Absolutely never. School is the most important aspect of their life (and their coach would be extremely p**ssed off it was any other way, frankly). The only thing I do is purchase whatever random supplies that they need for whatever project, will drive to libraries, and will print it out at the end.
We do expect them to be at the top of the class, as that is what they are intellectually capable of, and what they will need to reach the academic goals they have in terms of post-secondary. So far, so good.
Having to figure out how to juggle school and skating has certainly helped them to learn to prioritize, organize, and self-manage. They also get in far less trouble than other kids their age as they are focussed on their skating and academic goals, and have a ready-made excuse to avoid house parties, video game parties, Facebook etc ... they also have to do chores, have outside interests, and get plenty of sleep.
BTW: I'm a teacher. We know darn well when the parents have done the work, and we reflect that in our assessment of the kid's work. Plus, if you've done their homework for them, then, the penalty to the kid is significant when the in-class assessment of their knowledge shows that they didn't learn what we needed them to learn in their homework assignments. I actually send very little home for homework; I'm not interested in what their parents can do, nor am I interested in what the single student who gets stuck doing homework for everyone knows