How much does testosterone improve performance?

Two doctors from the University of Northumbria found in tests that footballers' level of testosterone went up "significantly" when they were playing on home territory.

Dr Sandy Wolfson and Dr Nick Neave tested the testosterone levels of footballers for a Unibond Premier League team before they played in training, at home and at away matches.

The players' level of the hormone was much higher prior to home matches.

The same tests were carried out on the under-19 squad of a Premiership team this time with matches against bitter rivals compared with clashes with against moderate rivals.

Not surprisingly testosterone levels were "hugely inflated" when the players were battling their bitter rivals.

Animals tend to fight harder when they are defending territory and our study suggests this could well be the same with humans

Dr Nick Neave

The home advantage is a well-known theory in football, with factors such as crowd support and familiarity with the ground put forward as key reasons.

But Dr Neave said their new study has prompted new interest in testosterone.

Dramatic change

"The teams were very interested in the results and what they really wanted to know is how much the level of testosterone could affect performance and what would be the optimum level," he said.

The researchers themselves suggest high levels could - as in the animal kingdom - be linked to a territorial factor.

Dr Neave said: "Animals tend to fight harder when they are defending territory and it our study suggests this could well be the same with humans."

Interestingly, levels of testosterone between the different matches changed most dramatically with the goalkeeper - whose role is most closely linked with the concept of defending territory.

Aggressive behaviour may be linked to early life events

Dr Neave said teams were also interested in the level of aggression which surged in players and whether the number of times a player was sent off had a link with his testosterone level.

But he added: "The link between testosterone and aggression is still hazy."

The question of why a person becomes aggressive was the basis of another study presented at the conference in Blackpool.

Professor John Archer from the University of Central Lancashire challenged the notion that aggression in males was linked to increases in testosterone at puberty.

The professor looked at a range of studies in adult males and said his data showed that the level of aggression did not rise in parallel with an increase in testosterone.

Instead the professor suggests "processes" which arise early in life have more of an effect on why men are more aggressive than women.

Boys tend to play with other boys when they are young, so the aggression influence can be passed between them

Prof John Archer

He said: "It's my guess that boys could be subjected to testosterone before birth."

Then the aggressive streak can be enlarged by boys grouping together and drawing out this characteristic, he said.

"Boys tend to play with other boys when they are young, so the aggression influence can be passed between them," he said.

If boys mix with combative groups - the junior version of gangs - this aggressive streak can be even more pronounced, he added.

Behaviour disorders

As for the football connection, Professor Archer said the testosterone rise was not just confined to the players.

"There was a test done fairly recently after one of the World Cups which showed fans' testosterone level went up after their team won and down if they lost," he said.

Professor Archer presented his data at the conference on Saturday.

His view was given further backing by Dr Stephanie van Goozen from the University of Cambridge and University of Utrecht in the Netherlands.

She examined studies of aggressive behaviour in children with a range of conduct and anti-social behaviour disorders.

Her findings she said suggested "that the impact of adverse early life experiences may explain levels of severe aggression in adulthood".