The Book of Tells (Peter Collett)[unlocked]

THE BOOK OF TELLS
up the stairs so that everyone thought he was fit. But it was
Ronald Reagan who managed to transform walking into a
form of art. If you ever watched him closely you'll have
noticed that he moved in a way that conveyed an impression
of weighty momentum - and, by suggestion, of
political substance as well. This was partly achieved by his
resolute stride - making it look as though his aides were
struggling to keep up with him - and partly by the
vigorous way in which he moved his arms.
When people walk, their arms swing through an arc in
the sagittal plane (i.e. the plane that's in line with the
movement of their body through space). The full extent of
the arc, forward and back, provides an index of vigour,
because young people tend to swing their arms higher at
the front and further up at the back, partly because they
move faster than older people. Swinging the arms across
the body also helps to create an impression of masculine
strength.
There are two factors at work here - one being the
difference between men and women, and the other being
the exaggerated effect of body-building on gait style.
When men and women stand upright, there's a tendency
for men's arms to rotate slightly inwards (what physiologists
call 'pronation') and for women's arms to rotate
slightly outwards (what physiologists call 'supination').
This sex difference is partly due to the fact that women can
bend their arms further back at the elbow than men. This
is called the 'carrying angle' and it's been explained as
resulting from the fact that women have wider hips than
men and spend more time carrying babies.
Because women have a greater carrying angle than
men, their arms swing further on the back-swing
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