Biomechanical Analysis of the Pelvis Angular Excursion in Sagittal Plane in Response to Asymmetric Leg Loading Tasks in Females with and without Non-specific Chronic Low Back Pain

BACKGROUND: Controlling pelvic excursions is the focus of stabilization exercises such as legs loading tasks in rehabilitation of non-specific chronic low back pain (NSCLBP) patients. Progression of these exercises is based on the ability to perform tasks with minimal sagittal pelvic excursions. In spite of emphasis on minimizing pelvic motions, no previous studies have investigated kinematic analysis of the pelvic excursions during leg loading exercises in NSCLBP patients. OBJECTIVE: This study aims to investigate the sagittal pelvis excursion during performing asymmetric leg loading tasks in individuals with and without NSCLBP. MATERIAL AND METHODS: In this cross-sectional study, kinematic data were collected from 15 NSCLBP patients and 15 asymptomatic participants by a motion analysis system during right and left leg loading tasks with 2 levels of difficulty. Pelvis segments were modeled using Visual3D motion analysis software. Maximum pelvic excursion in the sagittal plane was calculated during each task. Mixed model analysis of variances (group, task difficulty level, side) was performed for statistical analysis. RESULTS: The maximum sagittal pelvic excursion values of all tasks in NSCLBP were smaller than those in the control group; however, no significant main effects and interactions were found between two groups. CONCLUSION: These results suggest that NSCLBP patients completed loading tasks without differences in sagittal pelvic excursions as compared to controls. Assessment of NSCLBP patients only based on pelvic angular excursion may not be sufficient for clinical decision making. Furthermore, asymptomatic individuals may need to practice for controlling pelvic excursion during leg loading exercises similar to the CLBP patients.