Just so I’m clear, everything after “Monday, June 9, 2008” came from the linked site. I tend to think of warmbloods bred for the hunters and jumpers as having a flat croup, LS to tail. Think about how the horse must tuck the pelvis to engage the core and balance with the hindleg under the hip. A flat croup is going to give you limited ability to “sit” with the pelvis and engage the core, and lift the withers. On the other hand, if the joints of the hindleg are too straight, this lessens the articulation of the hindleg, which is undesirable because you have less pushing power and less elasticity, like the shock absorbers on your car.
But, if you want to jump, a more open angle in the hip, not the stifle and hock, might be desirable because it has a greater vertical range of motion, like a hinge. The “direction” in which jumpers and dressage horses want the most pushing power is going to be different, so they will value different structure in the hind end. Of course, this all might matter less if you have a horse that really loves to jump or really loves the dressage-- the rideability comes above all else.
For fun: I’m looking at a horse right now with Aliano on one side and Consul on the other:
Aliano. This picture isn’t straight on from the side, but you can see he has a more “closed” angle from LSJ to hip to stifle, even though his croup is flatter. They advertise him toward jumpers and dressage; he shows the I2 and trained to GP, I believe.
Aliano’s sire, Aljano, has a steeper croup. His angles are a little more open than Aliano. Another dressage horse.
This is where things get interesting. We go back two generations (There’s nothing about his grandsire, don’t ask me why), and find Ahorn Z, who show jumped internationally, and his sire, Alme. Flat and short in the croup, show jumped internationally. More open hip angle.
Iron Spring Farm’s Consul: Steeper croup, this is a pretty closed angle. He show jumped in Europe and went to fourth in the States.
His sire, show jumper Nimmerdore, has similar angles, though I think he’s a little more open. He’s kind of standing weird. Super show jumper.
Behind them, Farn and Fax 1, both have open hip angles:
Hopefully you can see from this that short and open has been historically preferable for show jumpers and closed with a “deep” hip preferable for dressage horses. There’s always a bit of cultural zeitgeist that surrounds what is desirable or popular (go look at the stallion posted in the dressage forum recently).
A teenager I knew made her graduation project an analysis of the hip and shoulder angles of the top 100 dressage horses from the previous year or something. She plotted the hip and shoulder angles against their average dressage score. I don’t know if she manipulated the data or if this was accurate, but they made a nice little bell curve. If you love data… http://www.lipizzan-online.com/download/files/{E1D77D2A-F9FC-467C-AD3E-AAFE9B1AC727}/Journal%20of%20Equine%20Veterinary%20Science.pdf
