Since the inception of modern strength training, the push-up has remained one of the top bodyweight exercises for targeting muscles of the upper body. While often referred to as an arms and chest exercise, the other muscles that push-ups work should not go overlooked. Considering that the push-up is a compound exercise that targets multiple muscle groups simultaneously, it has great potential to build upper-body strength. When incorporating push-ups as a part of a well-balanced training program, they can build significant strength in the pectoralis, triceps, and anterior deltoid muscles.

Source: Healthline