Why The 10% Rule Isn’t Always Right by Brian Kunz

For as long as I’ve been running there has been one sacred rule: never increase your mileage by more than ten percent. Granted, being a teenager when I first started running this rule was broken often, very often, and you know what? I turned out fine. My high school PR for the 5k was a 16:05. So clearly, I did all right for myself. Now, many years later I’ve been forced to question the legitimacy of the 10% rule. Where did it come from? What’s the basis for this rule?

After doing some digging I discovered there isn’t really much basis for the rule; it’s something that just kind of works. And for the most part it does work. However, in some cases it doesn’t. The reason I’m being so critical of the 10% rule is because lately I have seen a lot of people acting like it’s a law. I’ve seen the entire spectrum–from people raising their weekly mileage by 10% every week religiously, to others who treat it as if you’re wishing death upon yourself by increasing anywhere near that much.

Above is a table showing what your mileage would be if you were to increase your mileage by 10% every week for 30 weeks. Granted this is taking the 10% rule to a new level. In all honesty nobody can increase their mileage by 10% every week indefinitely. It’s not a good idea and as you can see here;

As seen here, for weeks 28 and 29 there is a 13 mile increase from one week to the next. Let me be the one to tell you: that’s crazy. I run these distances and I would die if I added on 13 miles one week to the next. But at the same time the inverse kind of situation can occur. The first few weeks show this whacked relationship:

One mile difference? That’s a total of seven minutes of running for the average guy. And it goes on for the about the first 10 weeks. From personal experience and from clients that I have coached, jumping from 10-20 miles in 3 weeks isn’t hard in the least. It just all depends on your fitness level. Here’s what all this essentially boils down to: 10% is not a golden rule. It’s a general rule that sometimes works. But if you’re in great running shape (e.g. you were running 60 miles a week but took two weeks off, so you need to back off  on your miles) it’s okay to go over 10%. And the inverse can apply– if you are a very out of shape never-ran-before-in-your-life person, 10% really would be asking for death.
What I have discovered with increasing your mileage is that you should always listen to your body; your body will tell you if something is wrong. Sometimes it can be difficult to differentiate discomfort from actual pain when it comes to running, but it’s important that you learn to be able to.

Summary of the above: 10% increase in weekly mileage as a cap is not always correct and sometimes too correct. Listen to your body more than generic numbers. If it feels too much, back off. If it feels too little go farther. And lastly, don’t believe everything you hear.

What to do to build mileage successfully:
According to a poll done by the national foundation of health and fitness, the average runner (runner being defined as in runs more than twice a week) runs 15-32 miles in one week. As a general rule running 40 miles a week is an optimal distance for mid to long distance runners you’ll need a bit more to get you through a marathon and a lot more of ultras but 5k 10k and 20k’s are not beyond you with 40 miles a week. So now here is how to build to that;

As you may notice above there are a few weeks were the mileage actually goes down. The reason for that being is to allow your body to catch up to the miles you’ve been running. As seen for the weeks 5 & 6 and for weeks 11 & 12 the mileage goes down. As said before this is to let your body catch up to your running so to speak. It just allows your body to rest so you can continue increasing your mileage.

Now this chart above is called a blitz mileage chart. It gets to you a good level of mileage fast and efficiently but at a cost, once you get to the desired mileage you need to hold it for a month before you can increase your mileage again, meaning after 14 weeks of doing blitz mileage increasing you need to stop and continue doing the mileage you ended at after 14 weeks, making an 28 week schedule look like this.

The reason there is a dramatic slowdown in the increase in mileage is, because once your mileage gets higher your recovery time increases, meaning your body doesn’t handle dramatic changed very well once you get up past 40 miles a week you need to slow down on your mileage increase, in my experience trying to increase your mileage at 10% a week increase is way too high.

I’m afraid this article is already over a thousand words and thus I need to wrap it up :( . But for more information on increasing mileage safely and effectively, and quickly please visit my site www.adayofrunning.com

About the author:
Brian Kunz is a certified athletics coach based in MN, he has ran a 2:20 marathon and a 1:07 half marathon, along with a 15:10 5k and currently authors the site http://www.adayofrunning.com/