A dip is an exercise which engages multiple muscles simultaneously (known as a compound exercise), and there are three dip exercises which are excellent at producing visible improvements in the lower chest, tricep, and shoulder areas. Different muscle areas can be isolated and focused on to a greater degree simply by leaning your upper body forward during the exercise, or by keeping your upper body straight throughout the movement.
This is the dip exercise which is most commonly known and perhaps the most commonly performed. To perform a traditional dip, you'll need to place yourself between two parallel bars placed shoulder width apart, and grasp the handles of the bars. Push yourself upward until your arms are straight and your triceps are full contracted. Keep your hips straight and your elbows in at your sides as you engage in this slow and controlled motion. Your legs should also be bent behind you at a 45 degree angle so that they don't reach the floor when you descend. Continue to keep your elbows in as you slowly descend back to the starting position, with your arms bent but not bowed out, and your chest area between the two parallel bars. Leaning forward during this exercise will work the lower chest muscles, while remaining straight will work the triceps.
Those who are new to this exercise, and who may have difficulty lifting their entire body weight in the course of this exercise, may want to consider using an assisted dip machine. These are very common pieces of equipment and consist of a counterbalanced knee platform stationed between the parallel bars. The counterbalanced weight can be set incrementally to reduce a portion of your body weight during lifting, making the exercise easier until you've trained enough to lift your entire weight repeatedly.
A variation of the traditional dip is the bench dip, which is somewhat easier to perform, as your legs don't have to be lifted in a bent position throughout the exercise. For this dip exercise, you'll need nothing more than a flat weight bench. Position both of your hands on the edge of the bench, with your fingers wrapped around this edge. Your arms should be extended fully and straight with your elbows close to your sides. Your legs should also be fully extended and straight out in front of you, with your heels resting on the floor and your toes pointed up at the ceiling. slowly lower your body, keeping your elbows in, until you feel a perceptible stretch in your chest, shoulders and triceps. Extend your arms straight to raise yourself up again, and repeat.
This is an interesting and extremely challenging variation on the traditional dip, which will require access to suspended gymnastic rings. The starting stance, positioning, lifting and lowering are all the same with a ring dip as they are with the standard parallel bar dip described at the beginning of this article. The key difference between a ring dip and a traditional dip, however, is that all of the inherent stability of the parallel bars is taken away. This is what makes the ring dip so difficult: it's up to you to keep the rings close by your sides as you lift and lower, utilizing a number of extra muscles in the process of stabilizing yourself.