“This research suggests that the drive to minimize energy costs is really strong in humans, even when we’re purposefully exercising as a way to expend more energy,” says David Raichlen, an evolutionary biologist who studies exercise at the University of Southern California and who wasn’t involved in the study. “We have a hard time overriding that desire to use as little energy as possible in any given task.
“For a lot of folks it’s the [pace] that’s going to feel quite comfortable and that we have this natural tendency to slip back into,” Selinger says. “It’s certainly the case that you can and do run faster in other settings; if you’re in a race, you’re going to push yourself beyond that energy-optimal gait.”
Whether walking, galloping, flying, or swimming, animals generally stick to the most efficient speed for their bodies, says Jennifer Hicks, a biomechanist at Stanford University and another coauthor of the report. The new findings indicate that humans share this trait. “From an evolutionary perspective, moving in the way that’s most energy efficient makes a lot of sense in that we can travel farther with less fuel,” she says.