The study groups were similar as regard to age, height, and maximum voluntary contraction but the drivers with LBP were heavier (Table 1).
Average lumbar paraspinal myoelectric activity during driving was approximately 1% of MVC in both groups (Table 2). The ergonomic low back support had no effect on paraspinal muscle activity in either healthy or LBP groups.
Average trapezius myoelectric activity during driving was from2 to 4% of MVC (Table 3). There was a side difference in trapezius muscle activity i.e. left side was loaded more than right side. There is evidence for higher trapezius mus- cle activity in non-LBP drivers compared with LBP drivers. The ergonomic low back support had no effect on trapezius muscle activity.