To block, or not to block

Hai-Binh Ly at thevolleyballanalyst asks the question, Is it Worth Blocking in Non-Elite Volleyball? In it he questions whether or not it’s even worth have players go up to block when they could pull back and play defense. In particular, he’s talking about smaller players effectively incapable of putting up a good block.

I’ve written previously on the question of how important is blocking? Once you reach a high enough level of attacker power and ability to hit the ball down into the court, blocking becomes important. If you can’t at least slow the attack down, or limit the space into which they can attack, you’re in trouble. Having an extra defender may not actually help all that much.

In this particular article a couple of ideas come up. I think they are worth addressing.

Blocking metrics

As his moniker suggests, Hai-Binh Ly (HBL) is analytically inclined. So naturally he developed a metric to attempt to capture individual blocker effectiveness. I have a couple problems with it, though.

First, HBL doesn’t include block touches which lead to dug balls on the defending side of the net. To my mind this is a major issue, as it speaks to preventing the opposing hitter from attacking the ball unopposed into our court. As noted above, that’s part of the purpose of blocking. It’s not just about blocking for points.

Second, HBL doesn’t use total player block attempts. Instead he uses block touches (except as just mentioned) to work out an efficiency. I think this leaves considerable information out, especially with regards to diagnostics.

Also, looking at blocking errors as the only negative blocking outcomes fails to capture the reality that poor blocking technique, timing, etc. often is the reason for an attacker being able to score off the block out of bounds (block out). That also speaks to diagnostics.


Using his blocking efficiency measure, HBL looks at the players on his team. He then makes a judgement as to which ones are worth having block and which aren’t. Putting aside my issues with the metric, I think we cannot just leave it as a simple block/don’t block judgement for each player.

One of the main purposes of statistics is to see what we’re doing well and what we’re not doing well. They help us develop our training priorities. HBL’s numbers bring a couple of questions immediately to mind.

1) Have the smaller players been trained to soft block effectively?. That means intentionally trying to deflect the attack upward and into their own court so it can be dug. Unfortunately, even if they are, this would not be captured in the blocking efficiency metric.

2) Are some blockers’ efficiencies low due to poor timing and/or poor location? In my experience, less experienced female players especially are often late on their blocks. Both genders have problems setting their blocks in the right location. As a result, the low efficiency levels may not be about lack of size and or jump. If so, we can improve them.

Maybe, maybe not

I should note I’m not against HBL’s thinking that in some cases it might be best not to block. When I coached at Brown one match we ran out of subs and a defensive specialist ended up in the front row on the right side. Needless to say, she did not block. Instead,  she pulled back and played the tip. Conveniently, that’s exactly what the opposing hitter did! So sometimes that’s exactly the best approach.

My point in all this is that I would first be sure we’re measuring things appropriately and that the players are doing a good job trying to execute useful blocks before completely abandoning it. Even smaller blockers can prevent hitters from just teeing off on the ball. As such they at least take some pressure off the defense. As such, I might try to look at broader metrics like Kill % or Hitting Efficiency with and without the block before making a final judgement.

John Forman
About the Author: John Forman
John currently coaches for an NCAA Division II women's team. This follows a stint as head coach for a women's professional team in Sweden. Prior to that he was the head coach for the University of Exeter Volleyball Club BUCS teams (roughly the UK version of the NCAA) while working toward a PhD. He previously coached in Division I of NCAA Women's Volleyball in the US, with additional experience at the Juniors club level, both coaching and managing, among numerous other volleyball adventures. Learn more on his bio page.

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