This is fascinating. I recognize it as something that is common knowledge to trained Feldenkrais Method practitioners. I have gained similar benefits from visiting a Feldenkrais practitioner and many more musculo skeletal benefits as well. They use very gentle, gradual and time-consuming "movement training" to "reset" muscular habits, many of which are harmful. It is amazing how much they can improve in every part of the musculo-skeleture, there are hundreds of muscles in complex patterns that can be getting inefficiently and parasitically employed. It can make a massive difference to the ease of daily life.When it comes to posture, trying to force the correct posture is hopeless; what is needed, is to "switch off" the muscles that shouldn't be "on", and vice versa. Most people can't just do that by mimicking a position. In Feldenkrais, mostly you are relaxed and lying on your back, and the practitioner gently performs repetitive counter-intuitive movements of your limbs etc which "persuade" muscles a certain way. Then when you sit up or stand up again, you tend to be "relaxed in the correct posture" rather than trying to force yourself into it.