A fellow blogger asked me a good question last week. I thought I'd post the question and answer here since others might have the same questions:
I have a goal of running in the Louisville Mini (13 miles) in the spring. I currently can run 5 or 6 mile runs, but I have seemingly hit somewhat of a "plateau" as far as what I feel I am capable of. I dont know if you have ever ran in a marathon or minmarathon (of course I know you have done the tris and dualathlons), but when you run during a training phase for that kind of distance, do you try to run as many days as possible, and as far as possible everyday of the week. Or do you stick to 2-3 mile runs a few days and one long run a week. Or do you have a few days with sprints mixed in with the long distances?
First, there are lots of helpful websites. I suggest you look up some 1/2 marathon training plans for beginners on-line. Runner's World has some good ones. Hal Hidgeon's (sp?) and Jeff Galloway also have some good ones.
I actually have run 2 half-marathons so I have a little experience. For a beginner, your goal is to finish and maybe feel good at the end. You'll want to plan out the number of weeks you have left until race day. You want to gradually space it out. I would plan on running 4x/week and doing something else 1-2 extra days/week that's soft on your joints (light weights, swimming, a walk, etc).
Of course, this depends on your schedule. If you don't have that much time, or if this is too much for your body, you can also choose to run less and have more off days. I found I did best with 3 days of running and 2 days of cycling when I was training for my half. I tended to get injured when I ran more than 4 days a week. Some people can handle it though.
I planned my shorter runs during the week and 1 long run/week on the weekend. If the long one is too taxing every week, do them every other week. This actually worked better for me, but you need to experiment. For instance, if I was running 4x a week, I might run 3 miles Monday, 6 miles Wednesday, 4 miles Thursday, and my long run on Saturday. Every week, I would increase the long run by 1 mile or less. You might choose to increase your long run every other week. Right now, I would start at 6 miles for your long run. The next week, you can try 7. Then stay at 7 for another week before increasing again and so on.
The other important thing (well 2 important things) is a) alternate hard days with easy days---the run after your long one should be easy and soothing, perhaps on the treadmill. The second thing is to make sure you go extra slow for your long runs. You should feel like you are going too slow at the beginning. It will feel harder by the last 2 miles. Be sure to have at least one complete rest day a week (you don't need to lay on the sofa all day on this day; just no structured, formal exercise). Be sure to include a Yoga or stretching regime to prevent injury, especially after your runs. Also, make sure you are eating a healthy, balanced diet. You'll need to have more carbs and you may need to increase your calorie intake. It's also very important to stay hydrated. I recommend carrying a fuel belt for runs over 6 miles with PowerAde or Gatorade or some kind of sports drink that agrees with your stomach. It makes a huge difference. You also want to eat a small, post-recovery meal after your hard runs that is rich in carbs with some proteins. I've been loving high-fiber cereal with skim milk for this. See what you crave. Listen to your body and adjust any plan you follow for you.
Hope this helps. Good luck!