Many computer workstation tasks are highly
repetitive. You may perform the same motions repeatedly
at a fast pace and with little variation. When motions
are isolated and repeated frequently for prolonged
periods, there may be inadequate time for your muscles
and tendons to recover. Combining repetitive tasks with
factors such as awkward postures and force may increase
the risk of injury.
- Computers require little task variation. Old
typing activities, such as adding paper or
mechanically advancing pages, have been reduced
or eliminated. Users can stay in their chairs and
type or perform mouse work for an almost
unlimited amount of time. Under these conditions,
a proficient typist can easily perform more than
18,000 keystrokes per hour. These repetitive
motions can lead to tendon and tendon sheath
injuries, especially if the wrist is bent during
the activity.
- Similar repetitions occur when using a pointing
device such as a mouse. Here, the hazard may be
greater because the motions are often
concentrated in only a few fingers of one hand.
- A computer operator may remain in essentially the
same posture for an entire shift. This forces a
few isolated muscles to repeatedly activate to
accomplish a task such as holding the head up or
focusing on a computer screen.
- A poorly designed workstation may cause you to
repeatedly reach to use a mouse or answer the
phone. This can fatigue the muscles of the
shoulder and irritate the tendons.
You can reduce repetition by properly arranging the
workstation and its components. For example, a mouse that
is placed close to the keyboard should minimize
repetitive reaching. However, even the best designed
workstation can not eliminate all highly repetitive
motions, especially for data input. For this reason, it
is extremely important to maintain good posture by
providing adequate adjustability at the workstation. You
should perform all hand tasks with the wrist in a
straight, neutral posture to allow the tendons to slide
easily without interference.
The following work process suggestions may also help
reduce repetition.
- Task Rotation or Job Enlargement - If you must
perform a variety of tasks, when possible,
intersperse them throughout the work day.
Minimize long blocks of uninterrupted computer
time by doing other non-computer tasks such as
photocopying, phone work, cleanup, etc.
- Micro Breaks or Rest Pauses - Build short micro
pauses into computer use sessions. Frequent short
breaks are desirable. Every hour, take a
five-minute break from computer tasks. Look away,
stretch, get up, or walk. These brief pauses
provide time for muscles and tendons to recover.
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