Sweep Me Off My Feet!
March 3, 2006 Revised Feb. 2013
This is another article that has undergone some huge revisions. Again, a major reason for this is that the technology around sweeping has changed so much since 2006 and I wanted to make sure this information was current.
One reason I had to start skipping was my severe allergy to sweeping. I break out in hives and itch all over anytime I need to sweep… Honestly, I don’t hate it that much, my team just thinks I do. There is actually something very satisfying about carrying a shot into the perfect position with a big brush. It can be as satisfying as actually throwing the shot and two sweepers working together can be almost artistic. Brushes aren’t quite as stirring as a pair of corn brooms pounding the pebble but there is still a lot of beauty in it. Brushing partners are constantly in motion, very close to moving stones and must be coordinated and in sync with each other. Perhaps the most celebrated duo of recent times is Be Hebert and Marc Kennedy from the Kevin Martin team. These gentlemen set a new standard for sweeping excellence and demonstrate clearly what good sweeping looks like. They personally are the epitome of fitness and show why fitness matters in curling.
What does sweeping actually do? These days I suppose, the term should be “brushing”, not “sweeping”. I’m a hold over from the old corn broom days and use the two terms equally. What really happens when you sweep remains the “black art” of curling. That is, there has been little conclusive scientific proof of what a curling brush accomplishes. A major study on sweeping was completed for the 2010 Vancouver Olympics and a huge amount was learned about the process however, there was nothing conclusively proven with respect to what was actually happening to the ice. The general belief is that the friction between the broom and the ice creates a very thin layer of water in the slide path. That thin layer of water acts as a lubricant beneath the stone as it travels down the ice. Because the water is very thin it re-freezes quite quickly. This “melt / freeze” effect is practically impossible to measure and so the true impact of sweeping has never been determined. The Scots have apparently developed a broom with sensors in it that measure a variety of factors including the force applied to the brush head however, this still doesn’t tell us anything about what happens to the ice.
Sweeping also reduces the amount a rock curls. How much can you really reduce the curl? That depends on many things including ice conditions, sweeping ability, stones, amount of rotation on the stone… Here’s an interesting question for you. If you have a fall in the ice (a spot where the rock moves in the opposite direction to the rotation) will sweeping make it fall more, or will it make it fall less? Typically, sweeping will increase the amount of fall. Sweeping also removes debris from in front of a traveling stone. It specifically does not intentionally leave debris on the ice. That’s actually in the rule book. If you have the bad habit of waving your brush in front of the stone while you’re sweeping then you may do this by accident. That’s my gentle way of saying, “keep your broom away from the front of the rock unless it’s on the ice”. Some times you’ll hear a skip yell “Clean”. This means they want you to keep the broom moving in front of the stone to keep debris out of the running path and to stay ready to sweep. Just dragging the broom down the slide path isn’t good either. Junk can build up on the brush head and fall off as you travel down the ice. Keep the broom moving or keep it out of the way. All players need to know what brushing actually does so that they can use it effectively. There are a lot of misconceptions about this. Probably the biggest is how much of an effect you can have. . It’s generally accepted however that world class sweeping on world class ice down the whole length of a sheet can likely take a rock up to 20 feet further than no sweeping at all. That’s world class, not club curling. Club curlers should be happy to get maybe 5 or 6 feet of extra distance. Think about that, 6 feet is the distance from the top of the house to the tee line. It’s likely not as far as you thought and it’s likely you don’t believe me. As for how much curl you can take out of a shot, well, that depends on such a great many factors that there is no true standard for this. A good team will know how well they can hold a line but ice conditions play such an important factor in this that it’s pretty much impossible set any sort of standard.
What can’t sweeping do? Sweeping doesn’t speed up a rock. If I had a nickel for every new curler that asked me if sweeping speeds up a rock, then, well, I’d have a lot of nickels! If you could speed up a rock by simply sweeping it then we could harness that energy and get rid of our dependence on oil. Also, if you could speed up a rock with sweeping then you could turn a guard shot into a take out with enough work. Obviously you can’t do that. By reducing the friction under the rock, sweeping can make the rock slow down slower. I know that sounds odd but it is not the same as speeding up. The instant you let go of the rock it is starting to slow down. The rock is slowing down because of the friction between it and the ice. There isn’t much friction but it’s enough to eventually stop the rock. Sweeping reduces the friction so the rock doesn’t slow down as fast. If that’s still confusing then think of it this way. Sweeping can make a rock travel father than it would with no sweeping.
It’s enough to say that sweeping gives you some control over shots; it’s up to teams to understand how much of an effect they can have. Good sweeping technique will help you increase that effect and two sweepers will have more of an impact than one sweeper. You might be tempted then to think that three sweepers would be even more effective. This is NOT the case. One thing that did conclusively come out of the sweeping study was that the third sweeper does nothing to improve the distance the rock will travel. In fact, the study showed that the second sweeper was only about 65% as effective as the sweeper closest to the stone! This is a huge revelation. The only time that a third sweeper has any effect therefore is when one of the original two sweepers drops out completely and lets the fresh body take over. For the most part however, skips should stay in the house because the disruption that the switch causes really negates any positive effect of having a new sweeper on the stone.
