The 10% rule is one of the most important principles for consistent, injury-free training for distance runners. The body (and mind) needs rest and recovery to adapt to new stresses from workouts, and reasonable mileage increases ensure positive adaptation, and reduce the risk of overuse injuries.
Principle #1: Easy Days Easy
About a week ago, I wrote about easy days easy, i.e. running easy on recovery days and running hard on workout days. Easy days easy is another important principle with similar goals as the 10% Rule: allow the body to adapt to stresses and become stronger and faster, and avoid common overuse injuries from pushing hard every day. In that blog post, I describe an unintentional progression run on an easy day, and what can happen when I don’t follow the “easy days easy” principle.
The 10% Rule Explained
The 10% rule simply states that runners should not increase mileage by more than 10% each week. This principle should be applied with a few considerations: (1) runner’s running age (how long have you been running), (2) recent injury history, (3) weekly baseline (is the weekly starting point 5 miles or 50 miles), (4) other foundational work (strength, mobility, speed), (5) sleep, stress, nutrition, hydration, (6) you get the point. It is also advisable to not increase weekly mileage linearly without taking a “down” week once in a while, i.e. increase +/-10% for 3 weeks (that’s a compounded 33% increase across 3 weeks), and then week 4 reduce slightly, before ramping up again week 5.
Today, I will share my experience ramping up mileage too quickly, and how that resulted almost immediately in an overuse injury for me. In addition, I will explain the impact of both higher mileage volume and higher intensity workouts. We’ll compare the first 10-week period during my initial 500-mile training block to the current 10-week period since my hernia surgery and metatarsal stress reaction.
10 weeks from June 4, 2018 to August 12, 2018 (“Bad Example”)
The orange bars in the back of the chart show the weekly mileage for the 10 weeks from June to August. Please note the decrease in weeks 6-8 due to knee injury.
I ramped up from 11 miles (week 1) to 22 miles and 26 miles for weeks 2 and 3, respectively, almost doubling mileage in the first 2 weeks, and more than doubling in 3 weeks.
To make matters worse, I increased not only the mileage volume, but also the workout intensity, which is a double “no-no”.
In week 1, I ran 8 x 400 in 1:40 with 90 second recovery. However, in week 2, I ran 2 workouts, early in the week 6 x 300 hill repeats with a jog back, and later in the week 2 x 1000 in 4:00 with 3 minutes walking recovery. In week 3, I ran a 3-mile tempo followed by 200’s, and later that same week I repeated the 8 x 400 workout, but at faster 90 seconds with 90 seconds recovery.
Although the mileage was slightly down at 22 miles for weeks 4 and 5, I continued to increase the intensity of my workouts. In week 5, I ran 7 x 300 hill repeats at a faster pace, and 8 x 400 around 88 seconds with 90 seconds recovery.
The following week 6, I felt a twinge on the outside of my left knee (most likely the iliotibial band or IT band), and I had to stop for 3 days, and then jog lesser mileage with a knee brace.
I ramped back up to 20 miles in the 10th week, with a single workout of 4 x 400 at 90 seconds with a 60 second recovery.
Although I (stupidly) doubled my mileage in the first 2 weeks, the overuse injury effectively reduced my mileage increase to doubling from 11 miles to 20 miles over the 10 weeks.
10 weeks from December 10, 2018 to February 17, 2019 (“Good Example”)
The blue bars in the front of the chart show the weekly mileage for the 10 weeks from December to February. Please note the relatively straight trendline (in red) (the decrease in weeks 5-6 was due to my China trip, not injury).
Having learned my lesson more than once (first the knee injury, and later the metatarsal stress reaction), I followed the 10% rule during these 10 weeks. In addition, although I ran a couple medium progression runs (see my bi-weekly training recaps), I did not increase my workout intensity for the first 10 weeks. The chart is self-explanatory – I tripled my weekly mileage from 5 miles to 16 miles without any overuse injuries – much more effective than not following the 10% Rule.
Important Principles as Guardrails
Going forward, I will continue to follow both the principles outlined in “easy days easy” and the 10% Rule. I will also take into account if/when to (safely) increase both mileage and intensity of my workouts, with the ultimate goal to maximize positive stress adaptation and minimize overuse injuries, and therefore achieve my goals through long-term and sustainable improvement.
I am grateful and happy for every mile that I run!