OCRA - A CONCISE INDEX FOR THE ASSESSMENT OF EXPOSURE TO REPETITIVE MOVEMENTS OF THE UPPER LIMBS

In the light of data and speculation contained in the literature, and based on procedures illustrated in a previous research project in whic h the author described and evaluated occupational risk factors associa ted with work-related musculoskeletal disorders of the upper limbs (WM SDs), this paper proposes a method for calculating a concise index of exposure to repetitive movements of the upper limbs. The proposal, whi ch still has to be substantiated and validated by further studies and applications, is conceptually based on the procedure recommended by th e NIOSH for calculating the Lifting Index in manual load handling acti vities. The concise exposure index (OCRA index) in this case is based on the relationship between the daily number of actions actually perfo rmed by the upper limbs in repetitive tasks, and the corresponding num ber of recommended actions. The latter are calculated on the basis of a constant (30 actions per minute), which represents the action freque ncy factor; it is valid - hypothetically - under so-called optimal con ditions; the constant is diminished case by case (using appropriate fa ctors) as a function of the presence and characteristics of the other risk factors (force, posture, additional elements, recovery periods). Although still experimental, the exposure index can be used to obtain an integrated and concise assessment of the various risk factors analy sed and to classify occupational scenarios featuring significant and d iversified exposure to such risk factors.