London, Ont. study reveals science behind curling's 2015 'Frankenbroom' ban

A Western University study suggests the so-called 'Frankenbrooms' banned by the World Curling Federation in 2015 may leave scratches in the ice that are up to four times deeper than their legal counterparts. 

The study results confirm what many believed to be true in the first place, that the high tech "directional fabric" in the broom heads may give sweepers the unprecedented ability to manipulate the rock's trajectory in ways they wouldn't be able to do with a regular broom. 

At least 50 of the world's top curlers signed a joint statement in October of 2015, saying they would not use the controversial brush heads, believing the technology would diminish the sport's integrity by lowering the throwing accuracy and athleticism required to play the sport. 

Megan Balsdon, a PhD researcher in Western's faculty of engineering and an avid curler since the age of eight, said the results of the study now lend evidence to what many leading voices in the sport suspected all along, that the sandpaper-like effect of the high tech brush against the ice can influence the game. 

"We found that what most people believed to be true was true. The illegal broom heads were leaving scratches in the ice surface," she said. "Upwards of four times higher than the legal fabric."

"The illegal broom heads would, depending on which direction you were sweeping, help steer the rock in that direction."

"It didn't necessarily affect the spin of the rock, but the direction of the rock. We didn't look at exactly the output of the rock itself, just the ice surface, what the fabric was doing to the ice surface."

Balsdon said the way they measured the difference was by using dental impression materials to take an imprint of the ice surface after being scoured by one of the brushes. 

"You can't really take a chunk of ice and put it in the microscope. So that's how we did it," she said. "We basically replicated the microscopic element of the ice and then looked at that in the microscope." 

The surface was then scanned by a piece of technology called an optical profiler, which was used to scan the depths of the marks left by the brooms. 

Balsdon said while the study does confirm the outlawed brooms were leaving deeper scratches in the ice than their traditional counterparts, further research is needed to understand how big of a difference those scratches make in how a team performs on the ice. 

"I think this research in conjunction with some future studies on how the actual output of the rock will just give us a little more insight so we can compare the actual scratches to the actual output of the rock."