(Credit: Wyss Institute at Harvard University)

If you have two functioning legs and a reliable nervous system, walking and running are generally ill-considered tasks. However, if you are carrying large amounts of gear on your back for a long time as a soldier, putting one foot in front of the other can be tiring.

This is where the idea for a soft, futuristic "Exosuit" was born in 2011 – when DARPA funded a project called Warrior Web. The US Army worked with researchers from the Wyss Institute at Harvard to develop a wearable device that can help military personnel lift loads and improve overall physical performance. By 2017, the army had a solid exosuit prototype that they had tested with researchers for three years. One big problem remained: the exosuit let the soldiers go fast, but they could not run without the device triggering them.

Researchers at the Wyss Institute therefore built on the earlier prototype to create an exosuit that would help users determine if they were running or To run. This also happens in a deceptively simple way. The latest version features a soft pair of tight-fitting shorts with thigh and waist cables that pull the legs in a certain way depending on the user's gait.

Research on the Exosuit, published on Thursday in the Journal Science, lays the foundation for this new technology. It also explains how to determine how to walk and run using an embedded computer.

DARPA has stopped funding the project several years ago. And the Exosuit's applications could go well beyond the military – possibly to hospitals or workplaces.

A not so easy move

Imagine a city street flooded with people rushing to work in the morning. When someone breaks out into a sprint to catch the bus, jogs across the street to snap a red light, or even climbs up a hill, his gait is completely different in each scenario. We barely notice the change in the movement, but training a machine to know when a person is walking, walking, or walking uphill is more of a challenge than it seems.

The Exosuit had to be tested until it was able to determine the user's gait with an accuracy of almost 100 percent. It's not quite perfect, but damn near – researchers reported that the algorithm guessed the correct gear in treadmill tests at 100 percent and in field trials at 99.98 percent.

While the cables of the exosuit pull on the legs of a wearer, the computer tells him exactly in which directions and with what force he should pull. Otherwise, says technical director David Perry, the suit may interfere with the movement rather than helping.

"There is no way to pull on the leg, which is helpful in both walking and running," says Perry. "If you miss a single step, it will really mess up a person's movement."

And the researchers spent a lot of time wearing the shorts themselves: before the last demonstration, during which six soldiers had to wear the protective suits during the training exercises, Perry said he and his colleagues had dressed around the research buildings and walked around them ,

It's difficult to say exactly what the shorts did, he says. With the high-tech exosuits they were able to reduce their metabolic rate by 9.3 percent when walking and by 4 percent when walking.

"Once you turn it off, your legs suddenly feel heavy and it's clear how much work the robot has done for you," says Perry. "It's like leaving the end of a walkway at the airport."

The shorts sell

According to Perry, the use of technology in the military environment is not entirely off the table, but without DARPA funding, the Wyss Institute is looking for new ways to bring shorts to a variety of markets.

They are currently working with ReWalk Robotics to deploy the technology in hospitals and physiotherapy to help stroke and multiple sclerosis patients regain their strength in recovery.

And Perry says these robo shorts could also be used to prevent injuries in industries where workers carry heavy loads. The Wyss Institute employs professionals from a variety of industries to market technologies such as the Exosuit, and the team even has apparel design experts looking for ways to adapt them to a wider range of body types.

So who knows – maybe one day you can buy some futuristic shorts.