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<0.001) during the quadruped, decreased LROM during squats (p = 0.05), and increased CoP dispersion during push-ups (p=0.04). Conclusion: Individuals with LBP exhibited adaptive trunk muscle activity levels while maintaining similar levels of balance and lumbar movement to healthy controls. Since research suggests no one mode of exercise is more beneficial in LBP rehabilitation, the practicality and safety of labile surfaces for LBP exercise rehabilitation must be questioned from this study.