Question: Do you do or suggest any kind of physical warm-ups (non-musical) such as hand or arm stretches before practicing or playing (or after as well)? I believe I read that you used to do yoga.
Albert's reply: In general, I suggest keeping your body in shape. Practicing the piano for long hours can take its toll on the upper body musculature. Neck, shoulder and back pain are all-too-common ailments among pianists. Even sitting doing nothing for hours can affect the muscles supporting the spine, let alone the constant physical demands that practicing piano puts on the back, shoulders, forearms, wrists and fingers.
Many ailments can be averted via good posture and a technique free of any tension that does not serve musical expression or a specific practice aim. This is the domain of an expert teacher who can supervise and train you one-on-one. Most pianists do tend to play with far more muscular tension than is necessary. (I was no exception.) Not only does the inability to control tension fail to result in the most beautiful sound in physically complex music, but over time it can do accumulative damage to the body as well.
I've done Bikram yoga as necessary physical therapy for my spine. For me, it fully lives up to its claims and more. This website is dedicated to learning piano, so it is not the place to extoll the virtues of yoga or other nonmusical exercises. In brief, I can't recommend it highly enough for spinal health.
Before practicing I often take a minute to stretch my shoulders. I do so because it loosens not only my shoulders but also the muscles around my upper spine and neck. There's no need to detail this or any other particular exercise here because your body might have different needs. I can say, however, that in addition to yoga numerous physical therapy exercises which I learned from exercise physiologist Pete Egoscue's books, as well as from physical therapists and personal trainers, have proven very helpful to me. (His book Pain Free at Your PC might just as well be titled Pain Free at Your Piano.)
I've written about warming up at the piano in other articles (those on warming up for lessons and warming up the hands). In general, in addition to scales and double notes, I find that the best warmup exercise for the hands is practicing counterpoint, such as fugues, since it requires the independent control of all fingers.