The old training adage holds that the more miles you log, the faster you’ll get. But equally ancient wisdom preaches that increasing mileage increases risk of injury, especially without proper build-up.
Now that millions are logging their training digitally—Strava’s user base reportedly grew by a million users every 40 days in 2018—researchers are starting to leverage this new data resource to answer two critical training questions: First, will adding mileage always make you faster, and always raise your risk of injury? And second, if you do choose to add mileage, how much can you safely add at once?
Mileage And Running Performance
Since high school, coaches and mentors have said that the more I run, the faster I’ll get. That old advice was put to the test in recent research exploring how training volume correlates with performance.
A 2017 Journal of Sports Science & Medicine study by researchers in Spain found that even with variables accounted for, higher mileage appears to lead to faster speeds.
The researchers predicted athletes’ half marathon personal bests that controlled for training volume, years of running experience, body mass index and body fat percentage. Even after controlling for all of other variables, half marathon performance dropped by about 1.75 minutes for each ten-mile increase in training volume.
Increasing Volume Without Getting Hurt
The famous 10% Rule for increasing training volume helps prevent overuse injuries but following it can feel painfully slow and unproductive, especially if you are only running ten miles per week to begin with.
Researchers are exploring the safest way to increase training volume. A recent study review indicated that the 10% rule might be overcautious, finding no evidence that increasing training leads to increased running-related injury for up to 24% average increase in weekly volume. Increased injury rates were evident only when runners increased weekly mileage by 30% or more.
The 10% rule isn’t right for everyone and it may be more conservative than necessary. Nonetheless, a 30% increase in weekly volume seems to be a bright red line guaranteeing injury.
Final Notes on Staying Healthy
We can see that the 10% rule isn’t the end all be all of increasing mileage and that it can be OK to increase mileage more aggressively. But it’s critical to recognize that every athlete is different. Some people may be more prone to injury than others. That said, go ahead and increase your training volume. Just remember to increase caloric intake accordingly and take rest days between big sessions. Most importantly, listen to your body and put extra emphasis on recovery.