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MILLIONS OF YEARS of evolution have enabled human beings to develop a smooth, energy-efficient way of walking.
But, biomechanical engineers suggested on Wednesday, there’s always room for improvement.
They unveiled an unpowered exoskeleton – a small, light, spring-activated device that fits on the lower leg and reduces the energy cost of walking by around 7%.
“The difference might seem small, but it makes a significant difference for humans,” said Steve Collins of Carnegie Mellon University in Pittsburgh, Pennsylvania.
It’s the rough equivalent of an infantryman being able to march 7% more in terms of time and distance for the same energy expenditure, or a trekker freed of the energy cost of toting a four-kilo (10-pound) backpack, he said.
Exoskeletons – externally-worn devices intended to augment physical actions or strength – have a long history.
Back in the late 19th century, pioneering inventors toyed with coiled springs tucked into the heels of cowboy boots, or harnesses with rubber bands that were attached to the legs and sought to make walking easier.
But the weight and design of the gadgets were often an energy drain in themselves.
Partly as a result of such setbacks, exoskeleton design today favours powered devices, but in turn has to struggle with challenges such as battery range and bulk.
The new gadget, described in the science journal Nature, is a carbon-fibre mechanical device weighing about 500 grammes (1.1 pounds) for each leg.
It comprises a spring that is attached at one end to a strap around the top of the calf, and, at the other end, to the heel of the shoe.
When the heel meets the ground, the spring becomes extended, and a tiny mechanical clutch engages to ensure that the spring briefly retains this energy.
When the heel is lifted, the clutch disengages and the spring is released, thus giving up its stored energy and providing discreet help for the calf muscles as they lift the lower leg.
There’s no motor, no battery and no computer, the inventors said proudly.
“The unpowered exoskeleton is like a catapult,” said Collins’ team-mate, Gregory Sawicki of North Carolina State University.
“It has a spring that mimics the action of your Achilles’ tendon, and works in parallel with your calf muscles to reduce the load placed upon them.”
The prototype was developed through tests on nine able-bodied volunteers, who wore an exoskeleton on both calves.
They were placed on a treadmill and filmed in order to find a spring whose tension offered the best savings in energy cost.
The reduction averages 7.2%, plus or or minus 2.6%, for healthy adults who used it under natural conditions wearing normal athletic shoes. The performance is comparable to savings with powered exoskeletons, according to the paper.
The device has been patented, and the hope is that it can be adapted for people with reduced mobility as a result of injury, stroke or ageing.
Further research is needed to ensure that long-term use of the device does not have an impact on body mechanics elsewhere, Collins said in an email exchange.
“The body is very complex, and it is difficult to predict such effects,” he said.
Walking takes up a big chunk of our daily energy use.
“People expend more energy during walking than any other activity of daily life,” said the study.
“We take about 10,000 steps per day, or hundreds of millions of steps in a lifetime.”
- © AFP 2015.
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My car reduces the energy I expend walking by 100%, and doesn’t make me look like Forrest Gump.
I’d like to see the damage at points of contact over any meaningful or substantial distance.
Red thumbs from some that think plantar flexion should be done after the last frost.
Heel be back
Funny
The yanks will love them.
True. The yanks love retaining as much mobility as possible into old age as they live longer and longer. The scoundrels!
To be fair, America will probably be one of the first to jump on this due to the military applications once the physical effects on other parts of the body are understood. They have been trying for years to find materiel ways of easing the burden on their troops, going so far as to develop and partially field robotic mules for carrying equipment in rough terrain.
jesus christ i didn’t realise walking had become such a f*cking effort
If you have certain disabilities then yes walking is a massive effort.
This device is mainly being designed for people who walk a lot and carry heavy gear (medical staff, soldiers, hikers/campers) or those who struggle to walk due to physical impairment.
I would love to be able to walk to the village, reach a bus service, and actually walk about the shops a bit without giving up.
I would be so happy to take a walk with grandchildren, the rare visitors and a bit of a trot by the sea too.
Life changing!
Moran, arthritis, nerve damage and age means it is. Walking is taken for granted but not by me. Remember, not all can get about and miss out ordinary daily things plus just a small drive and walk is turned down as it is not possible.
Giant steps are what you take…
You’d want these for that http://upload.wikimedia.org/wikipedia/commons/6/63/Poweriser,_Brn%C4%9Bnsk%C3%A9_b%C4%9Bhy_2010_(05).jpg
We don’t need the effort taken out of walking. All these advancements are making humans weaker and less healthy.
I hope they can be posted,because there’s no way Iam walking all the way to the shops to buy a pair.
And here’s me using my legs like a Sucker
I thought this article was pulling my leg, but now I see it’s pushing it.
Er, let’s find more ways to get the population even fatter.
have your say