Test-Retest Reliability of the Biodex Isokinetic Dynamometer

Abstract

The purpose of this study was to determine the test-retest reliability of the Biodex (Biodex, Corp., Shirley, NY) isokinetic concentric mode for a healthy active population for knee extension/flexion utilizing the parameters peak torque and work. Nineteen healthy active male and female subjects ages 20-35 with no history of knee injury were tested bilaterally for concentric knee extension and flexion at 60, 180, 240, and 300 degrees /sec., utilizing standard Biodex protocol. Seven days following the pre-test, a post-test was administered using identical protocol. Data collection of pre- and posttesting was done via a Compaq Desk Pro personal computer and Biodex software programming. The parameters of peak torque and single repetition work were analyzed for knee extension/flexion. Statistical analysis of data showed the intraclass correlation coefficient (ICC) of knee extension peak torque at 60 degrees /sec to be r = 0.95; at 180 degrees /sec, r = 0.96; at 240 degrees /sec, r = 0.95; and at 300 degrees /sec, r = 0.97. Knee extension work ICC values were at 60 degrees /sec, r = 0.96; at 180 degrees /sec, r = 0.97; at 240 degrees /sec, r = 0.96 and r = 0.95 at 300 degrees /sec. All ICCs are significant at the 0.05 level. Therefore, the isokinetic concentric mode of the Biodex dynamometer was reliable for test-retest measures of peak torque, and single repetition work. J Orthop Sports Phys Ther 1990;11(7):298-300.