If you have a competitive streak a mile wide and an affinity for putting your bike through its paces, you may want to give these mountain bike racing a try. With several different styles, you're sure to find one you like. Don't forget a helmet.
Cross country. Cross-country (XC) mountain biking is an endurance sport, and one of the oldest and most popular forms of mountain biking. With most events ranging from just a few miles to more than 100 miles (160 kilometers), multiple lap and sometimes multiday races can test the strength and endurance of any hardened rider. Most competitive mountain biking courses involve long stretches up and down hills, so riders need to be fit and efficient cyclers with bikes that can handle both uphill and downhill riding. Cross-country bikes are generally the lightest of all the mountain bikes, weighing in between 21 and 28 pounds (9 and 12 kilograms) [source: Partland].
Downhill. Downhill mountain biking isn't as simple as it sounds. While it may be easy to coast down a long, paved hill, a downhill mountain biking run can be steep and full of obstacles. Rocks, ditches and other unknown debris are everywhere, and since your downhill speed is increased by gravity, you have to think fast to avoid mishaps, like tumbling over the handlebars. Downhill mountain bikes are built tough to take a beating, with great suspension to ease the rocky ride. As a result, they tend to be heavier than other mountain bikes -- more than 35 pounds (15 kilograms) -- which makes them less than ideal for cross-country or uphill riding [source: Snyder].
Four cross (4X). In this type of mountain bike racing, four cyclists are pitted against each other in a race through a series of natural and man-made obstacles. The course can be very technically challenging, featuring a host of bumps, hills, jumps, sharp turns and steep drop-offs. It's usually only a few hundred yards long.
Dual slalom. Have you seen those Olympic skiing events where skiers dodge in and out of a series of colored poles at breakneck speed? Replace the snow and the skis with dirt and a mountain bike, and you have the gist of dual slalom racing. In dual slalom, two bikers race to the bottom of a hill while strategically zigzagging in and out of gates (poles with flags on them).
Up to this point, we've discussed a number of mountain bike racing categories. Not all mountain biking involves trying to get the fastest time. On the next page, we'll explore some of the more leisurely but still potentially death-defying categories of mountain biking.