During a chest flye exercise, which muscle is primarily engaged?

The pectoralis major is primarily engaged during a chest flye exercise. This exercise is designed to target the chest muscles, and the pectoralis major is the largest muscle in that area. When performing a chest flye, the arms are extended out to the sides and then brought together in front of the body, which emphasizes the contraction of the pectoralis major as it works to adduct the upper arms across the chest.

The activity primarily relies on the horizontal adduction motion facilitated by the pectoralis major, supporting the overall shoulder movement. The involvement of this muscle is essential for generating the necessary force to bring the arms together, which is the primary action of the chest flye. Additionally, while other muscles may play a secondary role for stabilization or assistance during the movement, the primary focus remains on the pectoralis major as the main muscle engaged in this exercise.