In news that definitely isn’t going to help me achieve my half marathon goal, a team of Canadian researchers is claiming that human beings are biologically wired to be lazy. Awesome.
In a study that appears this week in Current Biology, researchers asked nine volunteers to wear robotic exoskeletons — similar to leg braces — that offer resistance when they walk. The team then studied how the subjects adjusted their movements.
Within minutes of donning the braces, each volunteer had unwittingly worked out how to modify his or her step frequency to expend slightly less energy (5%). From the paper:
Our findings suggest that new optima are encoded in an updated prediction of the energetically optimal gait and leveraged to rapidly select preferred step frequency. When subjects were held away from their preferred step frequency using a metronome and then released, they returned to their new preferred step frequency within seconds. These adjustments are likely too fast to be governed by blood gas sensors, muscle metaboreceptors, and other known direct sensors of energetic cost.
Despite a lifetime of experience walking under natural conditions, people readily adapted established motor programs to minimise energy expenditure, and they did so for quite small energetic gains. It is sensible that motor programs remain malleable because people’s bodies, and the tasks they are presented with, can change. Continuous energetic optimisation benefits motor adaptation by keeping movements close to energetically optimal, helping people to efficiently adapt to changing terrains, compensate for injury or motor deficits, and learn new tasks.
In other words, a complex series of biological sensors are constantly trying to figure out how you can be more energetically efficient lazy. And for good evolutionary reason: Our ancestors needed to save their calories for chasing down mammoths and running from tigers. We can also thank our half-starved hunter gatherer forefathers for the fact that we love fat and sugar.
Evolution can be a real bitch sometimes.
Top image: Peter Mooney / Flickr