Method
Experimental muscle pain was induced by the injections of 5% hypertonic saline in the upper trapezius and extensor carpi radialis longus in 20 healthy volunteers respectively. Coordinative work of upper extremity was performed through the computer simulation games which were controlled by the motion of forearm pronation and supination using the steering handle. The performance scores were measured during the tasks requiring the relatively high level (driving mode) and low level (tracking mode) of coordination. Electromyographic activities were measured from the pronator teres and biceps brachii simultaneously.

Results
The performance scores were decreased after induction of muscle pain in the high coordinative task and their decreasing rate was higher in the distal muscle pain. There were no statistical differences of electromyographic activities according to the intensity and pain site and level of coordination.

Conclusion
The upper limb coordination which required high speed and complex activities was decreased in the presence of the muscle pain. (J Korean Acad Rehab Med 2003; 27: 115-120)