Introduction: Pain related fear and pain intensity have been identified as factors that potentially negatively influence Functional Capacity Evaluation (FCE) performances in patients with chronic low back pain (CLBP). Conflicting results have been reported in the literature. The objective of this study was to analyze the relationships between pain intensity and pain-related fear on the one hand, and performances during an FCE on the other hand in two samples of patients with CLBP.

Methods: Two cross sectional observation studies were performed with two samples of patients with CLBP (study 1: n=79; study 2: n=58). Pain related fears were operationally defined as the score on the Tampa Scale of Kinesiophobia in study 1, and the Fear Avoidance Beliefs Questionnaire (FABQ) in study 2. Pain intensity was measured with a Numeric Rating Scale in both studies. Avoidance behavior observed during FCE was in both studies operationally defined as the unwillingness to engage in high intensity performance levels of three different functional activities: high intensity lifting, prolonged standing in a forward bend position, and fast repetitive bending at the waist.

Results: A total of 25 correlations between pain and pain related fear, and performance variables were calculated, out of which 7 were significant (p< 0.05). The strength of these significant correlations ranged from r=−0.23 to r=−0.50. Multivariate linear regression analyses revealed non-significant relationships in most instances. Pain and pain related fear contributed little if any to these models.

Conclusions: The relation between pain and pain related fear and FCE performance is weak or non-existent in these samples of patients with CLBP. The hypothesis that pain and pain related fear are important factors in FCE performance was not supported in this study. Possible explanations will be discussed during the presentation.