A lot of people when they start writing, they usually start with a single scene in their head. Maybe they imagine the final confrontation between their hero and villain, maybe it's a scene in the middle where the story has a major turning point. Maybe they've imagined the opening scene and can see the how they want it all to end. No matter what part of the story they imagine first, it's only the beginning and it's actually usually a very small part of the story.
A good example would be one of the scenes I've envisioned for my work The Nightmare Factory. The scene I picked out is actually from the middle of the story, where we first truly see the identity of the monster that is running the show. One of the secondary characters interacts with him and enters her death throes in what I envision to be a fairly spectacular way. Here's the thing though, to get to that part of the story, I have to introduce the main character, the secondary character, the antagonist, the location and bring them all together. That's a lot of back story just to get to a scene that might, if I'm lucky, be a thousand words long.
While the whole story may be pushed along by the action scenes, it's important to remember how small a part of the book they actually are. After all, if you can't catch and hold your reader's attention in the first place, they'll never make it to the brilliant action scene you've put together. In addition, even if your beginning is strong and gets them to the first scene, you still have to travel to the second one, and then to the finale.
I think the spaces in between is what gets a lot of new writers. It can become very tempting to just cut the sections in half with phrases like "Two months later...", "He waited for hours." and other ways to describe the passage of time in a single sentence so they can skip a lot of the in-between areas.
A proper, good story though takes advantage of the ravines that must be crossed between the fancy action scenes. You can take the time to delve into background, show the characters interacting with other people, even if those other people are just there for them to interact with in that moment. Try to remember, probably seventy percent of your story is going from point A to point B to point C. The points themselves might be important, but they aren't going to take up as much of your story as you would like.
The space in between might seem like extra compared to the main events of your story, but in actuality they are every bit as much, if not more important. The spaces in between tell us how we get to the events, they tell us about the characters so that when the main event happens we actually care about what happens to them. The spaces in between are what make a story a story. You just have to remember; people don't read to reach a destination, they read to enjoy the journey.