Daniel sent us this one — he's been watching curling at the Winter Olympics, or trying to, and he's stuck on the brushing. The people who frantically sweep the ice while a forty-pound granite stone slides toward a target. He wants to know: are these sweepers specialists who only brush, or do they rotate with the person who throws? And the bigger question — if someone was dead set on becoming an elite-level curling brusher, what would their actual training day look like? I have to say, I've wondered the same thing. Curling is the only Olympic sport where the most visible athletic motion looks like someone trying to scrub a stubborn stain off a kitchen floor.
It's the only sport where the equipment is literally a broom. I mean, not a kitchen broom, but the lineage is direct — curling brooms were actual corn brooms until the nineteen-eighties, when synthetic brush heads took over. There's something deeply satisfying about a sport that hasn't fully shed its household-chore origins.
The athletic pinnacle of aggressive housekeeping.
So to answer the first question: no, there are no dedicated brushing specialists on a curling team. A team is four players — the lead, the second, the vice, and the skip. Every single one of them throws two stones per end, and when they're not throwing, they're sweeping. The lead throws first and sweeps for everyone else. The skip throws last and sweeps for the lead and second, then stands in the house calling strategy when the vice and skip stones are thrown. It's a fully rotating system. Everyone brushes, everyone throws.
The person doing the most intense sweeping in any given end is probably the lead, because they throw first and then spend the rest of the end sweeping for the other three players.
Right, and the lead is often chosen specifically for sweeping endurance. Teams absolutely factor that in. The lead and second are sometimes called the "front end," and their sweeping ability is a major selection criterion. They might throw lighter takeout weights less often, but they sweep constantly.
Which means if you want to be an elite brusher, you're actually training to be an elite curler who happens to specialize in the front-end role. There's no separate brushing track. You can't just show up and say "I'm here to sweep, put me in coach.
That's what makes the training question so interesting. Because brushing in elite curling is not just scrubbing hard. It's one of the most biomechanically specific motions in any sport, and the science behind it has gotten incredibly precise. I pulled some research on this. The brush head applies pressure and friction to the ice, which creates a thin film of water through something called the tribological effect — basically, the friction momentarily melts the ice surface. That water film reduces friction under the stone, which makes it travel farther and curl less. So a brusher isn't just cleaning debris. They're actively manipulating the physics of the shot.
Wait, so the sweeping is literally melting the ice in real time to change the stone's trajectory?
The temperature increase is tiny — we're talking fractions of a degree — but it's enough to create a micro-layer of water that alters the coefficient of friction. Competitive sweepers can make a stone travel three to four meters farther than an unswept stone, and they can significantly reduce the amount of curl. The difference between an elite-level sweep and an amateur sweep is enormous.
Three to four meters. That's the difference between landing perfectly in the button and sailing through the house entirely. So the brusher is essentially steering the stone after it's been thrown.
In real time, yeah. And the skip is reading the ice, watching the stone's speed and line, and yelling instructions — "hard," "clean," "whoa" meaning stop sweeping. The sweepers are the actuators. The skip is the guidance system. The thrower is the launch platform. It's a distributed control problem played out on ice.
The skip yelling at people with brooms. The most Canadian distributed control problem imaginable.
I mean, curling was invented in Scotland, but I'll allow it.
Let's get into the training day. Daniel's second question. What does a day in the life actually look like for someone training to be an elite front-end curler?
I found some fascinating material on this. The short answer is that elite curlers train like hybrid athletes — part strength and conditioning, part technical skill work, part strategy. But the sweeping-specific training is where it gets really specialized. Let me walk through a typical training day for someone at the national-team level, say, a lead on a Canadian or Swedish elite squad.
Walk me through it. I'm picturing someone waking up at five in the morning to sweep their driveway before breakfast.
Not far off, actually. A typical day starts around six thirty with a mobility session — dynamic stretching, foam rolling, hip openers. Sweeping puts enormous stress on the hips, the lower back, and the shoulders. The motion is asymmetrical — you're bent over with your body weight pressed through one arm on the broom, your hips rotated, pushing laterally down the ice. Do that for two and a half hours in a tournament game and your body needs to be prepared.
