Applying the 80/20 Rule to Running
Are you a runner that constantly checks if you are on pace during your recovery runs? I used to think the best way to get faster was by putting in 110% every single run. I understood that that having a rest day was important, and if I went all out every run I would get injured, but I also felt that running at a mere comfortable pace was just being lazy.
The 80/20 rule (also known as the Pareto Principle) is a concept created by Italian economist Vilfredo Pareto, its origins lie in the common trends that exist in the world. Pareto noticed that a small minority (the top 20% in Italy at the time) held most of the wealth. Similarly, that 20% also had most of the influence in society. At present, the Pareto Principle is mainly used as a framework to create more useful goals or spend most of your effort targeting the highest value customers if you are a business owner. However, the Pareto principle can also be applied to running.
Using this principle when running
To apply this principle to your training, structure your running week or cycle with the idea that having a low quantity but high quality of workouts will provide the greatest benefit. You don’t have to strictly follow the 80/20 rule in that if you run 5 days a week; you are only allowed one workout, but two workouts, and at max three should be sufficient for most.
The evidence
In 2007, researchers assembled two groups of semi-elite Spanish runners (their 10k PR's were in the low 30 minutes). Both groups ran a 6.5 cross country style time trial at the beginning of the study. Then the first group was given a training plan with 80% of the runs at a very low intensity, and the remaining 20% at a moderate to high intensity. The second group’s plan only scheduled 65% of their runs at low intensity, and the rest of their runs at medium or high intensity. At the end of the study (after 5-months), both groups ran the same 6.5-mile race again. Although all the runners improved, the first group's average improvement was 36 seconds higher, even though they spend less time running at race pace. While 36 seconds might not seem like a statistically significant number, at that level, each second of difference is significant.
Look at the elites
If you still don’t believe in the 80/20 rule, look at some elite runners. Sally Kipyego runs at around a 5 minute per mile pace during a 10k. However, she does most of her training at 8:30 pace. Another example is Kenyan marathoner Moses Mosop who ran 70% to 85% of his mileage at 1.2 times slower than marathon pace when training for the 2011 Boston Marathon (where he placed second).
The science behind this
From a scientific perspective, running majority easy runs makes sense. In the presence of oxygen, our body uses the aerobic system to fuel our muscles. When we run at high intensities or lift weights, there is not enough oxygen so our muscles use the anaerobic system: using a process called lactic acid fermentation. Easy runs help improve our aerobic system; and even with races as short as a mile, 80 percent of our energy contribution comes from the aerobic system. So, improving our aerobic system is certainly beneficial.
There are three major ways our aerobic system improves
- Capillary development — Aerobic training increases the number of capillary blood vessels in your muscles. Capillaries are small blood vessels that transport oxygen and nutrients to your muscle tissue, so by increasing their number, you increase the efficiency of oxygen and nutrient transport to your muscles.
- Increases myoglobin count in muscles — You can think of Myoglobin as a fishing net for oxygen. Myoglobin is a protein that binds oxygen in the muscle cells. This means that during oxygen debt (like at the end of a race), you have a reserve of stored oxygen left in your muscles, which you can now use to power your aerobic system a little longer.
- Increases mitochondria density — You probably remember hearing in a biology class that the mitochondria are the powerhouse of the cell. That is completely accurate, as mitochondria are responsible for glucose into energy your body can use (ATP). More mitochondria = more energy = able to run faster and longer.
Wait, but doesn’t running at high intensities also increase your aerobic system?
Yes, and no. Running at high intensities also benefits your aerobic system, the rate of aerobic improvement peaks during slower runs. Here is a chart with the specifics.
Put 110% effort into running easy on recovery days
A common problem I face, and I’m sure many of you face as well, is the temptation to push the pace on easy days. One problem I used to suffer from was the pressure of wanting every run I posted on Strava to not dip over a certain pace. I no longer suffer that feeling and now still go 110% for my easy runs, except the focus is not directed on running faster. The focus is on running comfortably, running upright, not overstriding, and enjoying the surrounding scenery. At least once a week I would suggest running without a watch (or phone) and just listen to your body.
However, if you really want to record your run with your watch, here is something you can try. Most running watches will allow you to create custom date screens on your watch; set it so the only thing it shows is your mileage and/or the current time.
So try structuring your training with the majority of your running being easy runs. However an important note is easy is a reference more to pace, not distance. So a recovery run does not mean to go out and run only a mile, it just means to run at a comfortable pace. Have fun running!
