Quantifying Attack and Defensive Awareness

19 Jun

Building on my last post which used running correlation to quantify the movement relationship between dyads of players this post will introduce two other metrics to measure the impact of player and more specifically sub-system coordination.

To do this I will again be analysing the Brazil vs. Japan game but specifically Neymar’s ‘wonder’ strike for the first goal.

I am looking to analyse the player distances during the build-up to the goal for the Brazilian attacking (Neymar, Oscar and Fred) and the Japanese defending sub-systems (Yoshida, Konno and Nagatomo).  This will be done through measuring the radius of each set of players over the period of the attacking movement. The aim is to show how Japan’s defensive structure was destabilised by not only the exceptional off ball movement of the Brazilian trio but also the inept game intelligence of the Japanese trio.

How Do You Do That Then?

To analyse this I have again generated my own XY coordinates by noting down the positions of the 6 players after each 0.3s frame (roughly). See the last post for more detail on this process.  After this I then calculated the distance between each player in their sub-system and then in their attacker and defender pairings.

By calculating this it allows you to see the shape of the corresponding systems, how they interact with each other at key moments and become destabilised.

Example of Brazil and Japan Radius

Example of Brazil and Japan Radius

Analysing Defensive Stability

To start with we will look at the changes in overall radius between the two aforementioned sub-systems.  Using the running correlation technique you can compare the relationship between the changes in radius for Brazil and Japan.  The r -1 across the first 4 movements indicate that the two systems are changing radius in opposite directions with Brazil shrinking (-1.5m) and Japan expanding (+5.2m).  This is a very important observation as it potentially shows the difference between good and world class players.

Radius correl

How I hear you ask? Well this indicates that the Japanese defenders are only able to process one set of information (in this case the trigger of Marcello’s turning: Movement 3) and are not able to see that Neymar et al have  by movement 4 changed direction and started to aggressively shrink in radius.  Why is this important? well as @SoccerStatHunt realised:

Tweet

This is the beauty of the running correlation it’s a simple but hugely effective tool.  In this case it isn’t that the Japanese players are so much ball watching it’s that they assume the attackers are just going to move towards the goal (why wouldn’t they they’re attackers after all?). If we look closer at the Japanese inter player dyad distance above, we can see a large expansion between Yoshida and Nagatomo.  In the game footage we can see Yoshida has initially tracked Neymar forward while Nagatomo has not tucked inside Fred to keep the distance constant and the unit stable.

By movement 5 (Marcello preparing to cross) it is too late and Brazil have succeed in breaking their relationships with their paired defender.

This is exemplified by graph below showing the distance between Neymar and Yoshida.  The distance initially shrinks by 1.4m to a gap of 0m by movement 5 when the distance swings by a massive 3.4m by movement 9.  If you watch the goal you will see Yoshida starts to automatically retreat towards goal in anticipation of Neymar doing the same.  Instead Neymar has faked and then changed direction to create the initial peel of space.  By the time Yoshida has realised this (Movement 10) it is too late for him to close down the distance only managing to recover the gap to 2.6m upon Neymar’s shot.

Neymar Yoshida Dist

While all this has only happened in a split second, this lack of awareness in reacting in synch to the trigger sets in motion a series of movements that combine to destabilise the relationship in favour of Brazil.

Japan Crumble

As the graph below shows you can clearly see that the Japanese radius is 4m smaller than Brazil’s at the beginning.  This would be expected for the defending team who would look to narrow their shape to become compact and hard to play through.

Very quickly we see a crossing of the lines at movement 3 which coincides with Marcello turning with the ball.  The distance between the two systems, while having inversed, stays stable at 4m before Brazil’s front line blow the stability of Japans defence apart at movement 6 (Marcello crossing the ball).  From here we see  a race between the two systems with Japan only regaining compactness at movement 11 which was too late as this is the moment Neymar unleashed his wonderful shot.

change in radius

So while this shows the change in the two systems total radius over the whole movement when we look at the moving difference in each systems radius we see a different picture.

Moving difference

The above graph shows a really interesting relationship between Brazil’s and Japan’s defence.  We can see that for the first 2 movements the two systems are in a steady state.  The first large difference occurs at movement 3 which reinforces Marcello’s turn acting as a trigger point for the 3 Brazilian forwards whilst the Japanese defenders are stuck in typical defence mode.

We can see that the two systems then stop expanding and contracting at movement 5 indicating that the distance between the players has steadied before again at movement 6 (the cross) we see Neymar, Fred and Oscar drastically reduce radius by 8.64m which is led by Neymar peeling of his defender and Fred stepping in to receive the cross. From here we still Brazil’s radius continue to reduce but at a slower rate as the players now purposefully position themselves with the flight of the ball before the goal is scored at movement 6.

Conclusion

Hopefully this post has shown how by adding inter player distance alongside using the running correlation we start to add the context of the situation through numbers.  This clearly shows that inter personal space is a key metric in understanding how goals/shots are created, but also gives a good indication of the gap in game awareness between sets of players.

 

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