http://www.yourpurebredpuppy.com/reviews/toypoodles.html

......The correct build for the breed is "square", which means their legs are long enough that their height is approximately equal to their length. These Toy Poodles are both elegant and athletic, moving with a light, springy gait.

Other Toy Poodles are built lower to the ground, with short legs and a long back -- these dogs have inherited a physical deformity called chondrodysplasia. They don't have the same elegance or agility as square Toy Poodles and they are more susceptible to disk disease.