Surface analysis of muscle activity has received increasing attention in recent years. Electromyography (EMG) has been useful in comparing muscular activity among different movements and it is a valuable tool in evaluating neuromuscular co-ordination. During maximal voluntary contraction several changes are observed in the root mean square (RMS) of the electromyograms. The RMS represents an average of the action potentials recorded at the electrode site. The RMS generally shows a gradual decrement during sustained maximum voluntary contractions, although conflicting results have been reported in this respect (Moritani et al., 1985). Oda and Kida (2001) investigated the occurrence of neuromuscular fatigue during maximal concurrent hand grip, elbow extension and flexion in eight physically fit subjects and reported a significant decrease in the RMS value in biceps brachii but no changes in the triceps.