This study was conducted to analyses the Biceps Brachii (BB) muscle contraction during different driving postures. Drivers’ posture is one of the factors that contribute to driving fatigue that eventually may lead to road accident and injuries. The experiment conducted for this study is using the surface electromyography (SEMG) method for objective evaluation of muscle involved in driving activities. A total of 14 participants are involved in the experiment. The experiment was done on three different posture based on comfortable angles published by previous research. From the results analysis, the RMS value for activity left turn is lower than activity for right turn for all three postures and results also shows that posture B with elbow angle of 134° is perceived as most comfortable based on the lowest value of muscle contraction with a value of 15.67μV. The outcomes from this study are hoped to benefit both manufactures and also car users in ensuring better and optimum driving postures that can avoid fatigue and injuries.
comfort ; seat design ; surface electromyography ; driving posture ; muscle contraction

Driving posture is one of the factors that need to be emphasized in ensuring driver’s comfort and to avoid road accidents and injuries. Meanwhile, fatigue has a strong relationship with comfortable posture and it contributes 15.7% of the total road accidents in Malaysia. Fatigue can reduce driving concentration and performances, thus increases the risk of road accidents and injuries. In order to determine the driver’s comfort, this study had measured muscle contraction using the objective measurement for comfortable and optimum driving posture angles. The equipment used for conducting objective measurement on 14 respondents was sEMG. The researcher had used sEMG equipment to evaluate muscles activities at upper extremities, which comprises of Biceps Brachii (BB), Deltoid Anterior (DA) and Trapezious Upper (TU) that were involved during controlling the car steering. It involves three driving postures parameters according to the fixed elbow and shoulder angles. The results from this study showed the BB muscle increased positively when turning the steering wheel to the right within 3 to 6 times value increased. Meanwhile, DA and TU muscles experience a contraction in the opposite direction with steering wheel turning action, which shows higher right side DA and TU muscle contraction when the driver turn the steering to the left with around 80% decrease for DA and within 60% to 80% decrease value for TU. BB muscle also shows an increasing value of muscle contraction with higher elbow flexion, meanwhile DA and TU muscles contraction also show an increment in-line with greater shoulder abduction. The results showed that posture B with elbow angle at 36° and shoulder angle at 134° are the most comfortable driving postures, hence the lowest muscle contraction value of 15.67μV (BB), 19.31μV (DA) and 12.36μV (TU) compared to the other two measured postures. The results of muscle contraction from this study is capable of assisting researchers and car manufacturers to understand the relationship of steering maneuvering when developing more comfortable and suitable vehicle’s driver seat compartment.