I stated earlier that I find a 75 min./day average of training ideal for the marathon (70-80 okay). Very few runners who take more than 3:30 to finish run that much and, after increasing the length of the long runs and running more of them, increasing weekly mileage should be the goal for improving times for these marathoners.
I have found that, regardless of finishing times, runners before their fastest marathons have their longest run done in about 165 minutes (150-180 okay). A typical week might then be 5 days of 75 minutes, a long run and a day off or six days of 60 minutes plus a long run. While that is probably the surest way to increase mileage, it is not ideal, because the marathon's challenge is running fast for more than 2 hours. Because there is a significant loss in fitness in training fewer than 4 days per week, the limit becomes 3 runs of 120 minutes and one of 165. The week I propose is:
Friday 0-30 minutes
I choose to start the week on Friday as it is common for runners to try to make up lost mileage and this ensures at least one easy day per week and puts the hard Saturday and Sunday runs early in the week.
I did a series earlier (see index for "energetics") that detailed my thoughts leading to an ideal week of training being intervals on tuesday, hill repeats on thursday, a fast continuous run on Saturday and a long run on Sunday. This is reflected in the above.
A question that arises is: if one is taking 4-6 hours to run a marathon, shouldn't the long run be that long? For a first marathon, that is a reasonable approach and there are many plans published which consist of increasing the length of the long run regularly until one runs marathon distance. Once one knows one can finish, the focus becomes fnishing faster and that is done (at this level of ability) by regularly running more than 90 minutes. The weekend runs total 4-6 hours; one doesn't recover completely in 24 hours, so this "doubling" common among ultramarathoners is a good substitute for one run of 4-6 hours.
One more consideration is high mileage. While some in the 2-3 hour range desire to run higher mileage than i advocate, they do it by running more than once per day. I think that these shorter runs are not specific enough to the marathon; instead I suggest additional 90-120 minute workouts substituting for the easy days. Running this long every day would lead to residual tiredness and slowing. For this reason, I would have the Monday, Wednesday and Friday runs be cross-training, preferably race-walking. Walking at speed is to running as swimming the butterfly stroke is to free-style: a slower way to get to the finish, using the same muscles in a different way. I found in my ultrarunning experiment that it is sometimes possible to walk almost as fast as one can run, but with much lessened impact shock. For these workouts, assume it will take 1.5 times as long to walk a distance as run it, once one has some experience with fast walking.
Big change in life today
4 days ago