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| Quantification Study on Driver’s Back Muscle Load |
1 Beijing Centers for Diseases Control and Prevention, Beijing 100013, China
2 State Key Laboratory of Automotive Safety Energy, Tsinghua University, Beijing 100084, China |
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Abstract 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%MVCof RES and RMM were significant (P<0.05), and the differences in MF30%MVC and MPF3%MVCof 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.
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