People instinctively run at their most energy-efficient speed

Findings from people running in the lab and in the real world show that men and women tend to run at a speed that minimises energetic costs, though men run faster

By Alex Wilkins

When people are exercising, they intuitively maintain the same running speed regardless of how many kilometres they cover, in order to be as energy efficient as possible.

In a race, people try to run as fast as they can for a given distance, which means someone might jog slowly during a marathon, but sprint at top speed during a 100-metre event.

But Jessica Selinger at Queen’s University in Kingston, Canada, and her colleagues found that recreational runners take a different approach. They analysed the running speeds over a variety of distances of more than 4645 runners, who wore wearable measurement devices during exercise outside. They also collected data in the lab, where they could use treadmills to control a runner’s speed while collecting and analysing the participant’s breath to establish the energy costs associated with running at each pace.

From the outdoor runners, Selinger and her team found that, on average, women run at a speed of 2.74 metres per second while men run at 3.25 metres per second. The data collected in the lab showed that these paces are indistinguishable from the energy-optimal running speeds for men and women.

“People have this strong preference for a particular speed, regardless of what distance they’re running,” says Selinger. “And that speed is in fact energy optimal. It’s the speed that’s the most economical that you could choose.”

The runners that Selinger and her team analysed in the lab were limited to younger, fit individuals. “In the future, it would be really nice to have the lab-based energetic measures for a broader swathe of the population,” says Selinger.

The finding isn’t surprising when examined from a biological perspective, says Andrew Jones at the University of Exeter, UK. “When people go out for an easy or steady run, typically over 3 to 5 miles… they’ll typically fall into a fixed, comfortable speed that is below the lactate threshold [when lactate can build up in the muscles and cause fatigue] and allows a steady state in oxygen uptake.”

Journal reference: Current Biology, DOI: 10.1016/j.cub.2022.03.076