Yes, the Alexander technique was developed by an actor around the start of the 20th C who suddenly lost his voice and couldn't get it back.
It turned out that it was because he was holding lots of funny muscle tension in his body, which in his case (maybe psychological too) meant he couldn't speak. By learning to keep all of the muscles that he could relaxed he solved the problem in the end. For other people they get sore backs, sore arms, sore necks, whatever. I've done a bit of Alexander technique (unrelated to PU) and I think my walk looks a lot more relaxed and comfortable now, so that probably contributes to your perceived alpha status in other people subconsciously.
Like all bodily habits it's a long term thing though - you can't change the way you walk overnight
HTH,
P