Wrist biomechanics for guitar players

Apart from contributing to the position of the hand the primary function of the wrist that has relevance for us is its role in adjusting the tension in the extrinsic muscles of the hand. The wrist flexors and extensors described previously insert onto the carpal bones, parallel to these the extrinsic hand muscles cross the wrist and continue onto the fingers.

Holding your wrist in a fixed position, say fully flexed, will cause the finger flexors to shorten and the extensors to lengthen. Having to work from this position causes a few problems. The flexors are already shortened because of the position of the wrist so asking them to shorten further uses more energy than it would otherwise (a phenomenon called active insufficiency) causing muscles to fatigue and eventually cramp.

Exercise

• Holding your wrist straight make a fist with your hand, shouldn't be a problem.
• Now flex your wrist and try to do the same thing.

Common wrist positions

It is not difficult to achieve a neutral wrist position on either side once the basic posture and shoulder positions are sorted. Having said that there are a number of common presentations that will always increase tension in the hand.

Flexion of the left wrist

If you tilt your guitar back to see the fretboard you're forced to reach around like this with your left hand. This shortens the flexors of the wrist and the fingers and adds considerably to the tension in the arm and hand.

If you're standing and have the guitar low on a long strap you'll also have to do this when playing barre chords. This will be a real problem if you're a rhythm player in a rock band.

Extension of the left wrist

This thumb position will cause wrist extension when the guitar is high on a strap or if you're sitting. This position creates significant passive tension (stretch) in the muscles that abduct and extend the thumb (blue line) and active tension in the finger extensors (red line).

Resting the right wrist on the bridge

This position is more problematic for acoustic players, increasing tension in the dorsal forearm extensors. The front of the wrist looks straight here but as you can see the back of the hand is pulled up away from the wrist in an extended position. Muscles that attach here have to shorten to maintain this position. It's the same dynamic as when you hold a mouse (your computers mouse) or use a trackpad incorrectly.

It's less of a problem for electric players, the thinner body and the lower positioning allow for a more neutral wrist.