Or even walk much. Hilarious. But wait, there's more.
I'm somewhat active in the gun rights and self-defense communities. I'm not a competitive shooter or instructor, but I'm at least aware of what is going on. It always amazes me when self-proclaimed serious self-defense enthusiasts are fifty or more pounds overweight. Some of them smoke like chimneys. Now I'm no pro athlete, but I try to keep myself somewhat healthy. Why? Because the first skill you want to have down for self defense is running away. Hotfoot your ass out of trouble. I can do that. My knees will be sore the next day, but the alternative is even less appealing.
Movement is the foundation of any serious self-defense system, both in defense and attack. You need to be able to get yourself physically away from trouble if you find yourself outmatched. You need to move explosively to properly employ cover and limit exposure in offense or defense. This is important. Plan your self defense training around it.
Self-defense is not about owning or carrying a weapon. The biggest part is mindset. Looking for threats and react to them before they get to you. Train so that you can properly use your defensive tools. Maintain basic physical health so you can handle the stress you will be under in these situations. I'll be the first to admit that I don't have all of these down, but that doesn't make any of them less important.