Comparing the Strain Index and the Revised Strain Index Application in the Dairy Sector

Repeated forceful efforts, high muscular loads in the wrist flexor and extensor muscles and awkward hand positions during milking can contribute to wrist and hand diseases. Thus, evaluating the risk of biomechanical overload of milking parlor workers’ wrist with an accurate method is fundamental. Aims of the study were: (1) evaluating the wrist’s biomechanical overload in the milking routine subtasks: pre-dipping, wiping/stripping, attacking, post-dipping; (2) comparing the results obtained from Strain Index and Revised Strain Index methods application; (3) evaluating the quality of the approach, the concordance and the possible difficulties in applying and interpreting the two evaluation methods. 3172 task cycles were evaluated on a population of fourteen male milking parlor workers using either SI or RSI. The results showed that both those index have not exceeded the limit value for pre-dipping and post-dipping tasks, whilst the wiping/stripping resulted to be the most risky for milking parlor workers for both RSI and SI methods. The RSI responded to the objectives of increasing the accuracy and the precision of the evaluation.