The non-ischemic forearm exercise test was developed for a safe and specific screening of patients with exercise intolerance. Some patients with normal tests presented a hyperCKemia 24 hours after the test. The aim of this study was to explore whether this increase was a hallmark of a disease and could be potentially useful for diagnosis. We retrospectively analysed all the patients who performed the non-ischemic forearm exercise test at the Institute of Myology between 1999 and 2016 and who presented a significant increase in CK 24 hours after the test. CK levels were considered significantly increased if their level rose by more than 300 UI/L 24 hours following the test. On 1486 subjects who performed a non-ischemic forearm exercise test, 56 (3.8%) had an increase of CK level 24 hours after. Among these 56 patients, 15 had no raise in lactate level related toglycogenosis V. For patients with normal elevation of lactates, 19 had a muscular dystrophy secondary to mutations in ANO5, DMD, FKRP, PLEC, SGCA, CAPN3 or DYSF genes. HyperCKemia is rare after a non-ischemic forearm exercise test. A normal elevation of lactates associated with hyperCKemia may indicate a muscular dystrophy with a pseudo-metabolic presentation.