I was told by many parents that gymnastics is the best thing for kids who are hyperactive. However, there is a different school of thought about gymnastics for ADHD kids, because some say it fuels their hyperactivity. I tend to agree with that (based on what I've seen with my daughter), but I still take her to gymnastics because she enjoys it and gives her something to do. I think martial arts is far better for helping ADHD kids learn to focus and concentrate.
Anyway, she will have to pick one thing eventually. Its wearing me out to juggle so many different activities for her.