Greek and Roman ankles

From a letter to The Times by R. J. Briggs

Several years ago I was told by the curator of a museum in Athens how to
identify an Ancient Greek statue from a Roman one. Because of the
mountainous topography of Greece the models used by Ancient Greek sculptors
were inevitably thin-ankled, those from Rome thick-ankled; climbing up steep
hills stretches the Achilles tendon. We then toured the museum identifying
the origin of statues using ankles as our criteria.