Non-specific chronic low back pain elicits kinematic and neuromuscular changes in walking and gait termination

Background: Chronic low back pain (CLBP) is associated with an increased trunk stiffness and muscle coactivation duringwalking. However, it is still unclear whether CLBP individuals are unable to control neuromechanically their upper body motion during a sudden termination of gait (GT), which involves achallenging balancetransition from walking to standing.Research question: Does CLBP elicit neuromuscular and kinematic changes which are specific towalking and GT?Methods: Eleven individuals with non-specific CLBP and 11 healthy controls performed walking and sudden GT in response to an external visual cue. 3D kinematiccharacteristicsof thorax, lumbar and pelvis wereobtained, with measures of range of motion (ROM) and intra-subject variability of segmental movement being calculated. Electromyographic activity of lumbar and abdominal muscles was recorded to calculate bilateral as well as dorsoventral muscle coactivation.Results: CLBP group reported greater transverseROM of the lumbar segment during walking and GTcompared to healthy controls. Thorax sagittal ROM was higher in CLBP than healthy participants during GT. Greater overall movement variability in the transverseplane was observed in the CLBP group while walking, whereas GT produced greater variability of lumbar frontal motion. CLBP participants showed higher bilateral lumbar coactivation compared to healthy participants after the stopping stimulus delivery during GT.Significance: These results suggest that CLBP can elicit a wider and more variable movement of the upper body during walking and GT, especially in the transverseplane and at lumbar level. Alterations in upper body motor control appeared to depend on task, plane of motion and segmental level. Therefore, these findings should be considered by practitioners when screening before planning specific training interventions for recovery of motor control patterns in CLBP population