Physical workload on upper extremities in various operations during machine milking

The aim of the study was to quantify the workload on the upper extremity fo r fundamental work tasks during machine milking. Eleven milkers working in a loose-housing system with a milking parlour participated in the study. Mu scle activity for the biceps and the forearm flexors, as well as positions and movements of the wrists were simultaneously measured by electromyograph y and electrogoniometry while videorecording the work. The milking work was broken up in three main tasks "Drying (the cow's udder)", "Pre-milking (th e First milk)" and "Attaching (thr: milking unit to the udder)" and three s upplementary tasks. All three main tasks show high muscle load values and a lmost no time for rest. The highest load values for the biceps and flexor m uscles were found during the tasks "Attaching, holding the milking unit" an d "Drying", respectively. For 10% of the recording time, the milkers held a ctive hands in 42 degrees dorsal flexion during the milking tasks "Pre-milk ing" and "Attaching" and in deviated positions exceeding 50% of their maxim um values during "Attaching" and "Drying". The high muscle loads in combina tion with extreme positions and movements of the hand and forearm might con tribute to the development of injuries among milkers. The result from the s tudy aims to form a basis for technical improvements of the milking equipme nt to decrease the risk for arm wrist and hand disorders.