Apple Macintosh PowerBook 150 - Manual (Page 63)

Arranging your work area and equipment
The suggestions in this section can help you work more comfortably with
your computer.
Chair
m An adjustable chair that provides firm, comfortable support is best. Adjust
the height of the chair so your thighs are horizontal and your feet flat on
the floor.
The back of the chair should support your lower back (lumbar region).
Follow the manufacturer’s instructions for adjusting the backrest to fit your
body properly.
Keyboard and trackball
m When you use the keyboard and trackball, your shoulders should be
relaxed. Your upper arm and forearm should form an approximate right
angle, with your wrist and hand in roughly a straight line.
m You may have to raise your chair so your forearms and hands are at the
proper angle to the keyboard. If this makes it impossible to rest your feet
flat on the floor, you can use a footrest with adjustable height and tilt to
make up for any gap between the floor and your feet. Or you may lower
the desktop to eliminate the need for a footrest. Another option is to use a
desk with a keyboard tray that’s lower than the regular work surface.
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