Résumé
Clinical models of chronic low back pain (cLBP) highlight the major role of excessive attention to pain in the rising of disability. cLBP is reducing patients ability to adapt their movements to external perturbations. For example, gait variability in cLBP is characterized by a decrease of complexity.Objective: to assess the role of maladaptative attentional behaviours in the decrease of gait complexity in cLBP patients, using a visual display as a distraction during walking.Methods: 14 cLBP patients with no prior surgery nor significant leg pain, and 7 healthy matched controls were included. Subjects walked on a treadmill at preferred walking speed, with and without distraction. Stride time fractal complexity was assessed using Detrended Fluctuation Analysis. A two-way ANOVA with repeated measures on distraction was performed on fractal exponents.Results : ANOVA showed a significant group x distraction effect on the fractal complexity of stride time series (F(1, 19) = 9,972, p = 0,004). Post-hoc analysis confirmed the isolated effect of distraction on cLBP patients, with an increase of complexity when patients were distracted.Conclusion: our results suggest that excessive attention to pain could explain cLBP loss of complexity. More targeted treatments are required to help patients recover motor adaptability.