When I was a kid, I was obsessed and infuriated with the way characters in Sesame Street* would bounce up and down when they "walked" behind that waist-high brick wall. I immediately declared that people don't bounce like that when they walk.
I began watching people walk, and studying the way their legs, bodies, and heads moved. Sure enough, people "bounce" too. I lined up two bookshelves with strings at eye-level, and walked directly towards them as they were lined up. I saw how they appeared to go up and down, as measured by my eye position relative to the strings. I tried very hard to walk without a "bounce."
It wasn't until later that year, when doing "indoor kickball" in gym class, during which we were not allowed to run (run being defined as "not walking" and walking being defined as heel-to-toe with one foot always on the ground), that I tried to figure a way to "walk" faster by lowering my body and therefore increasing the length of my stride. I noticed that I could move without a bounce that way.
I went home and rearranged the bookshelves, but this time I put the strings lower so that when I was crouched down, they were at eye level. Sure enough, I could move without bounce, and pretty quickly too.
When I started shooting, and shooting for defensive practice, I naturally applied this technique when moving. I had no idea other people did it, it just made sense to me. No, I'm not an instructor, neither am I a guru of any sort. I'm not the one who taught the other instructors. I just happen to have discovered one technique which apparently is special in some way. I still benefit from instructors, as I did not magically figure out everything by myself, nor could I.
* I have three little brothers, and was not in charge of the TV. I watched Sesame Street far longer than any growing boy should.