The Tour de France is the ultimate race in the bicycling calendar, but the Olympic road race that comes around once every four years is special, too. It’s special not just because of its infrequency, but also because of the toll it takes on riders’ bodies.

The Tour ends on July 22, and the men’s road race at the 2012 Summer Olympics is July 28, followed by the time trial four days later. For cyclists who want to participate in all of those races, it’s going to be a rough season.

On one hand, it’s good to keep pedaling during that time period. It keeps riders in racing form and doesn’t give them too much time to over-think any event.

However, rest is crucial, and most riders aren’t getting much of that these days. A six-day turnaround is extremely short to go from one grueling race to another.

At least the Olympic road race is just one 155-mile stage, unlike the Tour de France, which is 21 events spread across three weeks with just two rest days interspersed.

Riders who want to concentrate on the Olympics might be able to drop out of the Tour, were it not for their sponsorship obligations. As Mark Cavendish told the AP via NBC:

The tour is my job. Commercially, if a sponsor puts in money, the Tour de France is a big deal. So I have to do it. I want to do it. It's what my season's about. I have to display my sponsor's logo. There's no better way to display your sponsor's logo than going over the line with your hands in the air.

Cavendish, a British racer who will be participating in the Olympic race on his home soil, might have thought harder about London 2012 after a Stage 4 crash during the Tour de France. He will continue to race in France despite the crash.

Other Olympic hopefuls competing in the Tour include Cadel Evans, Oscar Freire and Sylvain Chavanel. They will all be pedaling on short rest at the Olympic Games.