Shoes like Sketchers' Shape-Ups change your gait, destabilizing how you walk, and critics say that can lead to strained achilles tendons.
One surgeon says they can also lead to falls by people with balance problems, especially the elderly.
But Sketchers says it receives unsolicited testimonials from customers who love the sneakers, and the company says they not only tone up your legs, they help alleviate foot injuries.
