Apple Macintosh PowerBook 145B - Manual (Page 46)

Repetitive stress injuries
Repetitive stress injuries (RSIs) can occur when a certain muscle
or tendon is repeatedly overused and forced into an unnatural
position. The exact causes of RSIs are not understood, but it is
thought that awkward posture, the amount of repetition, the
force used in the activity, and your physiology and lifestyle may all
contribute to their occurrence.
One RSI often discussed in connection with computer use is a
wrist problem called carpal tunnel syndrome, which may be
aggravated by improper use of computer keyboards. This nerve
disorder results from excessive pressure on the median nerve as it
passes through the wrist to the hand. The information on the next
few pages can help you recognize hand positions that may cause
discomfort.
Since the effects of repetitive movement associated with
computer use can be compounded by those of other work and
leisure activities to produce or aggravate physical problems,
proper use of your computer system must be considered just one
element of a healthy lifestyle. No one can guarantee that you
won’t have problems even when you follow the most expert
advice on using computer equipment. You should always check
with a qualified health specialist if muscle, joint, or eye problems
occur.
30 Chapter 1: Setting Up Your Macintosh PowerBook