Biomedical Engineering Reference
In-Depth Information
Fig. 13.3
Effects of expertise on movement initiation and displacement. Four examples of the
virtual attacker's movements:
dark grey
—DM-R (deceptive movement
right
), DM-L (deceptive
movement left), NDM-L (non-deceptive movement
left
) and NDM-R (non-deceptive movement
right
) and the corresponding influence on movements of an expert (
purple
)andanovice(
orange
)
defender. Displacements represent the lateral movement (cm) of the COM (center of mass) over
time (s) [
15
]
have indeed immersed soccer goalkeepers (10 novices and 2 experts) in a virtual
environment and observed their motor strategies in front of different conditions of
free kicks. Their results have demonstrated that the most experienced goalkeepers
wait longer before initiating movement. This allows him to observe the ball trajec-
tory during a longer period and thus allows him to better interpret the curvature of
the trajectory before initiating movement. In our case, waiting longer would also
allow the defender to obtain more reliable information about the true direction of the
attacker and finally be closer for intercepting him.
Such an exploration is very interesting for understanding novices vs. experts dif-
ferences in terms of displacement strategies. For researchers, a permanent difficulty
is to be able to explore performance during a situation that is as close as possible to the
real and complex situation and that keeps a high level of perception-action coupling.
In this case study, virtual reality presents the opportunity to recreate a situation in
which the defender can move freely as in a real game situation. It allows researchers
and coaches to access to quality and pertinent knowledges about expert strategies.
Indeed, the results previously presented can be used on the field for training attacker's
ability to perform deceptive movements and attacker's ability to intercept them.
