Ergonomic studies of keyboard operators with soft tissue disorders

We have carried out a descriptive ergonomic case study of a small group of keyboard operators with soft tissue disorders of the upper limb, identified in an earlier epidemiological study, of the influence of work activities on risk of soft tissue disorders.The aims of the study were to determine (1) what activities at work required the specific movements we found in our earlier study to be associated with risk of soft tissue disorders; (2) what ergonomic factors might have contributed to the risk, and (3) what, if any, modifications to equipment or working practices were suggested by these observations.Out of seventeen cases invited, nine agreed to participate, three of whom were studied at their place of work. Subjects were observed at work or interviewed at home. In only one case did it appear that operating the keyboard itself required one of the movements previously found to be associated with risk of soft tissue disorder (in this case, keeping the thumb flexed); instead these risky movements appeared to be required by other activities that keyboard operators do, such as turning the roller on a manual typewriter, turning pages, operating a hole punching machine, gripping a pen tightly, and lifting heavy files above the head. Falls onto the hands outside work also sometimes preceded the chronic condition. Economically unsound postures related to poor positioning of seats and equipment were common in the group.This small case study has generated the hypothesis that the excess of soft tissue disorders in keyboard operators is partly the result of the ancillary, non-keyboard, activities that keyboard operators do, possibly initiating some tissue damage which may then be exacerbated by keyboard operation. If this is true, modifying or avoiding some of the ancillary activities might be beneficial. Additionally, it may be helpful to determine the benefit of a period of rest after falls on the hands, before manual work is resumed. Lastly, attention to ergonomic principles in the provision of seats and positioning of equipment is likely to be advantageous.