Originally Posted by Skyhuntress
agreed. The extensions - or lack of extensions, aren't winning or losing the classes.
I don't believe I posted anything about a horse losing because they may get a lower mark on one movement or even in the collective marks.
The video you presented while showing GP movements are not done at the quality expected for GP level and that particular horse is not showing very much knee action at all.
The OP is at the lower level of dressage so I will show her a video at her level that she can relate to. The following is a test on a breed that is normally associated with knee action competing at the lower levels.
And another one schooling. A little more knee action that some judges will accept and others will not.
Having judged all types and sizes I can tell you that knee action can be good and bad. As you progress up the dressge levels the higher action (and all the following assumes the hind end is working according to the level shown) is helpful in the collected movements (piaffe/passage) but detrimental in the extensions.
For while the hind end may be doing its job correctly and reaching forward the front end is not. Hence some movements no matter how good the haunches working will get penalized. Dressage is not only about doing the movements correctly but in how elegant and pleasing that movement appears in its entire context.