Brushing
A brush is not a rock magnet
A brushing tactic I continue to see being used by younger teams is to brush the ice adjacent to the stone when trying to ‘carve’ or accentuate curl. I’m not sure where this tactic began, but there is no point in brushing ice that the running band of the stone will not pass over as the stone continues its trajectory. Brushing to increase curl requires brushing ‘high-side’ (in the direction of the stone’s rotation). Precisely where the stroke begins and ends for optimal effect depends on a number of factors, the most important being the velocity of the stone and the force profile of the athlete(s) doing the brushing. But there are several other variables that may play a role, including the roughness of the stone’s running bands, the ice conditions, and environmental factors (temperature, humidity, dew point) to name just a few. These variables are not completely understood, and we know from testing – at different clubs with various
Foamgate, existing, and forthcoming research
At this point, many competitive curlers in Canada should be familiar with the recent announcement from World Curling about the withdrawal of specific foams in a small selection of brushes from World Curling’s approved equipment list for competitive play for the upcoming 2025 – 2026 season. World Curling came to their decision based on the outcome of brush testing in Morris, Manitoba during the Victoria Day weekend, along with feedback from the researchers on World Curling’s equipment advisory group, of which I am a member. To a significant extent, World Curling really didn’t have a choice but to try to address the concerns first brought to their attention with the players’ manifesto that was put together just prior to the Grand Slam event in Guelph this past January at the WFG Masters. The players who signed onto the manifesto were concerned that the brushes approved for competitive play this past season were too good: either they permitted additional carry above reasonable
We are getting closer to understanding the physics of curling
Last year, 2024, marked the 100th anniversary of the first scientific article that I’m aware of that investigated the physics behind the sport of curling; a 1924 paper [5] by E. L. Harrington and his colleagues in the College of Engineering of the University of Saskatchewan in Saskatoon. In the 100 years since Harrington’s work, scientists and engineers have investigated various aspects of the sport, but our understanding of one of the sport’s singular fundamentals – why does a curling stone “curl” – remains incomplete, if not vague. There have been dozens of articles, authored by scientists and engineers from Canada, Sweden, Finland, China, Japan, and Korea, that have investigated the question of why stones curl the way they do, frequently contradicting each other’s mathematical models and none of them fully explaining all of a stone’s observed behaviours. At the same time, there are other aspects of the sport, particularly surrounding brushing, that have not been studied extensively and remain
Curling brushes – Try before you buy – Part Quatre
This article is joint work with Dr. John Newhook of Dalhousie University. This past weekend featured Provincial men’s and women’s championships in most of the Canadian provinces, and what was interesting to me was the number of teams who switched to Balance Plus brush heads for their respective territorial championships. As one example, Saskatchewan hosted the combined men’s and women’s provincial championships in Kindersley. All four of the teams in the men’s and women’s CURLSASK finals are regularly Hardline users (if not sponsored by the company). However, during Provincials two of the teams – Steve Laycock on the men’s side, and Nancy Martin on the women’s side – switched to using Balance Plus RS or RS XL brush heads with prismatic Hardline Hybrid handles. This situation was the reverse of a number of instances last season that saw teams (Kaitlyn Lawes in particular) use Balance Plus LiteSpeed handles with an IcePad brush head. While we are some ways away from
Curling brushes – Try before you buy – Part Trois
This article is joint work with Dr. John Newhook of Dalhousie University. In earlier articles, we documented the mass of commercial brush heads and in addition documented that today’s commercial brush heads distribute pressure across the brush pad in very different ways. In parts 1 and 2 of this article on “Try before you buy”, we argued that brush handle characteristics do matter and, in the second part, presented measurements of various commercial handles with respect to handle diameter. In this, the third part of “Try before you buy”, we present measurements of another important characteristic of brush handles: flex, or more properly their bending moment, or flexural rigidity. As curling equipment manufacturers continue to offer lighter-weight products, athletes may discover that there are significant differences amongst the various commercial offerings of handles in roughly two dimensions: weight and flex, in much the same way that today’s hockey sticks come in a variety of “flex” degrees as do tennis or
Should I brush faster? Stroke rate, displacement, and vertical force
This article is joint work with Dr. John Newhook, professor and Dean of Engineering at Dalhousie University in Halifax. Over the past year we have been asked numerous times by athletes and coaches alike if they should brush faster – that is, with a higher stroke rate – than what they are doing currently, with the underlying assumption that brushing more quickly will lead to improved brushing performance. A possible reason for these questions is the success of several of the women’s teams from Asia over the past few seasons, who from observation do brush a bit more quickly than their typical Canadian competitors. However, as with many things brushing any answer is dependent on a number of variables and trade-offs, and in no small way is also dependent on the force profile(s) of the particular players. In this article, we’ll take a look at the science in the available literature, coupled with our own experiences, and try to supply