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目的研究30 d头低位卧床对志愿者腰部核心稳定肌最大抗阻收缩能力、抗疲劳能力和快速反应能力的影响。方法 14名健康志愿者参加为期30 d的-6°头低位卧床试验(HDBR)。测量腰部多裂肌(LM)和竖脊肌(LE)最大平均肌电(AEMG)值、疲劳试验平均功率频率(MPF)、上肢重锤试验的快速反应时间和屈放松试验躯干最大屈曲条件下平均肌电值,评价志愿者腰部核心稳定肌最大抗阻收缩能力、抗疲劳能力、快速反应能力和放松能力。结果 1)LM和LE最大随意收缩AEMG分别下降36%(P<0.05)和47%(P<0.01);2)LM和LE疲劳试验过程中MPF下降率分别提高64%和56%,差异无统计学意义;3)LM在最大屈状态下的AEMG提高167%,出现明显的屈放松消失现象;4)LM和LE的快速反应时间分别延长21%和25%(P<0.01)。结论 30 d头低位卧床能够显著降低LM和LE的最大抗阻收缩能力、抗疲劳能力、屈放松能力和中枢运动控制效率,其原因可能与神经肌肉运动控制系统的适应性变化有关。
Objective To investigate the effect of low bed rest for 30 days on the maximum resistance to contraction, anti-fatigue and rapid response of the lumbar stable muscle in volunteers. Methods Forty healthy volunteers were enrolled in a -6 ° head-down bed rest (HDBR) for 30 days. Maximum AEMG values of the lumbar multifidus (LM) and erector spinae (LE), average power frequency of the fatigue test (MPF), rapid response time of the upper limb weight test, and maximum torso flexion condition Average EMG, evaluation of volunteers lumbar stable muscle maximum resistance to contraction, anti-fatigue ability, rapid response ability and relaxation ability. Results 1) The maximum systolic AEMG of LM and LE decreased by 36% (P <0.05) and 47% (P <0.01), respectively; 2) The decrease rate of MPF in fatigue test of LM and LE increased by 64% and 56% Statistical significance; 3) LMEM in the state of AEMG increased by 167%, apparent relaxation phenomenon disappeared; 4) LM and LE rapid response time were extended 21% and 25% (P <0.01). CONCLUSION: The 30 d head-to-lie bed can significantly reduce the maximal resistance to contractility, anti-fatigue ability, flexion-relaxation capacity and central motor control efficiency of LM and LE, which may be related to the adaptive changes of neuromuscular motor control system.