuity task pre- and postflight.
In the three subjects on whom landing day data were available, each exhibited a characteristic of increased tripping risk on landing day: either a decreased median toe clearance or an increased interquartile range (a measure of variance). For all crewmembers, toe clearance median and interquartile range were not significantly different from preflight for the other postflight sessions (the earliest being 1 d after landing). A follow-up analysis showed that changes in foot pitch, ankle dorsiflexion, and pelvis roll angles were significant predictors of changes in toe clearance.
The landing-day observations indicated an increased risk of tripping, which may pose a hazard during locomotion immediately upon return to Earth, especially in an emergency scenario. However, tripping risk on subsequent days was not different than preflight. The joint angle analysis suggested that the crewmembers tried to reestablish their normal walking pattern postflight, instead of developing a new motor control strategy.
宇航员在长期太空飞行返回后会出现感觉运动变化，这可能导致步态运动学改变，并可能增加绊倒风险。行走过程中的脚趾轨迹是一项涉及双腿的精确运动控制任务，因此提供了运动控制的综合指标。本研究的目的是确定宇航员在长期太空飞行返回后绊倒风险是否增加。这是通过评估跑步机行走过程中飞行前至飞行后脚趾间隙的变化来实现的。
10名机组人员在跑步机上行走，同时在飞行前和飞行后执行视力任务。
在可获得着陆日数据的三名受试者中，每人在着陆日都表现出绊倒风险增加的特征：要么是中位脚趾间隙减小，要么是四分位间距增加（一种方差度量）。对于所有机组人员，在其他飞行后阶段（最早为着陆后1天），脚趾间隙中位数和四分位间距与飞行前相比无显著差异。后续分析表明，足部俯仰、踝关节背屈和骨盆滚动角度的变化是脚趾间隙变化的重要预测因素。
着陆日的观察结果表明绊倒风险增加，这在返回地球后立即行走时可能构成危险，尤其是在紧急情况下。然而，随后几天的绊倒风险与飞行前没有差异。关节角度分析表明，机组人员在飞行后试图重新建立正常的行走模式，而不是制定新的运动控制策略。
