"Machine Pec Deck Fly" is a video demonstrating an exercise using a Pec Deck machine, designed to target the chest muscles, specifically the pectoralis major. To perform Machine Pec Deck Fly, you typically sit upright with your back against the machine's seat and grasp the handles provided. With elbows slightly bent, you bring your arms together in front of your chest, squeezing the pectoral muscles, and then slowly return to the starting position, controlling the movement throughout. This exercise primarily isolates the chest muscles, aiding in developing strength and definition. Videos typically emphasize proper form, technique, variations, and the benefits of incorporating Machine Pec Deck Fly into a workout routine to enhance chest development and overall upper body strength.