Prolonged sitting in an office chair can increase stress in the back, neck, shoulders, arms and legs...and can add pressure to the spinal discs. That's why it is important to use an ergonomic chair, which can help provide back support and encourage good posture. But even if you have an ergonomic chair, here are some important measures to be taken for maximizing your chair's effectiveness.
ELBOW MEASURE
Sit comfortably close to your desk so that your upper arms are parallel to your spine. Rest your hands on your work surface if your elbows are not at a 90-degree angle, adjust your chair height either up or down.
THIGH MEASURE
Check that you can easily slide your fingers under your thigh at the leading edge of the office chair. If it is too tight, you should adjust the chair height.
CALF MEASURE
With your buttocks pushed against the chair back, try to pass your clenched fist between the back of your calf and the front of your chair. If you can't do that easily, then the office chair is too deep. You should adjust the backrest forward and check for low back support.
LOW BACK SUPPORT
Your buttocks should be pressed against the back of your chair...and there should be a cushion that causes your lower back to arch slightly so that you don't slump forward or slouch down in the chair as you tire over time.
RESTING EYE LEVEL
Close your eyes while sitting comfortably with your head facing forward. Slowly open your eyes. Your gaze should be aimed at the centre of your computer screen. If your computer screen is higher or lower than your gaze, you need to either raise or lower it to reduce neck strain.
ARMREST
Adjust the armrest of the office chair so that it just slightly lifts your arms at the shoulders. Use of an armrest on your office chair is important to take some of the strain off your neck and shoulders, and should make you less likely to slouch forward in your chair.
Finally, always remember to stand, stretch and walk for at least a minute or two every half hour. Even some minimal movement - such as walking to the water cooler or bathroom - will help keep the joints, ligaments, muscles and tendons loose, which in turn promotes an overall feeling of comfort, relaxation and ability to focus productivity.