(Article found at bullyingstatistics.com)

There are many types of negative physical interactions that can occur between young people, including fighting, practical jokes, stealing, & sexual harassment. These things are not considered physical bullying unless:  The same victim is targeted repeatedly; The bully or bullies intend to hurt, embarrass, or intimidate the victim; The actions occur in a situation with a real or perceived imbalance of power, such as when the bully is stronger than the victim or has a higher social standing.

In this context, physical bullying can take many forms:

Hitting; Pushing; Tripping; Slapping; Spitting;Stealing & destroying possessions, including books, clothing, or lunch money. Physical bullying may also cross the line into sexual harassment or sexual assault...