Ergonomic assessment of three computer keyboard in correlation with wrist and forearm kinesiology

ABSTRACT

The use of the standard [flat] keyboard design for long periods without sufficient recovery periods may result in cumulative trauma disorders [CTD]. Accordingly, many ergonomic [alternative] keyboards have been produced. So, the present study aimed to perform a sort of comparative ergonomic assessment among 3 commercially available keyboard in correlation with the kinesiology of the wrist and forearm; they are the standard, the natural and the split designs. Ten professional computer operators were subjected to video recording while typing on the 3 designs. Chosen snap shots were printed and the different angles were measured by a goniometery; namely, pronation/supination of forearm, extension/flexion, ulnar/radial deviation angles of the wrist. The present results showed statistically significant differences of the angles among the 3 designs tested. Both ergonomic keyboards placed the forearm and wrist closer to the neutral position than did the standard ones; while, the split keyboard markedly reduced pronation, the natural keyboard kept the forearm in moderate pronation. No significant difference in preference [questionnaire] was found between the standard and natural designs, both of which were preferred over the split. So, it could be concluded that of the 3 keyboard designs evaluated, the natural design incorporated moderate changes to the standard ones. These changes promoted a more natural hand position while typing, thereby reducing the potential for CTD