Poster 93: Reliability of the isokinetic measurements of resistance to passive knee motion and the influence of hip angle on peak torque values in healthy subjects

Abstract

Objectives: To determine (1) the test-retest reliability of the isokinetically measured resistance to passive knee flexion and extension movements at different angular velocities and (2) the impact of different hip angles on the measurements. Design: Cross-sectional study. Setting: Outpatient rehabilitation facility. Participants: 30 healthy volunteers (20 women, 10 men) between the ages of 21 and 39 years. Interventions: Resistance to passive knee flexion and extension movements at 60°, 120°, 180°, and 300°/s were performed twice in the sitting position (hip at 90° of flexion) with a 20-minute interval between the 2 tests. The same procedure was performed in the supine position (hip at full extension). Main Outcome Measures: Peak torque measured the resistance to passive knee motion. Results: The intraclass correlation coefficients (ICCs) ranged between .25 and .65 and .23 and .52, respectively, when the results of the 2 sitting and 2 supine position tests were compared. The ICCs ranged between .22 and 0.6 and .15 and .59 when the results of the sitting and supine position tests were compared in the first and second measurements, respectively. Conclusions: The measurements of resistance to passive knee motion by isokinetic dynamometry were not reliable. Hip position during testing, for example, in the sitting and supine position seemed to have an effect on peak torque values, but because the values for 2 consecutive sitting or supine positions already differed, the difference cannot be directly attributed to changes in the hip position.