try play doh. seriously. i've been doing that lately and it not only strengthens, but doesn't destroy any nerves from overuse or overextension.
Do you know what happend to Shumman.
the same thing applies to everything. example hanon and chopin etudes. going crazi with it will get u injured
Can't you go into music shops and ask to try out pianos pretending you want to buy one?
too often and the shop assistants will get annoyed [about practising on pianos in music shops]