Punching is actually more than just making a fist and smacking your knuckles against someone. There is a proper way to hold your fingers, a proper way to hold your wrist, and a proper way to position yourself for optimum power.

Despite all above, there is often as scene in books and movies where a character, who has no training or experience, just can’t hold their anger anymore and throws a punch. This character has never punched anything before, yet somehow manages to knock that other person out cold, while sustaining no injuries. Is this possible? Yes. Is it likely? No.

The human face is surprisingly hard, so punching one for the first time might feel like you just punched a brick wall. Hold your wrist wrong while punching, and you might break it. Hit with fingers rather than knuckles, and you might break those too. Hit correctly, and you might still get broken and bleeding knuckles, especially if you hit a face.

First time punchers often tuck their thumbs into their hand(which will often result in a broken thumb), not lock their wrist in line with their forearm(which can cause a wrist injury), and not use proper form (which limits the power of the punch drastically, and may cause injuries like an overextended elbow).

Even for professional fighters, a broken wrist from punching wrong is a common injury, and there is even a hand injury named after boxers called a “boxers fracture.”

If professionals can make a mistake and get injured, what about an untrained character? Well, if you want to make it realistic, have the character at least have some sort of injury, even if it is just bruised knuckles. It can help greatly to look up the proper way to make a fist(see video below) so you can better understand how it should work, and also what your character might do wrong.

As well as that, consider not having them knock the other person unconscious, because even in a professional fighting setting, that is surprisingly uncommon. Most professional fighters would love to do that, and yet most matches are won by points, or by a choke hold.

Of course, all of this is just if you do want to be realistic. There is no shame in writing how you want even if it is not mirroring how things would go in real life. Writers have the creative freedom to not have to worry about that, so feel free to go with your gut on this.