Transitioning from cycling to running is not as easy as falling off a bicycle
Weak muscles and low bone density can cause problems for focused cyclists transitioning to running
Elite cyclists are among the fittest people on the planet. The Tour de France is often called one of the toughest sporting events. Those that claim honours are either the fittest in the world, most doped-up in the world, or both.
Cynical humour aside, cycling is known for its ability to develop athletes with fantastic cardiovascular fitness and an incredible lactate threshold to generate so much power, for so long, and for so many consecutive days on a tour.