Increasing your mileage: is the 10% rule true or false?

The 10% rule is a good safeguard… but your body cannot count.

It is one of the best-known pieces of running advice: do not increase your training volume by more than 10% from one week to the next. Simple and reassuring. But what does science say?

Results more nuanced than you might think

• In the Netherlands, a study compared two groups of beginners preparing for a 4-mile race: one followed the 10% rule, the other progressed much faster. The injury rate was about the same in both groups, around 20%.
• In Denmark, a small study using GPS watches observed that beginners who stayed injury-free had increased their volume by about 22% a week on average. Be careful: this does not mean that +22% is risk-free, as the injured runners had often had large increases.
• Another Danish study, of nearly 900 beginners, showed that those who increased their volume by more than 30% over two weeks had more distance-related injuries (knee, tendons, stress fractures).

In short: the 10% rule is no magic law, but large increases remain risky.

How to progress with peace of mind

• Increase in steps and keep an easier week every three or four weeks.
• Do not change everything at once: more kilometres, more speed and more elevation in the same week is too much.
• Listen to the signals: pain that persists the next day, unusual fatigue, disturbed sleep. If so, ease off.
• Beginners and comebacks: be even more careful, as tendons and bones adapt more slowly than the heart and muscles.

Sources

• Buist I. et al., "No effect of a graded training program on the number of running-related injuries in novice runners", American Journal of Sports Medicine, 2008. See on PubMed
• Nielsen R. O. et al., "Can GPS be used to detect deleterious progression in training volume among runners?", Journal of Strength and Conditioning Research, 2013. See on PubMed
• Nielsen R. O. et al., "Excessive progression in weekly running distance and risk of running-related injuries", Journal of Orthopaedic & Sports Physical Therapy, 2014. See on PubMed