Peak performance

It's the high-point of the mountain biking season, and it's being held in the UK - at Fort William in Scotland - for the first time ever, from 3-9 September.

If you have never heard of the UCI Mountain Bike and Trials World Championships, fear not.

Here's the BBC Sport Interactive beginner's guide to the pinnacle of mountain biking.

WHAT'S IT ALL ABOUT?

First held in 1991, the Mountain Bike and Trials World Championships are staged annually, and competitors ride for their countries, rather than for trade teams or sponsors.

In Fort William, more than 700 of the world's top riders from over 50 nations will battle it out across the four mountain bike disciplines of Cross-Country, 4-Cross, Downhill and Trials.

Over 40,000 mountain bike and outdoor fans are expected in the Highlands for six days of spectacular action.

WHAT ARE THE FOUR DISCIPLINES?

Cross-Country: This is the only Olympic mountain biking event. It's a test of endurance lasting up to 2.5 hours (for elite men), normally over five to six laps on a 6-8 km course. Cross-country courses have a combination of climbing, descents, single track, trails and technical sections (tight turns or difficult terrain).

4-Cross: Four riders compete simultaneously on a specially designed course, taking between 25 seconds and one minute. Courses can be a mixture of natural and man-made obstacles, including stutter bumps, doubles, table tops, step-ups, drop-offs, moguls, bermed corners and gap jumps.

The difficulty of getting over these obstacles at high-speed whilst being jostled by three other competitors means there are plenty of crashes.

The competition starts with a limited number of riders competing in knock-out stages until there are just four left in the final.

Downhill: In Downhill, the test is to see who is the quickest from the top to the bottom, who brakes latest, who corners fastest and who rides nearest to the edge of their ability. Downhill is the ultimate test of nerve and bike control.

Riders race individually against the clock, pitting themselves against a succession of jumps, bumps, berms (cambered corners) and drop-offs - all the terrain challenges you could imagine, and they've got to tackle them flat out!

Trials: Whilst the other mountain bike disciplines are ultimately decided by speed, Trials also involves a test of skill and bike handling. The main objective for Trials riders is to make their bikes do amazing things up, over and around natural and artifical obstacles where most of us would have difficulty walking, in the fastest time without putting down a foot or using any part of the bike other than the wheels for balance.

Riders complete two laps of eight sections and the winner will have the lowest score of penalties. There are two wheel sizes in Trials, 20" and 26", and it's not unusual for riders to compete in both disciplines.

WHO ARE THE ONES TO WATCH?

Cross-country: With Liam Killeen, the UK's leading Cross-Country rider, out for the season due to a mystery virus, home support will be focused on Commonwealth Games Silver medallist Oli Beckingsale .

But he'll have his work cut out to beat France's Olympic and world champion, Julien Absalon , and Switzerland's Christophe Sauser .

In the women's competition, if Norway's Gunn-Rita Dahle Flesjaa can rediscover her 2006 form, she should clear up. This Olympic and world champion completely dominated the 2006 World Cup series with five wins, and she has had four wins at previous Fort William World Cup events.

However, she has been struggling with illness this season.

4-Cross: The Czech Republic's Michael Prokop and the US's Jill Kintner are currently the undisputed king and queen of 4-Cross. But Prokop will be pushed hard by American Brian Lopes , who is leading the 2007 World Cup series, Germany's Guido Tschugg and France's Cedric Gracia .

The Brits are also strong contenders, led by Gee (4th in 2007 World Cup standings) and Dan Atherton in the Men's, and in the Women's, Joey Gough and Fionn Griffths (3rd in 2007 World Cup series).

Downhill: Britain is one of the most powerful nations in Downhill, with Steve Peat and Tracy Moseley winning the 2006 World Cup Series, and four Britons in the men's top 10 rankings and five in the women's top 10.

But the competition will be fierce, with Australians Sam Hill and Nathan Rennie in the men's, and France's Sabrina Jonnier in the women's, likely to be the ones the Brits will have to beat.

Trials: In the 20"-wheel, Daniel Comas Riera and Marco Hosel lead the powerful Spanish and German teams respectively, with Poland's Rafal Kumorowski always a threat.

In the 26" category, it is the French and Belgium teams that dominate, with France's Vincent Hermance and Belgian Kenny Belaey often fighting it out for top spot.

Britain has a long tradition of bike trials, often linked with a strong motorcycle trials background in areas such as Yorkshire. Danny Butler , Robert Poyser and Ben Savage are likely to be the leading British threats.

Source: BBC Sport