The hottest trend in exercise footwear makes some pretty unbelievable claims. Get fit just standing? Burn more calories when walking? Improve posture and relieve tension in your knees, hips and lower back? This we had to check out.

The hottest trend in exercise footwear makes some pretty unbelievable claims. Get fit just standing? Burn more calories when walking? Improve posture and relieve tension in your knees, hips and lower back? This we had to check out.

Here's how they work: The shoe's curved sole burns more calories and builds muscle by mimicking walking in sand. They force you to use a different group of muscles simply by keeping your balance with each step.

Skechers' Shape-Ups are probably the most popular of these, but I tried the MBT, aka Masai Barefoot Technology, the shoe that started the trend.

First impressions of these shoes aren't good. The thick sole gives them that "special" look, and you can't help but feel self-conscious while wearing them.

They're heavier than your usual walking shoe, and the thick sole takes some getting used to. (More than once I almost tripped on nothing.)

Would I recommend them? Yes, definitely (but not for running). A road test of three miles - which felt more like five - got me hooked. They simply make walking feel like a better workout.