I was just watching a show on the Science Channel where they showed the guys who ride bicycles downhill on a snow-covered mountain.

One guy had just achieved his personal best of ONE HUNDRED AND SEVEN FREAKING MILES AN HOUR.  On a bicycle.  In the snow.  And did I mention down the side of a mountain?  In the snow? 

Do you know how you stop yourself on the snow should you happen to fall off the damn bike at 107 MPH?

YOU DON'T.

You keep moving until inertia and drag cancel each other out or you hit the side of a '73 Chevy pickup that's been left at the edge of the field because somebody put freaking SNOW on top of it and you don't know it's there.

Or you hit a tree.  From personal experience, I can tell you that trees are nature's solution to inertial dampening.

Also notice I said guys, and not people.  I didn't see any women doing this so-called sport.  Girls are probably way too smart of such foolishness.