This Avatar Predicts the Amount of Energy People Use by Looking at the Way They Walk

Scientists are coming much closer to fully measuring the effects of energy expenditure based on people's gait, thanks to a recent study.

Many of us have seen at some point in our lives the human evolution charts that offer a visual representation of our long journey from walking on our hands and feet to now walking on two feet: they serve as a reminder of the progress of evolution. Despite this progress, however, a growing body of research is suggesting that there are some features of our walking which can be described as downright lazy.

Researchers from the Ecole polytechnique fédérale de Lausanne's (EPFL) Biorobotics Laboratory, which part of the technical university's School of Engineering, designed a study that looks at the subtle ways that people naturally adjust their gait, or walking pattern, to expend the least amount of energy. It's bradly referred to as energetic economy

To achieve their results, they used an avatar with programmable software. This gave the research team the option to add various quantifiers like weight and height, stride dimensions, walking distance and even foot lift. More delicate features like stress indicators could also be added, assisted by the changing energy and calorie numbers. The team even made available a downloadable application to see how the simulator works in action.

The Challenges For Researchers

Despite scientists' best efforts, measuring the full range of easily visible, and difficult to detect, factors that go in one person's gait represents the biggest challenge in this area of research.


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One example of this is a set of experiments from three years before in which researchers from Simon Fraser University in Canada also took a look at the mechanics behind energetic economy, but in their study their approach involved the use of robotic exoskeletons that captured the dynamic range of movements made by the human subjects. 

Their findings were that "energetic cost is not just an outcome of movement, but also continuously reshapes it", adding a new level of complexity for the researchers.

“[T]he nervous system subconsciously monitors energy use and continuously re-optimizes movement patterns in a constant quest to move as cheaply as possible," study co-author Max Donelan explained


A Work in Progress

The team designed their study as a way to combine research methods from recent literature, their hopes being that the software would offer more possibilities to researchers in terms of data and design modifications. 

Still, Salman Faraji, EPFL researcher and co-lead author on the study involving the avatar, acknowledged that more work is needed to develop a technique that comes closer to achieving more consistent data collection results:

“The way humans walk is extremely complex. The level of control required is a huge challenge for humanoid robots, which often don’t get it quite right.”

“We have a long way to go before we really understand all the parameters that go into human, animal and robot locomotion," he added.


Details about the study appear in an article, titled "A simple model of mechanical effects to estimate metabolic cost of human walking", which was published on July 20th in the Scientific Reports journal.