You SHOULD arch when you do a bench press. Even if your goal is the build the muscle. Of course the degree of arch should be different with a bodybuilding bench press compared to a powerlifting bench press, but arching your back, especially your upper back is what you SHOULD be doing if you want to build pecs. Arching protects your shoulders. Arching increases pec activation If you’re a powerlifter, arching a little bit harder decreases the range of motion which allows you to press more in compe

No arch, no wide grip! The arch in a bench press achieves a number of things that allow you to bench press more weight safely. The most important part of the arch is the upper back. This is called thoracic extension, and this is paired with another movement of the shoulder blades, which is called scapula retraction (pulling your shoulder blades back). This position is what you need if you want to be able to comfortably position your arms in a wide grip for a bench press, and if you’re not archin