Registered: Jul 2022
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Watching Hebert/Gallant sweep today has cemented that so many top teams are now turning their brush head to sweep lengthwise when sweeping for curl, different to how they sweep for distance.

Does anyone know why this is preferred? What is the science on this?

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Registered: Jun 2017
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Where have you seen this?

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Registered: Jul 2022
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For example, on this shot:
https://youtu.be/a4kndz8ttXQ?t=2658
Kennedy calls on Gallant to make it curl and he turns his broom sweeping with it pointing at the house instead of across the sheet. Same thing on this shot: https://youtu.be/a4kndz8ttXQ?t=3759
BJ does it on this one: https://youtu.be/a4kndz8ttXQ?t=4385

When they sweep for distance, they're pushing across the stone as we're used to seeing. Like this: https://youtu.be/a4kndz8ttXQ?t=6319

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Registered: Nov 2008
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I had to watch the video to see what you meant - I had interpreted your initial wording as referring to the brushing motion, rather than the orientation of the broomhead itself.

The broomhead is essentially a straight line. It appears that when sweeping for distance, they are keeping the broomheads perpendicular to the path of the stone. But when sweeping for curl, it appears they change the broomhead orientation to be parallel to the path.

As a very rudimentary illustration:
Distance: <<< | >>>
Curl: <<< --- >>>

I imagine the theory behind this has to do with the two ways in which sweeping impacts the stone - heating and scratching.

If you are sweeping for distance, you want to heat the path of the stone through friction. To do this, it is likely most helpful to maximize the surface area being impacted by the brushing, and therefore a perpendicular orientation would have the greatest impact. Conversely, a parallel orientation might have a more concentrated impact on a smaller area, but it might also fail to heat the entire path, and it might leave patches un-swept if the brush-rate can't keep up with the forward motion of the stone.

If you are sweeping for curl, you are trying to create micro-scratches on the surface of the ice. It was discovered about 7-8 years ago that a rock seems to follow these scratches as it travels along it's trajectory (especially with since-banned highly abrasive materials), so you can make a stone curl by scratching at an angle to the current trajectory.

Perhaps the theory of orienting the broomhead parallel to the path of the stone for curl (or rather, to the desired trajectory, or parallel to the vector most likely to achieve the desired alteration to the trajectory...sorry) is that it will create slightly longer scratches, or perhaps scratches that are more concentrated together and more likely to influence the stone's path.

The above assumes a basic understanding of directional sweeping (i.e. angle of brushing motion relative to path of stone), so I didn't elaborate on that aspect.

It's also pure speculation on my part. I'm not an elite player nor have I spent time researching sweeping. I could be completely wrong.

Last edited by bpm on 09-19-22 at 05:28AM

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