What is the 10% Rule?

The “10% Rule” states that you shouldn’t increase your weekly mileage by any more than 10% from one week to the next; the rule is said to help prevent injuries associated with big jumps in mileage. When people first start running and get the bug, they tend to fall into the trap of the Terrible Too’s - Too Much, Too Soon, Too Quickly. This too-rapid increase in running volume has been shown to increase the rates of injury'; to be honest the research is fairly limited, and this common rule advice seems to have been “around” for a long time.

I tend to use this approach when training complete beginners, a steady increase in mileage is just a common-sense approach, especially at the start of a programme.

3 miles + 10% = 3.3miles

5 miles + 10% = 5.5 miles

However, as the coach/runner relationship develops then individual ability to adapt is a far more successful method to increased performance, reduced injury and helps with motivation. Some runners may be able to safely increase more that 10% each week, it depends on so many other factors that need to be taken into consideration, work, homelife, training load, training age, chronological age and more.

Sticking to a rule without looking at the overall bigger picture could have a detrimental effect on a runner, increasing by 10% each week with a low weekly volume can take a long time to get to 10-mile race for example if they are starting at 5k. Conversely if you have a high weekly volume then 10% can be too much, even for a seasoned experienced runner, going from 55 miles a week to 60.5 miles would be a risky increase.

I’d see the rule as a guideline, not something that is set in stone, you can distribute the volume of your mileage over the course of a week, you don’t need to stick all your increase onto your long runs. And don’t forget your down weeks, this is a cutback week, so a reduction in volume, roughly every 3/4 weeks.