Forget "slow and steady wins the race," claims a recent study, alternating between walking and running, or wogging, is the best way to conserve energy and reach your destination on time.
The Ohio State University researchers examined how people budget their time as they travel on foot to reach a destination at a particular appointed time. The study found that when people have neither too much time nor too little time to reach their destination, they naturally switch back and forth between walking and running, which turns out to be the best strategy for saving energy. The study is the first of its kind not conducted on treadmills and it supports the notion that the human body has an innate sense of how to vary speed to optimize energy when we're on the move in our natural environment.
"We don't live our lives on a treadmill," said co-author Manoj Srinivasan. "To better understand how we move in our everyday life, and how our spontaneous movements relate to energy expenditure, we have to study what people do away from the treadmill. Once we have a good enough understanding of how we naturally move to conserve energy, we can build a solid theory and apply it in practical ways, designing better shoes, or better prosthetics that let people walk using less energy." In tests, 36 college students were asked to travel a distance a little longer than a football field, either on pavement outdoors or inside a school hallway.
The researchers were most interested in what the students would do when they were allotted travel times between these two extremes. On a treadmill, people have to adjust their pace to match the machine in order to stay on the conveyer belt, but this study would reveal how people manage their gait, or movement pattern, when they can speed up and slow down whenever they want. The study revealed the existence of a "transition region" between 4.5-6.7 miles per hour (about 2-3 meters per second) when the students tended to make the trip through a mix of walking and running.
Regardless of any variable--fitness level, height, weight, leg length, the amount of time they were given for the trip, whether they were indoors or out--all the students employed a mixture of walking and running when they were moving at speeds within the transition region. Using data previously recorded by other researchers who measured the typical human energy costs for walking and running at various speeds, Long and Srinivasan calculated that dividing up the trip into spurts of walking and running saved energy. "Students seemed to naturally break into a run or slow down to a walk to save energy while ensuring that they arrived at their destination on time," Srinivasan observed.
The findings resonated with Leroy Long III, study co-author and doctoral student in STEM (Science, Technology, Engineering and Mathematics) education at Ohio State. As a recreational runner, he always feels less fatigued if he varies his gait at a natural pace. But other researchers have posed different hypotheses as to what physical factors cause people to vary their gait. "Previously, some researchers have argued that the speed at which we break into a run was really determined by other factors, such as muscle forces. However, such factors cannot explain why we sometimes use a mixture of walking and running.
Our findings suggest, qualitatively at least, that the body actually tends to move in ways that will conserve energy," Long III said. Next, Srinivasan will work on developing calculations that can be used to optimize everything from shoes and backpacks to prosthetic devices, and even assistive devices such as exoskeletons. The study appears in Journal of the Royal Society Interface.