Runners often swear by the 80/20 rule for organizing their training—but this is no relation to the Pareto principle of the same name. Let’s talk about where the 80/20 idea comes from, how to implement it, and when it is and isn’t a good idea to train this way. Briefly, it’s the idea that 80% of your running should be low intensity, and only 20% at medium or high intensity.
Recreational runners (like you and me) often run closer to a 50/50 split. The 80/20 rule suggests that we should take some of those faster runs and slow them the heck down to reach a better training balance. The 80/20 rule was popularized in a 2014 book, 80/20 Running , by Matt Fitzgerald.
Fitzgerald, in turn, based his recommendations off research by Stephen Seiler , who found that elite athletes in a variety of endurance sports, including running, cycling, and cross-country skiing, did about 80% of their training sessions at intensities much lower than they would ever use in racing. In other words: To train your body to go fast, you have to log a lot of miles going slow. This is similar to the idea of “polarized training,” which means that you stick to the extremes—either working very easy, or very hard, rather than spending much time in the in-between.
Note that 80/20 here only refers to how you split up your training: 80% easy versus 20% hard. This is not the Pareto principle, which states that 80% of your results come from 20% of your..
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