摘要
目的 通过观察慢增长率(GOR)模式+Gz暴露时的表面肌电(sEMG)变化,分析做HP抗荷动作时下肢及腹部肌肉的用力特点,探讨sEMG在综合抗荷措施防护效果评定中的应用.方法 6名男性志愿者在载人离心机上进行了 4组GOR模式+Gz暴露试验:GOR1、GOR2、GOR3、GOR4模式.4组受试者在感觉周边灯消失时终止暴露,同时记录+Gz暴露时的双侧腹直肌、股直肌、胫骨前肌及腓肠肌sEMG信号.结果 在4种(GOR1、GOR2、GOR3、GOR4)+Gz暴露模式下受试者加速度耐力依次增加,差异有统计学意义(F=174.477,P＜0.01).GOR2、GOR4+Gz暴露时股直肌、腓肠肌和胫骨前肌的积分肌电值(iEMG)平均值较安静时均显著升高(P＜0.05);与GOR1模式相比,GOR2模式时股直肌(P=0.014)和腓肠肌(P=0.027)的iEMG平均值增加显著.与GOR2模式相比,GOR3模式股直肌(P=0.044)和腓肠肌(P=0.020)及GOR4时的两侧腓肠肌(P=0.023)iEMG平均值均显著降低.在GOR1、GOR3和GOR4模式下,腹直肌贡献率最高,GOR2时胫骨前肌贡献率最高.GOR4时3名受试者的小腿肌群先激活,另2名受试者是腹直肌先激活.不同试验组间各肌群的中值频率斜率值无统计学差异.结论 通过分析+Gz暴露时的sEMG变化,可从肌肉紧张用力程度和疲劳水平等方面为综合抗荷措施的防护效果评定提供客观依据.
Abstract
Objective To analyze the force characteristics of lower limbs and abdominal muscles during HP anti-G maneuver and discuss the application of surface electromyography(sEMG)in the evaluation of protective effect of comprehensive anti-G measures by observing the changes of sEMG under+Gz exposure in gradual onset rate(GOR)mode.Methods Six male volunteers were exposed to four+Gz GOR runs on the human centrifuge:GOR1,GOR2,GOR3 and GOR4 mode.The four groups of subjects all terminated the exposure when they felt the peripheral light disappear.The sEMG signals of bilateral rectus abdominis,rectus femoris,anterior tibial muscle and gastrocnemius muscle during+Gz exposure were recorded.Results The acceleration tolerance of subjects increased successively under four+Gz exposure modes of GOR1,GOR2,GOR3 and GOR4,with a statistically significant difference(F=174.477,P＜0.01).The mean integrated electromyography(iEMG)of the rectus femoris,gastrocnemius and anterior tibial muscles exposed to acceleration in GOR2 and GOR4 were significantly higher than that in quiet state(P＜0.05).Compared with GOR1 mode,the mean iEMG of rectus femoris(P=0.014)and gastrocnemius(P=0.027)in GOR2 mode increased significantly,while the mean iEMG of rectus femoris(P=0.044)and gastrocnemius(P=0.020)in GOR3 mode and gastrocnemius(P=0.023)in GOR4 mode were significantly lower than that in GOR2 mode.In GOR1,GOR3 and GOR4 mode,the contribution rate of rectus abdominis was the highest,while in GOR2 mode,the contribution rate of anterior tibial muscle was the highest.In GOR4,the calf muscles of three subjects were activated first,and the rectus abdominis was activated first in the other two subjects.There was no significant difference in the median frequency slope of each muscle group among different groups.Conclusion By analyzing the changes of sEMG during +Gz exposure,we can provide an objective basis for the evaluation of protective effect of comprehensive anti-G measures from muscle tension and fatigue level.
基金项目
空军武器装备技术基础科研计划项目(212GJBKJ0007)
维普
万方数据