I have several pairs of the Stella leggings and I love them more than I can say. They're the perfect weight to wear as actual pants in cooler weather. I can run in them, walk in them, or do some yoga inside. They are temperature adaptable...is that a real phrase? Regardless, they seem to work for a variety of athletic pursuits. And while they're warm, they aren't so thick that you can't wear them under a skirt or even under a loose pair of hiking pants. I'm 5'4" and weigh 155#. I have an athletic build with muscular legs and a medium fits me snugly. I have a couple of pair in large and they're a little too big in the waist (I lost weight) but they still work and I wear them happily.