Ever watch a kid play in the park? If you have not ever taken the time do so, find a park and try not to look too creepy. You will notice that very few kids have flexibility, mobility or stability issues. They jump off of things and start sprinting at full speed at whim. You will find these kids all look pretty athletic. Sure, some may possess more natural ability to jump higher and run faster but, provided the kid is in good shape, most kids have the same athletic ability.
As we get older, our life choices either cultivate this athleticism or hinder it. Some of us stop running around and jumping strictly for fun and restrict it to when we play organized sports while others sit in front of a computer screen or a t.v. for entertainment and get stiff, immobile and lose kinesthetic sense as the years go by.
While we may all start out as athletes, most of us definitely do not stay like that.
Not Everything Is Appropriate