Abstract
The feeling of fatigue and muscle strength in the upper limb regions in male and female operators engaged in a flight seat reservation system with computer-aided character displays were studied. Feeling of fatigue was the most dominant in the shoulders, neck, and upper back. Next, it was frequent in forearm flexors and extensors of both arms in females and in the right hand areas in males. The mean rate was markedly higher for female operators than for males in each of these regions except the right hand. Fatigue increased on busy days predominantly among female operators whose rate of local pain in such regions reached more than half of that of a feeling of fatigue. Repeated sustained muscle contractions in operating the keyboard while watching the display may be presumed to be accountable for the feelings of fatigue. The female operators group with a high rate of fatigue in upper limbs proved to be of smaller body weight or to have less gripping strength, finger flexion, upper arm abduction, and back strength than the group with a low rate of fatigue. No similar differences could be seen among male groups. The female low-strength group may likely be easily affected by the overloading of the upper limbs due to inadequate working conditions.
