How can I properly show the difference in size/ability/personality when two characters are fist fighting? Do a bigger and stronger guy throw a punch differently than his younger shorter opponent? Is that even a thing in real life?
The great irony, despite all media has taught you, is that two people of different heights, weights, and genders will actually fight (mostly) the same way if they are they are trained in the martial same style. Everybody learns the same move set, what makes the difference is how well they execute it and how disciplined they are when they start to flag.
The easiest are with people who don’t know what they’re doing versus people who do. For trained fighters, a lot of personality is going to get shed when they settle in and focus. You can have a cocky shit who talks a lot of trash outside the ring before the match and then say absolutely nothing inside it. Talk wastes air and you need oxygen to keep your endurance up. The person who talks during the fight gets punched, and should because they’re not focused. They deserve it.
No, they really do. Competitive fighters will take advantage of that kind of distraction. If someone’s talking in the ring, they’re doing it at a safe distance (at starting distance/outside arms reach) while both they and their opponent are searching for an opening.
The best fighters are the ones with the highest technical proficiency and the least amounts shits to give about their opponent’s future.
Let’s talk about technical proficiency for a second:
Technical proficiency relates to how skilled your character is i.e. how good they are at executing their techniques. What is technique?
It’s more than just a punch. It’s every minute movement involved in the movement of your body as it executes that punch. This includes
A) Your stance: the width of your feet in comparison to your shoulders, the degree at which your knees are bent, creating a centralized point of balance as you move.
B) The twist of your hips as you punch. This is, in combination with your shoulders, is your main generator of momentum i.e. power. (Yes, this has nothing to do with how many muscles you have.)
C) The position of your hands in relation to their distance from your face before you throw your punch. (This would be part of the fighting stance.)
D) The twist of your shoulders in time with your hips. Did they move together or are they out of slightly sync?
E) The position of your elbows. Were they inside or outside the body, is your arm in line with your shoulder when it extends?
F) The extension of your arm. Did you overextend past that front foot in your stance and put yourself out of balance?
G) Did you properly lock your fist when you punched? This is all five fingers clenched together when you punch, locked by your thumb. If your thumb is inside your fingers or outside your hand, you’re at risk of breaking your fingers. (Yes, beginners do this.)
H) Did you lock your wrist in line with your fist and your elbow and your shoulder? (Yes, beginners also do this.)
I) Did you do lock up at the fraction of a second before you struck your target? Thus applying maximum force? Momentum = movement + speed. If you lock too early, you slow down in the critical instant before striking and blunt your force/create more opportunity to be blocked.(Yes, beginners do this. They also flinch.) Punching a target, even a soft target, hurts. It will hurt when you do everything perfectly. That’s before we get to the psychological aspect of hurting someone else and the affect of that indecision on your physical body.
J) Did you return to resting or flow smoothly into your next combination/strike? Or did you just stand there like an idiot?
K) How quickly did you manage it? Again, this entire move happens within a fraction of a second, often too quickly for the untrained eye to follow. It’s fast. (Fun Fact: film cameras lose frames of professional martial artists/martial arts actors like Jet Li and Jackie Chan when they go full tilt.) Most of the time, audiences at professional matches mistake and respond to the secondary, follow-up strikes rather than the actual winning hit.
These are only some of the considerations toward basic technical proficiency, there are more and more ways you can screw up a simple, basic punch. When we say someone has “flawless technique,” we mean they can execute every aspect of the technique flawlessly from start to finish. The best contenders will all be in that range, especially when looked at by outsiders. A strong technical foundation is essential to success. In fact, it’s necessary. Strong foundations aren’t just needed for strong defenses, offenses, or executing your techniques successfully, they’re also energy efficient. A fighter with an excellent foundation and high technical proficiency continues when the their opponent with a shoddy foundation flags. You can win when you’re opponent is tired.
If you have a poor foundation, you are poor in everything. You’re technique is inefficient, you’re slower, your defense has more openings, your movements are bigger and thus have more tells, wasted movements means you’re wasting more energy. You’ve essentially hobbled yourself.
Now, poor foundations can be fixed. Technique is tightened with practice. The more experience a fighter has, the more they’re willing to address their flaws and work toward improvement then they have a chance to become better. Martial arts is skill based, not talent based. The person who works the hardest, the longest, and is the most determined is one who eventually stands among the best.
The best way to address this in your writing is to start looking at different how to videos on YouTube from martial arts masters discussing how to perform different techniques. You’ll be able to see the breakdowns, have them explained, and see what it looks like when a person with experience does it right. If you’re trying to write a character describing another character as inexperienced, it helps at least get a window into what the technique is supposed to look like.
I must say though, that even with a technique as simple as a single punch (whether front hand or backhand) there’s a lot of variation in technical detail between different martial styles. So, different characters could punch in different ways depending on their backgrounds.