Self-reported physical function is strongly related to pain behavior and pain interference and weakly related to physical capacity in people with chronic low back pain.

The participant sample was recruited from a specialized pain center and the Bay Area community, which may not represent the typical psychosocial or socioeconomic profile of patients in general outpatient clinics. Most participants were Caucasian and had higher socioeconomic status, limiting generalizability. The objective capacity measures used, while common in clinical settings, may lack the sensitivity to detect subtle movement patterns or motor control phenotypes that more advanced tools like motion capture could identify. The study design is cross-sectional, so it describes associations at one point in time and cannot determine causality or how these relationships change over time.

None declared.

Do not interpret the lack of correlation between self-reported disability and objective capacity as evidence that patients are exaggerating or underestimating their function. The measures are assessing different constructs; self-report is closely tied to pain behavior and interference, while capacity tests measure physical performance.