Punching bag

A punching bag is a tough bag which is supposed to be punched a lot. It is used in exercise or stress relief to improve one of three areas: physical strength, aerobic fitness or punching technique.
History.
Punching bags have been used in martial arts for as long as there has been a written history of military training. Similar apparatus in Asian martial arts include the Okinawan "makiwara" and the Chinese "mook jong", which may have padded striking surfaces attached to them.