In the running world, the 10% rule is similar to the Golden Rule. It states that one should never increase one’s mileage by more than 10% per week.
The trouble with the 10% rule is that it’s not based on scientific data and is not appropriate for all runners. Runners come from all different backgrounds and experiences, and so there is hardly ever a one-size-fits-all approach.
Last year, when I was coming back from a hamstring injury, I became attached to increasing my mileage by 10% every week. However, I kept having setbacks. Why? Because I ignored other considerations such as cutback weeks and the time it took for my tendon to strengthen. The 10% rule did not apply to me.
Conversely, other runners coming back from other types of layoffs can start back faster, whereas new runners may need to increase volume more slowly than 10% a week.
This guide will help you avoid the traps of ramping up too quickly or decreasing mileage too slowly by helping you set a starting point and increase your volume based on your own experience and background.
What Is The 10% Rule?
The 10 percent rule simply states that when increasing weekly mileage, you should never increase mileage more than 10% at a time in a week.
Thus, if you’re running 20 miles, you should increase to 22 miles the following week, 24.5 miles the next week, and so on.
The 10% rule ensures that runners increase their mileage conservatively week to week throughout their training program.
“The rule is based on building your mileage slowly so as to decrease your risk of injuries, and because of this, yes, there’s merit in being conservative and safe at times,” explains Steve Stonehouse, certified running coach and director of education for STRIDE.
However, this guideline does not apply to everyone.
So How Valid Is The 10% Rule?
Certified running coach Laura Norris says the 10% rule is arbitrary.
“That is not to say that it does not work; it will work fine for many runners. However, there is no solid evidence to support it.
Many runners can still get injured under the 10% rule since it does not account for adaptation cycles or cutback weeks,” she explains. (I can vouch for that).
For example, a study on bone restructuring1Franklyn, M., & Oakes, B. (2012). Tibial Stress Injuries: Aetiology, Classification, Biomechanics and the Failure of Bone. In www.intechopen.com. IntechOpen. https://www.intechopen.com/chapters/28466 in response to high-impact exercise, suggests that increasing mileage by 10% every week can make bones weaker for about a month after a new stress while they resorb tissue and remodel the bone structure. Therefore, it makes sense to wait about a month before increasing training volume to help decrease the risk of running injuries.
10% Rule Alternatives – Are There Better Ways To Increase Mileage?
Let’s take a look at what legendary running coach Jack Daniels suggests on the matter.
Daniels advocates for increasing mileage based on the “equilibrium” rule. This involves increasing mileage in larger chunks to account for the bone adaptation:
Instead of increasing volume week over week, you would increase about 30% every 3-4 weeks, which would result in about the same volume as if you increased by 10% every week.
Thus, if you are running 20 miles a week, you would increase to about 30 miles the following 3 to 4 weeks. With the 10% rule, in 3 to 4 weeks, you would also arrive at about 30 miles in a month.
By increasing mileage in bigger chunks every few weeks, you get about the same volume while accounting for skeletal adaptations.
Related: How to Train for a Marathon in 3 Months
How Can I Start Increasing Mileage?
When charting their path to increasing mileage, runners should first pinpoint their baseline mileage, which is the current mileage they feel comfortable increasing.
“Most of your training cycles should start slightly under this baseline to ensure you start at a realistic workload. When you’re building up to your baseline, the miles are still very comfortable at this point, so you can increase your mileage more quickly than 10% per week,” advises Stonehouse.
Instead, you can safely add 15-20% more per week – at least initially.
With that said, as soon as you get above your baseline mileage, it’s helpful to be more conservative. Rather than adding 10% per week, sometimes it’s best to add 5-10% every other week.
Novice runners should begin by increasing training based on time. Rather than thinking of low mileage and high mileage, think of the total running time per week.
“In the early stages, it’s just about getting your body used to the work and building some aerobic capacity (endurance),” said Stonehouse.
After 1-2 months, beginner runners can start logging miles and making weekly increases accordingly.
What Are Other Considerations For Increasing Mileage?
When increasing mileage, it’s important to include cutback weeks about every month for injury prevention and to avoid overtraining.
“On these weeks, you’ll reduce your mileage to about two-thirds of the previous weeks’ mileage,” explains Stonehouse.
“A good way to do this is to plan your training in 3-5 week cycles, using the first 2-4 weeks to push the training and introduce the stress, and then use the final week of the cycle as a recovery week to absorb the training just done, make the necessary adaptations, and recover so you can handle the upcoming heavier training load.”
Stonehouse also likes to repeat training weeks for runners who have built up to their baseline mileage to allow the body to adjust to increasing mileage, intensity, and duration of quality workouts.
“I find it’s helpful for all runners but specifically those prone to injuries or beginners who need extra time to recover from and adapt to their workouts,” he shares. “After you surpass your baseline mileage and don’t feel comfortable, implementing these repeats is more helpful.”
How should I increase mileage based on experience or injury history?
Norris explains that if an experienced runner is rebuilding to a previous mileage after a post-race recovery, they do not need to follow the 10% rule. Instead, they can increase more rapidly until they return to their baseline mileage, almost like a reverse taper.
The same applies to an injured athlete; after full recovery, they may only need six to eight weeks to return to their previous mileage safely.
If a beginner runner builds to a new mileage, a better system is an increase-adapt pattern, with consistent cutback weeks every four to six weeks.
Beginners can increase up to 15-20%, depending on mileage (higher mileage runners increase a lower percentage per week; lower mileage can increase a higher percentage per week).
This allows the musculoskeletal system to better adapt to the demands of increased mileage and to try and keep runners injury-free, says Norris.
What Is An Example Of A Mileage Building Process?
Here is an example of a runner building from a baseline of 30 miles per week to 40 miles per week:
- Week 1: 30 miles
- Week 2: 34 miles
- Week 3: 34 miles (repeat week)
- Week 4: 38 miles
- Week 5: 30 miles (cutback week)
- Week 6: 38 miles
- Week 7: 40 miles
Related: Check out my Marathon Training Plans
How Should I Increase Mileage When Introducing New Stimuli Like Hills Or Speed?
When introducing new stimuli like speed, duration of quality workouts, or hills for the first time or the first time in a long time, it’s important not to increase mileage at the same time.
“You want to maintain your mileage for a few weeks as your body adapts. For injury-prone runners or fast-twitch runners who fatigue easily with higher mileage, the better choice may be to temporarily decrease mileage while introducing a new stimulus,” suggests Norris.
Stonehouse reminds runners of what is the only rule in running that truly applies to every runner: when increasing mileage, “run easy on easy days to truly recover and hard on hard days to provide stress.”
When you give recovery the same amount of attention as running, your workouts will flourish, and you’ll be a better, stronger runner.
Increasing mileage gradually is a great way to help avoid overuse injuries, whether you are training for the New York marathon, a half marathon, an Olympic triathlon, or any other distance for that matter.
For a closer look at some tell-tale signs you are on the brink of an injury and may need a break, check out our next guide:
