Physical fitness and chronic low back pain. An analysis of the relationships among fitness, functional limitations, and depression.

The purpose of this study was to describe the associations between physical fitness and important aspects of chronic low back pain problems, specifically, pain, depression, physical dysfunction, and psychologic dysfunction. Ninety-six persons with chronic low back pain were evaluated with a battery of physical and psychologic disability measures and basic physical fitness tests for aerobic capacity, strength, and flexibility. Greater overall physical fitness was significantly correlated with less physical dysfunction (R = -0.48) and fewer depressive symptoms (multiple R = -0.42), but not with psychologic dysfunction (R = -0.20) or pain (R = -0.20). Fitness accounted for 23% of the variance in physical dysfunction and 17% of the variance in depression in this mildly dysfunctional chronic back pain patient sample. Strength, as compared with aerobic capacity or flexibility, was the fitness variable contributing most to these observed associations.