Study Design: Prospective cohort, test-retest design.
Background: Directional preference (DP) with centralization (CEN) and DP without CEN are common pain-pattern responses assessed by Mechanical Diagnosis and Therapy (MDT). Although there is evidence that MDT can reduce pain and disability in the short term by treating the patient with direction-specific exercises concordant with the patient's DP, the mechanism responsible for this is unclear.