 His description of the exercises clearly demonstrate the importance of the relationships among the elements of the training scale.The inclusion of the Entwickeln work in the Shoulder-In, Renvers and Travers is the only source available in the English academic equitation literature.These techniques were handed down to Zettl from Colonel Aust, who himself built upon the legacy of Julius Walzer who served as the trainer of the gold medal winning German Olympic Dressage Team in the 1928 Games of the IXth Olympiad in Amsterdam.