This isn’t meant as an insult, but you are physiologically lazy. We all are. Using treadmill testing, scientists have established that, like other animals, humans naturally aim to use as little energy as possible during most movement.
When we walk or run, our bodies tend to choose a particular cadence, a combination of step length and frequency, that allows us to move at any given speed with as little effort as possible.
A series of recent studies involving runners, walkers, metronomes and virtual reality curtains suggests that while the tug of physiological laziness is strong, it can be controlled, or tweaked, with some effort, and perhaps your iPhone playlist.
In the first and most revelatory of the studies, physiologists at Simon Fraser University in British Columbia asked adult volunteers to walk on a treadmill at an easy pace. Using motion capture technology, the scientists determined how many steps each person was taking per minute at this speed.
A person’s pace depends, of course, on both step length and step frequency. But because the two are inextricably entwined – lengthen your stride and you’ll take fewer steps over a given distance – studying one provides sufficient information about the other, and frequency is easier to enumerate.
After establishing each volunteer’s preferred step frequency, the scientists then sped up or slowed the treadmill, and the researchers measured how quickly people’s legs responded.
The walkers were adjusting their step frequency within less than two seconds after the treadmill speed changed. They then fine-tuned their pacing after that. But the first adjustment came almost instantly. The same process occurred with runners. If the treadmill speed changed, the runners’ step frequency shifted almost immediately, too fast for internal physiology to have played much of a role.
These instant adjustments suggest our brains very likely contain huge libraries of preset paces, Dr Max Donelan, associate professor of biomedical physiology and kinesiology, and his colleagues have concluded. It seems probable that over our lifetimes, Donelan says, our brains develop and store countless templates for most pacing situations.
Just how the brain recognises that we are moving at any particular speed is not completely understood, Donelan says, but almost surely it involves messages from the eyes, feet, ears, nervous system, skin and other bodily systems.
But the scientists have found one signal that seems to override the body’s strong pull toward its preferred ways of moving: a strongly rhythmic beat. When Donelan and his colleagues fitted runners or walkers with headphones tuned to a metronome, they found that they could increase or decrease volunteers’ step frequency. They would also maintain that pace for as long as the metronomic rhythm continued unaltered. The volunteers aligned their movement to the beat.
This finding suggests music may be one of the best ways to affect the pace of your running or walking, especially if you are trying to maintain a pace with which you are not familiar, Donelan suggests.
