Having been a D1 athlete and also having earned a Ph.D. (my partner has an MD and was a D1 athlete) we agree that it is sports that taught us to work hard. School never became difficult. There were hoops to jump through, a dissertation to write etc.. but nothing very mentally challenging. The daily grind of being an athlete is much more difficult than school. Having to be up early, play games that end late and still pull the same grades as your peers is what teaches you to not waste time. You learn to complete assignments and study for tests early because you don't have later. We prioritize athletics and academics in our house. DD makes perfect grades without breaking a sweat. She is performing three grade levels above peers academically (on average). Allowing her to skip one grade or even two will not make school hard it will just force her into a situation where she is socially awkward. Sports (which she loves) force her to work hard. Every child is different, but I would encourage anyone who has a child interested in athletics to give them the opportunity to play. There are so many posts on this board about teaching children to work hard, athletics will do that. It will teach them skills that academics will not.
http://www.thedp.com/article/2015/02/student-athletes-work-hard-and-play-hard
