Here are a few examples:
Jeff Galloway. You'll notice that he only has you running 3 days a week.
Hal Higdon. Hal has a novice, 2 intermediate and 2 advance marathon training plans.
I guess I'd start off an intermediate runner with an introduction to the 4 different types of run:
1) Slow Distance / Easy Pace / Conversational.
2) Tempo run -- for increasing your lactate threshold.
3) Interval run / Speed workout -- for form and increasing glycogen storage.
4) Hill run -- speed workout in disguise.
5) Recovery run.
Oh, I guess that's 5. And would be 6 if you include maximum oxygen training. Well, you'll just have to figure out the details yourself.
Beginning runners typically do not run anything but slow distance and can do so for months as the mileage builds up to, say, 20 miles a week. Eventually a runner will enter a couple of races, starting with a 5k, maybe a 10k, and about the time a half marathon comes into view, he's starting to get to the point were some type of speed workout will be helpful. The best explanation of these different types of run is on the Runner's World web site. And since it takes a couple clicks on this page to get the desired data, I'll reproduce it here.
By the way, that previous Runner's World link takes you to their training pace calculator. It's a great tool that I've used all along. It takes your most recent 5k or 10k finish time as an input and tells you what pace to run all your different types training runs.
Oh, here's another type of training I nearly forgot to mention -- heart rate training.
Basically, you strap a heart rate monitor on (basically a bra without the cups) and do all your training at specific heart rates, as a percentage of your maximum heart rate. You keep the heart rate pegged, and as you increase in fitness, you go faster at the same heart rate.
Here are some links:
Runner's World
Cool Running
Polar
MarathonGuide.com
"If you want to run longer, you just have to run a little slower."
So really, everything you've learned in becoming an intermediate runner will take you from a fast 5K to a marathon and beyond. You just keep increasing training time and distance. Well, I guess there are a couple more things you learn as you increase distance:
1) Equipment -- better shoes, socks, wicking clothing, and the most important thing, anti-chafing stuff. For some people, there just isn't enough vaseline in the world.
2) Fueling -- the human body can store 2 or 2 1/2 hours of energy in the form of blood sugar, and since most runners take 3 1/2 or more hours to complete, where does that additional energy come from? I'll try to outline your options here, in the future. If you don't learn and apply this you will succumb at mile 20 to an effect known as "the wall".