Lumbar and thoracic kinematics during step‐up ::comparison of three‐dimensional angles between patients with chronic low back pain and asymptomatic individuals

While alterations in spinal kinematics have been repeatedly observed in patients with chronic low back pain (CLBP), their exact nature is still unknown. Specifically, there is a need for comprehensive assessments of multisegment spinal angles during daily‐life activities. The purpose of this exploratory study was to characterize three‐dimensional angles at the lower lumbar, upper lumbar, lower thoracic, and upper thoracic joints in CLBP patients and asymptomatic controls during stepping up with three different step heights. Spinal angles of 10 patients with nonspecific CLBP (six males; 38.7 ± 7.2 years old, 22.3 ± 1.6 kg/m2) and 11 asymptomatic individuals (six males; 36.7 ± 5.4 years old, 22.9 ± 3.8 kg/m2) were measured in a laboratory using a camera‐based motion capture system. Seven out of the 12 angle curves had characteristic patterns, leading to the identification of 20 characteristic peaks. Comparing peak amplitudes between groups revealed statistically significantly smaller sagittal‐ and frontal‐plane angles in the patient group at the upper lumbar joint with the two higher steps and at the lower lumbar joint with the higher step. Significantly reduced angles were also observed in sagittal plane at the upper thoracic joint with the two smaller steps. Moreover, a higher number of significant differences between groups was detected with the two higher steps than with the smallest step. In conclusion, this study showed the value of a comprehensive description of spinal angles during step‐up tasks and provided insights into the alterations with CLBP. These preliminary results support prior research suggesting that CLBP rehabilitation should facilitate larger amplitudes of motion during functional activities