This post is inspired by @portal.ido cheeky last post. But my pic is WAY CUTER. I joke. I joke. My beard doesn't compare at all. I think Ido is great because he doesnt support one "godlike" source of movement. He learns for himself what works and doesn't. There is no "one correct way"
Im a yoga teacher. Yoga is one of those practices that can capture you into thinking you need to strive for this eternal perfection of posture. Various disciplines have their specific rules and reasons, but in the end, just choose what serves you. Believe me I love me some Iyengar and Ashtanga. I love having strict rules to follow and 5 am practice every morning. I love 'proper' alignment and use it my students so that they can arrive into prescribed postures safely and strong.
However the rest of me yawns. Break the rules! What are rules anyway?! Dogma is overrated and I feel you have to think for yourself, with your own brain, how you want to practice and what this practice of yoga and movement means to you. To me, I find this union of body and mind by play. I found a natural trapeze/lyra/ok it's a vine in an old fort and played with it forever. Thats my peace and my release.
Sthira sukham asanam. Steady and comfortable seated posture. This is all Patanjali wrote about yoga asana in the Yoga Sutras. Hustling into scorpion pose with your feet trying to touch your head doesnt seem steady and comfortable. No mention of warrior 2 or half moon. He didn't explain how the magical yoga energy will free your bound soul after practicing 20000 rounds of surya namaskar. So what then? You like it? It serves your purpose? Do it! Its your practice.
Is there scientific evidence or theory in the practice of specific asana? Hells ya. Take yin for example, in which the entire practice is based on Chinese Medicine and meridians.
A sutra that seems more meaningful is Tapah Svadyaya Isvarapranadhnani Kriya Yoga. It loosely translates (to me) as diligence and discipline in self study of a practice that requires hard work and effort, with unshakable faith in Absolute Reality to expand the self, moving with purpose and goals in new growth and clarity of mind.