Winter Olympics guide - Bobsleigh
Imagine sitting in a small metal pod, flying around 90-degree bends at 95mph, just inches away from a frozen surface harder than concrete.
That should give you some idea why bobsleigh has been dubbed Formula 1 on ice.
It is hair-raising stuff, with teams of two or four launching a sled down an icy course and trying to steer the quickest path as they hurtle towards the finish.
In bobsleigh, every hundredth of a second counts, and sled designs are constantly evolving in an attempt to squeeze that extra bit of speed out of every run.
HOW THE COMPETITION UNFOLDS
Men's bobsleigh has two-man and four-man events. Women compete in teams of two.
A two-man (or woman) team consists of a driver and brakeman, and the four-man event adds two more team members, who provide extra pushing power at the start.
The crew start by pushing the sled for about 50m. This is a crucial part of the run as it generates the speed which the bob will carry down the course.
A 0.1sec advantage at the start can grow into a 0.3sec advantage at the finish.
After the push, the crew jump into the bob and tuck low to reduce wind resistance as the driver tries to steer the best line to the finish.
Any contact with the walls of the course can cut speed dramatically.
The brakeman's only duty beyond the explosive start is applying the sled brakes at the end of the run.
In Olympic competition, there are four timed runs.
The starting order is drawn on the basis of different merit groups decided by the results achieved by the teams in the previous World Cup.
After the four runs, the team with the fastest overall time wins. In the case of a draw, there are two winners.
If the sled overturns, but all members of the team pass the finish line inside the sled, the descent is considered valid.
WHAT IS A BOBSLEIGH?
Bobsleigh basics with GB coach Peter Gunn
The hull (or cowling) of the bobsleigh is made of fibreglass and steel and is open at the rear to allow team members to board and sit down.
The bob sits on two independent sets of steel runners and the steering is operated by the driver using a system of pulleys controlled by two handles.
There are handles on both sides of the hull to allow the athletes to push at the start, and these retract once the team members have jumped in.
There are minimum width restrictions for the cowling and spoilers of the bob, and overall weight limits also apply.
The top sled weight in women's bob, with crew and equipment combined, is 350kg.
In the men's events, the two-man maximum is 390kg and the four-man maximum is 630kg.
Given the high speeds involved in bobsleigh, crash helmets are a must and the athletes are also allowed to wear spiked shoes to help with grip at the start.
WANT TO GET INVOLVED?
There are obviously no places in the UK to bobsleigh, but do not give up hope just yet.
Try the British Bobsleigh Association's website to find out about taking part overseas with specialist bobsleigh trips.
Development days for the general public are run in Bath at the push practice facility. The BBA's website has details on these.
And for more news and information on the sport around the world, check out the International Bobsleigh and Skeleton Federation's website.