I've been involved in a couple of small debates about punching mechanics in karate - debating what the right way is to execute a punch. There are nuances to punching technique - do you move the hand or hip first, do you tense the body at impact or think of the fist/forearm as something you've thrown at the target, do you rotate at the waist or stiffen. Interestingly, people can hit very hard using many different combinations of these methods, though logically one of them must be best, at least for any given person and situation.
So here I am, self proclaimed internet guru (that title is meant to be tongue in cheek, and it means that I have no legitimate special expertise or knowledge in this area, yet I blog about it anyway), arguing with highly respected karateka from around the world about the best way to throw a punch. Why do I do this? What's at stake here?
I like to break these discussions down into two levels, in the sense that techniques can be bad in two importantly different ways:
1. A technique can be 'wrong' in the sense that executing it that way puts orthopedic or biomechanical stress on the body in a way that is likely to be injurious to a typical practitioner. These techniques may or may not 'work' on an opponent, but I don't care.
2. A technique can be 'wrong' in the sense that it is less effective than another method (slower, less powerful, less likely to prevent you from getting hit/ hurt) but doesn't meet the standards of #1.
For my favorite (and simultaneously most horrifying) example of #1, I once trained with a guy who got 'snap' into his punches and kicks by forcibly locking out at the end of the motion as hard as he could. In other words, the 'snap' was the thud of his own joints locking into full extension. That is bad. I don't care how hard he was hitting things (I have no idea if he was), that kind of technique will break your body down in undesirable ways, given enough time.
For examples of the second kind of 'worse', we have to hurt somebody's feelings. But you don't have to agree with me on particulars to agree with me on the general idea - take the sine wave body movement from tae kwon do. I think that's bad movement - slower and less powerful and less defensible than linear mechanics. But if you're a tkd practitioner and you think I'm wrong, then of course you think that linear (or maybe we should say planar) mechanics are 'worse' - either way, one of these systems of movement is worse than the other, but neither is particularly hard on your joints or connective tissue. One of them is definitely 'worse' in that second sense.
When someone is using techniques that are bad in the first sense, that is they are likely to hurt you if you perform them, then there is no argument that there's a lot at stake in figuring out that the technique is bad, fixing the problem, and perhaps even leaving your instructor over it. If you're being taught to do things that are going to break down your body you need to find a new teacher. End of story. There is nothing good about being injured regularly.
A much more interesting question, however, is what you should do about the second type of 'worse.' What do you do if you think you're being taught a less - than - best (but still not injurious to you) way of doing something?
Here, again, I'm going to divide martial arts students into two groups. The first group is people who really need to use their skills in violent situations regularly. This might include prison guards, doormen, bodyguards, people whose jobs put them into fistfight situations at least some of the time. For this group, they need pretty effective techniques. In other words, even if they don't need the absolute best technique, they certainly can't afford to experiment too much or give too much away by trying things that might not work. For them it could literally be a matter of life or death (or at least injury vs. not injury).
But for the vast majority of martial arts practitioners, our art is purely impractical. Most of us will never get into a 'real' fistfight, ever. And most of us don't even spar in such a way that having less than optimal technique is likely to get us badly hurt. For most of us, doing technique the 'best' way is completely irrelevant in any practical sense. In fact, many of us train in such a way that we could easily go our whole lives doing something 'wrong' (in the second sense of wrong, as in less-than-most-effective) and never even know it.
I, personally, definitely fall into that last group. The debates I've been having are not between 'ways that will hurt you' and 'ways that are mechanically safe' - these debates are about which of 2 (or more) methods of executing a technique are best, while they're all 'good' enough to not cause the puncher injuries. So why do I bother, given that even if I train in a less - than - best way to punch or kick, it's almost definitely never going to affect my quality of life?
The simple answer is that I enjoy thinking about these things. I personally like to study different techniques, analyze their pros and cons, and engage in debate about which way of punching (or blocking or kicking or standing) is best. It's fun for me. I love to see a UFC fighter use a weird stance or show a weird way of punching, then analyze the advantages and disadvantages of that style. And I practice this - I'm currently obsessed with the notion of holding my lead hand low, near my waist, when sparring (someday I'll write an article about why I do this and what I like about it, but I'm still working on the details).
People train for different reasons. There are lots of people who like to train but have no real interest in thinking about training. Lots of people intensively study the history and background of their art; others simply don't. Lots of people care about self defense applications, others don't.
I'm not one to claim that EVERY practitioner of martial arts should spend time thinking about the best way to punch. If you're happy learning good punching technique from your instructor, and then diligently practicing that, that's great! Maybe your instructor is teaching the 'best' way. Even if she isn't, as long as the way you're learning isn't 'wrong' in the first sense (bad for the integrity of your bodily tissues), then have at it.
But if you're interested in discussing and debating best technique, if you get excited by the idea of doing mathematical analysis of how center of mass is affected by hand position in fighting stances, if you're that kind of student of the art, then by all means, participate! Challenge the conventional wisdom (respectfully and quietly, I mean - don't interrupt your teacher in the middle of class and suggest a better way to do something. That's just rude). Practice new things and see how they work out. Maybe you'll develop something great! And maybe you won't, but that's fine too. The joy is often in the journey.