I am in love with the muse bottoms! I have an athletic build -5’5” 145lb (161.1 cm, 65.7 kg) and carry most of my muscle in my bum and thighs. I could have definitely fit into a medium, however, the smalls fit well. Snug, but not digging into my hips. I would size up if you find yourself debating between sizes. All in all, I love the cut, the fit, the quality....everything!!