So you're essentially training to be lopsided in a very specific, controlled way.
You have to train both sides, because you sweep on both sides depending on which side of the stone you're on. In a game, two sweepers position themselves on either side of the stone's path — one on the left, one on the right. They're mirror images. So you have to be equally competent sweeping from both sides, which means training both sides equally. That's rare in sport — most athletes have a dominant side and they stick to it.
You're training ambidextrous sweeping. The phrase alone is worth the price of admission.
After mobility, they'll do a strength session — and this is not just general gym work. Elite sweepers do specific exercises that mimic the sweeping motion. One of the key tools is a slide board with a resistance band or a cable machine set at ice level. They'll get into sweeping position and do timed intervals pulling against resistance, exactly replicating the stroke pattern. The stroke rate in elite sweeping is about three to four strokes per second — that's roughly two hundred strokes per minute — and each stroke involves pressing your body weight down through the broom head while driving laterally with your legs.
Two hundred strokes a minute. That's faster than most people can drum a table.
The force is substantial. Studies using pressure sensors in broom heads have shown that elite male sweepers apply between forty and sixty kilograms of downward force per stroke. Elite women apply thirty-five to fifty kilograms. That's basically doing a one-armed plank while shuffling sideways at a sprint pace, for minutes at a time.
Forty to sixty kilograms. So you're pressing more than your body weight through one arm, repeatedly, while moving. This is starting to sound less like housekeeping and more like a very aggressive form of physical therapy rejection.
Heart rate data backs this up. During intense sweeping sequences — what they call "hard sweeping" for a long draw shot — heart rates hit one hundred seventy to one hundred eighty-five beats per minute. That's comparable to high-intensity interval training. These athletes are in serious cardiovascular condition.
After mobility and strength, what's next? On-ice work?
Mid-morning is usually on-ice technical work, and this is where the real art of sweeping comes in. They'll spend two to three hours on the ice. But here's what most people don't realize — they're not just sweeping stones over and over. Elite sweepers train with specific feedback tools. One of the most common is the "speed trap" — a laser timing system that measures stone velocity at multiple points down the sheet. The sweepers can see, in real time, exactly how many centimeters per second their sweeping is adding to the stone.
It's quantified. You can literally see the marginal gain from your sweep technique.
Down to the centimeter per second. And they'll do drills where the thrower deliberately throws the stone light — say, short by two meters — and the sweepers have to bring it into the house through sweeping alone. Or they'll throw with extra weight and the sweepers have to judge when to stop sweeping to let it die. It's incredibly nuanced. The difference between sweeping at ninety percent effort and one hundred percent effort might be the difference between the stone stopping six inches short or sliding perfectly onto the button.
The marginal gains obsession has reached curling. Every sport eventually gets Moneyball-ed.
Curling got Moneyball-ed about fifteen years ago, honestly. The Canadian teams were early adopters of sports science. But there's another layer to this — sweeping technique has been through a massive controversy and rules overhaul. I don't know if you remember the "broomgate" scandal?
That sounds like a scandal involving a negligent wizard.
It was around twenty fifteen, twenty sixteen. Certain brush heads — specifically the "icePad" from Hardline and some other directional fabric heads — were found to be so effective at altering the ice surface that they were essentially steering stones in ways that broke the game. Sweepers could make a stone curl more, not just less. They could drag a stone sideways. It was called "directional sweeping," and it created an existential crisis for the sport.
They could make the stone curl more? I thought sweeping always reduced curl.
That was the assumption for centuries. But directional fabric brushes — where the bristles or fabric have a nap that orients in one direction — could scratch the ice in a pattern that guided the stone in specific ways. A skilled sweeper could essentially steer the stone left or right by changing the angle and direction of their sweeping relative to the stone's path. It made the thrower almost irrelevant. The World Curling Federation stepped in and standardized brush head materials and fabrics. Now there are strict rules about what brush heads can be used in competition, and they're tested for "scratching" effect.
