The bridge is an exercise that activates all of the core muscles. In the bridge position your body should be in a completely straight line with your abs, glutes, quads, and shoulders flexed. The only thing that is in contact with the floor is the forearms and the tips of your feet. This position is typically held for intervals or until muscular failure. It can be included in a warm-up to activate the core, or it can be part of a workout routine.