Universities Space Research Association, 2101 NASA Parkway, SK/B272, Houston, TX 77058, USA.
Exp Brain Res. 2010 May;202(3):649-59. doi: 10.1007/s00221-010-2171-0. Epub 2010 Feb 5.
Astronauts returning from space flight and performing Earth-bound activities must rapidly transition from the microgravity-adapted sensorimotor state to that of Earth's gravity. The goal of the current study was to assess locomotor dysfunction and recovery of function after long-duration space flight using a test of functional mobility. Eighteen International Space Station crewmembers experiencing an average flight duration of 185 days performed the functional mobility test (FMT) pre-flight and post-flight. To perform the FMT, subjects walked at a self selected pace through an obstacle course consisting of several pylons and obstacles set up on a base of 10-cm-thick, medium-density foam for a total of six trials per test session. The primary outcome measure was the time to complete the course (TCC, in seconds). To assess the long-term recovery trend of locomotor function after return from space flight, a multilevel exponential recovery model was fitted to the log-transformed TCC data. All crewmembers exhibited altered locomotor function after space flight, with a median 48% increase in the TCC. From the fitted model we calculated that a typical subject would recover to 95% of his/her pre-flight level at approximately 15 days post-flight. In addition, to assess the early motor learning responses after returning from space flight, we modeled performance over the six trials during the first post-flight session by a similar multilevel exponential relation. We found a significant positive correlation between measures of long-term recovery and early motor learning (P < 0.001) obtained from the respective models. We concluded that two types of recovery processes influence an astronaut's ability to re-adapt to Earth's gravity environment. Early motor learning helps astronauts make rapid modifications in their motor control strategies during the first hours after landing. Further, this early motor learning appears to reinforce the adaptive realignment, facilitating re-adaptation to Earth's 1-g environment on return from space flight.
宇航员从太空飞行返回并进行地球活动时，必须从适应微重力的感觉运动状态迅速过渡到地球重力状态。本研究的目的是使用功能移动性测试评估长期太空飞行后的运动功能障碍和功能恢复。18 名经历平均飞行时间 185 天的国际空间站机组人员在飞行前和飞行后进行了功能移动性测试（FMT）。为了进行 FMT，受试者以自己选择的速度穿过由几个标枪和障碍物组成的障碍课程，障碍物设置在 10 厘米厚的中密度泡沫基座上，每次测试共进行六次试验。主要结果测量是完成课程的时间（TCC，以秒为单位）。为了评估从太空飞行返回后运动功能的长期恢复趋势，对对数转换后的 TCC 数据拟合了多层次指数恢复模型。所有机组人员在太空飞行后都表现出运动功能改变，TCC 中位数增加了 48%。从拟合模型中，我们计算出典型受试者大约在飞行后 15 天恢复到其飞行前水平的 95%。此外，为了评估从太空飞行返回后的早期运动学习反应，我们通过类似的多层次指数关系对第一次飞行后会议的前六次试验的性能进行建模。我们发现长期恢复和早期运动学习的测量值之间存在显著的正相关（P < 0.001），这是从各自模型中获得的。我们得出结论，两种恢复过程影响宇航员重新适应地球重力环境的能力。早期运动学习有助于宇航员在着陆后的头几个小时内快速修改其运动控制策略。此外，这种早期运动学习似乎增强了适应性重新调整，促进了从太空飞行返回后对地球 1-g 环境的重新适应。
