These Robotic Shorts Make Running Easier
Do you dream of having superhuman abilities to run faster and farther, or simply to get through the day more easily? A team of researchers developed robotic shorts that act as a second set of hip extensor muscles, reducing the amount of energy runners expend by as much as 5.4 percent.
Here’s how the team of scientists created these super shorts:
1. Start with an exosuit that’s made of soft, textile-based materials
The research team built on existing technology to create a new one. To make the robotic running shorts, Philippe Malcolm, an assistant professor of biomechanics at the University of Nebraska Omaha, Conor Walsh, the founder of the Harvard Biodesign Lab and a core faculty member of the Wyss Institute for Biologically Inspired Design, and their team used a soft exosuit that was previously developed in Walsh’s lab with the help of textile design experts, Malcolm said. It consists of two thigh wraps and a waist belt.
This soft robotic exosuit is already more functional than many other exoskeletal designs, he said. Some other exosuits are made of rigid, heavy materials. Sometimes, the joints that are built into these suits don’t align well with the user's actual joints. This restricts movement, Malcolm explained.
He hopes the soft exosuit he helped develop will provide more freedom of movement and more comfort than other, more rigid designs.
2. Add forces that propel runners forward
Running requires force. However, it’s not enough for this force to be applied only when we begin running. After all, other forces, including gravity, slow us down. If the force that’s propelling us forward doesn’t continue to act on our bodies, we screech to a halt.
When we run unassisted, we use our own muscles to keep racing (or dragging) forward. However, that comes at a metabolic cost, the amount of energy we spend. The researchers wanted the exosuit to reduce this cost.
To measure metabolic cost, the researchers outfitted runners with portable gas analysis systems. The gas analysis system covers the runner's mouth and measures the amount of oxygen taken in and the amount of carbon dioxide being expelled, Malcolm said.
Two thick cables attach to the thigh and waist belt portions of the exosuit. The cables attach to an external box, called an actuation unit. The researchers control the actuation unit, which loosens and tightens the cables. The pulling action of the cables mimics that of the hip extensor muscles inside the human body, providing additional force that propels runners forward. When applied at the right time, this added force reduces the amount of energy a runner spends while running by 5.4 percent.
Running toward the future
Right now, the exosuit can only be used inside while running on a treadmill. And while the researchers demonstrated that the exosuit can be used to reduce runners’ energy consumption, they haven’t shown yet that it corresponds to actual improvements in running performance, like faster running times.
Before scientists can develop a portable exosuit for running on a track or on city sidewalks, the weight of the system needs to be diminished, Malcolm said. The team estimates that a portable system will need to weigh less than 5 kilograms, or about 11 pounds.
So, if you dream of using this exosuit to run faster and farther on your daily jog, the technology isn’t quite ready–yet. Still, this reality might be closer than it seems.
Researchers are “already developing fully portable suits, not for running but for assistance with walking,” Malcolm said.
As they’re looking to optimize the exosuit’s performance for running, the researchers might study other ways to apply force using the shorts. They might even explore applying force in a way that doesn’t occur naturally in our bodies, Malcolm noted.
“There are no biological muscles that go from the front of your leg to the back of your leg and vice versa,” but in the future, the team might explore whether applying external force in this way provides even better results, Malcolm said.
At this stage, the research has opened up “a lot of really exciting possibilities,” he said. In the future, the team hopes to study how the exosuits can be used to help people recover from stroke or injury.
Want to learn more about what soft robotics can do? Meet roboticist Kari Love.