Punching Bags
Punching bags have been used in martial arts and swordplay for the entire written history of military training.[1] Similar apparatus in Asian martial arts include the Okinawan makiwara and the Chinese mook jong, which may have padded striking surfaces attached to them.[2]
In martial arts and combat sports—such as karate, taekwondo, and Muay Thai—"heavy" bags, standing bags, and similar apparatuses have been adapted for practicing kicking and other striking maneuvers in addition to developing punching technique.[2]
Construction
Punching bags are often filled with grains, sand, rags, or other material, and are usually hung from the ceiling or affixed to a stand.[3] Other bags have an internal bladder to allow them to be filled with air or water. The design of a
punching bag allows it to take repeated and constant physical abuse without breaking. The bag must also absorb the impact of blows without causing harm to the user.
Source