عنوان مقاله [English]
The purpose of the present study was to investigate the effect of fatigue on speed-accuracy tradeoff in different difficulty indices. The statistical population consists of female athletes of karate in Ahwaz with the age range of 13-17 years. First, participants were given a speed-accuracy swap test with different difficulty indices under fatigue conditions, then modified Astrand protocol was used for fatigue. Difficulty index and number of correct kicks and misses to a target were calculated using the difficulty index software, the time of a move, the average time of movement by multiplying slow and fast tracks by two- and three-goal shapes. The results showed that in fast and slow multiplication conditions with fatigue difficulty index of three goals had a significant effect on subjects' performance but no significant effect was observed in the condition of two-objective difficulty index. In addition, there was no significant difference between the right, left, and low targets in the two-goal difficulty level with slow beat multiplication at rest, but in the fatigue beat multiplier at three targets, there was no significant effect on subject performance. According to the findings, difficulty index is a critical nature of motor performance affected by fatigue conditions.