Following my latest post, I have found this great interview of Andre Patin, the mythical coach of  Asnieres Volley 92 (Paris, France). The video (below) is in french but here's a translation:

"What makes the difference, right at the top [of the pyramid], is the emotional stability. It's all there, that's what makes the difference.
Mental skill is central.
Physical skills, technical skills etc... are only accessory.
Physical skills without technical skills are only the ruin of efficiency.
Technical skills without mental skills are only the ruin of performance.
Quote from Claude Sarrazin, former prof. University of Montreal: "Excellence comes with time, effort, discernment, and tenacity.
So is the excellence of the authentic champion".

Now I assume that what Andre Patin means when he says "Mental skill is central" could be tied to Andrea Zorzi's concept of chunks, the cognitive ability to use memory structures as units of perception and meaning, and the learning mechanisms leading to the acquisition of these memory structures(chuncks).

Mental skills allow the player to process a huge amount of data: statistical knowledge of the opponent's team combined with information gathered "onsite" (e.g. The pass being off the net usually means no threat from the quick attack but stats from this particular setter show that he/she likes to set in the middle when far from the net). This leads to the creation of information used by the player to make a decision. Mental skills are central.

Where the two experts seem to differ, however, is on what is most important.

Zorzi seems to consider the mental ability as predominant important (see update below) :

[Having a bigger Chunk means to deal with a lot of information as a single unit of perception. Obviously, the victories depend on many other factors, as technical skills, physical conditions, right emotional approach an so on.]

UPDATE: Andrea told me by email he disagreed with the following statement:

"Zorzi seems to consider the mental ability as predominant". He added :"A champion has to be a mix of different ability and you cannot win relying only on the mental ability without physical and technical skills.Then I saw many potentially good athletes wasting their talent due to a small mental ability."

Patin seems to consider emotional stability as predominant. A note next to "emotional stability" on the top right corner of his pyramid's diagram reads:

[Maintains the level of play regardless of the conditions of the game]

Please note that these are my understanding of Patin's and Zorzi's respective theories, based on a couple of blog posts and a short interview. I may be wrong, and perhaps both of them agree on the matter. Anyway, my goal here is not to artificially oppose two volleyball experts (I have the utmost respect for both of them), but instead to try to look at the big picture. What do you need most to become a great volleyball player ? What makes the difference ? What sets the great players apart from the good ones ?

Height ? Speed ? Power ? Vertical jump ? Flexibility ? Technical ability ?  Cognitive skills ? Self confidence ? Emotional stability ?...

If you can't have all of them, which one would you pick ? When recruiting for your team, what do you look for ?

In 1999, I decided that I wanted to play in Asnieres Volley 92, lead by Head Coach Andre Patin. He had "made" so many great players, (like Hubert Henno, Mathias Patin (his son), Sebastien Frangolacci etc...) that I, too, wanted to learn from the master . The try-outs lasted 2 weeks, practicing everyday, with 2 other candidates. I didn't make it. He chose Philippe Barca-Cysique instead.

I have been working hard on my emotional stability ever since...