Friday, November 26, 2010

JQAS Article Examines Relationship Between Opponent's Blocking Strategy and Allocation of Sets to Different Hitters

The latest issue of the online Journal of Quantitative Analysis in Sports includes the article "Relationship between the Opponent Block and the Hitter in Elite Male Volleyball," by Rui Manuel Araújo, José Castro, Rui Marcelino, and Isabel R. Mesquita. A brief summary (abstract) is available here. Full-text access is by subscription, but the journal has guest viewing privileges for individual articles.

This study is based on observations from the 2007 World Cup of men's volleyball. The authors studied setters' allocation decisions in relation to two features of the opposing block:  the spacing of the blockers along the front row at the start of the point, and the type of block being faced (none, single, double, triple; the latter two also categorized as "compact" or with open spaces between the blockers). Analyses (via chi-square) were entirely two-way (allocation vs. spacing; and allocation vs. type of block), with no three-way analyses.

Because the article refers extensively to the six zones of the court often used in coaching, I created the following diagrams of the blocking team's side to illustrate the different types of initial block spacing described in the article (click here for more information on the zone system). The distinctions among the blocking arrangements mainly boil down to whether one or both outside blockers are "spread" (i.e., positioned toward the sideline) or "pinched" (i.e., positioned toward the middle blocker).

Overall, 41.2% of the sets went to teams' two left-side or "ace" hitters; 32.1% to teams' opposite (right-side) hitter; and 25% to teams' two middle hitters. The setter himself took the remaining 1.7% of attacks. Of the findings relating set allocation to characteristics of the block, here are what appear to be the main ones:
  • A "lower [frequency] than expected between ... pinched starting points and attack of the 1st middle hitter..." (of the team's two middle hitters).
  • "The individual block happened more than expected when the attack was performed by the middle hitters..., because most attacks of this player are fast and executed on the central zone of the net close to the setter ... not often allowing the double or triple block formation..."
  • "...the opposite player performed the attack against the double block situation... more than expected..."
  • "Concerning the [left-side/ace] outside hitter [both of a team's two], this player faced the individual block lower than expected and the triple block, the open triple block and the compact double block more than expected."
  • "...the open triple block was more used than expected against the [1st] left-side hitter..."
The article concludes, in part, "This study highlighted that the blockers’ 'starting points' are taken in consideration by the opponent setter to create the best conditions for the offensive players (hitters)" and that the game "at the elite male level is characterized by a constant adaptation between setter’s options and the opponent block tactics and strategies."

The article was, for the most part, straightforward to follow. However, a few little things were confusing, such as some percentages in one of the tables that should have added horizontally to 100% (where the total at the end of the row even said 100%), but the numbers didn't in fact sum to 100. This kind of research is difficult to do, however, with extensive videotaping and coding of matches, so I commend the authors for their work.

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