The purpose of this study was to investigate the effect of change of force and response time to peak force on the forcee variability. The subjects were six male students in the department of physical education at seoul national university. They pulled the immobale handle at the three change of force(30, 60, 90%) and three response time conditions(100, 300, 500ms) . A three by three(change of force by response time to peak force) factorial analysis of variance with repeated measures used to dertermine whether or not the effect on the force variability was significant (P< .0l) . The results obtained from the data analysis were follows First, there was significant difference of change of force in the force variability. Second, there was have no significant difference of response time to peak force in the force variability. Third, there was have no significant difference of the relation change of force and response time to peak force variabiliyty.