If you're writing any kind of fight or chase, get hold of little action figures or toys so you can carefully and slowly choreograph the sequence on your desk. The excitement of a scene is instantly destroyed if your reader is confused about how a character's arm got from round his enemy's neck to punching him in the liver without the necessary physical transition. Block out every move in the sequence like the director of a dance show and you'll avoid asking your characters to bend over backwards or suddenly sprout extra limbs.
Once you've choreographed your sequence, cut half of it. Then cut half of it again. Reduce every fight or chase to its essence. You want maximum impact, minimum space on the page. For every twenty moves you'd see in a fight on film, write one. But make it count. In my first draft of my first book, Jimmy Coates: Killer, the helicopter chase was twenty pages long. In the final version, it's four pages. But because it's shorter it's more thrilling, it's more memorable. It should feel like it takes up more of the book than it actually does.
Jimmy does not punch people. The knuckles of the first two fingers on Jimmy's right hand connect with his enemy's clavicle. For example. Get a diagram of the human anatomy and work out precisely the bones and ligaments that are crunching or grinding or twisting and how. Be specific not just position and action but with degree - how hard is someone hitting? How fast is someone moving? The common adjectives are too loose. Better to cut adjectives altogether and use stronger verbs. Even better, show the effects of a blow and you don't need to explain how hard it was. Show how the character feels the speed and you don't need to say it's fast.
Sometimes you want to project the mess or speed of a fight or get across that so much is happening so fast nobody can keep up. That's when you need to step back and let the reader fill in the gaps. Don't itemise every blow with the detail you would if you were being specific. This works well towards the end of a book when the reader has already imagined enough specifics to be able to know the detail instinctively when you only suggest an outline. So switch to overall dynamics. You'll need to rely a little more on metaphor and simile to make it work. This might not make much sense without an example, so here's a fight between two young would-be assassins near the end of Jimmy Coates: Power...
The two boys swung round each other like Olympic gymnasts on monkey bars. They traded blows with such pace that the noise of each strike echoed into the next. It sounded like rapid drumming. Jimmy let his mind drown completely in his programming. He wheeled his legs round, throwing himself in complete rotations to spin and kick again. At the same time he blocked Mitchell’s attacks with alternate hands – while his right defended against a savage kick, his left held on to the strut above his head, then viceversa.
Eventually, actions merged together. The fight became a blur in Jimmy’s head. He felt like he was in a trance, with a red haze seeping from his centre out towards the tips of his limbs. It was the feeling of murder. He knew Mitchell felt it too, and the longer the fight went on the hotter it burned.
We've all seen a fast car crash into a market stall. We've seen a lot of fights in movies. Do better. When the movie Bad Day at Black Rock came out in 1955, very few people knew about karate. The fight sequences in that film are short and powerful. A one-armed man has a skill he learned fighting the war in Japan and the result is utterly gripping, even now. It's even more exciting if you imagine never having seen karate before. So do some research. Find something that thrills you. If you find yourself writing a cliché, make a note to come back to it later and tweak it out of existence.
Play with time
A fight or chase shouldn't take the same amount of time to read as it would take to happen in real life. You can accelerate when you want to (especially if you're being 'vague', as above) or you can slow things right down and indulge in the right simile, the right bone hitting the right soft tissue, the maximum impact for a single action that would otherwise be lightning fast (especially if you're being specific, as above). Your job is to create a fight in the reader's head, not to commentate on the fight in your head.
Finally, remember: every single line of every fight or chase should tell the story. If it doesn't, an action sequence will feel kinetic but stagnant. Do not mistake movement for action. Do not mistake motion for emotion.