NEC POWERMATE VP Manual page 204

Although some studies have shown an association between
increasing hours of keyboard use and the development of
some musculoskeletal disorders, it is still unclear whether
working at a computer causes such disorders. Some
doctors believe that using the keyboard and mouse may
aggravate existing musculoskeletal disorders.
Some people are more susceptible to developing these
disorders due to pre-existing conditions or psychosocial
factors (see "Pre-existing Conditions and Psychosocial
Factors" at the end of this appendix).
To reduce your risk of developing these disorders, follow
the instructions in this appendix. If you experience
discomfort while working at your computer or afterwards,
see a physician as soon as possible. Signs of discomfort
might include pain, tenderness, swelling, burning,
cramping, throbbing, weakness, soreness, tingling and/or
numbness in the hands, wrists, arms, shoulders, neck,
back, and/or legs.
A-2 Setting Up a Healthy Work Environment