Study on changes of sEMG under+Gz exposure in gradual onset rate mode
YANG Jinghui
LI Baohui
WEI Xiaoyang
JIANG Ke
WANG Hong
YANG Minghao
WANG Haixia
ZHANG Lihui
XU Yan
GENG Xichen
LI Yifeng
JIN Zhao
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.
Keywords：accelerationhuman centrifugegradual onset ratesurface electromyography
Publication Date：2024-02-28
Online Publishing Date：2026-08-26(First online date of this platform, not the publication date of the document)
Pages：5( 175-179 )