Influenza dei fattori forza e frequenza nella valutazione del rischio biomeccanico degli arti superiori in agricoltura

Abstract

The aim of the research is to highlight the factors of risk of the upper limbs biomechanical overload in some agricultural operations and to show how strength and frequency factors are particularly involved. Nowadays, the UL-WMSDs (Upper Limbs - Work Related MusculoSkeletal Disorders) constitute a major health problem for agricultural workers. The latest European and Italian statistics on work-related health problems confirm this and these pathologies are the most common sort of problem experienced. To achieve the objectives of the research, tests have been carried out to aimed at deepening the exposure to biomechanical overload due to repetitive movements of upper limbs as can been seen in certain sectors of Mediterranean agriculture. The risk assessment was performed by means of a method OCRA (Occupational Repetitive Actions), which is a method recognized by the international literature and recommended by ISO 11228-3 and EN 1005-5. The first results confirmed the effect of the "frequency" parameter in the calculation of the biomechanical risk index and generated important question about the use of the Borg Scale, which is to evaluate amount of exertion workers experience in the course of their work, in this matters. These results led to further investigation of the two key markers of risk (force and frequency) during the manual pruning of vineyards with the intention of better understanding how the OCRA method, which was originally designed for highly structured work environments that are very different from the agricultural sector, can be better used in that sector. With regard to the force factor, we conducted laboratory experiments making the effort to replace the Borg scale, using values obtained from the specially made sensorized shear, which was used to cut branches. The five sensors on the shear were capable of detecting the strength and duration of the force applied during the cuts. The results confirm that during the operation the hand forces are function of diameters and cultivated varieties, and certain areas of the hand can be particularly stressed and that methodology and instrumentation used in the experiments was able to show this phenomenon and also the difficulties the workers have in making objective judgments about the strength necessary. Regarding the frequency of cuts, the research has proved that wave pattern of the work productivity curves under consideration is similar to that of the OCRA index and they were calculated on an hourly basis. This trend cannot be ignored when performing investigations in the agricultural sector. In conclusion, the results of the tests carried out have shows that there is a necessity to undertake a proper study of work organization in agriculture. This future investigation should be able to identify and show the trend of frequency curve or there is the possibility of serious miscalculation in the estimation of risks from biomechanical overload., The studies undertaken suggest the basis for an evaluation agricultural workplaces that is not limited to economic concerns but also take into consideration wellbeing, health and worker-safety.