After my Mom's cousin told us he had leukemia, I decided to join the registry, too. His sister ended up being a match, but unfortunately he got Graft versus Host Disease and recently passed away. So first of all, thank you so much for joining the registry! It is unfortunate you can't time your donation, but if you are a match I hope it will still be rewarding for you.

I did a lot of research to see what the donation process would be like and tried to find as many donation stores online as possible. It all really depends on the kind of donation you end up doing. If you do the "classic" bone marrow donation where they drill into the hip I've heard it takes around two weeks. Marrow.org suggests you could be back to "regular activity" in a few days. I'm not so sure about that. Here's some experiences from people who have done it: http://www.transweb.org/people/marrow.htm
http://www.marrowdonor.net/

If you do a PBSC donation the recovery time is a lot quicker. I think my Mom's cousin's doctor said it was becoming a preferred method. This is the donation his sister did. Apparently the shots and days before donation are the worst because your bones can ache from stem cell production. The time on the apheresis machine is supposed to relieve the pain. My Mom's cousin, who is actually in poor health, said she felt tired after her donation and felt like "she'd climbed a mountain." I think she just rested a few days. You would probably have a much quicker recovery. Other stories I've read suggested once the procedure was done everything could go back to normal. Here's one detailed account: http://tinyurl.com/2pwwtf

Hope this helps a little bit. I'm sorry I don't have any first hand experience especially from an athlete standpoint. Good luck with everything.