A pec deck machine is designed to increase strength and muscle mass in the chest. It’s so effective that the American Council on Exercise ranked it as one of the best exercises for building chest muscles.

“The pec deck works both your chest and its supporting muscles, primarily your pectoralis major, which is the muscle that allows you to swing and bring your arms together,” explains Caleb Backe, a certified personal trainer and health and wellness expert for Maple Holistics.

“This strengthens your torso and stabilizes your shoulder blades. Meanwhile, your supporting muscles, like the serratus anterior, are also activated during a pec deck. It opens up and strengthens the backs of your shoulders to allow you to complete the exercise.”

Even though a pec deck isn’t the only exercise for chest muscles, one reason it ranks high is its ability to provide an intense chest workout.

“It’s superior to other exercises that only work the chest as an added bonus,” Backe says. “The pec deck’s primary function is to activate the chest muscles, which can strengthen your overall core and arms.”

Understanding the proper technique can help you avoid muscle injury.

1. Select the weight for the machine.
2. Sit on the platform. Press your back firmly against the back of the platform with your feet flat on the floor.
3. Grab one handle of the machine with each hand. Depending on the model, the pec deck may have a resting pad. If so, place your forearms on each pad. Bend your arms at a 90° angle and keep your elbows at chest level.
4. Gripping the pec deck handles, pull your arms toward your body while contracting your pectoral muscles. Bring the handles or arm pads in front of your chest, hold the position for a couple of seconds, and then slowly release back to starting position.
5. Repeat the desired number of reps.

Safety is important while using a pec deck machine. This includes knowing proper breathing techniques to ensure your muscles receive enough oxygen.