Top marathon runners tend to be lean and light, star swimmers
are gangly things with huge feet and gold medal weightlifters
are solid blocks of muscle with short arms and legs. So does
your physique - and indeed the way your body works - fit you for
a particular sport, or does your body develop a certain way
because of your chosen sport? "It's about 55:45, genes to
environment," says Mike Rennie, professor of clinical physiology
at the University of Nottingham Medical School in Derby who
cites the case of identical twins from Germany, one of whom was
an endurance athlete, the other a power sportsman, "They look
quite different, despite being identical twins." A five footer
has little chance of becoming an elite basketball player, but
being six foot nine with the springiest tendons in the land
doesn't automatically propel you to Olympic gold. Craig Sharp,
professor of sports science at Brunel University, made this
point at a recent Royal Institution event at which the limits of
human performance were debated.