One of my latest injuries left my right calf, ankle and foot very weak, sometimes I feel like I can't control their movement well so that when I spotted this ad in which they were touted as a surefire way of strengthening your calves I soon rushed to grab a pair...two actually...one for walking and another one specific for running. I soon slipped them on in the hopes of strengthening my foot, the left one got quickly accustomed to them while the right one tended to tighten up with even a few steps...on the occasion of a trip abroad I wore them all the time hoofing it to the spots that I wanted to visit after my early morning runs...my legs suddently felt like they were made of lead, especially my hamstrings..."well it means that they work" I thought....back from my trip I rested few days then went for a 30 km off road run along a rather hilly path, I couldn't control very well the movement of my right leg which tended to freeze, on the following day I went for a 18 km fast run...O.K., perhaps this was too much I know but my left leg felt strong and in perfect shape...just toward the end I started experiencing cramps on my left harmstring too...needles to say in the evening I felt completely maxed out...now, after resting for two days my left leg is back in shape while my right quad (which is recovering from an old injury too) tends to...it's like I couldn't relax it completely when I'm sitting but it's O.k. when I walk while my right foot just "drops" when I walk as if it was disconnected from the rest of my body. Yesterday I was browsing and reading posts about these shoes, some people were completely stoked about them while others said they'd caused them pain in the back (mine is O.K. in spite of all the kilometers that are adding up) and feet....but no comment was posted by any runner so I'd like to know if anyone of you has ever walked in them and for how long or if anyone has ever tried running in them, I got the ones for running too but I haven't tried yet as I first wanted to master walking in them. As a matter of fact both my parents got those shoes too (on my suggestion) and are stoked about them especially my dad who suffers from varicose veins says his legs have never felt so good...so, are shape ups good just for people whose legs are not taxed by other heavy work outs? Should I nix them or limit their use to few hours a day or a brisk walk once or twice a week? gimme your feed back please!!!