CALGARY - An unprecedented leap in sweeping technology threatens to dramatically change the sport of curling.

While they wait for their sport's governing bodies to catch up and impose new rules, some of the world's top curling teams say they won't use broomheads that can actually slow down, and change the direction of, a rock in motion.

It's an awkward position to take for the teams who are sponsored by the very equipment manufacturers who produce the controversial brushes.

But Olympic gold medallists Brad Jacobs and Brad Gushue and former world champion Glenn Howard are among 22 domestic and international teams who signed a statement stating they will not sweep with brooms that have "directional fabric."

"Where do you draw the line?" Jacobs asked. "We've decided as a group of players to draw the line right now. It's about the integrity of the game and the hard work of teams."

When a new gadget fundamentally alters a sport, the powers that be often step in and declare it illegal in competition. Curling's top teams aren't waiting for the World Curling Federation or Curling Canada and are policing themselves. They hope other teams follow suit.

The curler throwing the rock aims for the skip's broom with the knowledge the stone will curl as it approaches the house.

Powerful sweepers can "hold" the stone and delay its curl or "drag" it extra distance into the house, but throwing accuracy and the skip's line calling are still paramount in the game.

New brushes hitting the market recently changed all that.

"It's a type of fabric that allows you to virtually steer the rock," Howard said. "I use the phrase 'joystick'. I can now joystick right, left, forward, back.

"Up until 18 months ago, it was 80 per cent shooter, 20 per cent sweeping and now in the last year and a half, it's become 20 per cent shooting and 80 per cent sweeping. It's just not acceptable.

"The problem is there's no rule against it right now. It's not as if you're cheating. It just doesn't seem right."

Coarse material on the broomheads creates a sandpaper effect on the ice. Jacobs describes it as "flattening" while others have described it as "scoring" or "scratching" the ice.

The bottom line is sweepers use the brush's impact on the ice to manipulate the rock in ways they never could before. As in any sport, if others are doing it and winning, you will do it too.

"When you see it, there's no second-guessing that something fairly dramatic or fairly extreme is occurring that in the right hands can cause a rock to curl much more than it would have normally, or to curl much less than it would have normally," explained Curling Canada's high-performance director Gerry Peckham.

"It's like having a rock with a steering wheel on it and you can pretty much get it to go where you want to or influence it substantially."

Curling equipment companies have been pushing the envelope on directional fabric. It came to a head this past week at the StuSells Toronto Tankard.

"It's not something I believed or my team believed until we saw it," Jacobs said. "It's quite incredible what has happened here. It's negating the purpose of having two sweepers on any kind of shot."

Gushue's team began using brooms with directional fabric this season "because we had an absolutely horrible record against teams using this equipment last year and we felt we were at a competitive disadvantage," he said.

Teams using the latest version of the broomhead caused the ice to deteriorate in Toronto and ruined subsequent shots, the skip said.

"It's really become . . . a pissing match between the companies to see who can come out with a sharper broom or one that has more impact. Where do we stop?" Gushue said.

"We need to draw a line in the sand and at least give the equipment companies an idea of the ballpark they're playing in. Right now they have an open canvas. They can make whatever they want."

There have been several broom technology advances since curlers put down straw and cloth brooms and picked up brushes 40 years ago, but none this dramatic, Peckham said.

He said Curling Canada, in conjunction with the WCF, will address the broom issue even if it means calling a moratorium on directional fabric until further study.

"Because the players have taken a position and made a statement, it will be much easier for associations to support the player movements," Peckham said.

"We will work with the World Curling Federation because there is some urgency here for all of us. There are events beginning to take place now that ultimately lead to a world championship."

News from © The Canadian Press, 2015