Bilateral surface and fine-wire electromyographic activity from the erector spinae at the 14–5 interspace was recorded from 10 female subjects during flexion, extension, rotation to righvleft, and sidebending to righvleft. Finewire electrodes demonstrated significant left-right electromyographic differences during terminal flexion. Surface and fine-wire electromyographic recordings demonstrated a symmetric pattern of activity during extension. A symmetric pattern of erector spinae activity was observed during rotation using fine-wire electrodes but not from surface electrodes. Increased electromyographic activity from the contralateral erector spinae was detected by the surface electrodes during sidebending to neutral movements]