Caffeine could give more kick to rugby stars

The New Zealand Rugby Union is looking at research promoting caffeine as a performance-enhancing stimulant for top rugby players.

The Auckland University of Technology study found caffeine in its pure form can make players more alert, reduce the impact of fatigue - and even increase their accuracy with basic skills like passing.

The tests - carried out on eight club rugby players - also found the combination of caffeine and exercise increased testosterone levels by around 60 per cent.

The main function of testosterone is to build and repair muscle. The male hormone can also increase aggression.

Caffeine, administered in these trials in capsule form, is a legal stimulant.

The findings have been given to the NZRU which says while they are "interesting", more detailed research would be needed before caffeine was administered to the game's elite.

Union spokesman Ken Quarrie said the union would need to fully examine the research before making any recommendations. "Other questions need to be addressed. Can caffeine make a player's focus too narrow, or make them jittery?"

AUT professor Will Hopkins said pure caffeine, rather than the diluted version used in coffee, had significant performance-enhancing qualities, especially in explosive team sports like rugby.

"The biggest surprise was passing at a target. And in sprints we were getting improvements of a few per cent," he said.

- HERALD ON SUNDAY