In each trial , the fatigue rate of the extensor muscles of all subjects in the 3 groups was higher than that of the flexor muscles . this result agrees with the findings of Mikanagi et al. (9) . Throughout all 3 trials, few changes were seen in the fatigue rate of the extensor muscles , while an increase was seen in the fatigue rate of the flexor muscles. This suggest that 10 min of rest allowed for complete recovery of the extensor muscles, but not for the flexor muscles, leading to increase fatigue during subsequent trials. That is , the extensor muscles had a high fatigue rate but a quick recovery , while the flexor muscles had a lower fatigue rate but a delayed recovery.