Cat/cow is a classic yoga movement wherein a person moves through spinal flexion (think of an angry or scared cat) and spinal extension (belly hangs low, like a cow). Hypermobile people who are attracted to things like yoga and ballet can easily get into impressive-looking cat/cow postures. But the problem is, they almost certainly shouldn’t be trying to exploit all of that range of motion on a yoga mat. Understand the distinction I’m making here: onstage, dancers need to do what they need to do. But in a yoga studio or strength training facility or on a Pilates reformer, their coach or teacher needs to make sure that they are staying within a safe range of motion.