The training day has to include understanding the regulatory landscape of your broom. Imagine telling someone in eighteen fifty that their great-great-grandchildren would be arguing about the nap direction of synthetic fabric on a competitive ice-sweeping implement.
The regulatory landscape of broom technology. It's a real phrase I just said and I stand by it. So after the on-ice technical work, elite curlers will typically have a lunch break, then an afternoon session that's either more ice time or video analysis. The video work is huge. They'll review footage of their sweeping mechanics frame by frame — body position, broom angle, head position, weight transfer. The optimal sweeping technique involves keeping your head up to watch the stone while your body is nearly horizontal, broom head flat on the ice, weight stacked over the brush, driving from the legs. It's a motor pattern that takes years to ingrain.
Head up, body horizontal. The sloth posture. I feel seen.
You'd be a natural, Corn. The aerodynamic profile of a sloth is ideal for ice friction reduction.
I choose to take that as a compliment. So what about the mental side? A lot of this seems like it's about split-second decision making under physical duress.
That's the piece that separates good sweepers from great ones. The best front-end players are essentially real-time physicists. They're watching the stone, feeling the ice through their feet, listening to the skip's calls, and adjusting their sweeping pressure and speed moment by moment. They have to judge stone weight within the first second or two of the throw — is it heavy, is it light, is it on line — and then execute the sweeping plan. And they're doing this while their heart rate is at one seventy.
The training includes cognitive load under physical stress. Simulated game-pressure scenarios.
A common drill is the "sweeping decision drill." The coach or skip will call out random scenarios mid-sweep — "the stone is light, bring it four feet," or "it's curling too much, open side sweep" — and the sweepers have to adjust instantly. They'll also do fatigue-state decision drills, where they sweep hard for two minutes straight and then immediately have to make a precision weight judgment on a thrown stone. The drop-off in judgment accuracy under fatigue is measurable, and training is designed to shrink that gap.
The elite brusher is part strength athlete, part endurance athlete, part physicist, part real-time decision engine, and they do it all while bent over like they're looking for a contact lens on a frozen lake.
I haven't even mentioned nutrition and recovery. Elite curlers at the national team level work with sports dietitians. Tournament play is brutal — at the Olympics or world championships, you might play ten to twelve games over nine days, each game lasting two and a half to three hours. The sweeping load for a front-end player across a tournament is equivalent to doing several hours of high-intensity interval training every day for over a week. Caloric needs are enormous. Hydration is critical because you're working hard in a cold environment where you don't feel as thirsty. And recovery protocols — ice baths, compression therapy, massage — are standard.
Ice baths for ice athletes. There's a symmetry there I appreciate.
They're already on ice. Might as well just lie down on the sheet after the game.
Let me pull on something you mentioned earlier. You said the lead and second are the "front end" and they're selected partly for sweeping ability. What does selection actually look like at the elite level? If I'm a young curler who wants to make a national team as a front-end player, what's my path?
The path typically starts in junior curling — under twenty-one — and you're usually playing all positions to develop well-rounded skills. By the time you're competing at the national junior level, coaches are identifying players who have the physical attributes and the motor patterns for front-end roles. The key attributes they look for: high aerobic capacity, strong lower-body power, excellent body control and balance, and what they call "ice sense" — the ability to read ice conditions intuitively.
That's the thing you can't teach in a gym.
It's partly teachable and partly innate. Ice conditions change throughout a game. The pebble — those little bumps on the ice surface that the stone rides on — wears down. The ice temperature changes. Humidity in the arena affects friction. Great sweepers can feel these changes through their broom and through their feet, and they adjust their sweeping pressure and technique accordingly without being told.
Explain the pebble. I've heard the term but I don't think most people understand what it actually is.
Before every curling game, the ice technician — the icemaker — sprays a fine mist of water droplets onto the ice surface using a backpack-mounted sprayer or a specialized machine. These droplets freeze into tiny bumps, like an orange peel texture. That's the pebble. The curling stone doesn't slide on flat ice — it rides on top of these little frozen bumps, which reduces the contact surface area and allows the stone to travel farther. Without pebble, a stone would only slide about half as far.
