Lifting capacity with low back pain. Discrepancy between self-rated and real lifting capacity in patients with back pain and pain-free controls

Background. The fear-avoidance model implies that in situations with physical demands patients with back pain will overestimate the demand and underestimate their own capacities. Patients and methods. A total of 71 patients with back pain and 48 pain-free control subjects carried out a standardized lifting test with a preceding estimation of their lifting capacity. Results. In both groups the self-estimation and real lifting capacity were in concordance for most group members with patients showing less disconcordance than controls. In the control group 35% of the subjects even underestimated their lifting capacity, which was the case in only 14% of the patients. Patients more frequently overestimated their capacity than pain-free controls (14% vs. 2%). Within the patients subgroups could be identified where patients in general either underestimated or overestimated their own capacity. A comparison between the groups demonstrated significant differences in pain intensity, fear avoidance beliefs and effort. Conclusion. As an explanation for these unexpected results it can be hypothesized that in cases of back pain, patients' attention is focused on pain-relevant issues which enables a more realistic estimation of their lifting capacity.