We are all splayed open through the front of our body. The muscles of the back tend to be too short and the muscles of the front tend to be too long. This is the essence of my belief that we all lean backwards and tuck our pelvis under. Instead of being straight up and down the way we think we are, people tend to be the back-end of a parenthesis—).
When people are standing up before me I always ask if their pelvis is tucked under and most people think that it isn’t. I then ask if the legs are under the hips or forward of the hips—most people think incorrectly that their legs are directly under the hips. This makes sense if you think you don’t tuck your pelvis but it turns out most people are wrong on both counts.
There is a lot to be learned from lying flat on your back. In the context of the video above, it is my take that the distance between the floor and the back of your thighs, is the distance that you sink your thighs forward when standing. In the same way you can learn a lot about the muscle tone of your trunk by feeling just how much of your rib cage touches the floor naturally.
As a practicing yogi I put a lot of effort in getting the backs of the thighs to the floor but they wouldn’t release. I then learned Block Lunges, one of my favorite exercises from Jenny Otto, and I went Block Lunge crazy. After about six weeks of block lunges three or four times a day, the backs of my thighs released to the floor and for the most part have not come back up. When I am having a bad psoas day, my right leg creeps slowly skyward but a little constructive rest usually relaxes that.