Gretchen Reynolds on the science of fitness. This isn’t meant as
an insult, but you are physiologically lazy. So am I. So are we
all. Using treadmill testing, scientists have definitively
established that, like other animals, humans naturally aim to
use as little energy as possible during most movement. So when
we walk or run, our bodies tend to choose a particular cadence,
a combination of step length and step frequency, that allows us
to move at any given speed with as little physiological effort
as possible. How we pick that cadence, though, and whether we
can or would even want to change it has been unclear. But a
series of recent studies involving runners, walkers, metronomes
and virtual reality curtains suggests that while the tug of
physiological laziness is strong, it can be controlled, or at
least tweaked, with some conscious effort — and perhaps your
iPhone playlist. In the first and most revelatory of the
studies, physiologists at Simon Fraser University in British
Columbia asked adult volunteers t