In a narrow grip bench press, which muscles are the primary agonists?

The primary agonists in a narrow grip bench press are indeed the anterior deltoid and triceps. In this variation of the bench press, the narrower grip alters the biomechanics of the lift, emphasizing the muscles at the front of the shoulder and the back of the upper arm.

The anterior deltoids play a crucial role as they are heavily involved in shoulder flexion, which is necessary to press the barbell upwards. The triceps are also critically engaged in this movement, as they are responsible for extending the elbows during the pressing phase. This shift in focus from the chest muscles, which are typically more activated in a wider grip, allows the upper arm and shoulder muscles to take on greater responsibility for lifting the weight.

Furthermore, the mechanics of a narrow grip bench press limit the pectoral muscles' involvement compared to wider grip variations, reinforcing the role of the deltoids and triceps as the primary movers in this exercise. Thus, this understanding clarifies why the anterior deltoid and triceps are the main muscle groups activated during a narrow grip bench press.