I'm a researcher and a student. I'm not a Sanskrit scholar or a lineage teacher. Everything here is cited, everything is written with genuine respect for the tradition, and everything is also filtered through my brain, which is constitutionally incapable of not asking difficult questions.

The fourth of Patanjali's eight limbs. "Prana" = life force. "Ayama" = extension. The practice of controlling breath to influence the flow of vital energy and through it, the nervous system.
Most directly connected to vagal tone research. The physiological sigh, box breathing, and alternate nostril breathing all have clinical evidence behind them. The ancient framework and modern neuroscience agree more than you'd expect. Ancient practices work!
The first of the yamas. It's the ethical guidelines that form the foundation of yogic practice before any posture is attempted. Non-violence toward others, toward living things, and toward yourself.
The concept most Western yoga ignores entirely by skipping the yamas and going straight to postures and cute outfits. It's also the concept that makes the guru abuse stories so devastating.
Mental and emotional grooves carved by repeated experience. The yogic concept maps surprisingly well onto modern neuroscience's understanding of neural pathways and habitual response patterns.
Relevant to trauma work, nervous system regulation, and somatic therapy. The Body Keeps the Score describes essentially the same phenomenon in clinical language, although anything from that book should be taken with a grain of salt.
The final three of the eight limbs, i.e. the internal practices. Concentration leads to meditation leads to samadhi, a state of complete absorption. This is goal the whole system is actually building toward.
What gets skipped most often in Western practice. The postures are the preparation, but the internal change is the destination.
Practicing respectfully means knowing where the practice comes from, crediting it accurately, learning the philosophy not just the postures, and supporting Indian teachers and Indian-owned studios when possible.
The new age "guru" model concentrates power in structurally dangerous ways. Honest engagement with yoga has to address this issue.
$180 leggings and a $40 class are not what the tradition was built for. I'm not saying you're a bad person if this is what your practice looks like right now, but you owe it to yourself and the cultural roots to dig deeper and practice respectfully and authentically.
I'm learning. Everything on this page is written with humility. If something is wrong, I want to know and am open to critique.