GRANDE PRAIRIE, Alta. - The Frankenbrooms have been banned from curling but the new sweeping technique they spawned has not.

It's common at the Canadian women's curling championship to hear a skip call one sweeper at a time on to a thrown stone while her counterpart slides alongside awaiting her turn.

The traditional tandem hasn't disappeared as plenty of light draws have required both women to furiously scrub together in front of a rock to drag it into the house.

There hasn't been enough time to test just how effective a single sweeper is with a "legal" broom using the new technique. That hasn't stopped teams from employing "directional sweeping" at the Scotties Tournament of Hearts.

"It works," Alberta third Amy Nixon stated. "There's no question there's results with directional sweeping.

"The question is the extent of it."

The briefest explanation is one sweeper enhances the rock's curl using a downward stroke with the broom, as the rock curls away from her. The other sweeper using the same downward stroke pushes opposite to the direction the rock is curling to keep it straight.

"It's a mild sandpaper effect that creates little scratches in the surface of the ice," Nixon explained. "Directional sweeping can work both to keep a rock straighter and to encourage a rock to curl a little bit more."

That technique with banned brooms altered stones' movements so dramatically the world's top teams refused to use those brooms even before they were outlawed by the World Curling Federation. The athletes feared their game of strategy and precision was becoming a sweeping contest.

A moratorium was declared on broomheads with "artificially-textured" fabric and hard inserts. Curling Canada subsequently limited the use of hair brush heads at this year's Scotties and Tim Hortons Brier because of the belief they score the ice with the same intensity as the banned brooms.

Directional sweeping's influence on a rock is definitely less with "legal" brooms, but still enough that curlers are continuing to use it.

"You think it makes the difference so you kind of have to go with your gut sometimes," said Jill Officer, who plays second for defending Canadian champion Jennifer Jones. "I can think of some shots for sure in the last couple of months that we've made because I think we've had the one sweeper versus the two."

Even though the theory now is two sweepers together counteract each other's efforts in terms of the stone's path, a double-team effort is still needed to keep a rock moving if it is thrown too light.

"You'd still use two sweepers if you need it for distance or speed, but you have to factor in the line on the specific shot too," Officer said. "If you're talking about an open draw to the eight foot, then yeah, two sweepers is still the best."

The WCF and by extension Curling Canada are expected to come up with more definitive rules about sweeping equipment this summer in the wake of the rapid change in broom technology.

But unless the governing bodies decide directional sweeping is not in the "spirit of the game", it is a significant change in the look of the sport.

"I think sweeping changes will stay. What those are I'm not sure yet," Jones said. "It will depend on what is decided with some of the equipment.

"In my view, we have to take measures on equipment versus sweeping style or sweeping mechanics."