I work as a physician and am on my feet all day. Additionally I'm pregnant. These shoes are fantastic. In 1 week they have alleviated most of my low back pain (caused by poor posture secondary to pregnancy). They combine what I love about hard-soled clogs and sneakers. This version in particular is great for work, professional, clean lines. It's interesting because I've read so many negative reviews about Shape-ups in general because of lack of stability. I find them very stable. They have helped my low back and knee pain already. I have experienced the calf burning, and think it would be wise for anyone wearing them to occasionally stretch out your calves as you would if you had done a "real" workout. Certainly if you are extremely overweight, have had issues with ankle injuries in the past or have serious knee or hip problems I would consult your physician and/or podiatrist before trying these shoes. By the same token, you probably aren't wearing 6" heels either. They may not be a butt-toning-miracle-in-a-box in terms of exercise, but they are fantastic for work, especially for being on your feet all day. I couldn't be happier with these shoes. They will be replacing 4 pairs of work shoes. Pay attention to sales online and at your local Sketcher's store. I ultimately bought this pair at the store for less than online. They can be found for <$60 a pair if you are lucky and patient waiting for sales.