Tilting at Windmills: The 10% "Rule"

By: Brad Deel

One of the oft repeated pieces of advice you routinely see is to avoid increasing your mileage by more than 10% per week.  Bear in mind that I’m not talking about people who have been running for a while.  I can have several weeks of relatively low mileage (30-40 miles) and can then run 70 miles with no ill effects other than a bit of fatigue.  I can do that because my body has adapted to running over the 4+ years I’ve been doing it.  I’m thinking more of newer runners who may have finished Couch to 5K or some similar program and are wondering where to go from there. 

The problem with the 10% rule is that too many people mentally translate, “don’t increase more than 10% each week” to “increase 10% each week.”  The semantic difference is slight but the difference in meaning is enormous.  Let’s look at what happens if you start at 10 miles per week, increase by 10% each week, and take a cutback week every 4th week.  That sounds reasonable and I’m willing to bet you can find plenty of resources that would advocate something very similar.  (In a nod to the math folks, I’ll admit to doing some rounding but it should even out).

 Week 1 – 11 miles (this is our first 10% increase)

Week 2 – 12.1 miles

Week 3 – 13.3 miles

Week 4 – 8 miles (our first cutback week)

Week 5 – 14.6

Week 6 – 16.1

Week 7 – 17.7

Week 9 – 10

Week 10 – 19.5

Week 11 – 21.5

Week 12 – 23.6

Week 13 – 14

Week 14 – 26  (What the heck?  Run the extra 0.2)

Week 15 – 28.6

Week 16 – 31.5

Week 17 – 18

Week 18 – 34.7

Week 19 – 38.2

Week 20 – 42

Week 21 – 22

Week 22 – 46.2

Week 23 – 50.8

Week 24 – 55.9

Week 25 – 61.5

Week 26 – 30

Week 27 – 67.7

Week 28 – 74.5

Week 29 – 82

Week 30 – 40

Week 31 – 90.2

Week 32 – 109.1

We’ll stop there.  Note that by unthinkingly increasing by 10% each week, even though we take a cutback week every 4th week, we end up at over 100 miles per week in less than a year.  While I’m sure there are a few young bucks out there who could handle that type of increase, my guess is that the vast majority of people would end up hurt or burned out long before they ever got close to that 32nd week.

An alternative I have seen advocated suggests increasing the number of miles by the number of days you run each week and then holding at that mileage for 3-4 weeks before increasing again.  Although I think this is better than the 10% rule, I’m not at all sure that every runner can increase by 4 or 5 miles in a week.  I do think it is a step in the right direction though. 

I have long advocated learning how to run by perceived exertion and see this as no different.  I think it makes sense to increase just to the point that the increase seems a bit uncomfortable.  It doesn’t matter whether the origin of the discomfort is psychological or physiological.  As soon as you start to feel that bit of discomfort, that’s your increase.  Then, I would stay at that level until it is comfortable (although never less than a week).  Sometimes you might be able to increase after a week.  Sometimes you might be at the same mileage for a month.  Sometimes, you might be able to increase quite a bit more than 10%.  Sometimes, your increase might be a lot less.  The point is that you are doing something that makes sense for you rather than following a generic guideline that may or may not suit you.  After all, what makes sense for an otherwise healthy 25 year old will not make sense for an overweight 55 year old.

As for cutback weeks, I have rarely had to deliberately take a cutback week as a late meeting or a sick kid or some other of life’s little distractions forces me to miss a day or two.  Still, if life somehow doesn’t interfere with your running plans, then by all means take the occasional cutback week.  Those very easy weeks are important for everyone from brand new runners to world class athletes. 

In one last charge at the windmill, I will say that I am not a fan of Couch to 5K.  I am bothered by the fact that it relentlessly increases the amount of running without ever giving your body a chance to figuratively catch its breath.  I realize that thousands have had success with it but I have personally witnessed people becoming discouraged when they couldn’t keep up with the program.  Moreover, I think it leaves people with the mistaken impression that they should always be increasing effort each week and that’s just not true.

Personally, I started at ½ mile, 3 times per week.  My increases were measured in blocks as in, “I made it to 20th street last week and I’ll make it to 18th street this week.”  What worked for you in those first few months?  Join in.  Tell us how you made it.

See ya out there.

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