Verbal framing, rather than measured cognitive-affective variables, is associated with short-term outcomes after spinal manipulation: a secondary analysis of a randomized controlled trial

Background Pre-treatment communication may influence short-term responses to spinal manipulation. This secondary analysis examined associations between expectations, attitude toward manual therapy, expectation fulfillment, and pain intensity (NPRS-11) and lumbar pressure pain threshold (PPT) across verbal framings.Methods Sixty-six young adults with chronic nonspecific low back pain were randomized to positive, neutral, or negative verbal framing delivered before lumbar spinal manipulation. NPRS-11 and lumbar PPT (L3–L5) were assessed at baseline (t0), immediately post-intervention (t1), and 24 hours post-intervention (t2). Group-specific correlation analyses and multiple linear regression were performed.Results Associations were sparse and inconsistent. Expectation fulfillment assessed at t2 showed no consistent associations with NPRS-11 or PPT at t1 or t2. In the positive group, higher expectations correlated with higher immediate PPT at t1 L4 (r = 0.47) and L5 (r = 0.43), and a more favorable attitude correlated with lower NPRS-11 at t2 (r = −0.45). In regression analysis predicting NPRS-11 at t2, only verbal framing group was retained (adjusted R2 = 0.26; p < 0.001): negative framing predicted higher pain (β = 0.35), whereas positive framing predicted lower pain (β = −0.26).Conclusions Short-term NPRS-11 and lumbar PPT were associated with verbal framing rather than with cognitive-affective variables.Clinical Trial Registration The ClinicalTrial.gov identifier is NCT06537739.