Football clubs with red team strips are more successful than those with other colours, according to a recent study
Red shirts give the team an advantage due to deep-rooted biological response to the colour. "In nature, red is often associated with male aggression and display," they said, giving the example of the red-breasted robin.
"It is a testosterone-driven signal of male quality, and its striking effect has even been harnessed by soldiers in the past," added the researchers, after analyzing data on English football league results since World War II.
They concentrated on home matches, because teams usually wear their main kit colour there. Curiously, the correlation between colour and success only happens when the teams are playing at home.
"The results were surprising," they said, citing significant differences in success levels between red, white, blue and yellow/orange teams. Red teams won more often, while teams wearing yellow or orange had the worst record.
Professor Robert Barton from Plymouth said there were two possible reasons: the first being that, over time supporters may have been subconsciously more attracted to a club wearing red.
"Secondly, there may be a positive psychological boost from wearing red, or being associated with a red team, that is reflected on the field of play.
Competing against a team in red could also impair performance," he said.
"It is certainly true that the influx of wealthy foreign owners has changed the resources available to some teams and this should result in increased success, regardless of their shirt colour," said Dr. Russell Hill.
"Nevertheless, in close matches where teams are evenly balanced, we still predict that wearing red could tip the balance between success and failure and the red advantage will still persist."
The research was carried out before the latest round of European Champions League matches, in which three red-shirted English teams -- Arsenal, Manchester United and Liverpool -- won through to the quarter finals.