Washington (AFP)

Even without spectators in the stadiums during the pandemic, European professional football teams playing at home continued to enjoy a substantial advantage over their opponents, according to a new study published on Wednesday.

The researchers took advantage of the exceptional conditions created by the Covid-19 - a life-size "experiment" - to study the phenomenon, one of the best known in sport.

"People generally think that the public is the main, or only, reason for the advantage of playing at home," lead study author Fabian Wunderlich of German Sport University told AFP. in Cologne.

But the effect of their absence "was less than expected".

The study, published in the scientific journal Plos One, however, concluded that the crowd did influence the refereeing.

The researchers compared more than 1,000 matches played without supporters with some 35,000 matches having been held with the public, before the pandemic.

Ten leagues were chosen from six countries - Spain, England, Italy, Germany, Portugal and Turkey - over the seasons ranging from 2010/11 to 2019/20.

The researchers were surprised to conclude that in the absence of spectators, a slight decrease in the home advantage was admittedly observable - calculated by the number of goals and points accumulated - but the difference was not statistically significant.

This means that researchers cannot say with certainty that this observed decline is not due to chance.

"Over the past 10 seasons, with home fans, home teams have won 45 out of 100 games, away teams 28 out of 100, and the other 27 were draws," said Fabian Wunderlich.

"During the pandemic, the home teams won 43 matches out of 100, those playing away 32, and there were draws in 25 cases out of 100," he added.

This decline is not sufficient to exclude the influence of a general trend of a reduction in the advantage of playing at home, observed over the last decades, according to the researcher.

Overall, he added, the study shed light on the role of other factors, such as the team's knowledge of where they are playing, as well as "territoriality" - increased hormonal stimulation. to defend its territory, very well documented in animals.

Travel fatigue plays a smaller role, according to Fabian Wunderlich.

Indeed, the researchers conducted a separate analysis comparing the performance before and during the pandemic of German amateur football teams, which usually play in the same city: they found an advantage for the home team that was comparable to that of the teams. professionals, who travel much further.

- Less pressure on referees -

Other indicators were effectively affected by the absence of the public.

Teams playing at home and without their fans showed a significant drop in the number of shots and shots on target.

One explanation could be that in the presence of supporters, they attempt more inconclusive shots.

In addition, in matches which took place with the public, home teams received fewer disciplinary sanctions compared to teams playing away.

This could be related to the pressure exerted by the public on the referees, who could use the noise of the crowd as an indicator of the seriousness of the fouls.

A phenomenon eliminated during the pandemic, teams playing outside being whistled for fewer fouls, and receiving fewer yellow or red cards.

According to the researcher, it could be useful to take this data into account, although it does not significantly influence the outcome of the matches.

"Since there is this bias on refereeing, the referees should be aware that it exists and perhaps it would be possible to train them more" to deal with it, he said.

© 2021 AFP