While exercise is good for your body - some may not be as good for it as others.
Mike Bogden is a physical therapist at Cleveland Clinic.
He says there are certain exercises you can do without.
One of them is the bench press.
Bogden warns, "As you're bringing that bar down, if you're brining it all the way down to the chest, it really stresses the front of the shoulder. It strains the rotator cuff."
He recommends if you choose to bench press -- use a lighter weight and avoid bringing the bar all the way down to your chest.
You should also mix in a variety of presses including incline and military.
Many people think doing one hundred crunches a day will get them rock-hard abs, but Bogden say that is a myth.
"Crunches only target one area of the abdominal region," he notes. "So several core-strengthening exercises should be part of any abdominal workout regimen."
How he does not recommend adding hanging knee raises.
He says typically, very few people do them correctly and never benefit fully from the movement.