no jokes please.

when im playing guitar i've got into the habbit of really bad hand position especially on power chords, where i lock my wrist at 90 degrees, i can't play for more than about a minuite without severe wrist pains :(. its seems if i really concentrate i can relax my wrist but as soon i change chord the poor technique comes back. so what i need to know is the best way to get out of this bad habbit.

I can give you ''hands on'' experience on this as last year i was battling with what we call RSI (repetitive strain injury) with my wrist ankylosing when playing for long periods. I had the habit to put my wrist in a 90 angle sometimes when practicing long scale runs and so on. while playing this proved to be a problem to a point where i could no longer push doors open with my left hand.

how to fix it? use your thumb, it's possible to finger most normal chord shapes (no maj add9 or any large stretch, they sorta require your hand to fan out to reach those notes and it forces your wrist to ''break'' into that angle, but once in a while isn't ALL THE TIME) by keeping your wrist straight and using your fingers (duh) to reach out to the notes. keep your fingers in an arc instead of extending them. it'll give you more precision for single note playing and probably fix some problems with your fingers deadening some notes (C chord open position voicing anyone?) but if you were to fret, say, a Fmaj7#11 chord

|---0--|
|---0--|
|---2--|
|---3--|
|---3--|
|---1--|

you have no choice but to arc your index, and to leave the top two strings open you need to ''break'' your wrist. but for any other normal chord/scale/general playing, focus on your thumb position to keep your wrist straight, the only place where there should be a bend is at your first knuckle, logically.

here's what i mean:

photo 1 : normal playing
photo 2: normal playing seen from back for thumb
photo 3: Fmaj chord, probably what your hand looks like when playing
photo 4: blues kinda playing, wrapping your thumb around the neck helps give support
photo 5: i was ascending a scale run, and when you reach the top strings, your wrist also arcs, but in the reverse direction of the Fmaj chord. this is as far as your wrist should go, sort of.

Hope this helps. it's worth it to correct this technique. if you don't, it can end up with carpal tunnel or tendonitis. i'm now free of all these worries after i've corrected my technique.