For Rafael Nadal, December has been no time to relax.

An off season is a commodity Nadal has been unable to afford this year. Tennis has probably the most gruelling calendar in world sport, there are no others which force its elite competitors to compete at the very highest level for nearly 11 months of the year.

Nadal looked physically and mentally spent at the ATP World Finals in November where he failed to win a match before dragging himself off to the Davis Cup final where he led the Spanish team to another resounding success.

From there instead of hitting the Mallorcan beaches, Nadal has gone straight into a training program ahead of the new season. In the tennis calendar, new challenges come thick and fast and the Australian Open looms large in most minds.

"I have been training for some time," said Nadal. "You could say I have not really stopped working because this year there was no possibility to stop. The players and the ATP are working hard to try to establish more marked guidelines for players to have a little more flexibility and relaxation.  Especially at the end of the year, no matter what happened to those who have played the final of the Davis Cup, you just do not have time to rest.”

"We will succeed and if not for our generation, for those that follow. We have a schedule that forces you to play from the first week of January until December, making it very difficult to achieve your goals."

The knee injury which kept Nadal out for a couple of months in the summer will mean that the Spaniard is not suffering as much as he might have been. Nadal plans to take a reasonable break between Australia and Indian Wells but you wonder the effect his prolonged season will have on his tennis and his increasingly fragile body in the important first month of 2010.