The Debate: High Mileage Versus High Intensity

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In a recent article by my former colleague, star author and longtime friend, Matt Fitzgerald, Matt takes up the issue of injury prevention for runners, using an initial mention of Unbreakable Runner, a book I co-authored with Brian MacKenzie, to make his point.

He writes, "In their book, MacKenzie and Murphy take it as a given that runners who run more get injured more. However, recent research suggests the opposite is true."

The first study Fitzgerald cites was a web survey of 668 marathon finishers. Sixty-eight of the respondents reported an injury that hindered their training for at least two weeks. From the data, researchers concluded that runners should put in no less than 18 miles per week before a marathon "to reduce their risk of running-related injury."

More: High Intensity: The Latest Evidence

Fitzgerald also refers to a 2014 study that looked at 517 runners with a 9-month follow-up. Researchers focused on overall mileage, speed and frequency of runs. From the data collected, they predicted that injury risk in regards to training load is affected by body-mass index and previous injuries.

Fitzgerald then effectively dismisses a program like CrossFit Endurance—the subject of Unbreakable Runner—with his own deduction:

"Why do runners who run more get injured less?" Fitzgerald posits. He answers that "running alone develops the specific kind of durability that makes the body resistant to running-related injuries."

He adds his bottom-line: "All of the strength training and technique drills in the world won't match the toughening effect of actual running."

More: How Much Base Training Do You Need?

To support this contention, he cites a 2012 study with 432 beginners, split into two groups, and where researchers had them prepare for a "four-mile recreational running event." Both groups would follow a 9-week training program, but the test group first prepared with a four-week phase of preconditioning comprised of walking and hopping exercises. Researchers concluded that the four weeks of hopping and walking didn't have a valuable effect on shielding newbie runners from injury.

Fitzgerald compares these results with a study that suggested that high school kids, preparing for the fall cross country season, should put in more consistent weeks of training than less, and that during those weeks they should mix the length of their runs.

"The lesson of these two studies is clear," writes Fitzgerald. "In order to minimize the risk of running-related injuries, you need to build durability. Only running itself builds the kind of durability that prevents running-related injuries. Drills and strength training just don't cut it."

This is an important discussion to have, and Matt brings up some valuable insight, especially for beginning runners. From the data, Matt extrapolates that "drills and strength training" just don't cut it. Let's assume he's talking about the inclusion of running drills, bodyweight gymnastic work, mobility and functional-strength training workouts in MacKenzie's approach, and not the 'hopping and walking' exercises that the pure beginners used before their 9-week running program. To clarify this is the primary message we wanted to get across in Unbreakable Runner: Unleash the Power of Strength and Conditioning for a Lifetime of Running Strong.

More: Get More Out of High-Intensity Training

I want to underscore the "Lifetime" part of the subtitle a little later on, but first, a stress within Unbreakable Runner I wanted to make is not that it's the best program or the only program worth following—something MacKenzie seems to be routinely accused of saying. There are so many different types of runners with different goals and different issues, I think a variety of options and ideas is a good thing. Lydiard isn't for everyone and CFE isn't for everyone as is Galloway isn't for everyone or Vigil isn't for everyone (pity the recreational runner who tries to follow Joe Vigil's 10K program, preferably performed at 8000-feet of altitude). I remember the moment I was sitting in the back row of a seminar, with Brian trying to make this point that what he was offering was an alternative approach. And that's a core message in the book: We wanted to communicate an accurate picture of CrossFit Endurance and offer it to those who might be frustrated with injuries from the programs they've been following, or for those who might find the variety and all-around athleticism appealing. But we weren't out to force it down anyone's throat. Recently, a link to a story on the book was announced with the Twitter text: 'Why Brian MacKenzie thinks that traditional training programs don't work." I've been talking and interviewing Brian for years and he's never even hinted at a sentiment as controversial and easily proved wrong.

Actually, if Brian preaches about anything, it's about why a runner needs to keep an eye on the long-term effects a training program has on a runner's health. He doesn't dispute that high-mileage programs can work—in fact, the forward is written by the human odometer, Dean Karnazes—what Brian does suggest is that a runner should look for every opportunity to minimize the wear and tear of running and factors, like a poor diet or not getting enough sleep, that lead to chronic inflammation, which science clearly links to premature aging. (All of these things, by the way, are key priorities for Dean and, he reports, are at the root of his longevity).

As an example, if you ask MacKenzie what the number one benefit of a CrossFit workout is for a runner, he's going to talk about how functional movements, performed under load and at high-intensity, can do wonders for a coach trying to sort out biomechanical weaknesses, imbalances and other "holes" that ultimately, down the road, will probably be the cause of an injury. The weaknesses are exposed well before they manifest themselves in a tweak.

More: Easy Does It: High Mileage and High Intensity