In my community excellence is demanded. Whether you're in acting, band, sports or all three, you're doing everything but your schoolwork. Many student athletes settle for mediocre grades when they are capable of getting A's because they sacrifice their study time to play sports. Sports in particular have this negative effect because they take time and energy that is needed to do anything but the minimum of what school requires.
One of the challenges of youth sports is that every sport fights to have a 100% commitment. Giving 100% is difficult if not impossible when you're on three to four teams in various sports. Athletes do this juggling act to make decisions concerning when you can miss a practice or a game depending on how many you have been to lately or how important the game is. These decisions are difficult and nothing good comes out of them. The athlete is normally punished one by missing playing time in games or some other measure.
On the rare occasion that I am only participating in one sport I get much more excited about it. I am able to focus on the sport to perform better. When I am playing more sports I often go to one sport to the next. Doing this does not allow me to get in my "zone" and I do not perform up to my potential. When playing several sports it is difficult for me to remember some parts of the game and much harder to execute. I have heard the comment from several different coaches that I seem to settle in the second half and play with more poise. I think this has something do to with me getting the feel back for the game and changing gears from what I was previously doing. Athletes perform better and enjoy the sport more when they are concentrating on only one sport.