Science | Research
Wearable data from over 4,600 runners proves that outside the lab we behave like any other animal. And in the wild, you only run to hunt or avoid being hunted.
When there are no medals involved, humans behave like any other animal: we run at the speed that entails the least energy expenditure, regardless of the distance. That’s the conclusion reached by a group of Canadian and American researchers after analyzing data from 37,000 runs recorded on wearable physical activity tracking devices. Listening to music with a higher rhythm, running with other faster people or having a coach who presses to increase speed are, yes, circumstances that break this trend.
“This is consistent with the preferences of other nonhuman animals for energy-optimizing locomotion, whether walking, flying, or swimming,” Scott Delp of Stanford University and colleagues write in the journal Current Biology. In nature, running is a costly mode of movement that animals use only to hunt, avoid being hunted, or escape natural phenomena.
The authors have been investigating the mechanics of human running for 15 years, but until now they had not been able to do so outside the laboratory, in conditions in which the subject runs without feeling like an object of experimentation and, therefore, to their liking. In their work, they have compared the data of the devices of more than 4,600 individuals – more than 28,000 hours – with those of 26 who had used treadmills in their laboratories and who, thanks to that, knew the energetically optimal speeds based on of oxygen consumption.
trend to fight
What has most surprised the researchers is that, regardless of the distance, the runners maintain the most energy-efficient pace. “Intuitively, we assume that people run faster for short distances and slow down for long distances,” says Jessica Selinger of Queen’s University and one of the authors. It is not like this. Most of the runners who participated in the study maintained the same speed in a 3-kilometre race as in a 10-kilometre one.
“When you go out for a run, you run for the best fuel economy. So regardless of the distance, you run in a way that burns the least amount of fuel per distance traveled,” says Delp. “Humans are incredible endurance hunters, so seeing how today’s humans run when out in the wild is an interesting window into how our physiology has been fine-tuned, over the millennia, to allow us to cover long distances.” .
Energy efficiency is something that we tend to and against which runners who seek to lose weight, gain resistance or improve records have to fight. Delp points out that coaches can help them by knowing their optimal speed and pushing them further. Plus, “Listening to music at a faster tempo has been shown to help increase stride rate, which can increase running speed,” says Selinger, for whom faster running partners are another solution.
“The good thing about this work is that the data is not contaminated by experimental artifacts. Studying the degree in natural conditions has not been possible until now, until portable devices have existed”, points out Juan Ignacio Pérez, director of the Chair of Scientific Culture at the University of the Basque Country. He, as a professor of Animal Physiology, has not been surprised by the results of the new study. «They have not caught my attention, although it is true that it has always been thought that speed is selected based on distance. Here it is clear that no, that there are very few differences between those who run long and short distances. Without being aware, we tend to go at the speed that implies less energy expenditure.
Eddie is an Australian news reporter with over 9 years in the industry and has published on Forbes and tech crunch.