Back and neck extensor loading and back pain provocation in urban bus drivers with and without low back pain

Average paraspinal myoelectric activity during driving was approximately 1% of MVC in both groups. Average trapezius myoelectric activity during driving was from 2 to 4% of MVC. Trapezius muscle activity was higher in back healthy drivers than in those with LBP. The low back support had no effect either on paraspinal or trapezius EMG activity. Low back and neck-shoulder fatigue increased during driving in both groups especially in those subjects with positive vibration pain provocation. The neck-shoulder pain and fatigue were more severe in drivers suffering from LBP. Low back support had no effect on low back and neck-shoulder subjective fatigue and neck-shoulder pain but tended to limit the LBP increase during driving. Paraspinal muscle loading in urban bus drivers was very limited and either LBP or ergonomic low back support had no effect on it. Trapezius muscle seemed to be less active in drivers suffering from recurrent LBP. Internal disc disruptions may expose to pain and fatigability during driving.