The Yellow Jersey (le maillot jaune)

Of the different contests in the Tour, the first and most important is the race for the yellow jersey - the rider who records the fastest time overall in the general classification (GC).

The overall winner of the Tour de France is the rider who completes the course in the shortest time, which is recorded cumulatively across the 21 stages. It is thus possible to win the Tour de France without winning a single stage.

The tactics involved in a bid for the yellow jersey can be complex. Cycling is a team sport, in which a group of riders will work for each other’s success – but particularly for the success of the team leader, the strongest rider capable of winning the race outright.

For example, 2010 winner Alberto Contador, currently riding for Saxo-Bank, will be able to call on his teammates to alter their tactics according to his needs. The same goes for newly-formed team Leopard-Trek, whose lead rider Andy Schleck pushed Contador all the way in the past two Tours.

GC riders are not worried if they lose time to the likes of sprinter Mark Cavendish on a day he wins a stage – but they will do everything they can to protect their position compared to their rivals for the overall race.

_____

The Green Jersey (le maillot vert)

Speed is the key to winning the green jersey, awarded to the rider who accrues the most points in sprints. Points are awarded for an intermediate sprint on each stage of the 2011 Tour, and for winning the stage outright.

The idea is simple, but in practice this is a multi-discipline contest. Riders in contention for points must decide whether to push hard for points on the intermediate sprint, or whether to hang back and go for the points available at the stage finish line.

With 15 career stage wins Britain's Mark Cavendish will be one of the favourites for the green jersey, but it remains to be seen how the new rules will affect him. Cavendish has stated that he favours winning stages over intermediate sprints - a policy which could work either way for him.

Cavendish's dream of wearing the green jersey on the podium in Paris will equally depend on the performance of his rivals, including previous winners of the points competition Thor Hushovd and Alessandro Petacchi.

_____

The King of the Mountains (le maillot à pois rouges)

The title of King of the Mountains rather explains itself – and the prizewinner gets to wear a fetching white jersey with red polka-dots.

Points are awarded for those who are first to reach the summit of the mountains, which are classified in categories according to difficulty. A Cat 4 climb is deemed the least challenging, followed in increasing difficulty by Cat 3, 2, 1 and finally the fiendishly tough HC (hors categorie, literally 'outside of a category').

Winning the King of the Mountains competition means getting to the head of the peloton on some of the most sapping terrain imaginable. The final week of the 2011 Tour de France features several punishing climbs when sprinter like Cavendish are sure to struggle.

But that will allow the Tour's specialist climbers to come to the fore. Many of the best climbers, such as Andy Schleck and Robert Gesink, may well stay back in the pack and sacrifice points in the King of the Mountains competition, preferring to conserve energy in the race to the yellow jersey.

That could mean a home favourite, such as Thomas Voeckler or last year's King of the Mountains Anthony Charteau, could come out on top.

_____

The Best Young Rider (le maillot blanc)

A comparatively recent addition to the podium, the rider aged under 26 who places highest in the GC gets to wear a white jersey. Some of the true greats of cycling have earned their spurs on the Tour with victory in this category - the likes of Greg LeMond, Marco Pantani, Jan Ullrich and Alberto Contador have all previously worn the white jersey.

Winner of the Young Rider competition in each of the last three years has been Luxemburger Andy Schleck. He is once again eligible this year for the white jersey, and if he did win it for a fourth time his achievement would be unprecedented.

But with dreams of winning the Tour outright and wearing the yellow jersey on the podium, Schleck would consider this no more than a mere consolation.

Follow ITV Cycling on Twitter