Swanenburg Jaap, Easthope Christopher A, Meinke Anita, Langenfeld Anke, Green David A, Schweinhardt Petra
Department of Chiropractic Medicine, Integrative Spinal Research ISR, Balgrist University Hospital, Zürich, Switzerland.
Faculty of Medicine, Institute of Anatomy, University of Zurich, Zurich, Switzerland.
Front Physiol. 2023 Jul 26;14:1196929. doi: 10.3389/fphys.2023.1196929. eCollection 2023.
Once more, plans are underway to send humans to the Moon or possibly even to Mars. It is therefore, important to know potential physiological effects of a prolonged stay in space and to minimize possible health risks to astronauts. It has been shown that spinal motor control strategies change during microgravity induced by parabolic flight. The way in which spinal motor control strategies change during partial microgravity, such as that encountered on the Moon and on Mars, is not known. Spinal motor control measurements were performed during Earth, lunar, Mars, and micro-gravity conditions and two hypergravity conditions of a parabola. Three proxy measures of spinal motor control were recorded: spinal stiffness of lumbar L3 vertebra using the impulse response, muscle activity of lumbar flexors and extensors using surface electromyography, and lumbar curvature using two curvature distance sensors placed at the upper and lower lumbar spine. The participants were six females and six males, with a mean age of 33 years (standard deviation: 7 years). Gravity condition had a statistically significant (Friedmann tests) effect spinal stiffness ( < 0.001); on EMG measures (multifidus ( = 0.047), transversus abdominis ( < 0.001), and psoas ( < 0.001) muscles) and on upper lumbar curvature sensor ( < 0.001). No effect was found on the erector spinae muscle ( = 0.063) or lower curvature sensor ( = 0.170). Post hoc tests revealed a significant increase in stiffness under micro-, lunar-, and Martian gravity conditions (all < 0.034). Spinal stiffness decreased under both hypergravity conditions (all ≤ 0.012) and decreased during the second hypergravity compared to the first hypergravity condition ( = 0.012). Micro-, lunar-, and Martian gravity conditions resulted in similar increases in spinal stiffness, a decrease in transversus abdominis muscle activity, with no change in psoas muscle activity and thus modulation of spinal motor stabilization strategy compared to those observed under Earth's gravity. These findings suggest that the spine is highly sensitive to gravity transitions but that Lunar and Martian gravity are below that required for normal modulation of spinal motor stabilization strategy and thus may be associated with LBP and/or IVD risk without the definition of countermeasures.
再次，将人类送往月球甚至火星的计划正在进行中。因此，了解长期太空停留可能产生的生理影响并将宇航员可能面临的健康风险降至最低非常重要。研究表明，在抛物线飞行引起的微重力环境下，脊髓运动控制策略会发生变化。而在部分微重力环境下，如在月球和火星上所遇到的情况，脊髓运动控制策略如何变化尚不清楚。研究人员在地球、月球、火星以及抛物线飞行的两种超重环境下进行了脊髓运动控制测量。记录了脊髓运动控制的三个替代指标：利用脉冲响应测量第三腰椎的脊髓刚度，利用表面肌电图测量腰屈肌和伸肌的肌肉活动，以及利用放置在腰椎上下的两个曲率距离传感器测量腰椎曲率。参与者为6名女性和6名男性，平均年龄33岁（标准差：7岁）。重力条件对脊髓刚度有统计学显著影响（弗里德曼检验，<0.001）；对肌电图测量指标（多裂肌（=0.047）、腹横肌（<0.001）和腰大肌（<0.001））以及上腰椎曲率传感器有影响（<0.001）。竖脊肌（=0.063）或下曲率传感器（=0.170）未发现有影响。事后检验显示，在微重力、月球重力和火星重力条件下，刚度显著增加（均<0.034）。在两种超重条件下，脊髓刚度均下降（均≤0.012），与第一种超重条件相比，第二种超重条件下脊髓刚度下降（=0.012）。与在地球重力下观察到的情况相比，微重力、月球重力和火星重力条件导致脊髓刚度出现类似增加，腹横肌肌肉活动减少，腰大肌肌肉活动无变化，从而导致脊髓运动稳定策略的调节发生变化。这些发现表明，脊柱对重力变化高度敏感，但月球和火星重力低于正常调节脊髓运动稳定策略所需的重力，因此在未定义应对措施的情况下，可能与下腰痛和/或椎间盘退变风险相关。
