If students are taught this way from the very beginning, they will never be limited by pain and injury. Their technique will be effortless and their musical endeavors will be a joyful challenge instead of a frustrating hardship. There will be fewer drop-outs and more adults with a genuine appreciation and workable knowledge of this fine art. Cultivating a vocabulary that works with young children is most important. Words like soft, light and moveable work well, as opposed to heavy, hard and stuck.
Imagery is also most useful.
One week I had a studio full of students whose elbows were suddenly stuck. I told them I had a truckload of elbow-jello delivered to my house, and would they please take a case home and eat lots and lots so that their elbows would move easily while they were practicing at home. It was fun, and it worked. Some of them could even use those terms to quantify how much different their movement had become. From the first lessons at the piano the idea of rotation at the elbow becomes a factor.