How and when to break the 10% rule

There is a lot of conventional wisdom in magazines and the internet about only increasing your mileage by 10% per week. The claim is that this helps to prevent injury. The underlying assumption is that the more you run or the more drastic the change to your training, the higher your chance of injury. There are several things wrong with this. Let’s look at a couple of issues with this “rule."

First it assumes that volume of training (distance) is the most important variable in your training. It's not; your body and training is much more complex than that. If you have been running a lot of hills and are transitioning to flatter routes, you can probably go more than 10%. If you've run longer in a previous training cycle, that neuromuscular fitness (or at least some of it) will still be there to support your running. If you’ve been going pretty hard and at the max volume you’ve ever run, 10% may be too much. Intensity is important. If you've finally figured out that your easy runs really need to be easy, you can probably increase mileage more than 10% safely. Other factors such as life stress, health, altitude, weather, etc., can all affect how and when you increase your mileage. The real thing is that it affects each person differently. You need to understand which variables are key for your training.

Secondly there's no scientific evidence to support it. That's right. There is no peer reviewed study that shows that 10% is some magic number. How this idea has persisted for so long is a mystery. It's almost as bad as the 180 steps per minute cadence "rule.”  Which is also not backed by any scientific evidence. In fact there is evidence to the contrary.  Just like your optimal cadence is a function of your particular biomechanics and pace, your optimal mileage progression is a function of your unique running and training parameters.
So you're probably asking yourself, "Okay, so how do I figure this out for me?"  I'm glad you asked:
  1. If you haven't already, incorporate running specific strength work after every run. There are great guides from RunnersConnect, Jason Fitzgerald, and Jay Johnson online. This is your best tool against injury prevention. The real issue is that you are not training your muscles and tendons hard enough through running alone. You need additional neuromuscular stimuli during training for your muscles and tendons to keep pace with your heart and lungs. Keep your chassis tuned as you grow your engine.
  2. Listen to your body. This is probably the most important element. If you feel like you need a day off take one. If you're feeling really good and want to throw in some easy miles on a day you usually don't run, give it a try. Understand the adjustments you can make in your stride to deal with potential injuries. When I get a a certain type of pain in my foot I know that focusing on landing with my lower leg vertical can alleviate it. Pay attention to what is happening with your body and adjust accordingly.
  3. Don’t be a slave to a training schedule. The vast majority of training schedules were not designed with your particular training history and lifestyle in mind. They are written for some ideal, average runner who doesn’t really exist. Don’t be afraid to make adjustments based on what your body is telling you and what is going on in your life. Many a day I have skipped a run because one of my kids kept me up half the night. I also move long runs and workouts around to adjust to various life events. Know how to adjust your training to make it work best for you.
Enjoy the Run

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