As I say, 2.5 seconds is clearly nonsense given the close proximity at corners, particularly given players often have specific marking assignments.
The 39 seconds average is interesting, and I suspect the arithmetic mean, with some players with relatively high times of contact offsetting others with very little close contact.
Regardless, I still think the bigger risk is a player becoming infected outside of the football bubble and then passing it on to some teammates.
(But I'm not suggesting curtailment is likely)
What I heard may have been in relation to training......but it was surrounding some data that had reduced the 3.3s ‘per incursion’ still further........agree the 39 will be an arithmetic mean.
https://www.independent.co.uk/sport...-distancing-statsports-research-a9515476.html
Using the data from 11 training sessions at four clubs between 25 February and 12 March, it was possible to measure a two-metre circle around players – dubbed the Subbuteo base by researchers – and precisely track how often it was encroached by teammates.
The main findings were that the average incursion lasts a mere 3.3 seconds, from an average of 350 incursions per session. Since that can be amplified by situations like set-piece drills, the majority of incursions last under one second. This is all considered lower than the threshold to contract coronavirus, particularly since it is outside.