Anyone who tells you yoga is about aerobics is full of it. Yoga is not gymnastics. It’s not aesthetics. It’s certainly not about stretchy pants. It’s about the mind. Patanjali implies this in his very deliberate layout of the Yoga Sutra.
The first sutra is simple: Atha Yoga Anushanam. You might interpret this as: Here we are, you’ve got everything you need, so let’s get it on. Patanjali then moves to the real heart of the matter, the second sutra, where he defines yoga: Yogash chitta vritti nirodhah. Patanjali mentions nothing here about touching your forehead to your toes or the fact that your sports bra should match your headband.
Instead, we learn that yoga is stillness. It’s the calming of incessant mental chatter. It’s the reality that you are not your thoughts or your feelings. You are not the sudden angry desire to punch the obnoxious dude in front of you in line at the bank.