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Training plan I made in college that mostly follows the 10% rule. |
Scholarship is sometimes a lonely endeavor. Especially when it feels like everyone else is “doing it wrong.” Today was one of those days—all the buzz online is about a new study titled “Can GPS be used to detect deleterious progression in training volume among runners?” in the Journal of Strength and Conditioning Research that purportedly shows that the oft-cited (and obviously arbitrary) “10% rule”—that is, you should increase your mileage by no more than 10% per week—is more conservative than necessary, and that novice runners may increase their mileage by 22% per week with no increased risk of injury. This stat made it onto several Twitter accounts I follow, the front page of LetsRun.com, and garnered a brief write-up in Runner’s World. Seeing all this, I did what I always do when a study comes out and makes some noise: I read the article.
There is a need to ascertain if an association exists between excessive progression in weekly volume and development of running related injuries. The purpose of this study was to investigate if GPS can be used to detect deleterious progression in weekly training volume among 60 novice runners included in a 10 week prospective study. All participants used GPS to quantify training volume while running. In case of injury participants attended a clinical examination. The thirteen runners sustaining injuries during follow-up, had a significantly higher weekly progression in total training volume in the week prior to the injury origin of 86 % [95 % CI: 12.9 to 159.9], p = 0.026 compared with other weeks. Although not significant, participants with injuries had an increase in weekly training volume of 31.6 % compared with a 22.1 % increase among the healthy. [...] Based on the results from current study, increases in weekly training progression may become deleterious at a weekly increase above 30 % which is more than the 10 % rule, currently used as guideline for correct progression in weekly volume by runners and coaches. Still, no clear evidence for safe progression of weekly volume exists. But is seems like some individuals may tolerate weekly progressions around 20 to 25 %, at least for a short period of time.
The study itself was mostly well-done: 60 novice runners from Denmark, none of which had any underlying health issues or injuries, and none of which had run further than 10km, were issued GPS watches and turned loose for 10 weeks of running training. 13 came down with a running injury during the course of the study, which was defined as “any musculoskeletal complaint of the lower extremity or back causing a restriction of running for at least one week,” which in my book is a fairly strict distinction. The injured runners had been increasing their weekly mileage (or kilometerage, as this was a European study) at approximately 33% per week, while the healthy group had averaged 22%. Notably, the injured runners had a statistically significantly higher BMI than the healthy runners—27.6 vs. 24.8 (a BMI of 25.0 is considered “overweight”; for a 5’9 person like me, that’s 170 lbs!). The average weight of the subjects in this study should give us a few clues that we aren’t exactly dealing with world-beaters. Unfortunately, because of the small sample size, the authors were not able to statistically extract the effects of weight and mileage on injury risk.
Week
|
Miles per week
|
Miles per run
|
% increase
|
1
|
1.65
|
0.85
|
|
2
|
2.01
|
1.03
|
22.0%
|
3
|
2.46
|
1.26
|
22.0%
|
4
|
3.00
|
1.54
|
22.0%
|
5
|
3.66
|
1.87
|
22.0%
|
6
|
4.46
|
2.29
|
22.0%
|
7
|
5.44
|
2.79
|
22.0%
|
8
|
6.64
|
3.40
|
22.0%
|
9
|
8.10
|
4.15
|
22.0%
|
10
|
9.88
|
5.07
|
22.0%
|
Avg
|
4.73
|
2.42
|
22.0%
|
Anyhow, one more point I should make is that a 21.6% injury rate among runners averaging less than five miles a week is (philosophically speaking) absolutely unacceptable. To me, that indicates that sedentary people have underlying biomechanical or strength defects that need to be addressed before or while they begin a fitness program. I don't believe that everyone was "born to run" 100 mile weeks, but nearly everybody ought to be able to jog around the block a few times a week without getting injured.
Lastly, I have some stern words for the folks who’ve already jumped on this “out-with-the-10%-rule” bandwagon: next time, please read more than the abstract. Or at least talk to someone who has. Perhaps LetsRun doesn’t have journal access (though any coach at a University ought to—just saying), but Runner’s World definitely does. Or should. Maybe more journals need to be open access. Or maybe exercise physiology and biomechanics needs an ArXiv equivalent. But even without, just because you’re out of school doesn’t mean you don’t have to do your homework...
Those are minutes on that chart of mine from college, by the way, not miles. Nominal mileage assumes 7:30 pace, which is on the conservative side.
Hallelujah! Preach on brother. Great post. As an experienced runner and experienced researcher I can't stress the importance of truly 'digesting' some of these studies that keep coming out... whether they are on minimalist running, injury rates, etc etc.. read the methods! I am interested to read this full article and see what they talk about in their discussion.
Thank you for doing this. Too often an academic study's conclusions, based on a small amount of very constrained data, are taken to be more than they are in the popular press. And journalists wonder why academics get annoyed with them...
Nice review! This is my first time reading your blog, but I'm quite a fan, and will be back. It's nice to see someone break things down and actually look beyond the title/abstract.
Absolutely true... but on this occasion the academics seem to be to blame. To me, they seem to be courting publicity by means of a sensationalist abstract.