Investigating the Fear Avoidance Model in People With Whiplash: The Association Between Fear of Movement and In Vivo Activity.

OBJECTIVES: The aims of this study were to examine the relationship between fear of movement and activity levels in people with whiplash-associated disorders (WAD) over the first 3 months postinjury, to determine the mediating effect of: fear of movement on the relationship between catastrophizing and activity levels, and activity levels on the relationship between fear of movement and disability in patients with WAD.

MATERIALS AND METHODS: Ambulatory monitoring of physical activity was conducted for a minimum of 8 waking hours on 2 consecutive days within 4 weeks postinjury and at 12 weeks postinjury for 103 (74 female) people with WAD. Time spent in upright postures (uptime) and time in motion (TIM) were collected along with measures of pain, disability, pain catastrophizing, and fear of movement. The association of self-report outcome measures with uptime and TIM were examined. Mediation analyses were performed to determine the mediating effect of: fear of movement on the relationship between catastrophizing and activity, and activity levels on the relationship between fear of movement and disability.

RESULTS: Fear of movement was significantly related to uptime but not TIM. Mediation analyses showed that the relationship between fear of movement and disability was not mediated by activity levels, and that the relationship between catastrophizing and activity levels was not mediated by fear of movement.

DISCUSSION: Our data suggests measures of Fear Avoidance Model are not related to general physical activity in people with WAD. Investigation of movements specific to the cervical spine and alternative explanatory models may be required.