Trunk–Pelvis Kinematics Variability During Gait and Its Association With Trunk Muscle Endurance in Patients With Chronic Low Back Pain.

The first purpose was to investigate the trunk muscle endurance, the second aim was to evaluate the trunk–pelvis kinematics during gait, and the third was to evaluate the relationship between trunk–pelvis kinematics and the trunk muscle endurance. Thirty participants (15 nonspecific chronic low back pain [NCLBP] and 15 healthy) were included. The authors first assessed trunk muscle endurance on endurance testing protocols. The authors next measured the trunk–pelvis kinematics during gait using a 3-dimensional motion capture system. Angular displacement, waveform pattern (CV_p), and offset variability (CV_o) were also examined. Statistical analysis revealed a significant difference in (1) the trunk muscle endurance and (2) sagittal, frontal, and transverse planes CV_p between groups (P <.05). A significant moderate correlation was found between supine double straight-leg raise and frontal CV_p (r =.521, P =.03) and transverse planes CV_p (r =.442, P =.05). However, a significant moderate correlation was observed between prone double straight-leg raise and sagittal plane CV_p (r =.528, P =.03) and transverse plane CV_p (r =.678, P =.001). The relationship between (1) lower trunk extensor endurance with transverse and sagittal planes CV_p and (2) lower abdominal muscle endurance with transverse and frontal planes CV_p suggests that gait variability in these planes may result because of trunk muscle deconditioning accompanying NCLBP. [ABSTRACT FROM AUTHOR]