Although it's a challenging strength movement, the chest dip is not the most effective chest exercise in terms of activating the pectoralis major, or main chest muscle. The chest dip is a more effective chest exercise than other body-weight movements, such as the pushup, but it's not as effective as presses and crossovers that use external resistance.
The Dip Exercise
Changing your body position allows you to change the muscle emphasis of the dip exercise. Performing a standard dip in an upright position -- your torso is perpendicular to the floor -- mainly targets the triceps muscles. The chest muscles are secondary movers. To emphasize the chest muscles, lean your torso forward as you descend into the dip. This transfers more of the load to your chest and away from your triceps.
The American Council on Exercise (ACE) tested nine chest exercises at the University of Wisconsin, La Crosse. Researchers rated the effectiveness of each exercise based on the amount of chest activity it elicited as measured by electromyography electrodes. The dip exercise rated the highest of the body-weight movements, but it only rated sixth overall. The barbell bench press elicited the highest chest activity, with the pec deck machine coming in a close second.
The ACE study does not specify what body position was used during the dip exercise, so the results may be different with a more forward-leaning body position. Researchers also did not add any external weight to the dips, which limits the effectiveness of the exercise. For the movements that used external resistance, subjects lifted 80 percent of their one-repetition maximum. But for dips and pushups, body weight was the only resistance. Participants only completed five repetitions of each exercise, which may not be enough repetitions to challenge their muscles with body weight only. You can use a weight belt to add external resistance to the dip exercise to increase the difficulty of the movement.
Chest Workout Routine
Although the ACE study demonstrates that the dip is not the most effective chest exercise, you can include it in your routine for variety. However, you should focus the majority of your workout time and energy on more effective chest movements. A 2005 study published in the "Journal of Strength and Conditioning Research" found the dumbbell press to elicit the same amount of chest activity as the barbell press. Alternate these exercises to stimulate your body and avoid training plateaus.