Then sign up to coach next year, seriously!

Also, as a long-time youth rec coach, I'll also say that some kids just have greater stamina than others. Some of my lesser athletic kids would beg me to come out and take a break after a few minutes. My athletic kids would be fine playing the whole game. I tried to push the non-athletic kids to play more and push themselves, but sometimes this plays a factor in comparing playing times---the fact that kids may be asking to come out. I realize that's probably not your situation, or you would probably know this was happening.