Yes it is a crime to resist arrest.
When you resist arrest and are lawfully being arrested then when you are arrested you will be charged with resisting arrest.
Resisting arrest will not prevent your arrest although it will make it more difficult for you as more police will be called in to help subdue you and get you arrested.
Resisting arrest could get you shot, tasered and even injured.
Either way you will be arrested and go to jail and have more charges against you.
And if you beat up on the law enforcement officer you'll be charged with battery of a LEO which is a more serious charge.
And beating up an LEO is more serious than beating up just a random person.
Resisting arrest can be a felony or a misdemeanor. Pursuant to ARS 13-2508, if physical force is used or threatened against an officer, or if your resistance created a substantial risk of causing physical injury to an officer, then resisting arrest is a Class 6 Felony.
A person is guilty of resisting arrest when he intentionally prevents or attempts to prevent a police officer or peace officer from effecting an authorized arrest of himself or another person.
Resisting arrest is a class A misdemeanor although it can sometimes be a felony.