It's done, usually not on camera, but it's done. Granted, the frequency is a lot lower, but it exists. I've coached HS sports (Varsity and JV) for many years, done college scouting, camps for kids, been around plenty of professional athletes; it's there.
It doesn't have to be just sports, it's typically a male bonding ritual. Much like griefing or the like, it's a "check" for tolerance levels. It's done not only with humans, but all species in some forms. A dog, cat, lion, bear, etc will continually "pulse" or "check" their position or status with other males. Most of the time it's playful, sometimes, it can get a bit more intense. Without that "check", we would all be a happy, harmonious, carefree, vegetable eating, tree hugging, dirt worshipping commune of the human race. In short, we would be prey to all the other creatures that do those things. Well, maybe not all the other creatures... but enough of them that it would wipe out our race. It's part of the whole, "survival of the fittest", in a microcosm.
