Abstract
This study compared the test results from two spinal isokinetic dynamometers, the Cybex TEF and the Cybex 6000-TMC (Cybex, Ronkonkoma, NY) in an effort to establish the measurement reliability of the latter device and to develop formulas for the interconversion of test results. A stratified random sample of 5,760 normal subjects (2,880 females, 2,880 males; mean age 25.0±9.9 years; age range 17–49 years) was tested on both devices under an alternate repeated-measures paradigm across the concentric isokinetic speeds of 30, 60, 90, and 120 deg/sec after standardized warmup procedures. Data for peak torque expressed as a percentage of body weight was collected from five maximal repetitions of spinal flexion and extension at all test speeds and then subjected to multiple statistical analyses. Results showed a high level of measurement reliability for both the TEF (intraclass correlation [ICC] = 0.927) and the TMC (ICC = 0.910); failed to show significant differences in subject performances across devices, speeds, genders, and motions; and showed comparison formulas of TEF = TMC + 13.325, TEF = TMC + 15.225, TEF = TMC + 15.775, and TEF = TMC + 16.775 for female and male spinal flexion and extension, respectively. The results may be useful for the design of clinical programs that include spinal isokinetic testing procedures.