system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 How did KickBoxers bodies become able to handle huge numbers of punches that could send untrained people to a hospital?
gpt
There are several things protecting kick-boxers.

The most important safety factor is the rules. There are a lot of things that you can't really protect yourself against and they're considered too dangerous for a sport so they're banned.

Part of the skill of kickboxing is to make sure the big strikes either miss completely or land on some part of the body where it doesn't matter so much. For example a slight drop of the shoulder can turn a potentially debilitating kidney shot into a fairly harmless punch to the elbow.

Finally physical conditioning not only increases pain tolerance but offers protection too. If you punch most people in the gut your fist will move pretty far into their abdomen and cause damage on the way. If you punch a kick boxer in the gut your fist will slam into a wall of muscle and, if you haven't learned how to punch properly, you'll probably sprain your wrist.

There are still serious injuries in kick boxing. Gloves are primarily designed to protect the wearer. They actually make things more dangerous for the person getting hit. Hands have a ton of tiny little bones, without gloves it's really easy to break those bones when you hit something hard and the head is pretty hard. Even Mike Tyson broke his fist on Mitch Green's face during a bar brawl. Gloves let fighters do a lot more head hunting and that results in more concussions.