Biomedical Engineering Reference
In-Depth Information
capture of duels in real situation and an experiment of the same duels in virtual
environment between a real goalkeeper and a virtual thrower. At last, they compared
the goalkeeper's gestures in the real and in the virtual experiments to determine
if virtual reality engendered the same movements in reaction to the same throws.
Their results showed that these movements were similar between the real and virtual
environments.
13.1.2.2 Displacements and Freedom of Movements
In the case of this last work, the high level of presence is also due to the freedom of
movements of the immersed subjects. The freedom of movement is indeed an impor-
tant requirement for the use of virtual reality for sport applications since it is inherent
in the physical activities. However it is not the only requirement. The displacement
of the immersed player is also important. In the example of duel between attacker
and defender in rugby (first case study), the displacement of the immersed player is
limited comparatively to other situations. The second case study shows an example
of such a situation: the soccer goalkeeper's action in front of a free kick.
In real sport situation the displacement of a player influences the displacement
of his opponent. In virtual reality, the coupling of the virtual and real environments
should be done to handle the interaction between the immersed subject and his virtual
opponent. A real time motion capture system should then be used. Moreover, it can
be used to concurrently handle the viewpoint of the subject. As mentioned before,
having an egocentric viewpoint is important to gather all the visual information.
Moreover, the motion capture of the immersed subject allows the biomechanical
analysis necessary to evaluate his reactions.
13.1.3 Some Applications of Virtual Reality for Sports
Virtual reality is more and more used for sports applications. In 1997, Noser et al.
already proposed an interactive situation in tennis [
42
]. If this study highlighted the
technological tool, the situation was not standardized: two real players confronted
each other through two virtual reality systems. Each real player then played against
the avatar of the other player. Since the situation was not standardized, no link can
be done between the decision made by one player and the actions of the other. Many
other simulators in virtual environments have been developed such as for rowing
[
66
], bobsleigh [
35
], etc.
Other studies have used virtual reality to study decision making of sports athletes.
For example, Craig et al. [
19
,
23
] used virtual reality to study the perception of soccer
goalkeepers depending on the effects of ball. Their study demonstrated that the
Magnus effect was hard to perceive by goalkeepers, even experts. Others have studied
baseball [
43
], rugby [
57
] or handball [
12
,
56
] to analyze the decision-making of sports
players.
