http://www.people.vcu.edu/~bhammel/chen/history_technique.htm
"Sometimes even a coin was put on the back of the hand during training in order to prevent the arm’s participation."
Another article also talks about the development of the piano techniques.
http://www.scena.org/lsm/sm5-5/technique-en.htm
The newer trend was started since Chopin and Liszt, who were figures of the early 19th C. We are in the 21st C. Amazing, how tradition works and how people worship authorities.