When you are trying to build muscle, you have the option of using free weights or machines. According to MayoClinic.com, both are beneficial as long as you use proper technique. The butterfly bench press is a chest exercise commonly done on a machine. In the fitness industry, this exercise is simply referred to as "flys."
When you do a chest workout, your goal is to perform exercises from multiple angles and directions to maximize recruitment. A standard bench press targets the middle area of the chest. Butterfly presses target the inner part. The difference between this exercise and a standard bench press is your arm position. With bench presses, you bend your elbows as you lift and lower the weight, and with butterfly presses you do not.
Execution of the Exercise
When doing the butterfly press, maintain proper form. This will ensure you reach full development and do not injure yourself. Sit on the seat of the fly machine and adjust the handles out at your sides so you feel a slight stretch in your chest when you grasp them. Keeping your back tight to the backrest and elbows slightly bent, move the handles out in front of your body until your fists are close together. Squeeze your chest forcefully for a full second, slowly move the handles back and repeat.
On a Cable Machine
A cable machine has two weight stacks spaced eight to 10 feet apart and pulley attachments that slide up and down and can be used to do flys from a standing position. Begin by attaching single handles to chest-high settings on the pulleys and stand in between the stacks with your feet in a staggered stance. Grab a handle in each hand and slightly bend your elbows. Your arms should parallel to the floor at this point. Keeping your core tight, move the handles across the front of your body until your hands almost touch. Slowly move the handles back and repeat.
Dumbbells can be used for flys as well. These are performed while lying face-up on a weight bench. Hold the dumbbells an inch apart above your chest with your palms facing each other and elbows slightly bent. Slowly lower the weights down to your sides until you feel a good stretch in your chest, then push them back up. Squeeze your chest forcefully for a second and repeat.
Although you cannot use as much weight with flys as you can with presses, you still want to tax your muscles. A good rule of thumb is to use a resistance that allows you to do eight to 12 reps with proper form.
Changing the Focus
The basic fly on a flat bench or machine targets the inner, middle chest. You can target the upper, inner chest by doing flys on an incline bench, and you can target the lower, inner chest by doing flys on a decline bench.