Mine could never do homework on gym days because there was no time and she was exhausted. She did homework on the weekends and on her one weekday off of practice through middle school. In high school it became impossible to juggle 20-30 hours of homework (really! and this is after numerous parents complained and one of the teachers cut back) plus 12-14 hours of gym each week. She retired from gymnastics and took up a sport that only requires 4 hours per week, and she still skips a lot of practices for homework.