Aside from long runs at goal pace, the key to running fast for long periods of time is long interval training. Long intervals combine VO2max and Anaerobic Threshold or Lactate Threshold training. A long interval is a distance of 800m to 1600m. However, my personal feeling based upon experience is that intervals of 800m only really contribute to helping your VO2max, while intervals of 1600m contribute to increasing both your VO2max and anaerobic threshold.
For those that did not click on the links. VO2max is your maximum capacity to transport and utilize oxygen. Your lactate threshold is the point at which lactate begins to accumulate in your blood stream faster than it can be metabolized. Exercising at a greater rate than your lactate threshold means that you are exercising without oxygen (going anaerobic) and will tire faster than if you were exercising at below your lactate threshold. Fortunately, doing specific workouts can increase your maximum oxygen capacity, as well as push your lactate threshold back (to a point pre-determined by your genetic make-up).
My long interval workout is as follows. Once a week I go to the track (in NY, I did my long interval workouts on a treadmill). One week I will do 800m intervals. The following week I will do 1600m intervals. Today was an 800m day. One mile warmup, then right into the first 800m interval. You typically want to run each of your intervals at exactly the same pace. I'm training with someone whose Boston Qualifying time is 3:30 and according to Yasso, our intervals should be 3:30 each. Read the article. Apparently there is a correlation between running 10 800m repeats in terms of minutes and seconds that tells you how fast you will run a marathon in hours and minutes with the same numbers. Again, read the article. For me and many others, this has proven itself time and time again.
When I qualified for Boston, I was running my 800m intervals in 3:10 and my 1600m intervals in 6:20. Later this year, when I go for a sub-3 hour marathon, I will be running my 800m intervals in 3:00 and my 1600m intervals in 6:00. Yea, that'll be fun.
So back to this morning's workout. We're not up to 10 800s yet. This week, we only did eight. After each 800m interval, we slow down to about 1 minute slower than marathon pace (9 minute mile) and do this for 1/2 a lap (200m). Once we hit the 200m mark, we go right into our next 800m interval. Every fourth 800m, we slow down to 1 minute slower than marathon pace for a full lap (400m). Once finished, we cool down with a very slow 1 mile jog. And you're done. Today, our times were 3:28, 3:29, 3:31, 3:32, 3:29, 3:29, 3:33, and 3:22. The last 200m of our last interval we just sprinted for kicks. Hey, we felt good. The keys are consistent speeds and not slowing down too much during your rests. You need to train your body to experience the peaks and valleys of the marathon gruel. This includes brief periods of recovering by slowing down, but not jogging or walking. If you cannot do 8 or 10 intervals in this fashion yet, then I'd recommend to start off with 3 or 4 and to slowly build up until you can do 8 or 10. It's better to do less right than to do more incorrectly.
1600m intervals are similar, but significantly harder. Same total distance. Next week, we will do 5 1600m intervals at 7:00 pace. Between each 1600m interval give yourself a full lap (400m) of running 1 minute slower than marathon pace. Every 4th interval, give yourself two full laps (800m) of running at 1 minute slower than marathon pace. 1600m are more difficult because of the need to sustain this speed for a longer period of time, but they are also more beneficial because not only do they increase your VO2max, but due to the distance, they increase your lactate threshold. Again, aside from the long training run that incorporates marathon pace, there is no other workout that will help you as much as 1600m repeats.
I typically start my speed work 14 weeks before a race beginning with 5 800m intervals and 3 1600m intervals increasing the number of intervals each week until I am at 12 800m intervals and 7 1600m intervals. My last 1600m interval workout is 3 weeks before the race. Two weeks before the race, I do 800m intervals and 1 week before the race I do 400m intervals just to keep the leg turnover going and not to wear out my legs.
Hope this makes sense. If you have any questions, let me know. Next week, I'll talk about the tempo run, which is the more traditional form of lactate threshold training.