posing and armor help

[sleek haven]

for context this is my first time ever drawing an action scene (crazy i know) but i would like to build this skill so i could potentially apply to an art school or two next year.. does anyone have any feedback on making the posing more visually interesting? or even just a little less stiff.

I also don’t mind feedback on the armor these two wear as they are my only two characters with armor (they are based off of chess knights)
I’ve attached my art along with the reference. putting this out there now so i can sketch out the background before coming back to them

[dark owl]

Actually im not an armour expert but maybe change the attacker's armour. Maybe some royale type shiny medival armour could work, less pointy. And change his facial expressions to a meaner look. And I think in most cases if u want to make it look serious, look after the background, change the ground pattern around the character's as if they are dueling for long time. Overall it's really good, even without considering my suggestion it'll look fine.

[sleek haven]

I’ll keep that thing about the ground in mind as i sketch, i never though of that before! I’ll definitely pull up some more references on his armor, i’m still not set on how it looks but I’ll probably still keep him pretty sharp in comparison to the other dude. i was planning to change the face later anyways since right now the sketch is still pretty cartoony compared to my usual style. BUT ALSO THANK YOU. I feel like i’ve never gotten this kind of feedback before and it was very helpful!

[fleet mango]

its difficult to tell where the motion is in your sketch. is the standing one being pushed back or bringing his sword down like in the ref? Is it supposed to be the moment of impact? i feel like your sketch currently doesn't answer any of those questions, it is in a nebulous middle ground between static pose and a snapshot of motion.
one option would be to do what the ref shows more closely, but really exaggerate the weight (wider stances, more tilt to the swing, etc.). imagine that if the crouching man didn't block, he'd be cleaved in two. imagine the insane force it would take to actually do that. now draw how the man is blocking with that force and effort in mind.
another option would be to imagine the follow through. like if the person being swung at is pushing the other off, try drawing the result of that instead.

tldr: visualize the forces at play and redraw with your mind occupied by that feeling of force.