Greg's always been open to discussing his training methods so I brought this post to his attention. Here is his email reply:
No problem. Happy to explain. In the last 9 weeks leading into Houston, we did two 200m repeat sessions (on 11/16 and 12/28) and two 400m repeat sessions (12/2 and 1/4). For the 200s, we did 20-24 x 200m w/ 200m jog in each session. The pace was only moderate (for Brett the goal was 32-33 - 4:16-4:24 pace) and the goal was for the recovery jogs to be moderate as well. For the 400s, we did the early workout (12/2) as 12-16 x 400m w/ 200m jog and the later session (1/4) as 8-10 x 400m w/ 200m jog. Again, these were not like when we do 400s for the 5K or 10k. They were moderate and we did them progressive. The goal was to run them in sets of four in 70, 68, 66, 64. (He was usually more like 69, 66, 64, 63.)
The reason for including short, moderately fast workouts in marathon training is three fold:
1) Short repeats improve running economy (the amount of oxygen consumed at a given pace) and improved running economy is very important in the marathon.
2) Short repeats break the monotony of training. Often, marathon training starts to put runners in a pace rut and short repeats help keep you out of that rut. They challenge the runner to turn their legs over and avoid the marathoners shuffle.
3) Short repeats allow marathoners to put some volume in at significantly faster than race pace. Brett's goal marathon pace was 4:55 so we were doing workouts at 4:15-4:40 which allowed 4:55 to feel easier.
Many runners only think about 200s and 400s like they do for collegiate races of 1500-10K - hard and fast - but you can adjust the intensity to help the marathon without being as anaerobic or tiring as they are for 5K-10K runners. All the short, fast workouts Brett did were very controlled. Could he have run them faster? Of course! But, that wasn't the goal.
Many great marathoners include(d) short fast repeats for the reasons I listed.
I will say, however, that they shouldn't be used for people with no speed. For example, I didn't include these workouts with Paige Higgins (2:33 in Houston) because she doesn't respond well to short, fast running. With Paige, we would do fartlek sessions (like 20-25 x 1' on 1' off) but these are more like a tempo run with surges than a track workout. This lower intensity exposure to running slightly faster than marathon pace works much better for her but that's another topic so I'll stop here.
Hope that helps.
Best,
Greg
There you go. Straight from the coach's mouth. NDK