I have been wearing the new balance 550 conditioning shoes consistently now and I can feel strength building up slowly in my weak left leg. Also feel the benefits of the muscle groups being worked. They are very comfortable to wear but after about 5 or 6 hours of running errands/going to dog park, I have a restless feeling and can hardly wait to take them off. As soon as I do, that feeling goes away and my feet and legs are fine. As I walk bearfoot (well, in my 2 pair of socks), I can feel the muscles continuing to make me walk correctly. After my current flair is over, I can hardly wait to try them on a treadmil.