AbstractThe purpose of this study was to compare the ability of maximum grip strength (MG) and pain-free grip strength (PFG) to assess valid change over time in patients with lateral epicondylitis at the elbow. Fifty-four consecutive lateral epicondylitis cases who attended a primary care sports medicine clinic and met the eligibility criteria took part in this study. MG, PFG, and pain intensity were assessed at the patients' initial and follow-up visits. At the follow-up assessment patients were asked to complete a five-point global rating scale which inquired about their perceived change. Also, an independent rating of clinically important improvement was assigned to each patient by the physician assessor. Correlations were computed comparing the change scores of MG, PFG, pain, and the patients' global ratings. Receiver operating characteristic (ROC) curves were generated using the physician's rating of important change. ROC curve areas for PFG and MG were 0.96 and 0.63, respectively. The results show that PFG is the preferred measure.