My first 10K in April was a resounding success — until the stress of the run made me fall sick and miss work for two days. Cue my (lazy, couch-potato) friends jokingly telling me that this is proof that running is actually bad for you.
That claim is false, but there really are a lot of studies about the health benefits, or downsides, of running. An hour of running might add seven hours to your life, but too much of it might be dangerous for the heart. We hear that it’s so high-impact that it hurts your joints, but some research suggests it might actually be good for the knees. So how do we evaluate all these claims?
Let’s get one big thing out of the way: running, like everything else, is dangerous if you do it too much. However, the plain truth is that most people aren’t exercising enough. “We know that regardless of what exercise you do, it’s going to be better than doing none,” says Brandon Alderman, an exercise psychologist at Rutgers University. “We have this huge problem of inactivity and that problem is much larger than the problem of the specific dangers of any one activity.” (So take that, so-called friends. I may have fallen sick, but my 20 miles a week give me more than enough reason to be holier-than-thou.)
When it comes to the studies, we can’t always apply every result to ourselves, says Jinger Gottschall, a Pennsylvania State University kinesiologist who studies running. Often, studies look at a very limited group of people, or a specific routine that might have nothing to do with your training regimen. Some studies have given us good, generalizable rules — like replacing your running shoes every 300 miles or so — but some of the individual results are too specific. For example, there has been a lot of discussion about barefoot running, but the number of people who can safely do barefoot running on a regular basis is “very small,” says Gottschall. And while running does put more stress on the joints than, say, swimming, she contends it’s mostly safe for the knees and can even strengthen them if you do hills.
So how can you tell if a study’s results might apply to you? First, look at the demographics of people who were studied. Are they similar to you in terms of age and sex? What about their activity level — were the people sedentary and non-active in the beginning, or lifelong runners? Good studies on running will also provide information on how much someone exercised before the study, which usually includes mileage per week and a pace, so you can compare even more accurately. And treadmill running, which can often use different inclines, versus trail training sometimes have different effects, too. The more similar you are to the participants, the more you can apply the results. So a study about older men who run for five hours a week on a treadmill might not give me the most insight into what makes sense for me, a young woman who would rather never move again than run on a treadmill. (If this information isn’t provided in the write-up you’re reading, it’s usually in the abstract of the study itself, which is usually linked in an article.)
Some exercise research is directly useful, but some studies are interesting just because they give us a glimpse into the habits of the most elite runners. I am firmly in the camp of “recreational runner,” and a slow one at that, which means I remain fascinated by those much speedier than me and how I can learn from them. Matthew Bundle, a professor of biomechanics at the University of Montana, has spent the past decade studying the gait of high-level athletes to see how we can use their secrets to help us improve. His lab has a high-speed treadmill that can go a little faster than 28 miles per hour. (That’s about how fast Usain Bolt was going when he set a 100-meter world record, so it’s safe to say that we don’t need much more than that for research.)
Bundle’s team recruits athletes to use the treadmill and provide data on the forces and collisions that take place between the leg and the ground. In one experiment, they took successful college athletes — the type already winning championships — and took videos of them running using high-speed motion analysis. High-speed motion analysis can take about 1,000 frames in a second; in comparison, the instant replay of sports on TV is usually about 60 frames a second. From that, they can get an “exquisite amount of detail,” says Bundle, like that sometimes the foot is only fully touching the ground for as short as 85 milliseconds, or that as much as 4.5 times the body weight hits the ground. After watching these videos, Bundle’s team gave detailed pointers on form — like how to adjust their stride — to the athletes, and the group became better by 7 percent within three days. “We think we’re onto something here,” he says.
Bundle’s team is also studying what’s possible for our endurance. It turns out that dedicated runners — those who can run a marathon under two hours and 45 minutes, but who wouldn’t make the Olympic trials — can run for two hours at about 92 percent speed of what they can run for five minutes. “There’s still additional loss of performance, but it’s much much slower,” he says, “and so we’ve been focusing on these very short events to try and understand how the byproducts of intense muscle activity start to poison the muscle and prevent it from being able to continue to generate the kinds of forces that it needs.”
Then, on the other end of the spectrum, are people who don’t run at all. (So, me as of a year ago.) For those just starting out, what’s the most important thing? Is it the type of shoe, the type of trail, the exact mileage?
Gottschall, the Penn State kinesiologist, says it’s the details of the training program: how often you run, how quickly you increase your mileage, and how consistently you do so. Get good shoes, but don’t get too caught up on special gear like athletic bands to support the knees, which really have little science behind them.
When it comes to gait, the beginning runner doesn’t need high-speed motion analysis. Do what feels natural, she says, and don’t worry too much about getting the “right” kind of step. (I’m guilty of obsessing over this, since I’m someone who takes short steps and is envious of more graceful-looking runners with longer strides.) The ideal program is probably three to five times a week, from half an hour to 75 minutes each time, according to Gottschall. But in the beginning, the important thing is to try to stick it out for six weeks. “That seems like a long time, but that’s the point when it really starts to stick,” she says. After my 10K, I fell off running for a bit and am finding it somewhat hard to get back in the habit. Maybe it’s time for me to re-commit for another six weeks, too.