离心机G载荷作用下肌电变化对G-LOC预警的有效性研究

Investigation on effectiveness of EMG for G-induced loss of consciousness forewarning under centrifuge G load

目的:研究离心机G载荷作用下肌电变化对于持续加速度引起的意识丧失(G-induced loss of consciousness,G-LOC)预警的有效性和可行性。方法:首先,参照2条件分析法,选取7名受试者进行高G训练和推拉训练。其次,对高G训练模式下和推拉效应下受试者发生G-LOC前后不同部位的肌电变化特征进行分析。最后,对同一名受试者临近2次载荷作用下的肌电特征参数综合绝对值(integrated absolute value,IAV)和波形长度(waveform length,WL)的变化进行研究。结果:所有受试者G-LOC前后的肌电波形呈现出不对称,且肌电波形不规则。在高G训练模式下,腓肠肌处的肌电特征参数变化比胫骨前肌处的肌电特征参数变化对于G-LOC预警更具有价值;在推拉效应下,肌电特征参数变化不明显,对于G-LOC预警效果不佳。同一名受试者在临近2次载荷作用下的肌电特征参数IAV和WL也呈现出特征性变化。结论:对于G-LOC预警,腓肠肌处的肌电变化比胫骨前肌处的肌电变化更有效;2条件分析法对高G训练模式下的G-LOC预警有效,但对推拉效应作用下的G-LOC预警效果不明显;对比同一名受试者在临近2次载荷作用下的肌电特征参数变化也能实现G-LOC预警。

Objective To explore the efficiency and feasibility of EMG changes for forewarning of G-induced loss of consciou-sness(G-LOC)under G load of human centrifuge.Methods Firstly,seven subjects were selected for high G training and push-pull training with reference to the 2-condition analysis method.Secondly,the characteristics of EMG changes in different parts of the body were analyzed before and after the occurrence of G-LOC in the subjects under the high-G training mode and the push-pull effect.Finally,the changes of two EMG characteristic parameters,including integrated absolute value(IAV)and waveform length(WL),were investigated under two sequential loads to one subject.Results The EMG waveforms of all the subjects were asymmetric and irregular before and after G-LOC.Under the high-G training mode,the changes of EMG characteristic parameters at the gastrocnemius muscle were more valuable than those at the tibialis anterior muscle for G-LOC forewarning;under the push-pull effect,the changes of EMG characteristic parameters were not obvious,and not effective for G-LOC forewarning.The IAV and WL showed characteristic changes under two sequential loads to one subject.Conclusion The changes of EMG characteristic parameters at the gastrocnemius muscle behaved better than those at the tibialis anterior muscle for G-LOC forewarning;the 2-condition analysis method was effective for G-LOC forewarning under the high-G training mode,while not in the presence of a push-pull effect;comparing the changes of EMG characteristic para-meters of some subject under two sequential loads can also be used for G-LOC forewarning.