头低位卧床期间体育锻炼30d对下肢肌肉的影响

目的:通过观察和比较30 d头低位卧床期间不同体育锻炼方式对下肢肌肉的影响,以进一步明确体育锻炼对失重后下肢肌肉萎缩的对抗效果。方法:15名男性健康被试者,随机分为对照组、下肢肌力训练组和自行车功量计训练组。实验期间测量小腿周径、小腿截面积、腓肠肌肌电平均振幅的变化。结果:与卧床前相比,对照组小腿周径随卧床时间延长显著减小(P<0.01);下肢肌力训练组在卧床第18～30天以及起床后的小腿周径显著减小(P<0.01);自行车功量计训练组在卧床第22～30天及起床后显著减小(P<0.01)。与卧床前相比,卧床第30天和起床后1周时3组的小腿截面积均显著减小(P<0.05)。与卧床前相比,对照组肌电振幅在第1和22天显著降低(P<0.05),下肢肌力训练组的肌电振幅在卧床第7、22、26和30天显著降低(P<0.05),自行车功量计组在卧床第7、10、22和30天显著降低(P<0.05)。结论:30 d头低位卧床可引起严重的肌肉萎缩。下肢肌力训练和自行车功量计训练对防止模拟失重所致肌肉萎缩,促进肌肉恢复有一定的作用。

Effects of physical exercise on lower limb muscle during 30 d head-down bed rest

Objective:To observe and compare the effects of physical exercise on the lower limb muscle during 30 days of head-down bed rest(HDBR),and to explore whether these protocols would reverse muscular atrophy in the simulated microgravity condition.Methods: Fifteen healthy male volunteers were randomly divided into control group,lower limb muscular exercise group and bicycle ergometric exercise group.The perimeter,cross-sectional area(CSA) of lower leg and mean amplitude(MA) of calf muscle electricity were measured before,during and after HDBR in three groups.Results:The perimeter of lower leg in control group decreased significantly(P<0.01) in a HDBR time-dependent manner compared with pre-HDBR.In lower limb muscular exercise group,the perimeter of lower leg decreased(P<0.01) from the 18 th day to the 30 th day of HDBR and after HDBR compared with pre-HDBR.In bicycle ergometric group,the perimeter of lower leg decreased(P<0.01) from the 22 nd day to the 30 th day of HDBR and after HDBR.Compared with pre-HDBR,on the 30 th day of HDBR and in the week after HDBR,the CSA of lower leg decreased in the three groups(P<0.05).Compared with pre-HDBR,the MA of calf muscle electricity in control group decreased(P<0.05) on the 1st and 22 nd day of HDBR.The MA of calf muscle electricity in the lower limb muscular exercise group decreased(P<0.05) on the 7 th,22 nd,26 th and 30 th day of HDBR while it decreased(P<0.05) in the bicycle ergometric exercise group on the 7 th,10 th,22 nd and 30 th day.Conclusion:Thirty days HDBR could lead to severe muscular atrophy.The limb muscular exercise and the bicycle ergometric exercise could partly prevent muscle from atrophy in the simulated microgravity condition.Physical exercise plays an important role in the recovery of muscle structure and function.