Monday, November 5, 2012

Perception and Motor Skill in Reading Shot Location in Beach Volleyball - Part II

Participants, Method, Stimulus and Procedure

The VU team invited 32 participants who were 8 expert beach players, 8 expert beach coaches, who formerly were expert players, 8 expert referees, who had not reached expert levels of play, and an inexperienced control group of 8 novices to participate.  Each group watched video clips of attacking sequences and predicted the depth and direction of the shot at various times before the attack.

All of the clips were culled from 25 women’s World Tour beach volleyball matches and included a pass, a set and an attack.  They were recorded approximately 6 meters behind the end-line, from the perspective of a defensive player.  Videos were progressively occluded at three different times:  (a) at setter-ball contact, (b) when the set was half-way to the hitter, and (c) at hitter-ball contact.[5]  Sequences were balanced for attacks from the left- and right-side, and in all sequences the blocker stayed at the net.   Also, because the defender was in view, clips equally balanced correct and incorrect anticipatory movements by the defensive player.  After viewing each sequence, participants had three seconds to decide whether the ball was attacked to the short or deep line or to the short or deep angle.[6]

Motor Experience Contributes to Reading Ability

Analysis of overall performances revealed that the expert players and coaches predicted shot location more accurately than novices, while the referees did not.   In addition, players outperformed both referees and novices in the latest occlusion condition.[7]  Accordingly, since “the group with the highest perceptual-motor expertise (and, notably, less watching experience) outperformed experience watchers,” the findings suggest that perceptual motor experience does contribute to anticipatory skills in beach volleyball.

An issue for further research, according to the authors, will be to study whether players were better readers because they more efficiently utilized cues from the video frame showing hitter-ball contact (3rd occlusion point) or because they were superior at culling information from the entire offensive sequence.

Reading Depth and Direction

Comparing results on depth and direction the results indicate that reading the shot depth in beach volleyball is significantly more difficult than reading shot direction.   Overall accuracy scores were higher for direction predictions than depth judgments in the latest occlusion condition with players, coaches and referees all outperforming novices in reading whether the ball was attacked cross-court or down the line.  The available evidence therefore suggests that coaches should include more opportunities in practice for players to read cues indicative of short and deep shots in the game.  Knowledge of this weakness may also counsel in favor of positional adjustments to defensive players and movement training to improve overall small area quickness and account for potential depth related mis-reads in the game


Like the indoor game, the sport of beach volleyball is overwhelmingly played between contacts.  While those contacts are extremely important indicators of success, the ability to anticipate opponent’s intentions and prepare for the next contact is a proven skill variable separating the most accomplished players from their less skilled counterparts.

Over a decade ago, sports science determined that “[t]here is little doubt . . . that the ability to extract and use the information available from an opponent’s movement pattern is a limiting factor to successful performance for less skilled performers.”[8].  The results of the present study provide experimental evidence that motor experience gained from playing beach volleyball contributes to the ability to anticipate opponent shots both directionally and for depth.  The findings also suggest training emphases and strategies for improving performances in the game.

Since its birth on the shores of southern California, the sport of beach volleyball is now an emerging collegiate sport in the United States, has enormous worldwide popularity, and is an official summer sport of the Olympic Games.  As research science continues to teach us how great readers anticipate we coaches have an obligation to learn the science of the sport and develop principled methods for training the next generation of beach volleyball athletes.  


[1] Aglioti, S.M., Cesari, P., Romani, M., Urgesi, C. (2008).  Action anticipation and motor resonance in elite basketball players.  Nature Neuroscience, 11, 1109-1116; Schutz-Bosbach, S., Prinz, W. (2007).  Perceptual resonance: Action-induced modulation of perception.  Trends in Cognitive Sciences, 11, 349-355.

[2] Aglioti, S.M., Cesari, P., Romani, M., Urgesi, C. (2008).  Action anticipation and motor resonance in elite basketball players.  Nature Neuroscience, 11, 1109-1116.

[3] Urgesi, C., Savonitto, M. M., Fabbro, F., & Aglioti, S. M. (2012). Long- and short-term plastic modeling of action prediction abilities in volleyball.  Psychological Research, 76, 542-560.

[4] Canal-Bruland, R., Mooren, M., Savelsbergh, G. (2011).  Differentiating expert’s anticipatory skills in beach volleyball.  Research Quarterly for Exercise and Sport 82:4 667-674.  I am grateful to Professor Canal-Bruland for providing me with a copy of the research.

[5] For an excellent discussion of the possible limitations of occlusion paradigms, see van der Kamp, J., Rivas, F., van Doorn, H., & Savelsbergh, G. (2008).  Ventral and dorsal contributions in visual anticipation in fast ball sports.  International Journal of Sport Psychology, 39, 100-130.

[6] Two stimulus conditions of the study have limiting effects.  First, it is unclear what impact, if any, visible blocker’s movements played in the participant’s predictions.  Also, anticipation ability was measured as a function of viewing randomized progressively occluded clips of offensive sequences.  Therefore, anticipation scores did not account for participant’s abilities to utilize other cues that commonly inform defensive reads in beach volleyball such as situational factors, opponent’s recent history and pattern recognition. 

[7] Only in the latest occlusion condition (at hitter-ball contact) did participants predict shot location more accurately than chance.

[8] Farrow, D., Abernathy, B. (2002).  Can anticipatory skills be learned through implicit video-based perceptual training?  Journal of Sports Sciences 20, 471-485.

1 comment:

  1. I may have misunderstood this, but this conclusion seems very flawed...

    “the group with the highest perceptual-motor expertise (and, notably, less watching experience) outperformed experience watchers,”

    As I understand it, the Referees are the "experienced watchers"?

    If this is the case, then the problem is that the referees are watching from a very different angle than the players (as are the spectators). Perhaps they should try the same study with videos from the referees stand and see what happens.