36+ Bench Press Arch Background. There are multiple factors that go into establishing a bench press's legitimacy due to arch. When you arch (left), you cut the range of motion another several inches.
Lie on the bench with a natural arch in your lower back.
Let's talk about the bench press—why you cannot arch your back and how to optimize your bench press form. To set up for a bench press i tell people to stick your chest out as far as you can, arch your upper back. Many people think the bench press is just a chest exercise, but i'm here to tell you that your triceps, shoulders, back, and even your glutes are involved. Can't arch my back during the bench press.