Get Involved: CYCLING - MOUNTAIN BIKE
Mountain biking is sure to provide some of the most thrilling sights at London 2012 as the fearless riders navigate the tricky climbs and gruelling descents of the 5km hillside course.
Ed Leigh, BBC Sport
"You are going to get all the speed and drama of road races, such as the Tour de France, but in an off-road scenario. Annie Last is Team GB's female rider in the mountain-bike discipline. It will be a big jump for her from the under-23 category, but she could push for a top-10 finish. Liam Killeen will do well to get near Frenchman Julien Absalon, who has dominated throughout the years. He will need all his experience to fend off the challenge from Jaroslav Kulhavy. The Czech is a huge man, which means he should be slow on the climb, but he somehow seems to defy physics and eats up the descents."
British athletes are yet to win a mountain bike medal at the Olympics and the situation is not expected to change this summer, with the main challengers set to come from continental Europe and North America.
The event tests the competitors' physical endurance to the limit as they hare across the rocky terrain for up to one hour and 45 minutes.
But, the punishment is not just reserved for the athletes' themselves, as the rulebook allows running repairs to be carried out as tyres go flat and bike chains snap.
These factors mean the attrition rate is so high that of the 50 riders who started the men's race in the Beijing Olympics four years ago, just 28 finished.
Why is it good for you?
Mountain bike riding is an exciting and physically demanding sport, which burns approximately 559 calories per hour.
The strain of keeping the bike in motion over long distances of challenging terrain increases the heart rate, lowers blood pressure and improves endurance.
As the thigh, calf and hip muscles are in constant use, it is an effective way to help build lower-body strength.
Unlike other high-energy sports, bike riding has a much lower risk of injury as there is none of the physical contact between athletes found in football or rugby, while it is much gentler on the knee and ankle joints than long-distance running.
Biking does not only have to be done as a sport. A study by the International Bicycle Fund found commuters who begin to ride their bicycles to and from work instead of driving lose an average of 13 pounds during their first year of biking.
Approximately two million people in Britain cycle at least once a week, and there are more than 80,000 members of cycling clubs.
There are four main mountain bike disciplines, with the downhill and 4-cross requiring nerve, fitness and great bike control as competitors hurtle down hazard-strewn tracks. The cross-country - which is used in the Olympics - and enduro/marathon put the emphasis more on sheer physical fitness.
Before hitting the course, it is essential to wear safety equipment such as a helmet, cycling gloves and elbow and knee pads. It is recommended that a long sleeved top be worn for added protection.
Can you compete?
Get your performance under pressure analysed in just 20 minutes by four-time Olympic gold medallist Michael Johnson
Some clubs allow members to hire bikes and helmets. A decent starter mountain bike costs around £250-£300.
Training days and taster schemes are run for people of all ages and abilities throughout the year. Visit the British Cycling, Cycling Ireland, Scottish Cycling and Welsh Cycling websites for more information.
Small fees are often required to take part in the 3,000+ meets held annually throughout the country.
For parents looking to get their children started in competitive racing, British Cycling are running a number of events for under-16s throughout the United Kingdom this year. Visit the 'Go-Ride Racing' website for more details.
Sky Ride are offering free cycling events across the country throughout the summer. Their website also contains information about where you can find your nearest cycling route.
Fun, free and informal bike rides just for women are also available through British Cycling and Sky Ride's Breeze scheme.
Want to get involved with sport in your local community? Why not Join In ?
'Join In Local Sport' aims to get as many people as possible to turn up and take part in activities at their local sports facilities on 18/19 August, 2012 - the first weekend between the Olympic and Paralympic Games.
The aim of the initiative is for every sports club and community group in the UK to put on a special event in a bid to encourage more people to get involved as members, supporters or volunteers.
More than 4,000 local sports clubs will be opening their doors to host events and show people just how they can get involved.
As well as tips on playing sport there will be information on coaching, supporting and how to help out.
Find an event near you.
The competition format at London 2012
- Hadleigh Farm in Essex is the venue for both races. On Saturday 11 August, 30 women will compete, with 50 men racing on Sunday 12 August.
- There are no heats: both the men's and women's events consist of a single race.
- The first rider to cross the finish line wins the gold medal and so on.
The rules at London 2012
Both races utilise mass starts, with the riders seeded on the starting grid in accordance with their International Cycling Union world ranking.
Great Olympic moment
Sabine Spitz left behind a much younger field to secure Germany's first Olympic mountain bike gold medal at Beijing in 2008. The 35-year-old even had time to stop 5m from home and carry her bike over the line.
For London 2012, races have been shortened so that the winning time is a maximum of one hour and 45 minutes. At the 2008 Olympics, the men's winning time was one hour 55 minutes and 59 seconds, while the women's winning time was one hour 45 minutes and 11 seconds.
Athletes must ride a predetermined number of laps of the course. Each lap is about 5km, but the actual number of laps will not be decided until the day before the women's race (although it can be changed up to two hours before the start of each race), and will depend on the track and weather conditions.
The aim is to ensure a winning time of between one hour 30 minutes and one hour 45 minutes. In the unlikely event of a dead heat that cannot be resolved using electronic means, the riders will remain tied.
Riders are allowed to make repairs to their bikes as they go along, but can only receive outside assistance in dedicated assistance zones should they have any mechanical problems.
A rider may be disqualified for a number of offences, such as pushing or interfering (jersey-pulling) with another rider, obtaining non-regulation assistance, committing acts of violence, going outside the race course boundaries, and in doing so gains an advantage or using radio links or other remote means of communication.
Ones to watch
Competitive off-road biking began in France in the 1940s and by 1955, the 'Roughstuff Fellowship' was established in Great Britain. The first use of the term 'mountain bicycle' is believed to have come in Oregon, USA, in 1966.
Did you know?
Four sections of the course - Rabbit Hole, Leap of Faith, Deanes Drop and The Breathtaker - were named by pupils from local schools in a competition organised by LOCOG
Around this time, Londoner Geoff Apps began experimenting with bicycles adapted to wet and muddy conditions. American Joe Breeze is credited with introducing the first purpose-built mountain bike in 1978, with mass-produced bikes appearing shortly after.
The first world championships took place in Durango, USA, in 1990 before mountain biking's ascension from a little-known minority activity to a mainstream sport was capped six years later in Atlanta when it made its Olympic debut.