J. Eklund et al., HEAD POSTURE MEASUREMENTS AMONG WORK VEHICLE DRIVERS AND IMPLICATIONSFOR WORK AND WORKPLACE DESIGN, Ergonomics, 37(4), 1994, pp. 623-639
An increased risk of musculoskeletal disorders, e.g. from the neck reg
ion, has been found among professional drivers of work vehicles. The p
urpose of this study was to identify causes of postural load and impli
cations for vehicle design and work tasks. A second purpose was to dev
elop the methods for measurement and analysis of head postures. Field
measurements of head postures for drivers of fork lift trucks, forestr
y machines, and cranes were carried out. The equipment used was an ele
ctric goniometer measurement system, containing a mechanical transmiss
ion, between the head and the upper trunk. Methods for data presentati
on and quantification were developed. The results showed that rotatabl
e and movable driver cabins improved head postures and viewing angles
substantially. Narrow window frame structures and large, optimally-pla
ced windows were also advantageous. The steering wheel, controls, and
a high backrest restricted shoulder rotation, which increased head rot
ation in unfavourable viewing angles. Improved workspace layouts and w
ork organization factors such as job enlargement decreased the influen
ce of strenuous postures. The results also showed that head postures s
hould be analysed in two or three dimensions simultaneously, otherwise
the postures taken will be underestimated in relation to the maximal
voluntary movement.