In the debate on just how far down the upper arms should go during the eccentric (down phase) during the bench press, remember that this is a subjective point. The most appropriate way depends on your physical limitations, bio mechanical joint structures, joint alignment, muscle density and goals.
The healthy shoulder joint, during the bench press, is designed to move 1200 which is 300 below the parallel. It's the most mobile joint in the body but structural stability is sacrificed for this mobility. Only a third of the head of the humerus is in contact with the much smaller saucer.
►AS THE WORKLOAD INCREASES
and when it's in a stretched position, the joint's ligament cannot produce as much force. At the same time, the resistance is at its greatest.
►DEPTH OF CHEST AND ARM LENGTH
will enhance or reduce one's mechanical advantage. The bar will touch the chest of a barrel chested and short-armed lifter sooner in the ROM (Range Of Motion), while the tall lifter with longer arms will have to drop his arms well below parallel to get the bar to his chest thus facing greater risk of injury.
■ WHEN BENCH-PRESSING, normal movement of the shoulder blades is disrupted. This demands that more movement must occur on the shoulder joint rather than being shared between it and the shoulder blades. As the bar is loaded with increasing weight, the normal mechanics of the shoulder joint is further strained, leading to the overloading of the shoulder. Impingement syndrome will then develop, resulting in inflammation and pain in the shoulder joint. Ailments like Bursitis and rotator cuff tendonitis commonly develop secondarily.
■ MOST SHOULDER INJURIES (during chest exercises) occur when the arms are at 100*-120* and the resistance is above 80% of 1RM. Do I hear "But I've been doing going deep for 10 years and never had an injury"? Well good on ya! Genetically, you may have an edge to go deeper, if you have a barrel chest, short arms and the strong regeneration capacity of collagen in connective tissue around the joint. But for the average Joe who's willing to listen... do the bench press range of motion test and you will not be sorry!
THE BENCH PRESS RANGE OF MOTION TEST
The test is essential as it determines the ROM of each person since everyone is different: Step 1 Place the arm in the bench press position and allow it to lower to its passive end range of motion. This is where the arm naturally stops without being forced. At this point, you have determined the exact point at which the shoulder joint capsule becomes the primary restraint to shoulder ROM. Step 2 Lift the arm 2-3 cm to find the optimal bottom position. This creates a small buffer zone (10-15 degrees), which will protect the joint capsule from overload when the weights (or egos!) get too heavy.
Another misguided criteria is keeping the lower back and the feet up - on the bench or in the air - in order to protect the spine. The human body was created with a S-curve instead of a flat spine. When the spine is flattened, the rib cage and subsequently the sternum drops down. This results in a greater distance for the bar to reach the chest. The scapulae, in reaction, will protract and elevate, subsequently moving the shoulder joint forward, which creates an extreme shoulder joint angle. So get your feet onto the floor, extend the spine to at least neutral if not slightly beyond (determined by flexibility and individual orthopaedic history), retract and depress the scapulae and at the same time push up the sternum and rib cage. This repositioning will reduce the distance the bar has to travel by elevating the height of the ribs and reduce the force of angle at the joint. Retracting and depressing the scapulae throughout the pressing phase will ensure optimal pectoral involvement. Another common mistake is to lift your head while benching! Keep your head firmly on the bench, or risk straining the shoulder joints and neck muscle.