BUENOS AIRES (Reuters) - Argentine football is to use a quickly-vanishing spray in an attempt to stop defensive walls from creeping forward at free kicks.
Referees will pace the regulatory 9.15 metres between the ball and the nearest defender and then spray a white line on the pitch to mark the correct position of the wall.
The line then disappears from the pitch within a minute.
"This could help put an end to the practice of walls moving forward in football," said Pablo Silva, who has led the project to develop the product.
In a rare instance of new technology in the sport, the Argentina Football Association (AFA) agreed at an executive meeting on Wednesday night to use the equipment during next season's second division campaign.
Silva, a sports journalist who has worked with chemical engineers to develop the spray, said the idea came to him when he was foiled at a free kick during an amateur game.
"It started seven or eight years ago when I was playing in an championship played amongst former school members," he told Reuters.
"In the 88th minute, we were losing 1-0 and won a free kick on the edge of the area. When I took the kick, the wall was three metres away. The referee didn't book anyone and didn't do anything.
"We lost the game and driving home later, with a mixture of anger and bitterness, I thought that we must invent something to stop this."
He added: "We have observed more than 1,500 matches all over the world and we have studied how long it takes to take the free kick and how far the defensive wall moves forward.
"We have proved this is not just an Argentine problem, it happens everywhere."
"Hopefully, this can contribute to enforcing the current rules and improve the time that the ball is in play," he said.
Silva recalled a recent Boca Juniors game in which Juan Roman Riquelme needed 2-1/2 minutes to take a free kick because of arguing over the position of the wall.
He said the spray was different to a product that has been used in some competitions in Brazil in the last few years.
"We started work in 2000 and we didn't make it public," he said. "The Brazilian one appeared in 2002 and the substances are completely different. One has nothing to do with the other."
(Editing by Ken Ferris)