I was (comparatively) undersized for the sports and positions I played. I've met plenty of people with more natural size, strength, and ability who don't care or don't work nearly as hard. However, I have since seen the world from some of their perspective.

Some kids simply don't have any interest in sports or in the specific sport they seem most gifted in. The mental aspect is just as big as the physical.

Some kids have an interest, and sometimes even an aptitude it sports that don't fit their body type. I coach shot put and discus. We have one thrower who looks like an ideal long distance guy. He also runs the 800, and when ever he checks in for that event, all the kids immediately assume that he is the favorite and go over to talk to him. He repeatedly tells them that he will likely get last, but none of them believe him.

He almost always gets last in all of his races (and usually by a large amount). On the other hand, over the past 2 years he has been one of the best shot putters and discuss throwers in the state.

The last category are the kids who have no parental support when it comes to sports.