Jogging is an extremely inefficient activity for humans.
In fact, a recent study published in the Journal of Experimental Biology found that for every 10 calories burned while running, less than 1 calorie is actually used to “maintain a constant forward velocity.” The other nine are spent mostly on tasks like maintaining our equilibrium and redirecting our center of mass.
This inefficiency is one reason why prolonged running burns so many calories.
Elliot Hawkes, a mechanical engineer at UC Santa Barbara and author of the aforementioned study, noticed this inefficiency while watching joggers at Golden Gate Park in San Francisco. Seeing things through an engineering lens, his mind instantly sparked with potential ways to make the action more efficient.
“It was kind of an interesting challenge because as an engineer, when you see a very inefficient system, you think, ‘Oh gosh that’s really bad; there’s got to be some low-hanging fruit that would improve it a bit,'” Hawkes told Science Daily.
Hawkes, who conducted this research while at Stanford University, worked with a team to find a method that would do exactly that. What they settled on was an “exotendon” made out of surgical tubing. The tubing was cut to about 25 percent of the runner’s leg length, which was long enough so it didn’t snap during running but short enough so it didn’t entangle the runner’s feet. Each end of the tubing was then clipped to one of the runner’s shoes.
Amazingly, binding the feet in this manner made runners 6.4% more efficient, on average.
This method naturally resulted in shorter strides taken more frequently, which has long been associated with improved endurance, partially because it reduces the amount of energy needed to support the body weight during each ground contact.
“Several investigators have suggested that exercise economy is an important factor in successful performance in running events, with better performers having a slightly shorter stride length and greater stride frequency compared to less successful performers,” reads an excerpt from the text Essentials of Strength Training and Conditioning.
However, the energy required for someone to consciously speed up their stride frequency can quickly offset any improved efficiency. That’s where the “exotendon” comes in.
“Naturally, people run at the 90 steps per minute. If you could take shorter, quicker steps, it would reduce the energy required to bounce, but it takes much more energy to swing your legs that fast, so you don’t naturally do it. However, the band removes this cost for leg swing, meaning you can easily take 100 steps a minute, reducing the energy required to bounce,” says Hawkes.
“It’s surprising; it makes you feel light and kind of fast…Pretty immediately your body figures it out.”
The tests were done exclusively with endurance running in mind and were conducted on a surface that was consistently flat. Also, the idea of there being a discernible training effect seems unlikely, as runners went back to their regular gait and efficiency after the band was removed.
“Someone compared it to an electric bicycle, where you just go faster, so it’s fun,” said Hawkes. “Why not?”
Photo Credit: Tony Taylor/iStock