Sever's disease or calcaneal apophysitis is the most common cause of heel pain in the growing athlete and is due to overuse and repetitive micro trauma of growth plates of the calcaneus in the heel. It occurs in children ages 7 to 15, with the majority of patients presenting between 10 and 14 years of age. It is in relation to Osgood-Schlatter disease which affects the knee rather than the heel/ankle.