The purpose elf this case study was to identify the work cycles imposing high loads on the upper
limb and low-back among trailer assembly workers for an ergonomic intervention. Several
changes in work methods, tools and work organisation were implemented. The number of
repetitions of fundamental work cycles and wrist posture were recorded from the video.
Exposure imposed on the upper extremity in driving screws and drilling was computed based on
experiments on force and time requirements. In lifting or carrying, the dose imposed on the lowback
was computed based on the load moment on the L5/Sl disk and duration of the cycle. It
was shown that after the intervention most workers worked less with deviated wrist and the
cumulative exposure on the upper extremity was lower in furniture fixing tasks. Lifting with
twisted torso was reduced. It was concluded that with relatively simple and low-cost solutions
exposure to important risk factors of upper extremity and low-back disorders could be reduced.