ABSTRACT
Muscular fatigue is common problem that an athlete faces repeatedly during sport competition or therapeutic exercise. Undoubtedly, fatigue affects the precision of subjects' performance and limits the range of physical and sport activities. Muscle fatigue advantages and disadvantages have been reviewed in many previous studies. To challenge this controversy fatigue evaluation requires reliable, stable and precise methods of analysis itself. Researches on muscle strength and subject's perception of fatigue have been done in many studies. Therefore; researchers in this study focus on temporal stability of both subjective perception of fatigue and produced muscle torque after fatigue. Fifteen healthy female between 20-30 years of age, who at least had some non-professional light sporting activities once a week, volunteered in this research. Each of volunteers was evaluated in 3 different sessions. The first session was to familiarize the volunteers with the Isokinetic tests. For the main test, each of the volunteers was evaluated once and then after one week interval. At each session after warm up, perceived fatigue was measured using Visual Analog Scale. Then Average peak torque and average power maximal concentric Isokinetic of quadriceps were measured at the velocity of 60 degrees per second. To perform the fatigue protocol, subjects were asked to perform successive maximal quadriceps contractions until the three subsequent quadriceps torque output drop below 50 percent of maximal torque output. Afterwards, for re-measurement average peak torque, average power and perceived fatigue were evaluated similarly. The interaclass correlation coefficient [ICC] of average peak torque, average power and visual analog scale before performing fatigue protocol were calculated%81.6,%87.4 and%47.9 respectively. The repeated ICC after fatigue has estimated%59.9 >%64.4 and%96.6 respectively. This research demonstrated that Isokinetic temporal stability parameters were high before fatigue. In other words, both torque and power are reliable in two repetition times in a session, as well after one week interval between. After fatigue; the stability rate of torque and power recorded by Isokinetic were repeatable and this repeatability has been moderate to high. However; VAS showed a completely opposite results, in which before fatigue the stability of imagined local fatigue perception has been very low and was not significant, although after fatigue the VAS showed high repeatability