If you don’t already have a pair of soft cotton leggings in your closet, prepare to invest. You'll love them as much as your spandex ones, since they're a wardrobe staple that personal trainers swear ...

Once reserved for sporty activities, the gym and yoga, women’s leggings are now one of the most popular fashion items.

I tried on similar leggings at Gap, Old Navy, and Athleta. As a Pilates instructor, there was only one pair I wanted to buy.