Fear of Movement Is Not Associated With Objective and Subjective Physical Activity Levels in Chronic Nonspecific Low Back Pain.

OBJECTIVES: To assess the association of physical activity measures, derived with an accelerometer and a self-reported questionnaire, with fear of movement in patients with chronic nonspecific low back pain (LBP) and to investigate the association between disability and fear of movement in this population.

DESIGN: Cross-sectional study.

SETTING: Outpatient physical therapy university clinics.

PARTICIPANTS: Patients (N=119) presenting with nonspecific LBP of >3 months' duration.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Physical activity levels measured objectively with an accelerometer (ie, counts per minute, time spent in moderate-to-vigorous and light physical activity per day, number of steps per day, and number of 10-minute bouts of moderate-to-vigorous physical activity per day) and subjectively with a self-reported questionnaire (Baecke Physical Activity Questionnaire); fear of movement (Tampa Scale of Kinesiophobia); pain (11-point numerical rating scale); disability (Roland Morris Disability Questionnaire); and depression (Beck Depression Inventory). The associations were examined with correlational, univariate, and multivariable linear regression analyses.

RESULTS: None of the objective physical activity measures were associated with fear of movement. The apparent association of self-reported physical activity levels with fear of movement (correlational analyses: r=-.18; P<.05; univariate regression analyses: β=-.04; 95% confidence interval [CI], -.07 to -.01; P=.04) was not confirmed in multivariable analyses. Fear of movement was consistently associated with disability in both correlational (r=.42; P<.01) and multivariable (β=.21; 95% CI, .11-.31; P<.001) analyses.

CONCLUSIONS: Our data support one aspect of the fear-avoidance model-that higher fear of movement is associated with more disability-but not the aspect of the model linking fear of movement with inactivity.