If you're anything like us, you have *cough* more days than there should be when you just don't have time to work out. As crazy as it sounds, though, what if you could get a great core muscle workout just by walking around and doing your regular daily routine? Skechers Women's Shape-Up Sneakers are designed to do just that. They force you to balance more carefully, using your core muscles and legs to keep upright, which in turn strengthens said muscles. It takes some getting used to, but we think it's well worth the effort!