Check out this week's article at the Ergonomic Site at BellaOnline. Choosing & Adjusting an Ergonomic Chair
Good posture is at the core of ergonomics. Good posture allows a stable base from which the movement of the arms flows. If the base is out of alignment, additional stressors will be placed on the arms and upper body placing you at greater risk for muscle fatigue and pain.
A good chair can make all the difference.
And as the article suggests - don't forget to get up, move and stretch througout the day!