Boxing is a combat sport where two contenders attempt to knock each other down with their fists. Dudley Dursley became interested in amateur boxing from 1995. He showed an aptitude for the sport, and quickly became good enough to be the Junior Heavyweight Inter-School Boxing Champion of the Southeast. His participation in boxing, in conjuction with the diet enforced by the Smeltings school nurse, rapidly brought a change in Dudley's physique; though he was as large as ever, much of that fat had apparently become muscle instead. Taking up boxing also improved Dudley's bullying tactics, to the point where all of the neighbourhood children, with the exception of Harry Potter and his gang, were terrified of him.
- Harry Potter and the Order of the Phoenix (Mentioned only)