The pectoralis major is a large, fan-shaped muscle located on the upper chest. It is involved in four different movements of the shoulder joint. Due to its many actions you must do more than bench presses to develop these muscles optimally. A study published in the Journal of Strength Conditioning concluded that bench angle ranging from flat to 56 degrees, affected different parts of the pectoralis major and anterior deltoid (front of the shoulder muscle). Athletes should do inclines and flat benches to maximise strength and mass in the chest and shoulders.