Thankyou for such an educational and descriptive lesson of the “basics”. I’ve not heard anyone explain these concepts so well. I really appreciate the detail and imagery (plate glass middle, hands on a table etc. ) I look forward to watching more.
The heels should NOT be down!! They should be FLAT! Heels down will put tension in leg. Person on horse sits PERCHED! The lower back should be FLAT! The person sitting in the saddle has rolled her seatbones FORWARD ( that's why she sits perched) they need to point down, not forward or backwards. Sitting on a horse that way throws rider AND horse of balance. This is Old-school teaching!! And not helpful!
Only one disagreement with the rider position for western, we should be far more seat based on our pelvic bones, not the seat bones. Seat bones are for sitting on chairs. The leg position here is far more suitable for some english style riding.