INTERVENTION ON SEAT ADJUSTMENT AMONG DRIVERS OF FOREST TRACTORS

The aim of this study was to clarify the ergonomics of forest tractor drivers' sitting conditions, to study how well drivers had adjusted th e seats of forest tractors and to study the short-term effect of the b ackrest adjustment and the use of accessory lumbar support on neck-sho ulder and low-back symptoms of drivers. The subjects in this field stu dy were 100 male forest tractor drivers aged 21-50 years (37 +/- 7 yea rs) from central and eastern Finland. The drivers were visited twice, and a two-week intervention on seat adjustment was carried out between the visits. The methods used were interview and assesment of the seat . The height and inclination of the seat, inclination of the backrest and the stiffness of the spring were measured; after the measurements, the technician adjusted the seat. Half of the drivers were given an a ccessory lumbar support (Camp 21025) and advice concerning its use. Pa in, stiffness and fatigue of the low-back and neck-shoulder at the end of the shift were reported to have diminished among nearly all driver s. There were no differences between the intervention groups regardles s of whether the inclination of the backrest was adjusted or not or wh ether the drivers had used the lumbar support or not during the two-we ek intervention period.