Reliability of Center of Pressure measures of Postural Stability in Anterior Cruciate Ligament Reconstructed Athletes: Effect of Vibration and Cognitive Load

Background: To evaluate intra and intersession reliability of the Center of Pressure (COP) parameters in Anterior Cruciate Ligament Reconstructed (ACLR) athletes with and without ankle vibration using a dual-task paradigm. Methods: Postural sway of 14 ACLR individuals was assessed during a single-leg stance on a force platform. COP parameters were assessed with manipulating sensory inputs via vision and ankle vibration under single and dual-task conditions. The outcome variables included COP displacement in medial-lateral (ML) and anterior-posterior (AP) range, mean velocity (mV), and area. During dual-task conditions, the auditory Stroop Task was applied. Intraclass correlation coefficient (ICC) values and standard error of measurement (SEM) were assessed for relative and absolute reliability. Results: The COP measures had moderate to very high intrasession reliability (ICC range: 0.51-0.93) for conditions with vibration and cognitive task, with the highest ICCs for mV and the lowest for area, regardless of eyes being open or closed. The intersession reliability was moderate to high for mV (ICC range: 0.60-0.82) and little to very high (ICC range: 0.21-0.97) for the range of ML and AP, as well as an area in conditions with vibration and cognitive task. Conclusion: The mV is the most reliable COP parameter for assessing postural control under ankle vibration and dual-task conditions for both operated and non-operated sides. During closed-eye conditions, the application of vibration affected the intersession reliability with decreased ICCs on the operated side and increased ICCs on the non-operated side.