This is a question that has been debated for centuries. Does exercise help you get smarter? I think there is a direct correlation between exercise and exceeding in education. I found a study done that proves the connection between exercise and IQ in children.
Maybe it has something to do with the discipline of the athletes. While many assume that the high grades are due to an athlete's discipline and fear of being kept from playing sports, there is much more to the story. Student athletes tend to perform higher academically, mainly because their physical bodies are a bit healthier. Exercise is known for allowing the heart to pump oxygen to the brain. In turn, the brain is more alert. Not only does the oxygen allow for clearer thinking, it also produces endorphins that allow children to calm down and focus on tasks at hand. I also think that exercise lets children express a creative side that also helps them engage their mind.

This is interesting information. Maybe that is why I always got good grades as a child... because I have been doing sports and have been physically active since 1st grade!

For me though, I think one of the reasons why I did well in school did have to do with sports, in a different way. Sports took up a lot of time and so I only had a little extra time each day where I had to fit in my homework and study time. Because my older brother always got good grades and I wanted to follow in his footsteps, it made me have to make sure I used that little free time I had to study. I feel like sports made me more disciplined because I had a more structured schedule than regular students. I think that helps.