The purpose of this study was to examine the differentiation of proprioception, invertor and evertor muscle strength, and time to peak torque at a velocity of 300 °/sec of the ankle joint in people with or without functional ankle instability (FAI). Nineteen subjects with a history of ankle sprain participated. All subjects were divided into FAI group (n1=9, Cumberland ankle instability tool (CAIT)≤24) and a control group (n2=10) based on their CAIT scores. Isokinetic dynamometer was used to measure the sense of active joint position of the ankle at mid-range and end-range of an inversion motion and invertor as well as the evertor muscle strength and time to peak torque at 300 °/s. The FAI group showed a statistically reduction in invertor and evertor muscle strength and time to peak torque when compared to the control group (p<.05). Muscle strength and time to peak torque of the invertor and evertor, as well as the sense of active joint position at end-range were also lower in the FAI group than in the control (p<.05). Correlations between CAIT score and position sense at end-range (r=-.577) and invertor muscle strength (r=.554) were statistically significant (p<.05). Individuals with FAI showed reduction in invertor and evertor muscle strength and recruitment time as well as in proprioception of the ankle joint. Thus, proprioception and invertor and evertor muscle strength of the ankle joint at fast angular velocity may be investigated when examining and planning care for individuals with FAI.

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.