Physical work and ergonomics in dairy farming : effects of occupationally oriented medical rehabilitation and environmental measures

The aim of this study was to assess the effects of occupationally oriented medical rehabilitation and environmental measures on dairy farmers' physical work and ergonomics. This aim was attained with 5 studies. The physical load, strain, and work pace of milking in 2 types of cowhouses were quantified in 2 studies, the effect of occupationally oriented medical rehabilitation on farmers' work techniques, musculoskeletal pain and perceived work ability were assessed in 2 studies, and 1 study described the physical strain of farmers with physical disabilities. In the studies, the number of subjects (aged 26-53 years) varied between 4 and 95. Machine milking was light or moderate work for the cardiorespiratory system both in the tie stalls and in the parlors. Bent and twisted back postures accounted for 29% of milking time in the tie stalls without a rail system, 10% in the tie stalls with a rail system, and 1 % in the parlors. Work postures with one or both arms at or above shoulder level were more typical in the parlors than in the tie stalls. However, the muscle activity of shoulder muscles was 2-8% of the maximal voluntary contraction in parlor milking. The use of a rail system in the tie stalls decreased the proportion of harmful back postures and increased work pace compared with milking without a rail. Occupationally oriented medical rehabilitation courses, lasting 3 weeks and organized in rehabilitation centers, changed the farmers' work techniques during a 1-year follow-up. Farmers worked with a bent or twisted back less often after 1 year when compared with the prerehabilitation situation. Training in lifting techniques did not decrease the biomechanical load of the back when sacks of 20 or 30 kg were lifted. The subjects had less musculoskeletal pain and better work ability at the end of the follow-up than before the rehabilitation. The mean aerobic strain of the farmers with physical disabilities (leg amputation, paraplegia) was mainly light or moderate during work. Impossible work tasks due to the disability were milking, handling of heavy materials, transferring of animals, operating and repairing tasks, and forestry work. Occupationally oriented medical rehabilitation courses and environmental measures proned to be feasible ways to develop ergonomics in dairy farmers.