A latex surgical tube, connecting shoes of running people, can improve running efficiency by 6.4%.
The tests were done exclusively with endurance running in mind. There were no tests of sprinters with their long strides and shorter race distances would derive benefits from this device. And, the running surface was consistently flat and level—so no trail running. There’s probably no discernable training effect; runners went back to their regular gait and efficiency when they removed the band.
Tens of Millions on Soft Exosuits
DARPA funded soft exosuit development for over 5 years at Harvard’s Wyss Institute. A team of researchers at Harvard’s Wyss Institute for Biologically Inspired Engineering and John A. Paulson School of Engineering and Applied Sciences (SEAS), and the University of Nebraska Omaha now has developed a portable exosuit that assists with gait-specific hip extension during both walking and running. Their lightweight exosuit is made of textile components worn at the waist and thighs, and a mobile actuation system attached to the lower back which is controlled by an algorithm that can robustly detect the transition from walking to running and vice versa.
The team first showed that the exosuit worn by users in treadmill-based indoor tests, on average, reduced their metabolic costs of walking by 9.3% and of running by 4% compared to when they were walking and running without the device.
The rubber tubing connecting shoes is better at reducing the energy needed to run by 6.4% instead of only 4% for the soft exoskeleton. The device weighs 5kg in total with more than 90% of its weight located close to the body’s center of mass.
Rubber Tubing Connecting Shoes
Human running is inefficient. For every 10 calories burned, less than 1 is needed to maintain a constant forward velocity – the remaining energy is, in a sense, wasted. The majority of this wasted energy is expended to support the bodyweight and redirect the center of mass during the stance phase of gait. An order of magnitude less energy is expended to brake and accelerate the swinging leg. Accordingly, most devices designed to increase running efficiency have targeted the costlier stance phase of gait. An alternative approach is seen in nature: spring-like tissues in some animals and humans are believed to assist leg swing. While it has been assumed that such a spring simply offloads the muscles that swing the legs, thus saving energy, this mechanism has not been experimentally investigated. Here, we show that a spring, or ‘exotendon’, connecting the legs of a human reduces the energy required for running by 6.4±2.8%, and does so through a complex mechanism that produces savings beyond those associated with leg swing. The exotendon applies assistive forces to the swinging legs, increasing the energy optimal stride frequency. Runners then adopt this frequency, taking faster and shorter strides, and reduce the joint mechanical work to redirect their center of mass. Our study shows how a simple spring improves running economy through a complex interaction between the changing dynamics of the body and the adaptive strategies of the runner, highlighting the importance of considering each when designing systems that couple human and machine.
Video of the researchers talking about it. I rried embedding the video but it did not work.
SOURCES – DARPA, Journal of Experimental Biology
Written by Brian Wang, Nextbigfuture.com