Why Children Are More Hyper Than Adults

I have put together some true evidence on why children are more hyper than adults.
First of all, children have very small bodies making it easier for them to run, jump, and, as they usually do, play.  But adults, adults have normal sized bodies (About 2-3 feet taller than children) which makes it harder for them to stay in shape. Also, an adult  should note when they were younger they had much more time to exercise, but now they have to work.