Acute effect of labile surfaces during core stability exercises in people with and without low back pain

Objective: The purpose of this study was to measure trunk muscle activity, whole body balance, and lumbar range of motion during core stability exercises in individuals with and without low back pain (LBP) on and off a labile surface. Design: Descriptive cross-sectional study. Setting: University laboratory. Participants: Ten individuals with chronic non-specific LBP and 10 matched control subjects. Main outcome measures: Bilateral trunk muscle activity was measured using surface electromyography (EMG); whole body balance was measured by quantifying the dispersion of the centre of pressure (CoP); lumbar range of motion (LROM) was measured with single-axis inclinometers. Results: Individuals with LBP had adaptive recruitment patterns during the side-bridge and modified push-up exercises. CoP dispersion and LROM were not different between groups for any exercise. The labile surface did not change the difference between groups, and only increased muscle activity during the side-bridge (p<0.05). The labile surface increased LROM (p=0.35) and CoP dispersion (p