Runner's rump

Runner's rump is a cutaneous condition characterized by a small ecchymoses in upper gluteal cleft caused by constant friction with each stride when running.{{cite book |author=Rapini, Ronald P. |author2=Bolognia, Jean L. |author3=Jorizzo, Joseph L. |title=Dermatology: 2-Volume Set |publisher=Mosby |location=St. Louis |year=2007 |pages=1371 |isbn=978-1-4160-2999-1 }}