Article

OBJECTIVE: To examine the effect of wrist orthoses on the electromyography
activities of the extensor carpi ulnaris, flexor digitorum superficialis, and
fibers of the upper trapezius muscles during computer work. DESIGN: A randomized,
3 x 2 factorial design: orthoses (no orthosis, wearing a custom-made orthosis,
wearing a commercial orthosis) and tasks (typing, using the mouse). SETTING:
Laboratory for biomechanics and rehabilitation. PARTICIPANTS: Healthy university
students (N=23), ranging from 18 to 26 years of age. INTERVENTION: Study
volunteers performed standardized tasks such as typing and using the mouse while
wearing 1 of 2 types of wrist orthoses or no orthosis. MAIN OUTCOME MEASURES: We
used surface electromyography and considered 100% maximum voluntary contraction
to represent the amplitude of electromyographic activity. RESULTS: We observed a
significant increase in the electromyographic activity of the trapezius (P<.05)
with the use of orthoses. No significant difference was observed in the
activities of the flexor digitorum superficialis or extensor carpi ulnaris in
participants who typed with or without orthoses (P>.05). However, when the
participants used the mouse, the extensor muscle presented an increase in
activity with both orthoses, and the same pattern was observed in the flexor
muscle when the volunteers used the custom-made orthosis. CONCLUSIONS: Wrist
orthoses affected the muscle activities in the upper limbs of healthy adults who
were using a computer. Electromyographic activity increased in the trapezius when
the subjects used either type of orthosis, and the same pattern was observed in
the extensor carpi ulnaris when the subjects used the mouse. The flexor digitorum
superficialis presented an increase in activity only when the subjects worked
with the mouse and used a custom-made splint.

Langue : ANGLAIS