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The Muscles Used in a Pec Deck Machine

author image Shannon Sukovaty
Based in Malibu, Calif., Shannon Sukovaty has been writing health-related articles since 1992. Her work has appeared in “Colorado Health” magazine, “Health and Fitness Journal” magazine and on various websites. Sukovaty is a certified personal trainer with undergraduate studies in exercise physiology and credentials from the Aerobics and Fitness Association of America and the American College of Sports Medicine.
The Muscles Used in a Pec Deck Machine
Pec deck machines work your chest and shoulder muscles. Photo Credit Photodisc/Photodisc/Getty Images

A pec deck machine is a piece of gym equipment that is designed to isolate the pectoralis major and minor, the chest muscles. This equipment uses a nautilus style weight system in which the weights are controlled by leverage. The pec deck engages the chest in a butterfly style movement, arms out to the sides pushing the weight of the machine forward to the center of the chest. Working on nautilus style equipment can help you produce faster results more efficiently than other strength training equipment, notes NASA's Wallops Flight Fitness Club.

Working the Primary Muscles

When working on a pec deck you engage your pectoralis major and minor, the chest muscles. These muscles are easier to isolate on a pec deck machine than many other exercises due to the fact that the movement requires less balance and control. The machine creates a safer exercise as the resistance is up to your force and may be done without a spotter. To make sure the chest muscles, or pecs, are isolated visualize squeezing the outside of your chest in toward the center as you push forward with the movement.

Working the Secondary Muscles

This machine requires you to sit on the bench with your arms out to your side, bent at a 90 degree angle, and press forward from the inside of the arms. Because of the positioning of the exercise it will also engage your shoulder muscles, or deltoids. The forward movement or push causes the anterior delt, or front delt, to work. To decrease activation of the shoulder muscle and place more emphasis on the chest, keep the shoulders down away from your ears and visualize squeezing your entire chest from the outside-in. It is also important to work in a weight range that is right for you, to keep proper form. Proper form will help keep emphasis on your chest.

Benefits of a Pec Deck Machine

Working your chest muscles on a pec deck machine helps you isolate the muscle without stress. You can use the machine without a spotter and easily increase intensity. The pec deck machine adds an element of safety, since the weight you are bearing is not directly over you and will not fall on you if you cannot hold it.

How to Use the Machine

To use the pec deck you must first adjust your seat and the weight setting. Adjust the seat forward or backward so that your your forearms and inside of your arms should align with the arm pads. Also adjust the seat so your feet sit comfortably on the floor. Your elbows should be at shoulder level or slightly below, never above and relaxed down away from your ears. Make sure your weight load is appropriate for you, if you set it too high you can create stress on your joints. Begin by pushing the levers forward toward each other; do not let them touch. Hold for three to five seconds and slowly bring them back to your starting point. Do not let the machine fall back into place; use the resistance of the machine to slowly release back into place. Repeat for two to three sets of three repetitions.

Hazards and Considerations

Using the pec deck machine incorrectly can create stress on your shoulder joints, back and neck. It is important to always make sure you are fitting properly on the bench with your arms in alignment to the levers without any hyperextension in your shoulders. Always adjust the seat to a proper fit prior to beginning any exercises. The pec deck machine is only effective if the exercises are controlled and executed properly. Performing the movements too fast and letting the machine do all the work on the way back to your starting position does allow momentum to do the work instead of your chest muscles. Always maintain controlled movement for maximum benefits.

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