Does the 10% rule make sense for every runner?

Regardless of where you’re at in your running journey, you’ve likely heard of the 10 per cent rule, which states that, when adding volume to their training program, runners should not increase their mileage by more than 10 per cent per week. The reason behind the rule is, of course, to prevent them from getting injured by doing too much too soon. But does this rule work for everyone? According to three studies, following the 10 per cent rule may not be necessary.

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The first study, published in 2007, asks the question “is a graded training program for novice runners effective in preventing running-related injuries?” To answer this question, the researchers split 532 participants into two groups and put them on a training plan for a four-mile race. The first group followed an eight-week program that had them increasing their mileage by about 50 per cent each week, while the second group followed a 13-week program that abided by the 10 per cent rule. By the end of the study, the eight-week group had a 20.3 per cent injury rate, while the 50 per cent group had an injury rate of 20.8 per cent.

The second study, published in 2013, used GPS technology to track 60 runners over the course of 10 weeks to see how an increase in volume correlated with injury rates. By the end of the study, 13 of the 60 runners had sustained an injury. According to the GPS data, the injured runners did increase their weekly mileage at a much faster rate than the 10 per cent rule dictates (on average about 30 per cent), but the 47 non-injured runners also didn’t follow the 10 per cent rule – they increased their weekly running volume by an average of 22.1 per cent.

The third study is from 2014, and followed 874 novice runners who started a self-structured running program. The researchers categorized them into one of three groups based on the progression of their weekly running distance: less than 10 per cent, 10 to 30 per cent, and more than 30 per cent. The researchers found there was no statistical difference in injury rates across the three groups, however those who progressed their volume by more than 30 per cent did have a slightly higher risk for certain injuries, like runner’s knee, IT band syndrome and shin splints, among others.

So what does this mean for runners? How much you increase your volume from week to week depends on multiple factors, and can’t be pinned down to just one arbitrary number. Your body’s ability to handle volume will likely differ from that of other runners based on your age, your running or athletic history, the amount of mileage you’re already running and your injury history. Additionally, none of these studies looked at injury rates over the long-term, and it is possible that your risk of injury could go up the longer you try to maintain larger weekly increases in mileage. For this reason, many runners may be better off erring on the side of caution and following the 10 per cent rule.

While controlling volume is a factor in injury prevention, your body mechanics, nutrition and ability to properly recover will likely have more influence on whether you stay healthy. Here are the main takeaways from these studies:

• Following the 10 per cent rule likely won’t increase your risk for injuries, but it may not offer as much protection as we give it credit for.
• It is possible to increase your weekly mileage by more than 10 per cent per week without increasing your risk for injury.
• While you may be able to add more than 10 per cent volume from week to week, adding more than 30 per cent does seem to increase your risk slightly for certain injuries.

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