The main benefit of wearing a rash guard in no-gi jiu jitsu is to help prevent "mat burn." Typically jiu jitsu is practiced on "tatamis," or mats made of an extremely durable foam pad with a textured vinyl surface that is waterproof and provides some traction. The textured surface of the tatami can cause mat burn when exposed areas of skin are pulled or pushed along the mat. While areas like the hands and feet cannot be covered, rash guards can protect the chest, back and arms from the pain of friction-induced mat burn.