The Lone Runner Series: Interval Training for Marathon Runners

Interval Training for Marathon Runners

by Ben Connelly

In a previous post, I introduced the topic of speedwork for marathon runners. I explained that, contrary to common belief, marathoners should not run all their runs at an easy pace. Beginners focused solely on completing the marathon can get away with skipping speedwork (although speedwork might help). But every runner who wants to improve their race time, or place competitively, should include speedwork in their training.

Starting today, I want to explain specific workouts in more detail. I will cover both the benefits of each type of workout, and how to perform it. Just as marathon training (or training for any race) begins more general and grows progressively more specific as the race approaches, I will start with the least specific (but still important) workouts and end with the more specific workouts. Today, I will discuss interval workouts. Later I plan to cover hill workouts, downhill workouts, tempo (lactate threshold) workouts, long runs, and marathon race pace workouts.

Interval Training:

While interval training could have multiple meanings, I define interval training the same way Jack Daniels does in his foundational book, Daniels Running Formula.[1] He uses I Pace (interval pace) to refer to a pace very close to vVO2Max (the velocity at which you run when you hit your VO2Max). You can run at this pace for about 11 minutes. For most runners, this is somewhere between their 3k race pace and their 5k race pace. You can simplify workout planning by using your race pace from one of those distances.

During I Pace workouts, you will run intervals of between 3 and 5 minutes, with lengthy rests. On the track, this often means anywhere from 800m-1600m depending on your speed. These intervals are long enough to challenge your VO2Max, and short enough that you can sustain I Pace. They are not all out sprints. Outside of hill workouts, these are the shortest repetitions you will do in any workout during marathon training. I recommend 4-6 intervals per session.

Unlike in 5k or 10k training, I Pace workouts are not crucial to marathon training. 6x1000m on the track is not specific to the marathon. This means you will do fewer of these workouts, and they will occur earlier in your training cycle.

Why do them at all? Even though they are less important at 26.2mi, VO2Max and vVO2Max still play a role in the marathon. Improving both of these physiological parameters will improve your marathon race times. Interval workouts are the best workouts for challenging VO2Max and vVO2Max, and over time will help you to improve them. Which will make you a better runner, full stop.


Early in your training, I recommend running an interval workout every two weeks. If you have access to a track, run 4-6 1000m-1200m intervals with a 600m-800m jogging recovery. If not, find a flat road or trail and run 4-6 3–5-minute intervals (for the rest period, either jog for an equivalent length of time, or jog for 1 minute less than your interval length).

Since these workouts are not specific to the marathon, you should prioritize other types of workouts. But they will help you improve your VO2Max and vVO2Max, which will translate into improved performance.



Ben Connelly is a freelance writer and an experienced runner. He has written multiple e-books on running and general fitness, including a marathon training guide, which you can purchase here. You can find him at his Amazon Author page, or at his website.

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