Wow, okay, didn’t expect a whole discussion on Sith philosophy… My question was more like, does Kylo Ren punching his own physical wound help him in that specific fight? Does it keep him from passing out, does it help his body perform any better, that sort of thing.
That’s because the most realistic aspect of Star Wars is the combat philosophy running behind the Jedi and the Sith, and they’re not totally terrible as a way to start learning about how philosophy influences martial combat. They are ultimately an extension of the trope: Martial Arts Give You Superpowers. This is not unique to Star Wars, and comes primarily from Eastern philosophies like the Tao and how they were applied to the martial styles developed there. Martial arts often do look like magic to the casual observer. Besides that, the enlightenment/understanding of yourself, your body, and the universe directly correlates with your ability to throw an opponent across the room. The best thing you can do for yourself is understand that Star Wars, specifically the Original Trilogy, are useful as an introduction to this side of martial arts.
There’s not much point in discussing the mechanics of the final fight between Kylo Ren versus Finn and Rey in The Force Awakens. It isn’t a great fight scene, and one that only serves to undercut Kylo Ren’s competency both as a combatant and as a villain. It’s bad on a multitude of levels from character, narrative consistency to choreography, though the cinematography itself is nice enough when we’re not comparing it to the Original Trilogy. Even injured, that was a fight which should’ve been no contest for Kylo Ren. Or allowed Rey to use the weapons she was actually good at using, rather than a weapon which is very good at cutting off your own limbs when you make a mistake. The lightsaber is the three-section staff of Star Wars, if you don’t know what you’re doing then you’re guaranteed a concussion first time out. (No, that is not a joke. The three-section staff does that to real martial artists all the time.)
On a setting or narrative level, you can’t divest Kylo Ren from the Sith philosophy and the behavior patterns which make a Dark Side user strong. In this case, both the Jedi and the Sith are more bombastic echoes of what real people can achieve in real life. We can’t talk about the physical applications of what Kylo Ren does without talking about his mental state and mind set. The useful effects of beating your wounded shoulder depend entirely on your approach to pain. As for Ren himself, he’s a fantasy character in a fantasy environment powered by the Force, which is essentially a concept straight out of the Tao. Him beating his wound has about as much relevance as him destroying a console with his lightsaber, and its also self-destructive. The script calls for it so he’ll look tough or more badass, and to remind the audience that he’s wounded.
A discussion on the Sith philosophy is crucial to Kylo Ren’s behavior as a character and how he uses pain to motivate himself, because the Sith use pain to motivate themselves and that philosophy is an offshoot of a real martial arts philosophy which exists in the real world. Powered by pain is a philosophy which directly relates to your mental state, and Kylo Ren beats his wound because he’s… trying to look tough. There’s no realism worth discussing with his fight decisions. In that way, he’s a moron.
You don’t want to get the blood leaving any faster or at all because you will start passing out from blood loss. When you fight, your heart starts beating more quickly, the quicker beat means the blood moves through your body more quickly, if your body has holes the blood will exit those holes quicker too. You do any physical exercise with an open wound you will bleed out faster. If you have a wound like that, you want to seal it off as quickly as possible.
The short answer is that Kylo Ren beats his wound to be dramatic because he’s a drama queen, and he likes to remind the audience that he is in pain. If he actually wanted to do do something about his wound quickly, stop the bleed out, and motivate himself with pain he’d cauterize the wound with his lightsaber. If he wanted to double that up as an intimidation tactic, he’d cauterize while Rey and Finn are watching in order to terrify them before the battle begins. This is a Sith tactic, and a method you can use to intimidate your enemies in real life. Sith have even been known to intentionally inflict injury before a fight begins because it gets them fired up. Kylo’s really not that clever though, which is why I call him a cosplayer rather than a Sith Lord. He showboats without any real substance. A better example of what Kylo Ren tries to do is found in your average Wuxia film. The original Die Hard with Bruce Willis is also better, and probably more useful for discussing realism and realistic injuries someone would sustain in an action film.
For what Ren does to work, you need a character who’s determination goes up in conjunction to the number of injuries they sustain. As I said, this is a Sith. The more you beat on a Sith, the stronger they get. This is an outgrowth of a real world philosophy regarding pain taken to extremes, which is: the more you beat on someone, the more painful their situation gets, then the more determined they get and the more motivated they are to succeed. There are people in the real world who do this, and this is a natural outgrowth of someone who has had a very difficult life and experienced a great deal of emotional/physical pain. The more pain you experience, then the more you adjust to it, grow comfortable with it, and start shaking off injuries other people would find incredibly debilitating. Often, this happens without the individual even realizing it because their base state for “normal” is skewed beyond recognizable and they adjusted to meet that state of pain in order to survive. This is The Determinator. You can rip them to pieces and like a human terminator, they. just. keep. coming. This occurs on sheer force of will alone, because your mind is more powerful than your body.
You beat your wound because it feels good, or you’re frustrated with your arm not functioning the way you want it to and insist on it working again. Pain feels good, and if you can’t imagine a character to whom pain feels good, who enjoys experiencing injury, or simply finds their body’s failings annoying then this character archetype is not for you. Running into real people who are shades of this in your real life might also terrify you. They’re out there, and they’re not just combat professionals, soldiers, or martial artists.
Kylo genuinely tries for this but his personality doesn’t match. Compared to other Sith in previous Star Wars movies (like Darth Vader or Count Dooku), he’s actually very wasteful in his combat style when it comes to physical action. He makes big sweeping moves, he’s ultimately very slow, leaves himself wide open, and he lacks Maul’s dramatic flair. He has a very heavy fighting style which is supposed to represent power, or link him back to Vader, but Vader had the benefit of a sword style performed by Bob Anderson. The first fight between Obi-Wan and Vader in A New Hope is actually fairly accurate to Kendo as duels go.
Kylo is the sort of character where any injury he sustains is supposed to make him more dangerous. In old school Star Wars canon, the injury he sustains in TFA shouldn’t benefit Rey at all. His injury should ramp up his connection to the Force instead, resulting in him becoming more dangerous and more deadly. That’s what the injury beating is supposed to show. However, this sense of danger is undercut by the narrative because neither Rey or Finn have any sort of training with the weapon they’re trying to use. Kylo being forced to fight on an equal playing field with Rey, even after defeating Finn, actually undercuts him as a villain and as a combatant. It frames him as incompetent when compared to his other Dark Side brethren, who all had the benefit of fighting someone who knew what they were doing or were taking it easy on someone who didn’t. (Darth Maul versus Qui-Gon Jinn and Obi-Wan Kenobi, Vader versus Obi-Wan Kenobi, Luke versus Vader in Cloud City.) Kylo Ren is allowed none of those opportunities, and he is the least threatening as a result.
He’s not a character who’s personality matches one you can kick out of a plane in a desperate attempt to get rid of them only to have them show up three weeks later, royally pissed off and ready to kill you all over again. This character is the outgrowth of and natural extension of the injury beating we see Kylo Ren do. This really is who he’s supposed to be and who he’s trying to be because that’s who Vader was. Vader got all four limbs cut off by his master, half-burned to death by lava, lost/attempted to murder his wife, lost his children, and went on to terrify billions across the galaxy.