驾驶人背部肌肉负荷定量研究

Quantification Study on Driver's Back Muscle Load

使用表面肌电图(sEMG)技术测定驾驶人躯干肌肌肉活动,定量驾驶人背部肌肉负荷水平。选取8名健康男性大学生作为受试者,有驾驶资质,右利手。在驾驶模拟器上以80 km/h的速度匀速驾驶。模拟器场景为三车道直道的自编场景,受试者在中间车道行驶共120 min,同步记录躯干肌中左右腰竖脊肌(LES和RES)和左右多裂肌(LMM和RMM)的肌电信号。在模拟驾驶前,测试LES、RES、LMM和RMM的最大自主收缩力(MVC),以此作为数据处理的基值,并测试模拟驾驶前后受试者30%MVC的肌电信号。对等长肌肉收缩期肌电信号(即30%MVC肌电信号)进行分析,时域分析指标为参考随意收缩肌电百分比(%RVE)和频域分析指标为中位频率(MF)平均功率频率(MPF)。对连续驾驶期间肌电信号采用振幅概率分布频率(APDF)方法进行分析。时域指标结果显示,LES、RES、LMM和RMM模拟驾驶前后%RVE值均显著上升(P<0.05);频域指标结果显示,模拟驾驶前后LES、RES、LMM和RMM的MF30%MVC值及MPF30%MVC值均下降,经检验RES和RMM模拟驾驶前后的MF30%MVC值及RMM驾驶前后MPF30%MVC值差异有显著性(P<0.05)。APDF分析结果表明,连续驾驶期间,LES、RES、LMM和RMM的肌肉负荷水平分别为7.55%±5.64%、5.78%±3.06%、6.13%±3.76%和5.69%±3.41%,为低负荷水平作业。sEMG研究表明,在连续驾驶期间,驾驶人的背部肌肉产生疲劳,躯干肌疲劳程度左侧高于右侧;在连续驾驶期间,背部肌肉负荷水平为持续低水平负荷。

To measure and quantify driver＇ s back muscle activity and load using surface electromyography, 8 college students who have drive licenses and right hand domination were recruited in this study. Driving operation was performed on driving simulator and the participants were required to drive in the middle lane at speed of 80 km/h. During simulating driving, surface electromyographic （sEMG） signals of divers＇ bilateral erector spinae muscle （LES and RES） and multifidus muscle （LMM and RMM） were recorded. Maximal voluntary contraction （MVC） of ES and MM were tested, and 30% MVC of ES and MM were measured twice, before and after driving simulation. Raw sEMG signals were processed and calculated with linear analysis methods. The parameter of the percentage of reference voluntary electrical activity （% RVE） was taken as amplitude analysis index, median frequency and mean power frequency （MPF） were taken as spectrum analysis indexes. These parameters were used to quantify sEMG signals of 30% MVC. Amplitude probability distribution frequency （APDF） method was used to quantify sEMG of dynamic muscle contractions during long term driving simulation. Amplitude analysis showed that % RVE values of LES, RES, LMM and RMM were higher than those before driving （P 〈 0. 05） , Spectrum analysis showed that the median frequency （MF）30%Mvc and mean power frequency （MPF）30%Mvc of the four test muscles were lower than those before driving, the differences in MF30%Mvc of RES and RMM were significant （P 〈 0. 05 ）, and the differences in MF30%Mvc and MPF30%vc of RMM were significant （P 〈0.05 ）. APDF analysis showed the muscle load of LES, RES, LMM and RMM were 7.55% ±5.64% ,5.78% ±3.06%,6. 13% ±3.76% and 5.69% ±3.41% respectively. In conclusion, long term driving operation results in back muscle fatigue, left side back muscles suffer more fatigue than right side. Back muscle activity is at low level for sustained muscles load during 2 hour constant driving.