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J Athl Train. 1995 June; 30(2): 167–170.
PMCID: PMC1317852

Interrater Reliability of Isokinetic Measures of Knee Flexion and Extension

Douglas R. Keskula, PhD, PT, ATC
Douglas R. Keskula is Assistant Professor in the Physical Therapy Program at Medical College of Georgia, Augusta, GA 30912-3209
Jeffrey S. Dowling, MHE, PT
Jeffrey S. Dowling is Assistant Director of Physical Therapy at Medical College of Georgia Hospital and Clinics.
Virginia L. Davis, MEd, PT, ATC
Virginia L. Davis is Clinical Supervisor at Medical College of Georgia Hospital and Clinics.
Paula W. Finley, PT
Paula W. Finley is Staff Physical Therapist in the Sports Medicine Program at Medical College of Georgia Hospital and Clinics.


The purpose of this investigation was to determine the interrater reliability of peak torque and total work values obtained with isokinetic measures of knee flexion and extension. Eight male and eight female students were evaluated on four occasions by four different examiners (range of isokinetic test experience: 0 to 10 yrs) using a standardized isokinetic measurement protocol. Subjects were randomly assigned to participate in a test sequence determined by a 4 × 4 balanced Latin square. Peak torque and total work values at 60°/sec and 180°/sec were obtained for the concentric measures of knee extension and flexion. The measures of peak torque and total work were corrected for the effects of gravity. Intraclass correlation coefficients and standard error of measurement estimates were used to estimate the interrater reliability for each test condition (test speed × muscle group). Intraclass correlation coefficient values ranged from .90 to .96 for peak torque and .90 to .95 for total work. Standard error of measurement estimates ranged from 8.9 to 13.3 Nm for peak torque and 11.3 to 16.8 Nm for total work. The results of this investigation demonstrate that reliable measures of isokinetic muscle performance of knee extension and flexion may be obtained by four clinicians with varied experience when following a standardized measurement protocol.

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Selected References

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Articles from Journal of Athletic Training are provided here courtesy of National Athletic Trainers Association