I have seen this in some of the tighter bred Dibo strains of dogs. My little Sally bitch that carried a lot of the Maloney breeding had no flex in the back leg . Was glad she did not throw it in the pups I got off her. Sure it could crop up in any strain of dogs. The opposite scenario of this, is a dog being cow hocked in the back legs.

Either way in a hard match against a equal dog that can push and drive hard. These type dogs can break down in the back end and not be able to stay on their feet. Will effect their over all balance. Cheers