Fatemeh Ghasemi Dehcheshmeh - Department of Physical Therapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
Mohammad Reza Nourbakhsh - Department of Physical Therapy, University of North Georgia, Dahlonega, USA
Zahra Amini farsani - Bayesian Imaging and Spatial Statistics Group, Institute of Statistics, Ludwig-Maximilian-Universität München, Munich, Germany
Babak Bazrgari - Department of Biomedical Engineering, University of Kentucky, Lexington, KY, United States
Amir Massoud Arab - Department of Physical Therapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran

Objectives: It is crucial to investigate the daily functions commonly utilized by individuals with low back pain (LBP) due to their implications for recurrence and chronicity. Stand-to-sit (StTS) task is one of the more repetitive functions in human daily life. This study aims to evaluate pelvic and lower limb joint kinematics during the StTS task in individuals with Non-Specific Chronic Low Back Pain (NSCLBP) compared to a healthy control group.Methods: Pelvic and lower limb joint kinematic data in all three planes were recorded from ۲۰ individuals with LBP and ۲۰ healthy individuals using a Qualisys motion capture system during the StTS task. A Functional Data Analysis statistical approach was employed to compare the kinematic data between the two groups.Results: In the initial phase of the movement, we observed a greater anterior pelvic tilt (P=۰.۰۲۸) and an altered pelvic frontal plane motion pattern (P=۰.۰۲۹) in the LBP compared to the healthy group. The only significant differences between the lower limb joint kinematics of the two groups were a less hip external rotation position (P=۰.۰۲۵) and a more knee adduction pattern (P=۰.۰۰۲) on the right side in the LBP subjects compared to the healthy group.Conclusion: Considering a few differences noted between the two groups across various joints and planes evaluated, it appears that the kinematic pattern of the lower limbs does not significantly differ between the NSCLBP and healthy groups during the StTS task in most comparisons. However, distinct kinematic patterns have been observed in the pelvic region, particularly in the sagittal and frontal planes, between the two groups.        Level of evidence: III

۳D motion analysis, Kinematics, Low back pain, lower limbs, Stand-to-sit