This study examined the test-retest reliability of a prototype device used to measure ankle inversion and eversion isokinetic average torque values. The purpose of this paper was to illustrate a situation where common isokinetic measures were reliable but not valid. Concentric and eccentric average torque was assessed at 90 deg/s on the Kin Com II dynamometer using 14 healthy subjects in two sessions; a manufactured prototype ankle inversion/eversion attachment device was used. Reliability was assessed by performing separate intraclass correlations (ICC 2,1) on the results. The data indicated that the average torque calculated from the clockwise direction was consistently higher than those values from the counterclockwise direction, regardless of ankle movement or side measured. The validity of this prototype device to accurately measure average torque for these two ankle motions is questionable. This finding demonstrates a situation where the measures appear to be reliable while the validity of the device used to obtain the measures is suspect.
Thomas W. Kaminski, Carl G. Mattacola, Joseph E. Szczerba, and Julie N. Bernier are doctoral students in Sports Medicine, University of Virginia, Charlottesville. David H. Perrin is with the Curry School of Education, University of Virginia, Charlottesville. Direct correspondence to Thomas W. Kaminski, Health and Physical Education, Memorial Gymnasium, University of Virginia, Charlottesville, VA 22903.