Nobody said anything about not protecting your head. That is a given.

I have had quite a bit of "real life" experience in bike and skiing wipeouts, and still maintain that in most situations there is no need to "sacrifice your arm/ shoulder".

I once got an applause for one of my more spectacular ski crashes, and recovery. A benefit of Judo is learning and practicing body control while flying through the air.

Here is something I found doing a quick search to make sure I was not giving out harmful information: http://www.telegraph.co.uk/health-fi...hout-injuring/

Do your own search; there are several other sites that say essentially the same thing.

"For the amateur rider, crashing presents subtly different challenges. While Cavendish's crash happened around 40mph, your average bike rider might travel at half that speed. Consequently, they have slightly more time to react – which, counterintuitively, can be the thing that puts them in most danger of sustaining an injury.

"It's the lower speed crashes where you seem to break your collar bone, because you have the time to put your hand down, and that's often when it happens," said Lloyd (the shock of the contact with the tarmac travels up your arm and only finds release when the vulnerable collar bone snaps in two). "You don't slide along the ground. Both times I broke my collar bone, it was low-speed."
So how does the amateur take action to avoid hurting themselves in a crash? "My inclination is that it's better to keep your hands on the bars," said Lloyd. "It seems that if you make yourself into a ball and land and roll, it spreads the impact."

His words are echoed by stuntman Rob Jarman, who told BikeRadar.com that during a crash in which you lose the back wheel and fall directly towards the floor, it's good practice to "drop your shoulder, so that the back of it can take most of your impact with the road."