Affiliations: [a] Department of Physical Therapy, College of Arts and Sciences, Andrews University, Berrien Springs, MI
Note: [*] Consulting editor.
Note: [**] Address reprint requests to Kent Timm, Sports Physical Therapy, St. Luke's Hospital, 3525 Davenport, Saginaw, MI 48602, USA.
Abstract: The purpose of this study was to determine the effect of a 24-hour and 48-hour interval on test-retest reliability of the Biodex isokinetic dynamometer. Sixty-three healthy, 18- to 35-year-old men and women were tested for unilateral concentric knee flexion and extension at 60, 180, and 300 deg/sec. Subjects completed a 5-minute cardiovascular warmup, three submaximal and one maximal pretest contractions, and five maximal test contractions. Testing was performed at the aforementioned speeds with a 30-second rest between each speed. Data from initial tests was compared with that from final tests. Statistical analysis of data showed highly reliable correlation coefficients of 0.94, 0.92, and 0.93 for peak flexion torque at 60, 180, and 300 deg/sec, respectively. Peak extension torque correlation coefficients were 0.97, 0.94, and 0.95 for the same respective speeds. Correlation coefficients for total flexion work at the aforementioned speeds were 0.90, 0.85, and 0.87. Total extension work correlation coefficients were 0.95, 0.94, and 0.94, respectively. The results of this study demonstrated (1) no statistically significant difference in the 24- or 48-hour interval between tests, and (2) a high overall degree of reliability for Biodex test-retest measurements of peak torque and total work.
Keywords: Reliability, testing intervals, peak torque, total work
