I fell of a horse and landed on tail bone first and then my back and then my head smacked the ground. If I wasnt wearing that vest I would no be able to ride anymore. I love them(:*When they are fitted right!*
I have fallen off plenty of times and landed on my back and tailbone, without wearing a vest, and still perfectly able to ride. I have also broken a helmet from one fall, and still am able to ride.
To the best of my knowledge, vests were first created to help prevent injury when a person fell off and was stepped on by a horse....not for impact of falling off. The material on the inside was supposed to take the impact of a horses hoof and disperse (for lack of a better word) it over more area. You would still get hurt, but just not as severly as the horse stepping directly on you. New technology has created the "airbag" vest, which is supposed to help soften the impact and still be able to disperse the hoof strike.