Ever waited for
a bus rather than take the short walk to work? Headed for the escalator instead
of the stairs? Humans clearly harbour a deep love of lethargy – and now we know
how far people will go to expend less energy. We will change our walking style on
the fly when our normal gait becomes even a little more difficult. The finding
could have implications for the rehabilitation offered to people with spinal
injuries. Researchers at Simon Fraser University in Burnaby, British Columbia,
Canada, strapped volunteers into a lightweight robotic exoskeleton and put them
on a treadmill. Initially, the team let the volunteers find their preferred
walking rhythm – which turned out to be 1.8 steps per second, on average. Then
the researchers switched on the exoskeleton, programming it to make it more
difficult for the volunteers to walk at their preferred pace by preventing the
knee from bending – and leg swinging – as freely. The exoskeleton didn’t
interfere with the human guinea pigs’ ability to walk faster or slower than
they preferred.
Within minutes
the volunteers had found a walking style that the exoskeleton would allow
without offering resistance. Remarkably, though, they did so despite the fact
that the exoskeleton only ever offered minimal resistance. By using breathing
masks to analyse the volunteers’ metabolic activity, They found that subjects
would shift to an awkward new gait even if the energy saving was only 5 per
cent. Millions of years of evolution, and the experience we each glean from the
millions of steps we have taken, can seemingly be overwritten in moments for
the sake of making tiny energy savings. That’s not to say it wasn’t evolution
that dictated our predilection for laziness in the first place. The finding
might be bad news if you’re trying to burn as many calories as possible on the
treadmill at the gym – your brain might subconsciously find energy-saving
shortcuts – but researchers’ point out that plenty of other physical activity
is enhanced by our energetic efficiency. Running a marathon, for instance,
might be made easier by our ability to make these tiny energy savings.
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