The effects of joint angle and reliability on knee proprioception

Purpose: The purpose of this study was to examine the reliability and effec ts of knee angle on the detection and subsequent response to passive knee m ovement. Methods: Twenty college-aged male and 20 female volunteers were ev aluated for proprioception by a newly developed perturbation test. Subjects were in a prone position on an isokinetic chair with their right lower leg attached to a freely moving resistance adapter. The knee was placed in a s tarting position of 15, 30, or 60 degrees of flexion. While relaxed, the kn ee was dropped into extension, and the subjects were instructed to "catch t heir leg" when movement was perceived. Five trials were completed at each a ngle, in a random order. An electrogoniometer was secured to the lateral po rtion of the knee in order to measure angular displacement after perturbati on in two specific phases: detection (displacement from leg release to move ment cessation) and response (displacement from movement cessation to peak knee flexion). A three-factor ANOVA (two repeated factors (knee angle and p roprioception phase) and one between factor (gender)) was performed on the average and standard deviation of the five trials for significant main effe cts and interactions. Results: The results demonstrated a significant phase by angle interaction, and no gender effect. It was shown that at a more ex tended knee joint position (15 degrees), significantly less knee movement o ccurred before perception, followed by a greater response, than in a more f lexed position (30 and 60 degrees). Conclusion: The major findings of this study suggest that the detection of passive knee movement, and the subseque nt voluntary response, may be dependent on joint angle. Considerations of t he present method for proprioception assessment are warranted to enhance te st-retest reliability.