Muscles trained: Triceps and core
Set a bar on the supports of a squat rack or cage set at about waist level. Grab the bar with a pronated grip that's just inside shoulder-width. With your body and arms completely straight and your weight on the balls of your feet, begin by slowly bending your arms and lowering your entire body head-first toward the bar. When your forehead is about an inch or two from the bar, pause for a second, then push back up to the starting position.