Exercise for your chest muscles

The assisted dip primarily works your chest muscles with a lot of emphasis on your shoulders and triceps, too. Use caution if you have elbow, shoulder, or lower back problems.
Getting set
For this exercise, deciding which plate to put the pin in can be confusing because you follow the exact opposite rule of every other exercise. In this case, you choose more plates if you want the exercise to be easier and fewer plates if you want the exercise to be harder. The more plates you select, the more your weight is counterbalanced during the exercise. For example, if you weigh 150 pounds and you place the pin in the plate marked 100, you have to lift only 50 pounds of your body weight. But if you put the pin into the plate marked 50, you have to lift 100 pounds.
After you’ve set your weight, step onto the platform of the assisted dip machine, and then carefully kneel on the knee pad or step on the foot bar as required by the machine at your gym. Grip the lower bars with your palms facing inward and straighten your arms. Pull your abdominals in and keep your body tall.

Other options
Traditional dip (harder): Stand facing a dip station, and place your hands on the dip bars. Hop up so your feet are off the floor. Straighten your arms and lift your body upward. Keep your legs straight, or bend your knees slightly and cross one ankle over the other. Remain tall and relaxed with your abdominals pulled inward. Bend your elbows and lower your body only until your upper arms are parallel to the floor. Straighten your arms to lift yourself back up.

Negative-only dip (easier): If you find a traditional dip too difficult, perform only the negative phase: Use your muscle power to lower yourself and then jump up to the start after every repetition. However, when you jump up, take it easy on your elbows.

Weighted dip (harder): Do the basic version of the exercise with a special waist belt designed to hold a weight plate on the end of it.