Symmetry of timing of hip and lumbopelvic rotation motion in 2 different subgroups of people with low back pain.

OBJECTIVES: To examine whether lumbopelvic motion associated with a clinical test of active hip lateral rotation (HLR) systematically varied between people classified into 1 of 2 low back pain (LBP) subgroups: lumbar rotation (Rot) or lumbar rotation with extension (RotExt); and, specifically, to determine whether the timing of hip and lumbopelvic rotation with HLR would be more symmetric, right versus left, in people in the Rot subgroup compared with the RotExt subgroup.
DESIGN: Two-group, cross-sectional.
SETTING: A university-based movement science laboratory. PARTICIPANTS: Subjects were 39 people (23 men, 16 women; mean age, 28.1+/-8.0 y) with chronic or recurrent LBP who regularly participated in a rotation-related sport and associated their LBP symptoms with participation.
INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Subjects participated in a standardized clinical examination to classify their LBP problem. A 3-dimensional movement system was used to capture kinematics of hip and lumbopelvic rotation during the test of active HLR. To examine timing of motion between the hip and lumbopelvic region, the difference in time between the start of hip and lumbopelvic rotation was calculated (startdiff). Symmetry of motion was indexed by the correlation (r) between right and left startdiff and the coefficient of determination (r2) for each LBP subgroup.
RESULTS: There were no significant differences between the 2 groups with regard to subject, LBP, activity, and range of motion variables (P range, >.05 for all comparisons). People in the Rot subgroup displayed significantly more symmetry of timing of hip and lumbopelvic rotation motion with active HLR than people in the RotExt subgroup (Rot subgroup: r=.94, r2=.88, P=.00; RotExt subgroup: r=.31, r2=.10, P=.12).
CONCLUSIONS: People in the Rot and RotExt subgroups displayed systematic differences in how they moved the hip and lumbopelvic region with the clinical test of active HLR. These findings are potentially important because such differences in movement patterns between subgroups of people with LBP suggest different contributing factors and may require different treatments to affect the movement patterns.