THE PROBLEM WITH TRADITIONAL TECHNIQUE
The bar is lowered until it touches the chest and then pressed back up to the start position. Everyone is expected to lower the bar to the chest; anything less is considered poor form, sub-standard, and even wimpy by fellow lifters. However, to perform the exercise under such guidelines requires a greater range of motion (ROM) than is found in the shoulder joint of most people - particularly male athletes. Why is it so important to work within the ROM of your shoulder joint? Some simple anatomy will help to explain this.
The movement-restricting factor during a bench press is not the muscles of the shoulder; it is the special connective tissue casing around the shoulder joint called the "joint capsule." This highly specialized structure is anatomically designed to not only allow just the right amount of motion to prevent joint damage, but also contains thousands of specialized nerve endings called "proprioceptors." Proprioceptors are special nerve endings that communicate with the brain to inform it of joint position and speed of movement, as well as pressure, tension and pain in and around the joint. Loading the shoulder and forcing it beyond the functional ROM limit will stretch the shoulder joint capsule. In most people this will occur by letting the bench-press bar travel until it touches the chest.
Additionally, because the bench press is performed on a flat weight lifting bench, normal movement of the shoulder blades (scapulae) is disrupted. This demands that more movement must occur in the shoulder joint itself. As the bar is loaded with heavier and heavier weights, the shoulder blades are pressed into the bench harder and harder, further disrupting the normal mechanics of the shoulder girdle joints and overloading the shoulder.