Chest flys are a strength training exercise primarily targeting the pectoralis major muscles in the chest. This movement involves lying on a bench and extending the arms out to the sides while holding weights, then bringing the arms back together above the chest. It can be performed with dumbbells or cables. To perform a chest fly, start by lying flat on your back on a bench with a weight in each hand. Keep a slight bend in your elbows as you lower the weights out to the sides, then raise them back to the starting position. This exercise helps improve chest strength and flexibility.