Biomedical Engineering Reference
In-Depth Information
means that are deemed most adequate to reach a goal in a given situation'
(our translation).
This minimal definition makes it possible to understand that a ges-
ture is a motor solution that the operator has identified to be both effective
and efficient to achieve his or her set goals. The goal of the work of the
ergonomist is, from this point of view, to design work situations that allow
operators to implement gestural solutions that are suited to the require-
ments of the current situation, as well as to the requirements of the opera-
tor in question.
Gestural variability: Opening up the space
of possible solutions
A gesture is a trade-off, a solution constructed by the operator at a given
moment to respond to the requirements of a task. The task can then be
viewed as a problem space (Durand, 1993). However, this problem space is
never frozen in the context of a work situation. It possesses its own dynam-
ics, which are the product of the variability of situations encountered by
operators: the variability of products and constraints, the variability of
environmental conditions and the variability in the operator, as shown in
recent research on working times (e.g. Barthe and Quéinnec, 2005; Toupin
et al., this volume). Because of this, it is reasonable to believe that ges-
tural variability is a resource constructed by operators to fit to the specific
dynamics of task constraints, the environment and their own state.
Furthermore, gestural variability allows operators to protect them-
selves from MSDs (e.g. Madeleine, 2010). By adopting a mode of operation
that allows recuperation of the tissues solicited during another strategy,
this gestural variability allows some form of repetition with no monot-
ony. Not repeating gestures in identical forms, and allowing gestures to
vary, allows the worker to solicit parts of his body in different ways. It
also allows breaking monotony, to create gestural variants, to search for
the gestural solution that is best suited to oneself and to the situation at
hand. In the event of these creative processes being hindered, the gesture
is cut off. It is the result of a hindered activity that 'locks the activity into
identical repetitions, involving the subject in compulsive activities where
the motor aspect is no longer handled through automatisms, but through
synkinesia. The latter refers to a system of movements that can only be
executed together, and always in the same way' (Clot and Fernandez,
2005, p. 74, our translation).
As we can see, gestural variability is a resource constructed by opera-
tors to cope with the unforeseen elements and the variability of work situ-
ations. It is an indicator of their skill and accounts for the active part that
they take from and commit in their work (Bourgeois and Hubault, this
