Horse with a braced back
This head and neck-position is also known as hyperflexion (rollkur). The neck is absolutely overstretched which lifts the back over the withers in an extreme way. The horse loses its dynamic movement. With this position of head and neck the horse also loses its hindquarters, and the center of gravity shifts to the forehand. Riding a horse with a hollowed or braced back increases the wear and tear on its connective and supportive tissue.
„If you put a horse often or permanently under tension with help of artificial aids, such as drawrains, or flex the poll by force you can cause pain and damage.“
Translated from Leitlinien der Arbeitsgruppe Tierschutz im Pferdesport des Bundesministeriums für Ernährung, Landwirtschaft und Verbraucherschutz