Effect of arm position on spatial distribution of upper trapezius muscle activity during simulated car driving

Abstract

The present study aimed to investigate the upper trapezius muscle activity during simulated car driving while adopting three different arm positions. Ten participants were instructed to maintain the following positions: hands on the steering wheel (Hands-On), hands not on the steering wheel (Hands-Off) and hands not on the steering wheel but arms on armrests (Armrests). During the tasks, multi-channel surface electromyography (EMG) was recorded from the upper trapezius muscle with 64 two-dimensionally distributed electrodes. Amplitudes of surface EMG in Armrests were lower than in Hands-On (p = 0.004). The spatial distribution of surface EMG changed with time in Hands-Off and Armrests (p < 0.05), but not in Hands-On (p > 0.05). These findings suggest that being freed from steering leads to the recruitment of various muscle fibers/motor units within the upper trapezius muscle and the use of armrests may help reduce the physiological burden loaded on the muscle of drivers.

Influence of forward head posture on muscle activation pattern of the trapezius pars descendens muscle in young adults

“…As a method to estimate motor unit activation or to provide more detailed physiological data, a highdensity surface EMG (HD-SEMG) technique has been developed recently that records surface EMG signals from large areas of muscle using multiple two-dimensionally oriented electrodes 12 . Previous studies reported region-specific muscle activity and muscle fatigue in the upper trapezius muscle 13,14 . Consequently, HD-SEMG could be useful to understand neuromuscular function and/or fatigue in people with FHP.…”