That's what I was thinking, e.g look at the impacts on mtb freestyle: http://www.youtube.com/watch?v=DDaqcEkQRnM&feature=related http://www.youtube.com/watch?v

That's what I was thinking, e.g look at the impacts on mtb freestyle: http://www.youtube.com/watch?v=DDaqcEkQRnM&feature=related http://www.youtube.com/watch?v=DDaqcEkQRnM&feature=relat... You can use tracker http://www.cabrillo.edu/~dbrown/tracker/ http://www.cabrillo.edu/~dbrown/tracker/ to calculate the decelerations on jumps. They are huge, bigger than the car hitting the back on the bike. The only way to do this is to monitor the direction of the deceleration, not only the magnitude.