Much has been written and taught about proper and effective technique at the piano, and, like politics and religion, passions run hot on the subject.
My approach to technique differs substantially from most traditional methods in that it focuses more on the power of the larger muscles, primarily the upper arm, and coordinated movements of arm, hand, and fingers, rather than on finger strength and "independence" of the the fingers. Much of the early development of philosophy of piano technique, as well as the exercises such as Hanon, Czerny, and the like, took place in the age of Mozart and Haydn, when pieces were less technically demanding, and the pianos of the day had a lighter action and required less strength. (Much of it even predated the piano and was based on technique for the harpsichord.) Those methods had few, if any, exercises to address the sweeping arpeggios of Chopin, the sustained passages of thundering chords and octaves of late Beethoven or Brahms, or the shimmery sounds of Ravel and Debussy. Furthermore, little was known in those days about injuries and disorders caused by repetitive muscle contractions.
The composer and pianist Robert Schumann thought his fourth finger was too weak and he developed and used his own set of exercises to strengthen it; he ended up injuring it permanently and had to stop playing. If he had known that is isn't about the strength of the fingers, but about the arm (which has plenty of power) he could have saved himself that pain and heartache.
If this were not true, how could we explain the fact that young children -- child prodigies for example -- play many of the demanding pieces that adults do, with small hands and without large muscles? Could their fingers alone have become so strong? Not likely. It is that they have discovered how to use and coordinate the power of their entire mechanism.
Watch a video of any great pianist, such as Martha Argerich, and you will see how active the arms are. Many people mistakenly believe it's "just for show." This is far from the case. The arms are what provide the power, as well as the continuity. The arm blends the smaller movements of the hand and fingers into an over-arching movement, which is how you get great phrasing, and what is known as "a long line."
Problems that befall pianists from overuse and improper use of the small muscles (i.e. the fingers) are tendinitis, carpal tunnel syndrome, and, perhaps worst of all, focal dystonia. Dystonia is "a neurological movement disorder, in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures. Treatment is difficult and has been limited to minimizing the symptoms of the disorder, since there is no cure available." (Wikipedia) Dystonia of the hand is even called "musician's dystonia." Several well-known pianists developed it, and had to curtail their playing or even stop playing completely.
To avoid these problems, you must find a teacher who can show you how to develop a solid technique based on real principles of anatomy and physics, not the out-dated ideas of 300 years ago. If you already have pain or strain in your hands, forearms, or back when playing, you are on the road to having more problems in the future. Because it is such a "hands-on" experience and method, it is impossible for me to describe every aspect of my approach to technique in this blog. But there are a few things you can do right away:
1. Make sure you sit properly at the piano. Most people sit too low. The bench that came with your piano may not be the right height for you (it can't be one size fits all). Use a pillow to sit higher, or invest in an adjustable bench. Sit so that there is a continuous downward slope from your shoulder to your hand and the line is not "broken" anywhere. Neither your elbow nor your wrist should be below your hand or the keys. If your wrist is below your hand, it creates a great deal of strain on the wrist, which is a delicate area, prone to problems such as carpal tunnel. If you cut off the power from your arm by sinking your wrist, you will have to rely mostly on finger strength, which will also cause strain (not to mention not giving you a big and beautiful sound).
2. Don't do repetitive finger exercises and scales (see my earlier blog post on this subject). There are more intelligent, effective, and musical ways to work on technique. But again, you will need the guidance of a great teacher.
3. Do not ever play through pain. If you feel pain in your hands or arms, stop immediately, shake out the tension and relax for a while. Analyze what type of playing caused the pain and don't keep doing that particular piece. If you think the pain will go away if you become "stronger" you are mistaken.
4. Some teachers will tell you to depress the keys all the way to the bottom (the "key bed') in order to get a rich sound. This is wrong -- it's an old idea and the physics just don't support it. There is a point where the hammer is tripped and hits the string (you can feel where that is by depressing the key slowly and feeling the point of resistance), and pressing past that is wasted energy and can't effect the sound, since the hammer has already been tripped. You can learn to have precise delivery of your power and get a great sound without the excess strain of pushing too far and too hard. If you are feeling strain, just play with a lighter touch for a while until you hopefully cure the habit of aiming too deep in the keys.
5. Read the book "Indispensables of Piano Playing" by Abby Whiteside. Abby was one of the pioneers in debunking the old ideas on playing the piano and showing her students a brilliant new approach. Although I believe it's difficult to learn something so physical from a book, at least it will give you an idea what to look for. She was my teacher's teacher, and he, Joseph Prostakoff, saved my life. Had it not been for him I would not still be playing today. When I went to him I had constant pain in my arms. Now I have none, no matter how many hours I play (and I do play the "big" pieces of Brahms, Beethoven, Chopin, etc), even though I am petite (5'2") and have no real muscle strength.
6. Go to the Abby Whiteside Foundation website, www.abbywhiteside.org, and go to the page titled Teachers. If you are lucky, you may find a teacher in your area that can help you. There are certainly other teachers besides those who studied with Abby or her students who know about these methods, but you may have to do some digging to find them.
I can only imagine the heartbreak of having to stop playing the piano due to injuries, especially if they were caused by playing, and could have been avoided. I hope this never happens to you. Please take the necessary steps now to avoid strain and injury.