Oohh I love writing action scenes. Like @sararosebr said, short, punchy sentences, even incomplete ones, are a great way to punch up narration. Long sentences work too - usually a long sentence slows things down, but when it's TOO long, it can feel frantic and breathless. Readers are good at picking up run-on sentences and it makes them uncomfortable, which can be a valuable tool for building tension. Especially if you then punctuate with a punchy one. With action you're building a mood that's supposed to feel a little off kilter and unpredictable so always feel free to break some rules (good tips for erotica too )
If your action scene feels like it's dragging on, you might be focusing too much on every action. Readers are totally happy to accept "he rained blows down upon him!" or "he slashed wildly but she blocked every strike." Sometimes I like to give two specific actions, fudge the middle with actiony language that gets the feeling across, then describe the final blow. Same thing goes for a chase scene or even an argument. Your reader has imagination, so don't be afraid to lean into that and let them fill in a few things while focusing on the emotions and characters moreso than the specifics.
Hope that helps!