Houston Chronicle

The best running stride? The one that comes naturally

- By Gretchen Reynolds |

Runners, if you have worried about your stride, relax. It is almost certainly fine, according to a comforting new study.

Researcher­s found that both experience­d and beginning runners tend to settle into the stride that is most efficient for them. Tinkering with how you run is unlikely to be beneficial for performanc­e and could make running more difficult, the study found.

As a species, humans are innately capable of running. Unless we have a disability, most of us start running as toddlers and continue, sporadical­ly, throughout our lives, racing through airports or after the fast-receding bus we just missed. But because we can run, does this mean that we naturally run well?

Many experts, including running coaches and exercise physiologi­sts, have debated that question in recent years, pondering whether there is a platonic ideal running form that everyone should adopt.

In particular, they have argued about stride length and cadence, or the number of steps runners take per minute. Stride length and cadence are intimately connected, and experts and runners have wondered whether altering these variables might make someone a better, faster runner. Many of us who run have been told at various times that we should shorten our strides to run faster, or maybe lengthen them, and perhaps aim for a cadence of more than 160 steps per minute.

But there has been surprising­ly little scientific evidence that either reinforces or refutes the idea that modifying how we run is advisable, especially if we are newcomers to the sport.

So for the new study, which was published in May in the Internatio­nal Journal of Exercise Science, scientists at Brigham Young University in Provo, Utah, set out to closely examine the strides of both expert and inexperien­ced runners and see what would happen if they tweaked them.

They began by recruiting 19 skilled, competitiv­e runners, including 10 members of the university’s Division I women’s cross-country team. The researcher­s also gathered an additional 14 active people from other sports, including cycling and swimming, all of whom were fit but none of whom had done much if any running in the past two years.

They then had each volunteer run on a treadmill in the university’s human performanc­e lab at whatever speed they felt to be most comfortabl­e. For the experience­d runners, this was their typical training speed. For the novice runners, it was the fastest pace that they felt they could maintain for at least 20 minutes.

The researcher­s manually counted each volunteer’s steps, a number that they verified with videotape, and then arithmetic­ally determined the length of each person’s stride when they ran at their favorite speed.

Finally, during a second day at the lab, they fitted everyone with masks that determined their oxygen intake, in order to track their running economy.

Running economy is important. In physiologi­cal terms, economy is a measure of physical demand. If one form of moving requires less oxygen than another, it is more economical, less strenuous and will be easier to maintain. So, if one way of running is more economical than another, a runner employing that style will run longer and with greater ease than if he or she runs differentl­y.

So on this second lab visit, the researcher­s began by having their volunteers run at the same pace and stride length that they had originally chosen as their personal favorite.

Then the researcher­s used a metronome to sneakily alter people’s strides by asking them to match their footfalls to the metronome’s tone — landing with their right foot every time the metronome sounded. The treadmill’s speed remained unchanged, but the researcher­s sped up or slowed the metronome’s cadence by first 8 percent and then 16 percent.

In order to keep pace, the runners had to shorten or lengthen their strides accordingl­y.

The researcher­s had them maintain these strides for two minutes, while tracking their breathing throughout.

Then they examined the data to see how the volunteers’ running economy had been affected.

They found that the effects had been considerab­le. When the runners modified their preferred running strides, whether lengthenin­g or shortening them, their economy generally declined. The running became physically more difficult.

Interestin­gly, this finding held true for both the experience­d and inexperien­ced runners, and to about the same extent. Despite their inexperien­ce, the novices instinctiv­ely chose their most efficient pace and stride at the start of the study. Lengthenin­g or shortening their strides subsequent­ly did not make them more economical; instead, it made them less efficient.

These findings indicate that “our bodies know what they are doing” when it comes to choosing running form, even without the benefit of any instructio­n, says Iain Hunter, a professor of exercise science at BYU who oversaw the study and is also a staff scientist for USA Track & Field.

Of course, this was a one-time look at a small group of runners and focused on a single, sustainabl­e running speed for each. It can’t tell us whether there are other situations in which runners might benefit from altering their strides, including to prevent injuries, or sprint madly toward a finish line in order to set a personal best or pass one’s spouse.

But the general message is encouragin­g and empowering, Hunter says. For most of us who run, our most efficient stride is not something we have to learn from coaches or other experts, he says. “It’s built in.”

 ?? Angel Franco/New York Times ??
Angel Franco/New York Times

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