 Because you're going to hurt yourself. And when you hurt yourself, you lose ground. Losing ground is like losing principle. I've ripped my bicep off trying to lift a car up off the ground. Used to be able to do it when I was a kid. When I was 50 years old, those tendons weren't the same. Boom, pop, gone. Bicep up, out of the way, into the shoulder. Had to be sewn back on. Now it's shorter, smaller, weaker.