No experience there. If you want to find out whether this might work for you before you buy anything, just experiment with some very gentle barefoot running. All you need is a surface that's smooth but hard, like a tar path or freshly paved sidewalk. A track could also work, but many rubberized tracks are uncomfortably rough for a beginner. The motion in FiveFingers is almost identical to barefoot, in terms of how the toes flex. The whole foot certainly does flex much more than in stiff shoes. That flexing is part of the reason you get less impact (on the knees and everything else).