Gopalakrishnan Raghavan, Genc Kerim O, Rice Andrea J, Lee Stuart M C, Evans Harlan J, Maender Christian C, Ilaslan Hakan, Cavanagh Peter R
Department of Biomedical Engineering , Cleveland Clinic, Cleveland, OH, USA.
Aviat Space Environ Med. 2010 Feb;81(2):91-102. doi: 10.3357/asem.2583.2010.
Decrements in muscular strength during long-duration missions in space could be mission-critical during construction and exploration activities. The purpose of this study was to quantify changes in muscle volume, strength, and endurance of crewmembers on the International Space Station (ISS) in the context of new measurements of loading during exercise countermeasures.
Strength and muscle volumes were measured from four male ISS crewmembers (49.5 +/- 4.7 yr, 179.3 +/- 7.1 cm, 85.2 +/- 10.4 kg) before and after long-duration spaceflight (181 +/- 15 d). Preflight and in-flight measurements of forces between foot and shoe allowed comparisons of loading from 1-g exercise and exercise countermeasures on ISS.
Muscle volume change was greater in the calf (-10 to 16%) than the thigh (-4% to -7%), but there was no change in the upper arm (+0.4 to -0.8%). Isometric and isokinetic strength changes at the knee (range -10.4 to -24.1%), ankle (range -4 to -22.3%), and elbow (range -7.5 to -16.7%) were observed. Although there was an overall postflight decline in total work (-14%) during the endurance test, an increase in postflight resistance to fatigue was observed. The peak in-shoe forces during running and cycling on ISS were approximately 46% and 50% lower compared to 1-g values.
Muscle volume and strength were decreased in the lower extremities of crewmembers during long-duration spaceflight on ISS despite the use of exercise countermeasures. in-flight countermeasures were insufficient to replicate the daily mechanical loading experienced by the crewmembers before flight. Future exercise protocols need careful assessment both in terms of intensity and duration to maximize the "dose" of exercise and to increase loads compared to the measured levels.
在太空执行长期任务期间，肌肉力量的下降在建设和探索活动中可能至关重要。本研究的目的是在对运动对抗措施期间的负荷进行新测量的背景下，量化国际空间站（ISS）上机组人员的肌肉体积、力量和耐力的变化。
对四名男性国际空间站机组人员（49.5±4.7岁，179.3±7.1厘米，85.2±10.4千克）在长期太空飞行（181±15天）前后进行力量和肌肉体积测量。对飞行前和飞行中脚与鞋之间的力进行测量，以便比较1g重力下的运动和国际空间站上的运动对抗措施所产生的负荷。
小腿肌肉体积变化（-10%至16%）大于大腿（-4%至-7%），但上臂没有变化（+0.4%至-0.8%）。观察到膝关节（范围为-10.4%至-24.1%）、踝关节（范围为-4%至-22.3%）和肘关节（范围为-7.5%至-16.7%）的等长和等速力量变化。尽管在耐力测试中飞行后总功总体下降（-14%），但观察到飞行后抗疲劳能力有所增加。与1g重力下的值相比，在国际空间站上跑步和骑自行车时鞋内的峰值力分别降低了约46%和50%。
在国际空间站上进行长期太空飞行期间，尽管采取了运动对抗措施，机组人员下肢的肌肉体积和力量仍有所下降。飞行中的对抗措施不足以复制机组人员飞行前每天所经历的机械负荷。未来的运动方案需要在强度和持续时间方面进行仔细评估，以最大限度地提高运动“剂量”，并与测量水平相比增加负荷。
