Energy expenditure in various types of motion is illustrated in the diagram below. It is seen that the bicycle represents a significant advantage in terms of energy use as compared to walking, running or skating. In all cases the energy requirement increases

non-linearly with the increase in velocity. The curve showing the power required to overcome drag due to the air suggests that very little work is lost in the mechanical components of the bicycle. At 7 m/s, 86% of the energy expended by a cyclist is used to overcome the air resistance. For a skater at the same speed, air resistance only accounts for about 57% of the total energy used.

Under steady state conditions, the energy use should correspond to energy production by the body, and this depends upon the rate of oxygen consumption by the body. For short sprints, stored oxygen may augment oxygen uptake in energy production.

From: Abbott & Wilson, "Human-Powered Vehicles,"
Human Kinetics (1995)