Reduction In Support Leg Active Range Of Motion And Increase In Postural Sway On People With Chronic Low Back Pain During Y-balance Test

People with Chronic Low Back Pain (CLBP) experience reduction in balance that might be inconsistently quantified during bilateral standing test. They also experience reduction in performance during Y-Balance Test (YBT). PURPOSE: Assess difference in lower limb reach, joint kinematics and postural sway between people with and without CLBP during YBT, and investigate the variable correlations. METHODS: 44 CLBP and 22 asymptomatic participants executing YBT. Normalized reach (nReach) calculated by dividing measured reach by leg length, Joint Active Range of Motion (AROM) calculated from motion capture while center of pressure (COP) total excursion (TOTEX), mean velocity (MVEL), normalized TOTEX (nTOTEX) and normalized MVEL (nMVEL) calculated from force plate during YBT. One-way Multivariate Analysis of Covariance (MANCOVA) used on joint AROM and COP variables, and pearson correlation on the significant variables. RESULTS: CLBP participants have reduced nReach and increased nMVEL in all directions. Anterior direction MANCOVA resulted in CLBP affects nReach F(1) = 7.322, p = 0.009, partial η2 = 0.107, and nMVEL F(1) = 7.987, p = 0.006, partial η2 = 0.116. CLBP affects nReach F(1) = 8.837, p = 0.004, partial η2 = 0.127, and nMVEL F(1) = 6.298, p = 0.015 partial η2 = 0.094 for postero-medial direction. CLBP affects nReach F(1) = 8.620, p = 0.005, partial η2 = 0.124, and nMVEL F(1) = 6.156, p = 0.016 partial η2 = 0.092 for postero-lateral direction. nReach is correlated with joint AROMs in all directions while nMVEL is independent. CONCLUSIONS: CLBP group experience increased postural sway quantified by nMVEL, and reduction lower limb reach quantified by nReach. Clinicians can consider nMVEL and nReach during YBT to help identify specific deficits in CLBP.