The influence of divided attention on walking turns: Effects on gait control in young adults with and without a history of low back pain.

The cognitive control of gait is altered in individuals with low back pain, but it is unclear if this alteration persists between painful episodes. Locomotor perturbations such as walking turns may provide a sensitive measure of gait adaptation during divided attention in young adults. The purpose of this study was to investigate changes in gait during turns performed with divided attention, and to compare healthy young adults with asymptomatic individuals who have a history of recurrent low back pain (rLBP). Twenty-eight participants performed 90° ipsilateral walking turns at a controlled speed of 1.5m/s. During the divided attention condition they concurrently performed a verbal 2-back task. Step length and width, trunk-pelvis and hip excursion, inter-segmental coordination and stride-to-stride variability were quantified using motion capture. Mixed-model ANOVA were used to examine the effect of divided attention and group, and interaction effects on the selected variables. Step length variability decreased significantly with divided attention in the healthy group but not in the rLBP group (post-hoc p=0.024). Inter-segmental coordination variability was significantly decreased during divided attention (main effect of condition p <0.000). There were small but significant reductions in hip axial and sagittal motion across groups (main effect of condition p=0.044 and p=0.040 respectively), and a trend toward increased frontal motion in the rLBP group only (post-hoc p=0.048). These findings suggest that the ability to switch attentional resources during gait is altered in young adults with a history of rLBP, even between symptomatic episodes.