Abdominal muscles are body armour. They help protect your vital organs from damage. They keep your body performing at maximum and, when the clothes come off, they make you look terrific. This workout is the anvil where that armour is fashioned.
A quick trick to test the doneness of your beef. The fleshy part of your palm mimics the tenderness of your beef. For example, if you like your steak rare, your beef should be as soft as your palm while it's wide open and relaxed.