Article

Internal models are constantly updated based on the actions and experiences of a
person in the world. In the present study, we proposed to assess the updating
process of internal models of action by providing new environmental constraints
for motor planning, postural control, and execution processes in daily tasks such
as STS and BTS. STS and BTS tasks were performed with different inclinations of
the support surface on which the participant and the chair were positioned:
horizontal support, support tilted 10 degrees to the right, or forward. Twelve
healthy adults participated in this experiment. Kinematic characteristics were
recorded using an optoelectronic motion analysis system. Movement duration and
trunk inclination amplitudes were analyzed for STS and BTS as well as trunk
orientation and strategies of head stabilization. Concerning the movement
analysis our results showed (1) temporal asymmetry between STS and BTS,
attributed mainly to the integration of the mechanical effects of gravity, and
(2) a decrease of trunk movements when the support was tilted forward, attesting
to an immediate adaptation process. Concerning the postural analysis our study
revealed that adults adopted selective head stabilization on space strategy with
respect to balance constraints. To conclude, young adults were able to
immediately update their internal model of action in order to optimize motor
control and vertical body orientation.
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Langue : ANGLAIS