There’s nothing like a pair of killer heels to make you feel put-together, confident, and sexy as hell. But wearing heels day in and day out can do a number on your feet, ankles, and calves. Here’s what we mean: When you wear heels, the lifting of your ankle puts your calf muscle in a shortened position, explains New York City-based personal trainer Jessi Kneeland. This can lead to pain in your ankles or knees. “We want to combat that by stretching and lengthening the muscles,” says Kneeland. “You also want to strengthen the glutes and hamstrings [butt and back thigh muscles] to make sure you are stable and have support.”