Mountain biking is one of the most exciting sports in the world.
There are four main disciplines in competitive mountain biking: downhill, four cross, cross-country and trailquest.
They all require fitness, bravery and amazing bike control at scary speeds.
But they are also very different in style from each other.
You have to be a real tough nut to make it as a top mountain biker in cross country - the only event available at the Olympics.
The riders need to have brilliant bike handling skills to manoeuvre over trees , branches, rocks and streams.
They must also be extremely fit as the event is incredibly draining and requires real endurance.
A race typically takes place on a marked lap of one to three miles in length.
There is climbing, descending, single-track and technical sections (tight turns or difficult terrain).
The number of laps you race depends on how much experience you have of cross-country racing.
Less experienced riders tackle fewer laps.
Elite level riders race for up to two and a half hours.
Downhill is the ultimate test of nerve and bike control.
It's about who is the fastest from top to bottom.
Which rider has the skill to brake the latest, corner the fastest and ride closest to the edge of their ability?
Riders race individually against the clock hurtling down a steep course over a series of jumps, bumps and drop-offs.
The difference between first and second at the finish can be a matter of seconds.
It's a long, rocky road to the bottom so the bikes used in downhilling have front and rear suspension.
And there are plenty of thrills and spills so a helmet is compulsory and body armour is recommended.
Four cross or 4X mountain biking riders compete on a specially designed highly-challenging course.
The races last between 25 seconds and one minute and are usually fast and frenzied.
The courses are a mix of natural and man-made obstacles covering a steep descent.
The array of obstacles include stutter bumps, doubles, table tops, step ups, drop offs, moguls, bermed or off-camber 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 4X competition starts with a limited number of riders competing in knock-out rounds.
The knock-out rounds can be decided by a series of heats called 'Motos' with riders competing three times before moving on to quarters, semis and final.
The final consists of the last four riders left in the competition.
Alternatively, riders compete against the clock to decide seeding positions before moving into the knock-out stages.
This discipline combines cross country mountain biking with orienteering.
Competitors must search for specific locations in forests or byways and clip special cards as evidence of their visit.
Each location has a specific points value, so competitors score points by visiting as many locations as possible.
The extra challenge comes with using maps and compasses to find these "control points".
Events can vary between two to seven hours, depending on the competition. However, it is not actually a race against time, so it's all about collecting as many points as possible.
Trailquest can be a solo or team event (two riders make up a team).