I am a healthy, active, obese 22 year old female. For the last 5 years I have been experiencing weakness in my right leg if walk a lot. I exercise a lot, enjoy swimming, and walk everywhere. Lately however, it has been getting a little worse. In fact today I did very little physical exercise, only a 40 minute walk, and after wards my right leg could no longer support it's weight. I had to hop around on one foot, and borrow my friends wheelchair for support. It doesn't hurt, and it doesn't seem to be muscle strain because my leg never hurts when it's weak or the next day. I often worry about falling if I do not have something to support myself when my leg is acting up, because it's happened before. Any ideas?