The entire sport is dependent on someone walking up and down the ice with what is essentially a crop duster for frozen water droplets.
The pebble wears down as stones pass over it. By the end of a ten-end game, the ice surface is fundamentally different than it was at the start. The sweepers are adapting to changing conditions stone by stone. This is why you'll see teams sometimes use a different sweeping strategy in the early ends versus the late ends. The ice is a living surface.
A living surface maintained by a person with a backpack mister. This sport is absurd and I mean that as the highest compliment.
It's absurd in the best way. But back to the selection path — after juniors, if you're good enough, you'll get picked up by a competitive men's or women's team, often built around a skip who's recruiting. In Canada, which is the deepest curling nation, there's a whole pipeline — provincial championships, then the Brier for men or the Scotties for women, which are the national championships. The winners of those often represent Canada at the world championships. The Olympics are the pinnacle, but the Brier and the Scotties are enormous deals in Canada — they draw hundreds of thousands of viewers.
For a front-end player trying to make one of these teams, is there a combine? A curling combine where you demonstrate your sweeping prowess?
Not a formal combine like the NFL, but there are high-performance camps where athletes are tested. The testing includes VO2 max tests, sweeping force plate analysis, and on-ice performance metrics. They'll measure your sweeping effectiveness — how many meters you can add to a stone at maximum effort, how consistent your sweeping pressure is, your stroke rate, your communication skills. Some national programs use a standardized "sweeping efficiency score" that combines all these metrics.
A sweeping efficiency score. Your worth as a human distilled to a single number based on how well you scrub ice. I love it.
The number actually matters. The difference between an eighty-fifth-percentile sweeper and a ninety-fifth-percentile sweeper can be the difference between making an Olympic team and watching from home. At the twenty twenty-two Olympics in Beijing, the margin between gold and silver in several games came down to a single stone — literally centimeters of placement — where sweeping was the deciding factor.
You mentioned twenty twenty-two Beijing. What does the current competitive landscape look like? We're in the middle of an Olympic cycle.
The next Winter Olympics are in twenty thirty, which is a longer cycle because the twenty twenty-six Milano Cortina games were just a few months ago. Actually, wait — Milano Cortina was February of this year. So we just finished an Olympic cycle. I should check whether curling was part of those games. It was — curling has been in every Winter Olympics since Nagano in nineteen ninety-eight, and before that it was a demonstration sport and then in the early games.
We just had an Olympic curling tournament. I have to admit I didn't watch it.
I caught some of the semifinals. The level of sweeping was extraordinary. The Canadian men's team, their front end was putting on a clinic. The stroke rate, the body position, the communication — it was like watching a highly choreographed athletic performance that also happened to involve brooms.
Which brings me back to Daniel's core question. The training day. You've described the physical preparation, the on-ice technical work, the video analysis, the nutrition and recovery. What about the psychological training? You touched on decision-making under fatigue, but elite sport has a whole mental skills component now.
Sports psychology is huge in curling, maybe more than in many other sports, because curling has these long pauses between shots where your mind can spiral. You throw a stone, then you have several minutes while the other team throws. If you made a mistake, you have time to dwell on it. If you're sweeping, you have to stay locked in for two and a half hours with intermittent bursts of maximum physical effort. The mental skills training focuses on arousal control — bringing your heart rate down quickly after a sweep so you can think clearly for the next shot — and on what they call "process focus," which means thinking about your sweeping technique rather than the score or the stakes.
The polite sports psychology term for "don't panic and over-sweep the stone through the house.
And they train this with breathing techniques, visualization, and sometimes biofeedback. A curler might wear a heart rate monitor during practice and work on dropping their heart rate from one seventy to one twenty within thirty seconds of finishing a sweep. That's a trainable skill.
The elite brusher's training day ends with... Journaling about broom angles?
