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Part A: Risk Factors

 

Figure 1A risk factor is a working condition that increases the chance of injuries. Each of the risk factors described here can cause health problems. However, workers who are exposed to more than one risk factor in their job tasks are more likely to suffer injuries. The risk factors that cause most of the injuries and discomfort to computer operators include:
  • Awkward posture: includes computer keying with the wrists bent, reaching for the mouse, or doing other tasks while bending or twisting
  • Repetition: performing the same motion such as keying, using a mouse, or other task every few seconds or on a continuous basis for hours at a time or even the whole work shift.
  • Duration/lack of recovery time: working long periods at a computer or other job without breaks and changing tasks.
  • Force: the effort it takes to move an object or to remain in a sitting, standing or other position for a long time (prolonged static exertion). Another type of force, known as contact stress comes from pressure against a part of a body, such as resting the wrists against a hard and/or sharp edge.
  • Uncomfortable environment: includes poor air quality, improper lighting, glare, noise and other conditions.
  • Organization of work: includes factors such as staffing levels, scheduling, workload and job pacing, electronic monitoring, performing monotonous tasks, and the amount of control workers have over how they perform their jobs. These are sometimes referred to as psychosocial factors.

Figure 2

POSTURE

Whether standing or sitting, there is a neutral position for the back, neck, arms and hands. This is the position that puts the least amount of strain on a given part of the body. Postures that differ from the neutral position increase stress on the body. The illustrations below show positions that are good and bad for different parts of the body. 

The wrists should be straight while keying. Operating the computer with the wrists bent backwards (extension) or forward (flexion) should be avoided. See Figure 1.

The computer operator should be able to reach the keyboard or mouse while keeping the shoulders and upper arms relaxed and bending the elbows at a 90 degree angle. See Figure 2. 

The operator’s back and neck should be straight while at the computer. The top of the monitor should be slightly below eye level. The worker should not have to tilt their head backward or turn to the side to see the screen. See Figure 3. 

Other awkward positions should be avoided while working at a computer, such as cradling a phone between the ear and shoulder.