Interactive effects of acute experimental pain in trapezius and sored wrist extensor on the electromyography of the forearm muscles during computer work

We investigated the interactive effects of shoulder pain and wrist extensor muscle soreness on surface electromyography (EMG) during computer mouse work. On day one, subjects (N = 12) performed computer work with/without acute muscle pain induced in the trapezius muscle. Subsequently, eccentric exercise was performed to induce delayed onset muscle soreness (DOMS) in wrist extensor muscles. In presence of DOMS on day two, computer work recordings with/without pain were repeated. EMG signals were recorded from the descending part of trapezius bilaterally, flexor carpi ulnaris and extensor carpi radialis brevis. Experimental muscle pain in trapezius led to a decrease in the muscular activity of the wrist extensor (P < 0.02) and decreased the relative rest time in the wrist flexor even in presence of DOMS (P < 0.01). The present result suggests that shoulder pain plays a role in the coordination of wrist flexors and extensors during computer work. (C) 2010 Elsevier Ltd and The Ergonomics Society. All rights reserved.