Honestly, probably a recovery session, a team meeting to review the day's data, and then dinner. Elite curlers aren't full-time athletes in the way NBA players are — many of them have jobs or are students. The funding in curling is modest compared to major sports. Even Olympic medalists often have day jobs. So the training day I described is an ideal training-camp day, maybe during a national team residency program. During the regular season, they're fitting this around work schedules — early morning gym sessions, evening ice time, weekends for competitions.
That almost makes it more impressive. These are people who train at an elite level while also holding down jobs, and their sport involves scrubbing ice with a broom while making sub-second physics calculations.
The sport has this beautiful democratic quality because of it. You don't need to be a genetic freak to play curling at a high level. You need skill, strategy, fitness, and thousands of hours of deliberate practice. But the physical baseline is accessible in a way that, say, basketball or downhill skiing is not. The best curler in the world could be five foot six or six foot four. It's one of the few sports where body type is genuinely not a limiting factor.
The everyperson's winter sport. Except for the part where you need access to a dedicated ice facility with a professional icemaker who understands pebble application.
It's not exactly pickup basketball. But compared to bobsled or ski jumping, the barrier to entry is a local curling club, and those exist in surprising places. There are curling clubs in Arizona, in Texas, in Israel actually — there's an ice rink in Metula that has curling.
I did not know that. Curling in the Middle East. The pebble must behave differently in that climate.
The ice technicians have to work harder to maintain consistent conditions when it's forty degrees Celsius outside. The humidity control is the real challenge — curling ice is extremely sensitive to ambient humidity. That's why elite curling arenas have sophisticated climate control systems.
Let me synthesize what we've covered for the listener who, like Daniel, has wondered about the brushers. There are no dedicated brushing specialists. Everyone on a four-person team throws and sweeps. The front-end players — the lead and second — are selected in part for their sweeping ability and endurance. An elite brusher's training day involves mobility work, strength training with sweeping-specific resistance exercises, on-ice technical work with laser timing feedback, video analysis of body mechanics, and mental skills training for decision-making under fatigue. They apply forty to sixty kilograms of downward force per stroke at two hundred strokes per minute while their heart rate hits one seventy to one eighty-five. They train both sides of their body equally. They learn to read ice conditions through their feet and their broom. And they do all of this knowing that the difference between gold and fourth place might be six inches of stone placement determined by the quality of their sweep.
That's a perfect summary. And I'd add one thing — the thing that makes curling uniquely compelling from a sports science perspective is that sweeping is one of the only actions in sport where an athlete can directly and continuously influence the outcome of a projectile after it's been released. In baseball, once the ball leaves the pitcher's hand, no teammate can alter its trajectory. In golf, once the ball is struck, it's gone. In curling, the stone is in flight for twenty to twenty-five seconds, and for that entire duration, two athletes are actively manipulating the playing surface to steer it. It's a real-time control loop that exists in almost no other sport.
The real-time control loop. That's the phrase that captures the whole thing. The brute physicality of scrubbing ice at maximum effort, combined with the cognitive demand of adjusting to a stone's speed and line in real time, is what makes it a genuine athletic discipline rather than a curiosity.
That's why the "curling isn't a real sport" take has always bothered me. The cardiovascular demands alone put it in the same category as rowing or cross-country skiing during intense sweeping sequences. The force production requirements are comparable to elite weightlifting for the specific muscle groups involved. The technical precision is on par with golf or archery. It's a composite athletic challenge that happens to look gentle on television.
Television is the problem. Curling on TV looks slow and peculiar. The camera angles don't capture the physical intensity. You can't see the sweat, you can't hear the breathing, you can't feel the vibration through the broom. It looks like people gently buffing a floor while a rock slides past.
The broadcast problem. I've thought about this. If you put a heart rate monitor graphic on curling broadcasts the way they do in Formula One with throttle and brake traces, people would understand immediately. Show the lead's heart rate spiking to one eighty during a hard sweep, then dropping to one twenty during the pause. Show the force trace on the broom head. Make the invisible visible.
The Formula One-ification of curling. "He's pressing fifty-eight kilos through the broom head, Martin, that's a personal best for this season.
I would watch that broadcast. Unironically, I would watch hours of that.
