This is a good reason why GURPS gives a bonus to damage to trained unarmed strikers:
The Science of the One-Inch Punch
""The first thing we found was that karate experts can punch much harder than normal, untrained people. Which isn’t exactly what you’d call Nobel Prize–worthy work," he says.
But Roberts also discovered that for the karate practitioners, muscle alone didn’t dictate strong punches. Rather, when he used motion-tracking cameras to track the puncher’s joints, he found that strikes that synchronize the many peak accelerations in one complex move—like Bruce Lee’s—were also the most powerful."
In other words, punching with just strength is inferior to punching with strength plus skill, and it's measurably different.
Technical Grappling extends this to grappling, where raw muscle provides the underlying basis for your grappling strength, but skill provides an addition to it. TG author Douglas Cole and I have chatted occasionally about extending that - and the concept of trained strength and damage bonuses - to everything, but there are complications. It would essentially make skill - already the win button in fights - into an even more powerful tool, and push striking damages up and up and up. You'd basically be giving skilled fighters a damage bonus (much like Weapon Master), and you'd need to re-jigger what Weapon Master does, what low skill does to damage, and what the expectations of armor DR are too, perhaps. It's an escalation, and ties skill to damage intimately in ways that would extend through the system. It's not a simple bolt-on if suddenly a ST 13 DX 12 Broadsword-15 fighter does 2d+4 instead of 2d with his sword, while a ST 13 DX 12 Two-Handed Sword-12 guy does 2d+2, and if maximizing one skill means much heavier or appropriate weapons are less useful than simply piling skill on to get more damage. I'd also be curious to see if there is any research suggesting this is true for weapon strikers - it probably is, but I don't know if it's been studied.
There are ways around it, but it's not so uncomplicated that I'm going to do it as a blog post. If we can work it out, perhaps it'll see life as an Alternate GURPS article someday.
But for now, you can bask in the feeling of "I guess GURPS was right about that" based on the article's findings about unarmed striking and skill.