Posted by: Joe English | May 13, 2008

Training: Should I run one or two 20 milers before my first marathon?

One of my athletes training for the Mayor’s Midnight Sun Marathon in Anchorage wrote to me today asking the following question:

Our training program has more time than some other programs and I see that we have the opportunity to run 20 miles twice to get ready for the race. Do we really need to run 20 miles twice to be ready?

I mention the fact that this runner is preparing for the Mayor’s Midnight Sun Marathon in Anchorage, only because that particular course has some hilly and unpaved sections that make it more difficult than many marathons. But my answer below really applies to most runners preparing for their first marathon in any race:
– First, running 20 miles at least once in training for a first marathon will normally ensure that a runner has the necessary preparation to finish the race without regard to a particular time goal. This means that the 20 miler is tool to prepare the run for the distance of the marathon and every runner should try to get in at least one run as close to 20 miles as possible.
– Running 20 miles more than once in training will improve how the runner feels in the last six miles of the race, because it will give the body an additional opportunity to exercise for a duration of 2/3rds to 3/4s of the total time needed to finish the marathon on race day.

– The last 1/4 of the race is going to be a struggle for most first time marathon runners after having only run 20 miles once in training. Runners that have the opportunity to do it more than once will have an easier time in the last quarter of the race, but it will most likely still be a struggle.
– If the runner is healthy and not having issues with over-training or over-use problems, my preference is to have them try to run 20 miles twice rather than once.
– If a runner needs more recovery, I will usually shorten the runs between between their two 20 mile runs, rather than shorten the 20 milers themselves. Dropping the distance in the weeks between the runs gives the body more recovery. Getting in that second 20 miler has more impact than shortening the 20 miler and doing a series of shorter runs.
– It’s important to think of these 20 mile runs as a long, slow exercise, and take your time getting through them. You’ll benefit from the total time you log in these long runs, by spending more “time on feet” than if you try to push the pace in these runs. Focus on goal pace in the slightly shorter 18 mile runs between the 20 milers and run plenty of goal paced miles during the week to learn your goal pace, but use the 20 milers as a way to log as much time in one single workout as possible.
Another way to think about this is that if you ran 9 miles per hour (for the sake of easy math) and you did 18 miles twice (2 hours) then on race day you would have to run a whole extra hour (3 hours) to complete the race — and that’s a big step up. I’d rather see my runners logging 20 miles at a slightly slower pace, and logging say 2 1/2 hours –then they only have to run an extra 1/2 hour on race day.
– And finally, a second 20 miler can be helpful if you are running a race over more difficult terrain, such as hills or trails. In a race like the Mayor’s Midnight Sun Marathon in Anchorage, I would have my teams run the first 20 miler on flatter terrain and then run the second one on hilly and some unpaved terrain. This is extra preparation at the longer distances to meet the demands of the course.

So bottom line, while we always need to be mindful of avoiding over-training, a second 20 miler may make good sense to improving the feeling in that last half of the race for first-time marathon runners.

See also:
First-time marathon runner 20 miler mental anguish
How should I feel after running 20 miles in training?

See the preview to our upcoming film 26.2 miles to Boston by clicking here.

Coach Joe English, Portland Oregon, USA
Running Advice and News


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