The relationship between power output and body weight is
everything in the sport of cycling. This relationship, known as
the power-to-weight ratio, is the single best predictor of a
cyclist’s race performance capacity. Power produced by the
cyclist’s body moves the bike forward. The weight of the
cyclist’s body resists forward movement. So the more a cyclist
can increase his power output at any given weight and the more
he can reduce his body weight without sacrificing power output,
the better he can perform on the bike.