Date Published: July 13, 2017
Publisher: Public Library of Science
Author(s): Kazunobu Fukuhara, Hirofumi Ida, Takahiro Ogata, Motonobu Ishii, Takahiro Higuchi, Alessandro Zagatto.
Recent studies have reported that skilled tennis players are likely to use proximal body information for anticipating the direction of their opponent’s forehand shot. However, in these studies, the visual stimuli did not include visual information about the ball. Skilled players may have used proximal information owing to the lack of distal information. To address this issue, we developed a novel methodological approach using computer graphics (CG) images in which the entire body was presented by a combination of point-light display (i.e., poor graphical information, PLD) and polygons (i.e., rich graphical information). Using our novel methodological approach, we examined whether skilled tennis players use proximal body information when anticipating shot directions.
Fifteen skilled tennis players and fifteen novice players tried to anticipate shot directions by observing four CG forehand strokes (ALPOL: all body parts were represented with polygon; RAPLD: racket and arm were represented with PLD; BOPLD: body parts without racket and arm were represented with PLD; and ALPLD: all body parts were represented with PLD). Our intention in creating CG models with such combinations (i.e., RAPLD and BOPLD) was that because of the richer graphical information provided by polygons compared to PLD, the participant’s anticipatory judgment would be influenced more by body parts expressed with polygons. The results showed that for skilled players, anticipatory judgment was more accurate when they observed RAPLD than when they observed BOPLD and ALPLD. In contrast, for novice players, there were no differences in the accuracy of anticipatory judgments with the four CG models.
Only skilled players made more accurate anticipatory judgments when body regions were expressed with rich graphical information, and the racket and arm were expressed with poor graphical information. These suggest that skilled players used proximal information to effectively anticipate shot directions.
The ability to anticipate forthcoming events is key to successful athletic performance in racket sports. A number of studies have attempted to understand how tennis players made their anticipatory judgments [1–9]. For example, skilled tennis players outperform novices by anticipating the direction of their opponent’s shots even before their racket made contact with the ball (e.g., [2, 3]). The spatial-occlusion method has been used to obtain critical information on the anticipation skills of tennis  and badminton players . In these studies, skilled and novice players observed video clips of shots in which some important reference points, such as the racket, the opponent’s head, or lower body, were occluded. These studies found that, although skilled players generally outperformed their novice counterparts, there were no significant differences in the accuracy of their anticipation when the racket, arm, and ball were obscured. Based on these findings, it was concluded that distal cues associated with the racket-ball contact were the most informative cues to anticipate the direction of forthcoming shots.
This study examined whether skilled tennis players use proximal body information to effectively anticipate shot directions using manipulation of graphical information richness. We employed a novel methodological approach in which the opponent’s forehand strokes were presented as CG models created with a combination of PLD and polygons. The intention in creating CG models with this combination was that, because of the richer graphical information provided by polygons compared to PLD, participants’ anticipatory judgment would be influenced more by the body parts expressed with polygons.
We introduced a novel methodological approach in which CG models created with a combination of PLD and polygons were used to identify whether skilled tennis players used proximal body information to anticipate their opponent’s shot directions. Result showed that skilled players used proximal information when the body regions were expressed with rich graphical information (i.e., polygons). In contrast, novice players’ anticipatory judgments were not affected by the richness of graphical information on bodily cues. These results suggest that skilled players use proximal information to effectively anticipate their opponent’s shots. Our novel methodological approach may be proposed as a new evaluation method to identify spatiotemporal information sources underlying skilled player’s anticipatory judgment in tennis.