Intra- and Inter-session Reliability of Static and Dynamic Postural Control in Participants with and without Patellofemoral Pain Syndrome

Abstract

Purpose: To determine the intra- and inter-session reliability of balance performance in people with patellofemoral pain syndrome (PFPS) and matched controls. Methods: In this methodological study, single-leg-stance performance of 15 participants with unilateral PFPS and 15 healthy matched controls was assessed using the Biodex Balance System (BBS) under 4 task difficulty levels (static and dynamic, with and without visual feedback). Intra-class correlation coefficients (ICCs), standard errors of measurement, and coefficients of variation were calculated for the overall stability index, anterior–posterior stability index, and medial–lateral stability index. Results: Static and dynamic postural performance during single-leg stance showed moderate to very high reliability in the PFPS group (ICCs=0.53–0.96) and in healthy control participants (ICCs=0.51–0.91). Both measures were more reliable with eyes closed than with eyes open. Conclusion: BBS stability indices appear to have acceptable reliability in people with PFPS, particularly in more challenging conditions, and may be incorporated into the evaluation and rehabilitation of this patient group.