One of the most-frequently used practical stunts is stage combat. Although contact is normally avoided, many elements of stage combat, such as sword fighting, martial arts, and acrobatics required contact between performers in order to facilitate the creation of a particular effect, such as noise or physical interaction. Stunt performances are highly choreographed and may be rigorously rehearsed for hours, days and sometimes weeks before a performance. Seasoned professionals will commonly treat a performance as if they have never done it before, since the risks in stunt work are high, every move and position must be correct to reduce risk of injury from accidents.