Tony Barton wrote: Incidentally , Shazzdan ( you and I share an obsessional archaeological interest , I believe) the horse archer cultures of the steppe, starting with the Scythians rode very short,so they could stand up in the stirrups to shoot. There's an excellent book called " The History of Horsemanship " by Chenevix-Trench, highly recommended).
The Western European style was long stirrups to withstand shock. The two styles of riding collided in the Crusades.
Stirrups don't do anything to withstand shock. That is an old myth first proposed by Lynn White Jnr. to support his dodgy feudalism theory.
http://www.classicalfencing.com/articles/shock.php
The best book I've ever found on this subject is Andrew Ayton's Knights and Warhorses.
During the Crusades, both sides used cavalry the same way. The Kurdish and provincial Arab heavy cavalry were virtually identical to European heavy cavalry. Turkish horse archers had a very small role in battles in this region at the time.