There is a difference between hiding it well versus not feeling it. As a martial artist, you pay up-front (desensitize drills) and draw on it when you need it. You train to push pain and feelings aside – you don’t want to show weakness in the battlefield because your enemy will leverage off it. When you take a hit and you need to suck it up as if it is nothing or your opponent will keep up the attack to the same spot.
Through training, you get better and better at blocking your emotions/pain to deal with what is in front of you. Look at the hot topic on the dangers of concussions especially to professional hockey players and football players. While the helmet can block visual damages (no blood), the effect of the impact often remains. Similarly, emotions or injuries still need to be dealt with at some point or it is going to haunt you in unexpected ways.
Knuckles need to be desensitized because if you bruise up your knuckles when you land your first punch, you will hesitate to hit even when the opportunity come up. Knuckles is just one part of the body. In the old days, you train your fingers, edge of palm, elbow, knees, foot and even your head against hard surfaces every day. However, you do not want to train to the extent of causing permanent damage to yourself. For example, I have seen old martial artists that cannot extend his fingers straight or struggle to hold a pen. There is a difference between desensitizing (which is needed) and taking things to the extreme that causes permanent damage. Having chronic pains caused by overuse / old-school training is far from having sport as a life enhancing tool.
Some may disagree with taking a middle of the road approach – they want to be the best. Everyone knows those that train 10 hours a week will be much better than those that train 2 hours a week. Then they extrapolate to say, 20 is better than 10 and maybe 40 hours is even better. However, there is a law of diminishing return where the extra little gain that you get with more hours may not be the best alternative past a certain point – maybe it is better to have planned rests, increase motivation and therefore intensity through variation/fun, or train via visualization versus normal training, etc.
For better or worse, something that you put your heart into changes you mentally and physically. Do know your goals and monitor yourself so that your future personal quality-of-life is maintained while trying to achieve your goals.
Exercise
Traditionally, people’s expectations can change based on gender. For boys, if they cry, parents often tell them to “man up” but for girls, they may think it is okay for them to cry to let out the emotions. However, if you think of “pain/emotion blocking” as a skill/training, then the skill should be applicable/needed and assessable to both gender. Furthermore, I do not know of any skills that is applicable to ALL situations and therefore you need to understand the limitations, purpose and assumption of the skill.
You do not just tell a person to just “man-up”. That is not only gender biased but judgmental. How do you actually train this skill?