concerning the piano's action...please READ

[beginner1011]

some pianos have a light touch,,while some require heavy pounding..does it have something to do with hand injury in the sense that playing with hard pianos can cause injury???

[nanabush]

Usually uprights can be very stubborn.  I don't know too much about the mechanics of a piano, but I'd be pretty sure that it has something to do with the action... 

Having to do with hand injury, I'm not sure what you mean.  Do you mean that if your hand is injured, you feel you have the pound the keys harder?  Or are you wondering if playing more stubborn pianos will cause an injury?
 

[daniloperusina]

If I understand your question, you're asking "will my hand be injured if I play on a piano with a heavy touch?"
Maybe, maybe not. I think injuries are not caused by pianos, but rather by keeping on working with muscles/nerves, or whatever it is, that are already exhausted.
Say for example that you are practicing a long and difficult passage in octaves. Even if you have excellent technique, this is bound to make your arms, wrists etc tired after a while. If you still go on for hours, day after day, you are likely to end up with an injury. Just pay attention to any exhaustion you might feel in your fingers, hand, wrist, arm etc, and you should be ok with any piano.

You can always check if the touch is light, normal or heavy by this simple means:
A normal touch requires ca 55grams, +- some,  of pressure to move the key down, dampers off.
Find out by a simple google-search how much coins in your currency weighs. Bring along 70-80 grams of those coins and test it. How much is needed to make the key slowly move? Do it with the damper pedal down. The dampers add weight. I don't remember how much they are supposed to add, but it's easy to feel if they add a lot, which they shouldn't. Sometimes the heaviness of an action is simply due to the dampers being to heavy.