In action writing, the pacing of your writing is part of what conveys the action. This means that the writing should speed up along with your characters. Action writing doesn't call for long descriptions of setting or character. Everything you write should pertain to the action.
See, for example, how John Le Carré handles the final action scene in <i>The Spy Who Came in from the Cold</i>:
Leamus was blinded, he turned his head away, wrenching wildly at Liz's arm. Now she was swinging free; he thought she had slipped and he called frantically, still drawing her upwards. He could see nothing -- only a mad confusion of color dancing in his eyes. Then came the hysterical wail of sirens, orders frantically shouted. Half kneeling astride the wall he grasped both her arms in his, and began dragging her to him inch by inch, himself on the verge of falling.Notice how Le Carré allows us to see both what Alec is doing and what he sees. Part of what builds the tension of the scene is the fact that he adheres to Alec's point of view. (It also makes it easier to describe if you're telling the story from third person limited. You don't have to worry then about describing everything that's happening in a scene; only your protagonist's slice of it.)
