A study of football referees has revealed they are the toughest people on the pitch.
Football referees take abuse in their stride
A psychological profile carried out by university researchers showed that they - not the players - are cool, confident, and have nerves of steel.
Dr Nick Neave, from Northumbria University, said only the strongest characters could survive the immense stresses of refereeing.
He found referees share similarities with policemen, military men and hard-nosed politicians.
A study of 42 experienced Unibond League referees showed they possessed or had
acquired powerful mental coping mechanisms.
Dr Neave said: "They are a very strong, robust, confident set of people who have developed a very strong set of coping mechanisms,"
"In psychological terms, they are very tough people."
They did not get nervous before games, were not concerned about sending players off or awarding penalties and took abuse in their stride.
While not immune to criticism, they seldom acknowledged being in the wrong.
Dr Neave carried out his research with sports psychologist Dr Sandy Wolfson.
'Shot to death'
They discovered that a football referee jogs about 10 kilometres in an average game.
Half the referees confessed to conflict between officiating at games and their jobs and family life.
But every one of them thought the time spent refereeing was worthwhile.
The biggest surprise came when the referees were asked about their reaction to abuse.
Dr Neave added: "Referees get punched, kicked, even shot to death by players, coaches, owners and fans.
"But they regarded abuse as being very, very low stress, which we hadn't expected."