I don't want to be the guy trying to prove this practical application. It is much more about situational awareness and avoidance.
The only first hand experience I have with one of the old stories was in 1982. My GM came to the US in 1974. He was performing a demonstration at a public venue during a summer social event. Using another person to tell the story, there was someone on a horse, presumably for example. He did not kill the horse. He did knock the horse down with a kick to the neck bring the rider to the ground. He got in a lot of trouble and spent a night in jail over the encounter. I was told membership went up significantly.
Hey, here's a video made in 1974 of a guy doing the same thing with a punch. Maybe it's the same guy?
...er, that would be Grandmaster Mongo...