I might have chosen the wrong word in stating effectiveness. Perhaps I should have said equitationaly correct.
I guess it would be harder if one leaned forward or just stand up in the stirrups in regards to the pace talk about milkshake guts.....eeek.
In the speed rack it makes more sense for freeing up the shoulders. Its a spectacle to watch that's for sure. At a couple of sanctioned shows I've been to had a speed rack class (usualy the last class of the night) that drew ppl from miles around even those not into the speed thing to watch them go. They sure can move it out. It can get kind of hairy at times and though not exactly "pretty" to watch but exciting none the less. I think the riders are little nuts to engage in such things but then again your looking/talking to someone who is not into speed (I don't have the need nor the heart for speed). However I have sen ppl ride speed rackers that did not lean back so much. This one guy just simply sat in the saddle and let his horse go. A boy did he go.
"The question is not, can they reason? nor, can they talk? but, can they suffer?" Jeremy Bentham