What is "Activity time spent" ?

In this article, introduced is Activity time spent shown in 'Tracking Statistics' PDF file on 2018 FIFA WORLD CUP RUSSIA.

This PDF file and other data are open for public consumption.

You can find these data in 'Match Facts' page of each match. (e.g., 'Match Facts' page of Farnce vs. Argentina, fifa.com)


Players and a ball always move in a match.

Activity time spent indicates time percentages of players' velocity zones.

Data

The following table is included in the bottom of 'Tracking Statistics' PDF file.

The red line in this table indicates Activity time spent.

Time percentages are against participation time.

As is written in the PDF file, 'zone' is velocity interval.

• 'zone 1' is from 0 km/h to 7 km/h.
• 'zone 2' is from 7 km/h to 15 km/h.
• 'zone 3' is from 15 km/h to 20 km/h.
• 'zone 4' is from 20 km/h to 25 km/h.
• 'zone 5' is faster than 25 km/h.

How to estimate Activity time spent

Here, simply introduced is how to estimate Activity time spent.

'Tracking data' is correction of 22 players' and a ball's position data per time.

Therefore, time difference of a player's positional coordinates is equal to the average velocity during a time.

Activity time spent is estimated from this velocity variation.


The following graph shows a simple example of a velocity variation.

A simple example of a velocity variation.

For example, a man standing (v=0) starts to run (the maximum velocity is vmax), and then stops (v=0).

On this velocity profile, arbitrary threshold velocities are set, here v1, v2, and v3.

If vmax is slower than v3, and  is faster than v2, the velocity profile is divided like below.

Times t2, t3, t4, and t5 divide the velocity profile into zone 1, 2, and 3.

Finally, one can obtain Activity time spent with simple estimations.

• In zone 1, it is ([t2 - t1] + [t6 - t5]) / (t6 - t1).
• In zone 2, it is ([t3 - t2] + [t5 - t4]) / (t6 - t1).
• In zone 3, it is (t4 - t3) / (t6 - t1).

Note that real velocity variation during a match is more complicated.