Both the vertical chest press machine and the barbell bench press are exercises that target the pectoralis major muscle of the chest. Some differences exist pertaining to the execution, benefit and safety of each exercise. Neither modality is particularly beneficial functionally, meaning they do not simulate many daily activities or athletic movements, but both offer benefits in muscular development and strength.
Because of its effectiveness in muscle development, the bench press is probably the most widely used exercise in gyms. Because the resistance remains constant using free weights, such as the barbell, it is known to have dynamic constant external resistance, or DCER. The force required to lift the barbell will change at different segments through a range of motion, but the weight remains the same. During the bench press, the initial push of the barbell away from the chest is the strongest point of the exercise. As the arms extend and the barbell moves from the chest, the mechanical advantage of the bones is lessened and so is the force applied.
Bench Press Advantages
One advantage that the bench press has is the increased range of movement. Muscle building is predicated on maximum contraction and extension. During the bench press, controlling the barbell down to your chest allows the elbows to drop beneath the bench, creating a maximum stretch of the pectoralis major. Furthermore, the bench press requires the recruitment of smaller stabilizer muscles in its execution. The serratus anterior, anterior deltoid, triceps brachii, and the coracobrachailis muscles are all recruited for support and thus developed during the bench press.
Bench Press Disadvantages
Due to the demand and load as a result of DCER, free weights take longer to master proper form and technique, which is why a "spotter" is recommended for a bench press. Furthermore, since the bench press is a plate-loaded exercise, it is more time consuming: Increasing or decreasing the resistance demands the constant loading and unloading of the plates. Finally, many injuries to the acriomioclavicular, or AC, joint of the shoulder occur as a result of the bench press. The bench press is used by gym-goers to determine or display physical strength, which can compromise the ligament at the AC joint.
Chest Press Machine
Sometimes referred to as the vertical chest press, the chest press is executed with the torso in an upright position. A weight stack requiring a pin insertion to select the resistance is used instead of loading plates. The stacks are connected to the movable component of the machine by a cable-pulley system. Chest press machines allow for variable resistance, in which the resistance is changed at various points of the exercise, thus changing the amount of force applied to move the resistance. Any non-circular, oblique-shaped pulley or cam on a weight machine denotes that it is a variable resistance machine.
Chest Press Advantages
Safety is one of the primary advantages of using a chest press machine. No spotter is needed to lift the weight, so focus can be on proper form and technique, expediting the learning process. It also is easier to isolate the targeted muscle group with machines. The chest press machine is time-friendly compared with the bench press in that there is only a simple pin insertion to change resistance.
Chest Press Disadvantages
There are a few disadvantages to using the chest press machine. Unequal distribution of force applied is possible -- one extremity could potentially do the work of both. With bench pressing, if one arm is weaker, the bar will tilt. With the chest press machine, one extremity could be receiving more of the benefit by doing more of the work. Also, it is not a functional exercise machine because very rarely in daily or athletic activities are you performing this pushing motion from a seated position.