The height of the work surface should be adjusted to the level of the elbows, with the arms hanging by the sides. If using an unadjustable work surface on a temporary basis, adjust the chair height so that the level of the elbows is approximately the same height as the keyboard.
If the feet do not rest flat on the floor or if excessive pressure is felt on the back of the legs, a footrest should be used (a phone book works well!)
Here we divide the area and briefly explain what should be used in which zone. Usual Zone: This area should contain only items that are used most frequently. e.g. keyboard, mouse, notepad. Occasional Zone: This area should contain items that are used periodically. e.g. telephone, calculator, in-out tray, rolodex. Rare Zone: This area should contain only items that are seldom used or just kept for display e.g. pen/pencil container, desk plant, photos, clock.
And finally the correct way in which the computer chair needs to be put to use:
Hope this article has helped you to maintain the right posture while using the PC and after long hours of work, get up without those aches and pains in the body.