Workers indicate that changes in the production system and in management techniques in three auto parts firms have brought some improvements but also resulted in greater mental and physical pressure. Improvements have arisen mainly with the introduction of technological innovations which have eased and simplified work. Increased pressure has derived from the intensification of the pace of work, which has resulted in increased cases of Repetitive Strain Injury (RSI) and the introduction of polyvalence. Male and female workers evaluated the effects of polyvalence in different ways. When women affirm that "nothing has changed" in their work with the introduction of polyvalence, it is possible that they are using the domestic sphere as their point of reference, where it is "natural" for them to perform a variety of activities simultaneously, to which additional tasks can always be added.