I know a lot about ergonomics having taken seminars in the subject matter. I've also done countless ergo evaluations in the workplace with excellent results. You see, there is a significant similarity--and danger--in any kind of repetitive motion activity such as being at a piano or a PC keyboard. You need to be very careful because recurring pain in the wrists could indicate that you're possibly progressing toward carpel tunnel syndrome which could be serious enough to ultimately result in surgery. So you'll definitely want to avoid that outcome if at all possible by doing some self help as the preliminary step. You're on the right track suspecting a problem with seating.
1) Knees do not need to be but 1 to 2 inches at most underneath the piano case.
2) Center the trunk of your body on the bench in front of middle C.
3) Adjust the bench height such that your forearms are parallel to the floor. Yes, some people sit higher or lower which make their forearms slant upward or downward, but there is more RISK of injury in doing so. Another way of getting the forearms parallel to the floor is to ensure that the tip of the elbow is level with the top surface of the keyboard. If the adjustment is difficult to see (i.e., you cannot see yourself in profile), a long mirror might enable you to observe your forearms. If not, have a family member observe you until the adjustment is made. We call this the neutral and naturally extended forearm whereby there is a fairly flat surface from the forearm over the flat wrist and top surface of the hand. If your arms slant downward from the shoulders, notice what happens to the wrists: they are automatically up-flexing. If you sit low, the wrists are then down-flexing. This up-flexing or down-flexing is not momentary. It's a posture present during hours of practicing. Is it helpful? No, not over time because it has the potential to be harmful. You greatly reduce that risk by having neutral, naturally extended forearms. It means getting them parallel to the floor by sitting at the height which will accomplish that aim.
4) Know how to keep the playing apparatus (upper arm, forearm, wrist, hand and fingers) relaxed. During practicing, tenseness can cause discomfort or even pain. Some pianists, not all, first notice this when during practicing their shoulders have risen upward such that they feel discomfort in their necks. Others first notice it in their hands. If tension occurs, here are some simple exercises to return to a relaxed state: a. Stand up straight and swing both arms forward and backward together, as if they were two clock pendulums. Do that for 15 seconds or so. b. Swing the arms directly in front of your body so that they criss-cross one another forming an X as they cross. Also 15 seconds. And c. Bend over from the waist and allow both arms to hang loose in front of you. Think of them as being loose ropes in a capricious wind so that they dangle in rapid and chaotic movements INCLUDING rotary motion of the arms as part of the motion, and likewise do this for 15 seconds. At the end of those three exercises you should feel way more relaxed and any discomfort should also be gone. If not, do NOT go back to the piano that day.
5) Play octaves with a loose, flexible wrist.
These might sound like minor adjustments, but small and easy remedies like this can work wonders. I see it all the time.
6) CAUTION: If these simple steps have not given you relief after a week or so of trial, then you should probably be seen by your primary care physician who might even refer you to a hand/wrist specialist.
"Interpreting music means exploring the promise of the potential of possibilities." David April
Last edited by Rachfan on Sat Jul 06, 2013 7:24 pm, edited 9 times in total.