How our bodies work hard to save energy

10 September 2015

Call it laziness or efficiency – either way, humans are wired to find the path of least resistance, according to a new MSFHR-supported study.

Researchers at Simon Fraser University studied the energy consumed by walking and found the body’s nervous systems are remarkably quick to alter the way we move so as to expend the smallest possible amount of energy. The study revealed that when faced with impediments to a normal stride, people are able to adapt their step frequency within minutes to find a new optimum rate.

“Even within a well-rehearsed movement like walking, the nervous system subconsciously monitors energy use and continuously re-optimizes movement patterns in a constant quest to move as cheaply as possible,” said 2006 MSFHR Scholar Max Donelan in a press release.

To measure this adaptation, the research team – including 2013 MSFHR Trainee Jeremy Wong – asked volunteers to wear a robotic exoskeleton that applied resistance to the knee, making it more difficult to walk. Faced with “energetic penalties” to a normal stride, the subjects quickly changed fundamental characteristics of their gait – established over millions of steps – to achieve modest energy savings.

“Had they simply suffered this small penalty, their energetic debt after one hour of walking would be roughly equivalent to the energy contained in a single peanut,” said Donelan. “The savings were literally peanuts!”

The researchers plan to follow up this study by exploring how the body measures energetic costs of other ways of moving.

The study was published Sept. 10 in the journal Current Biology.

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