My hands do ache once in a while by the pinky and elbow but some other people I know say its pretty normal from playing, since their wrists hurt from playing just for 5 minutes. If you could tell me any symptoms of the tendonitis that would help.
What, their wrists hurt for just playing 5 minutes?! Okay don't listen to what they say seriously, it is absolutely not normal to have hurting wrists in 5 minutes. If you are practicing right, your hands, fingers, forearms, and wrists should not hurt at all. Professional pianists often practice maybe 8 hours a day for some. When you get to that level, it is -usually- the mental fatigue that make them take breaks, not the physical fitness of your hand.
My suggestion is that if you feel any part aching you should stop at least for 10 or so minutes before you resume again and see if it's just from fatigue. Never play when you feel stiff or sore wrists/forearms! It'll greatly increase your chances of injury.
And I recommend stretches prior to practice. There are many exercises. The ones I use are the 5 following ones:
*Note* if it hurts doing any of these exercises don't force yourself
1) Stretch both arms out straight in front of you as if you were to punch someone, make your hands into fists, then bend them down towards the ground. This stretches your tendons on the outer side of your arm
2) This one's for the inner side of your arm. Stretch one arm out, the one you wanna stretch, with the palm open, facing towards the sky. Then use your other hand to pull your stretched hand towards you.
3) This one's for stretching the little tendons between your fingers. THis is how you do it. I dunno howta explain, but just put your right hand pinky on the middle C, then put your ring finger on a G or something, just try to go as much distance as you can to stretch. Do you feel that? Do that for every pair of adjacent fingers.
4) Stretch out your arms in front, stretch your fingers as much as possible, then make them into tight fists. Repeat a few times to relax them.
5) This one's for your thumb tendons. Just say we're focusing on the right hand. Put your thumb across your palm, then lay your fingers on top of your thumb as if you were grabbing your thumb. Hold your arm straight out in front of you, then try to bend your whole fist towards the ground while you're holding your thumb.
Yup hope that helps everyone

And how does tendonitis symptoms? You won't be able to stretch your fingers as far as it normally would (my right thumb cannot stretch as far as my left thumb permanently after a really bad case of tendonitis). And it would hurt then you stretch your fingers with tendonitis. You would not be able to play up to normal tempo and it'll just really suck. So don't go around learning bad habits.
Anways have fun with your piano