And that's the real answer to Daniel's question — the day in the life reveals that these are serious athletes doing something far more demanding than it appears. The training is systematic, quantified, and brutally physical. The fact that the implement is a broom is almost a misdirection.
The broom as camouflage. The athleticism hiding in plain sight behind a household object.
Which might be why curling has this persistent cultural status as the quirky Olympic sport. It's approachable. Everyone understands the basic concept — slide rock toward target. But the gap between "I could do that" and "I could do that at an Olympic level" is a canyon.
I think that gap is what makes it fascinating. Most people can't even imagine attempting a triple axel or a downhill ski run. They know those are impossible for them. Curling looks possible. It looks like something you could try at a corporate team-building event. And you could — that's the beauty of it. But the Olympic version is as remote from the recreational version as a Formula One car is from a Toyota Corolla.
The Toyota Corolla of winter sports. Reliable, accessible, slightly baffling to people who've never driven one.
I think we've thoroughly answered the prompt. No dedicated brushers, everyone rotates, the training day is a hybrid of strength, endurance, technique, and cognitive work, and the sport is far more athletically demanding than it appears on screen.
The broom is regulated by an international governing body. Never forget the broom regulations.
The World Curling Federation's brush head specifications. I have them bookmarked.
Of course you do.
They're interesting. The fabric has to be a specific type of nylon oxford weave. The foam backing has density requirements. There's a whole testing protocol involving a robotic arm that simulates sweeping while measuring ice surface alteration.
A robotic arm that simulates sweeping. The broom equivalent of a crash test dummy.
It's called the "SweeperBot" and it was developed at the University of Waterloo. It applies consistent pressure and stroke rate so they can test different brush heads under controlled conditions. The fact that this exists brings me joy.
The University of Waterloo built a sweeping robot to settle broom arguments. The most Canadian sentence ever uttered.
I believe the National Research Council of Canada was also involved. It was a whole government-academic partnership. Taxpayer dollars went toward determining whether a particular fabric weave was giving certain teams an unfair advantage in ice scrubbing.
Money well spent. I mean that without irony. If you're going to have a national sport, you should have a national sport science infrastructure to support it.
The Canadians take this seriously. Curling is part of their cultural identity in a way that's hard to overstate. The Brier final draws over a million viewers. That's comparable to a major league baseball playoff game in the US, adjusted for population.
The context for Daniel's question is that he's looking at a sport that, in some countries, is a cultural institution with a full athletic development pipeline, and in other countries is a curiosity that shows up on TV every four years and confuses everyone.
The answer is that the people doing the brushing are elite athletes who've spent years in that pipeline, training in ways that are highly specific and scientifically optimized. They're not just the people who didn't make the cut as throwers. They're specialists in a skill that looks simple and is anything but.
The skill that looks simple and is anything but. That's the epitaph for this episode.
Should we do the fun fact before we wrap?
Let's do it. And now: Hilbert's daily fun fact.
Hilbert: In early medieval Greenland, Norse settlers carved small, detailed butterfly shapes from walrus ivory, but they had never seen a butterfly — Greenland has no native butterfly species. The carvings were based entirely on oral descriptions passed down from traders who had visited continental Europe, making them a rare example of art created from secondhand ecological knowledge.
Art from hearsay. I respect the commitment.
To wrap this up — I think the thing I'll take away from this conversation is that curling is a sport that rewards attention. The more you understand what's happening in those twenty-five seconds of stone travel, the more impressive it becomes. The brushers aren't support staff. They're active participants in a real-time physics manipulation that requires elite fitness, technical precision, and years of dedicated training.
If anyone listening wants to become an elite brusher, find your local curling club, start as a lead, and prepare to spend a lot of time bent over with your heart rate at one seventy. The path exists. It's just very, very demanding.
Your broom must comply with World Curling Federation specifications.
Thanks to Hilbert Flumingtop for producing, and thanks to everyone listening.
This has been My Weird Prompts. If you enjoyed this episode, leave us a review wherever you get your podcasts — it helps. We'll be back soon with more questions you didn't know you needed answered.
See you next time.
