At the 2002 Winter Olympics in Salt Lake City, almost six million people1 in the UK watched Rhona Martin and her curling team win a gold medal for Team GB. The game itself is a mix of shuffleboard and bowls, but it is most often compared to chess. For once a curler slides the opening stone down the ice, so begins a compelling game of move and countermove where victory hinges putting your pieces into the perfect position.
A Championship curling match consists of 10 “ends,” where each team of four curlers alternate to slide their “stones” towards a “house” target, each player throwing two stones per end. Teams consist of a Lead, Second, Vice-Skip and Skip, and typically throw in that order—the Skip handling the strategic final throw and directing the overall strategy of the game. Only one team can score from each end, the winner based on the closest team’s stone to the center of the house, with an extra point for each additional scoring stone in the scoring rings.
In Search of a Competitive Edge
Chess can quickly become highly complex. For example, after both players have moved their first piece, there are 400 possible board setups2. This rises to 197,742 possibilities after each player has moved again, and 121 million after three moves. Curling can be similarly chaotic and hard to predict. It’s why British Curling now puts its faith in a data-driven coaching program that uses technology to give teams a competitive edge both strategically and technically.
It starts with data capture. British Curling films critical parts of the training its curlers undergo at the National Curling Academy (NCA) in Stirling, Scotland, as well as capture footage of teams in competition. Practitioners like Kenny More, a performance analyst with sportscotland institute of sport, then put in place a methodology to acquire data from that footage, defining seven or more attributes that can be attached to every shot.
“In curling parlance,” explains More, “we would say the ‘lead’ has played a ‘Left 8 foot,’ ‘clockwise draw’ to the ‘front of the house,’ with level of difficulty ‘2,’ scoring ‘three out of four,’ because it was ‘light’.” This translates to a shot by the player who throws the first two stones for a team, aimed at the left side of the 8-foot circle (the second largest of the four circles on the ice), in which the handle of the stone is rotated clockwise. It should finish in play without hitting another stone, within the front half of the target (aka “house”). But in this case, the shot merited 3 points out of 4, as it was marginally short of its target.
Playing the Percentages to Win
Logging this data, the performance analysts can subsequently turn it into a match report, which can then be turned into a more useful metric. “You turn those 1 out of fours, 3 out of fours, 4 out of fours into a playing percentage,” adds Kenny More. “So, at the end of the game, you’ve played 20 stones and when you accumulate those 20 stones, [the player] might be shooting at 82% for the game. That immediately resonates with us because we know at what level you need to be playing to be on the podium.”
Coaches will collectively upload data on approximately 750 games during the course of a typical season, with 400 of those games having supporting video. All of this data is ultimately stored in the British Curling Performance Archive, an online database underpinned by Intel® Xeon® processors powering the cloud. This “experience bank” is a rich source of data for Scotland/Team GB competitive play, opposition scouting, and strategic planning, both post-match and in-game.
“We’ve also created a predictive model called ‘game state probabilities’,” says More. “This has taken all the data we've acquired in the most recent past and put it into a machine learning [environment] to create a predictive model.” This enables coaches to look at any game-score scenario and see, from the historical data, the tactical decisions that will give us the best percentage chance of winning.
“In a certain game state,” continues More, “we might have a 65% chance of winning. We can look at the data and say: if we score a one [at this end], what does that chance become? If we score a two, what does it become? The game state probabilities allow a coach to say: guys, a one here will do. Or we can go really aggressive, saying that: a three here is essential.”
Strategy Is Useless Without Consistency
Like chess, picking the right strategy is all important. But there’s a caveat. “However good your strategy is,” says Nigel Holl, Executive Performance Director British Curling, “it’s only good if the players can put a stone where you ask them to put it. So, if I'm calling the strategy, I might say: ‘I need you to put a stone right here, by drawing it round behind that one.’ And it's got to stop exactly in the right place. If you can't do that, my strategy goes out the window. And for a player to deliver that shot, we need consistency of delivery.”
So, the guiding philosophy of the current coaching team at British Curling is consistency. “We're trying to produce curlers that can consistently produce line and weight appropriate to the task, without thought to the underlying mechanics [of shot making].” Says Kenny More. “This is where performance analysis comes in. We are trying to produce curlers who are tactically astute, so we analyze everything. In the past, we’d move coffee cups and salt cellars around the table and go: ‘do you remember, our stone was there, and they put it here.’ Now we can horseshoe around the data projector, with video of the game, and go: that's exactly what it looked like.”
British Curling’s access to shot making data is used to understand player development and the scouting of opposition for game tactics. Score line analysis, meanwhile, delivers tactical insights, keeping coaches attuned with how well the team is performing. This knowledge also shapes the development priorities for coaching, while the game state probabilities act as an in-game decision making tool that helps guide strategy and tactics.
The whole performance analysis workflow relies on laptops, tablets, and an online performance databank powered by the latest Intel® Core™ processor and Intel Xeon processor technologies. “Intel Xeon produces the unseen power behind the data acquisition and processing parts of the approach that we have developed on behalf of British Curling,” says Kenny More. With its performance archive data instantly available via Intel Xeon processors powering the cloud, coaches and curlers now have unparalleled access to a wealth of video information and statistical insights, anywhere and anytime they need it.