Seeing these videos always reminds me of high school. We weren't allowed to even put a foot on the gym floor in anything other than sneakers or stocking feet, but at one of our basketball games the half-time show was a silent drill team from some service academy. Just like these guys, there was a lot of pounding of M14 (or M1, or 1903) steel-armored butt plates on the gym floor, not to mention patent leather, hard-soled shoes -- and nobody said a thing.