often quoted and its foundation is explained extensively
(Das and Grady, 1983). The normal working area
(Figure 1) is the zone on the working surface where the
hands may work with relaxed upper arms and relaxed,
unrestrained and natural movements of the forearms
and the wrists (Das and Grady, 1983; Das and Behara,
1989). Among others this area is determined by the
spatial relations between shoulder, elbow, hand and
edge of the working surface. The guideline assumes
that the upper arms are relaxed when the trunk is
upright and the hands are together on the working
surface at the mid line of the body with the elbows
situated above the edge of the working surface.