Try this:https://www.pianostreet.com/smf/index.php?topic=42557.0Also, you're probably stabbing too much with the arm- rather than feeling a proper connection to the key from the finger itself. This is almost always the cause of notes being held for too long.
The wrists became sore the morning after I started with the Hanons, so my guess is that they are just not used to the more intense exercise they have been getting.. but could be something else, too.As for why I believe it to be strength, well, without muscles it becomes difficult to control movement properly.. no?