运动锻炼对30d-6°头低位卧床所致承重骨丢失的影响

目的观察下肢肌力锻炼和功率车锻炼对30 d-6°头低位卧床引起骨丢失的防护效果,为筛选航天员暴露于空间微重力环境下运动锻炼方法提供参考。方法15名男性青年受试者分为卧床对照组、下肢肌力锻炼组和功率车锻炼组,每组5人,在30 d-6°头低位卧床期间,两个运动锻炼组共进行了25 d(次)的运动锻炼,下肢肌力组每天锻炼16~18 min,功率车组每天锻炼30 min。分别于卧床前和起床后测量了全身骨密度(BMD QDR-4500/W Hologic)和腰椎骨小梁比值(CTPhilips-Mx-8000)。结果与卧床前相比,对照组卧床以后全身骨矿含量显著下降(P0.05)、左髋总骨密度和右髋大转子骨密度显著下降(P0.01),第2~4腰椎骨小梁比值显著下降(P0.05),功率车锻炼组虽然全身骨密度显著增加,但是第3~4腰椎骨密度却显著下降(P0.05),下肢肌力锻炼组全身和腰椎及髋部等承重部位的骨矿含量和骨密度均无明显下降。结论30 d-6°头低位卧床可引起腰椎和髋骨等承重部位明显的骨丢失,功率车锻炼方法不能改善腰椎部位的骨丢失,下肢肌力锻炼方法对于维持全身和承重部位的骨密度具有明显的防护效果,该结果将对我国载人航天飞行失重对抗措施方案的制定提供重要的参考。

Effects of Exercise Training on Weight-bearing Bone Loss during 30 d -6Head-down Bed Rest

Objective To observe the protective effects of the lower limb muscular strength exercise training and the bicycle ergometer exercise training method on weight-bearing bone loss during 30 d - 6°head-down bed rest (HDBR) , and screening available exercise training method for space flight astronauts exposed to space microgravity. Methods Fifteen men were divided into three groups, control group (A ) , lower limb muscular strength exercise training group (B) and bicycle ergometer exercise training group ( C) , with 5 in each group. The both exercise groups were conducted 25 times exercise training during 30 d -6°HDBR. B group was 16 -18 min everyday, and C group 30 min. The exercise training was carried out in -6°head down tilt supine position. Before and after 30 d -6°HDBR, the whole body bone mineral density ( BMD QDR4500/W Ho-logic) , whole body bone mineral content (BMC) , and lumbar spine trabecular ratio ( CT Philips-Mx-8000) were measured. Results Compared with pre-HDBR, in group A;the left hip total BMD, the right hip trochan-ter BMD and the lumbar spine(2～4) trabecular ratio significantly decreased; in group C, even though whole body BMD increased significantly, the lumbar spine(3～4) BMD decreases significantly; in group B, the whole body BMD and weight-bearing bone BMD did not decrease significantly. Conclusion This study showes that the control group weight-bearing bone ie. lumbar spine and hip bone BMD significant decreased during 30 d -6°DBR, the bicycle ergometer exercise training methods even though whole body BMD increase significantly, but not maintain lumbar spine BMD during 30 d -6°HDBR, however, the lower limb muscular strength exercise training methods has significant protective effect on whole body and weight-bearing bone BMD during 30 d -6°HDBR. These study results provide valuable basis in fomulating counter-measures protocols for space flight astronauts exposed to space microgravity.