体坛英语新闻：Role of running cadence not as much as previously thought

CHICAGO, March 28 (Xinhua) -- Running at a prescribed, one-size-fits-all "optimal" cadence doesn't play as big a role in speed and efficiency as once thought, said a study posted on the website of the University of Michigan on Thursday.

To find out what determines cadence and how much cadence really matters, Geoff Burns, an elite marathoner and UM doctoral student in kinesiology, had the top 20 elite male and female runners record their cadence during the 100K International Association of Ultrarunners World Championship in 2016.

While the average number of steps per minute was 182, the number of steps per minute per mile varied enormously by individual.

"Some ran at 160 steps per minute and others ran at 210 steps per minute, and it wasn't related at all to how good they were or how fast they were," Burns said. "Height influenced it a little bit, but even people who were the same height had an enormous amount of variability."

The main takeaway for runners is that cadence is highly individual, and the body knows what's optimal. This means runners shouldn't necessarily try to manipulate cadence to reach the 180 steps, but rather, monitor cadence as their running progresses.

"It's a barometer and not a governor," Burns said. "There's no magical number that's dogmatically right for everybody."

For years, many coaches and practitioners thought that cadence should remain constant as speed increases, which required longer steps. Burns says longer steps takes more energy, and his study found that cadence naturally increased four to five steps per minute per mile as runners ran faster.

Other findings also surprised Burns. First, step cadence was preserved through the race, even during the torturous "ultra shuffle" near the end, when racers shuffle across the finish line, barely lifting their feet.

Another unexpected finding is that by the end of a race, cadence varied much less per minute, as if the fatigued runner's body had locked into an optimal steps-per-minute turnover. It's unclear why, but this deserves further study.

The research has been published in the February issue of Applied Physiology.