Why is exercise important?

Why exercise is important is because there are all kinds of exercise. Swimming helps you grow big and strong. So does Soccer, Football, Skateboarding, Basketball, Baseball and Snowboarding. I don't think Motocross and Golf gets exercise for you, do they? Lifting up wheights gets body building, and I'm a Pre-Teen for swimming, my favorite thing to do to grow big and strong. I like growing up because it's my favorite thing to do.