Friday, January 16, 2015

Set Distribution from UCLA vs BYU Jan 16, 2015

With the new men's college volleyball season underway, I am looking to watch volleyball and track some kind of stats that are not otherwise available. Tonight #4 UCLA played at #7 BYU. BYU took the match in 3 sets (25-12, 25-17, 25-17). The rankings this time of year are not always the greatest. They are more about expectations than any track record on the current season. Both teams are trying to fill some big shoes. UCLA in particular is a young team. They should get better as the season progresses, but they are rough right now.

The available video for the match was primarily from the side. This makes a lot of stat tracking difficult. I decided to track something I haven't done before, set distribution. Set distribution is something that can be easily extracted from standard volleyball box scores. Just take the hitting attempts for each player and divide by total team attempts. A team that distributes the ball really well might have the two outsides and the opposite each getting about 25% of sets and the two middles getting about 12% a piece. Typically teams have one player who receives a whole lot more. I wanted to get a little more (and different) information.

What I decided to do was look at set distribution by set type, rather than by individual hitter. I tallied sets to the hitter in zone 4 (front left), zone 3 (quicks in the middle), zone 2 (front right but also including back row sets on the right side, or zone 1), and zone 6 (middle back). I also tracked setter dumps. I did not include free balls, hits on the second touch, or over pass hits. To get a little more out of it, I tallied whether the hit was an attempt at a First Ball Side Out (FBSO) as a 1 and other attempts as a 2. I circled kill attempts that scored to get kill percentage.

















There was a pretty big discrepancy in kill percentages by set location, and FBSO percentage. UCLA was only more successful in sets to 6. BYU had a hitting efficiency of .400 for the match to UCLA's .139.  UCLA had 53 attempts at FBSO compared to only 29 for BYU. Some of this is due to the volume of serve receive opportunities that happen when the score is lopsided.

I think the biggest factor in UCLA's low FBSO% is passing. There wasn't a big difference in service aces, but UCLA had a lot of passes that took them out of system. UCLA had 10 more service errors than BYU on 27 fewer service attempts. Some of UCLA's service errors might be due to altitude, but altitude should only account for about 3 feet of extra travel according to this discussion of baseball at similar altitudes. This match was won (and lost) by serve and serve receive. UCLA gave up a lot more points in service errors, and their offense was hindered by bad passing. On the other side of the net BYU had only 7 errors on 74 serves, and they were in system for more of the match.

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