Iron vest is an internal practice sometimes trained along with iron palm that is designed to help the body absorb damage from strikes. In iron vest training, the student performs certain movements for repitition increase the qi and, over time, allow it to withstand harder and harder strikes from an opponent.
Iron vest also typically involves some standing meditation in addtion to preset movements.
Iron vest should be practiced only under the guidance of a qualified instructor, as incorrect practice can potentially cause damage to the qi flow and internal organs.