Knuckle Push-ups

The knuckle press-up seems to be popular within martial arts circles for strengthening the fist. It also seems to have a degree of machismo nonsense associated with it. I have been made to do these together with the rest of the class including children on a wooden floor when I couldn't even do a traditional push-up. So what's going on here?

Old style martial artists used these because they develops wrist and forearm strength more so than the standard flat handed push-up. It will also condition the hand bones to improve their strength. Overall this makes your punch more effective since the combined strength of the wrist and hand bones contributes to impact. Knuckle push-ups also exercise slightly different upper body muscles since the hand position is closer together. The problem is that it can injury the knuckles by causing overgrowth of bone or injury to the joint resulting in arthritis and limitation of mobility. This is surely undesirable even for combat ready Samurai. Additionally, it can damage developing bones, so knuckle push-ups are a good addition to training only when they are done on a padded surface and in people who have finished growing - 16 years+