The work load of an operator (1) during the performance of a cycle of manual operations is evaluated considering the simultaneous presence of forces applied on a given part of the body of the operator and an oscillation angle of one or more articulations associated to said part of the body of the operator. Means are provided with sensors of said forces and said angles (3, 5) and the pairs of values of force and angle are processed using - as classifying parameter - the data of an electromyographic detection which measures the muscular activity and the muscular fatigue of the operator during the performance of the cycle of manual operations.