Remember, those two are in sync. They’re in a comfortable position and suddenly “Skippy” comes out and gets in the way. Also, if the skip is sweeping then no one is watching the line. The odd time you don’t need someone watching line but most times that’s critical. The ice melts during sweeping because of a combination of pressure and friction from the broom head. It follows then that the broom head is a pretty important surface. Another huge finding from the sweeping study was that the old style broom heads would “bleed” about 40% of the heat generated up the shaft of the brush. This is where the “EQ” head was born. Essentially there is a piece of reflective foil between the plastic head and the foam in your broom so it reflects that generated heat back onto the brushing surface. There are some other differences in the EQ head as well. The sweeping study found that wet broom heads were significantly less effective than dry heads so, the new EQ heads have a much more water resistant fabric on the brushing surface.
Now, it’s not all in the tools. As a brusher, you still have to remember that technique matters! Your technique should create as much friction and pressure in front of the rock as possible. Remember, IN FRONT OF THE ROCK. I’ve seen way too many people sweeping their brains out six inches off to the side of the rock. You may as well sweep behind the bloody thing if you’re not in the slide path. (Oh, and no, sweeping behind a rock won’t slow it down…) To create pressure on the broom head is a simple matter of putting as much force on it as you can. The easiest way to do this is to use the weight of your body. Sweepers hands should be about ¼ of the way from the end and about a foot apart. The top portion of the shaft should be tucked under your arm close to your body and it should stay there as you sweep. There are findings with respect to technique as well but for now, lets work on the standard sweeping method. I’ll try to describe the higher level sweeping techniques in a newer article.
Ideally, you will be wearing two grippers when sweeping so you can use your legs to push your body weight down on the broom. This is most easily done by using a “hop step” to propel yourself down the ice. Many people don’t use two grippers when sweeping however and they try to use heir arms to push down on the broom. This is simply more work than you have to do. Why not lean on that broom and use gravity? Believe me, you’ll be able to sweep longer and harder if you let your body do the work. To create friction the broom head has to be moving. I’ve seen sweepers who simply lean on the broom and slide down the ice thinking they are doing a great job. They’re doing half of a great job and they could be doing a lot more by moving that brush head a little. The head of the brush should move across the front of the rock and really no more. There is nothing to be gained by brushing a big wide path across the stone. Remember, the stone runs on a fairly small little circle on the bottom. Sweeping more than that width is really a waste of effort. A sweeper needs to communicate with the person holding the stick. This means, they need to give the broom holder some idea of what weight the rock has. In order to call line accurately skips have to have this information. We skips may believe that we can accurately judge weight from the house but the reality is that sweepers are in a much better position to do this. The person in the house should never call sweeping for weight unless the sweepers have severely misjudged the shot. It’s up to the sweepers to judge weight and act accordingly. Alternatively, sweepers should never try to call line. It’s tempting when you can see a rock closing in on the center line but trust the call coming from the house. It’s the skips / vices job to make this call and as a sweeper you don’t have the best look at the stones in play. You can’t see the plan B shots (alternatives to the called shot) and you don’t have as good a perspective as you may think. Stick to your job and let the person in the house do theirs. You can bark at your vice (your skip would NEVER get it wrong) later for making the wrong call…
Other tips on sweeping include, “looking up”. I know you’re trying to judge weight and you can’t do that if you’re not looking at the rock but remember your skip may be trying to get your attention. Also, as you get close to the house you need to look out for stationary stones already in play so you don’t trip and kill yourself. Another big sweeping tip is, “breathe”. Yes, I know, silly but it’s not actually. Next time you have to sweep a stone all the way down the sheet, think about this. Did you breathe all the way down? Too many people forget to do this. I once played with a fellow who swept very hard and always forgot to breathe. He would regularly get a nose bleed at some point during the game. If you think a hair affects the running path of a curling stone you should see what a sticky drop of blood does. Besides, no one wants you passing out while sweeping…you might burn the stone…
A previous article covered the different sweeping devices out there (are they brooms or brushes??) but it bears a little repetition. The most common sweeping device in use today is indeed a brush. Some brush heads have a synthetic head and others still have the hair bristles. Many competitive teams have a couple of different brooms for different conditions. The hair brushes are more effective on frosty ice because the hair can get down between the pebble much better. Still, teams rarely use hair brooms by themselves. It’s much more common to see a synthetic head close to the rock and a hair broom further out. This is prevention against loose hairs dislodging and getting caught under stones. Brooms can get pretty fancy (read that as expensive) these days with carbon fiber shafts and heads that adjust to different positions. Like any other piece of equipment you should find one that you can use most effectively. The recent innovations in brush technology are pretty impressive actually but if you don’t feel comfortable using a certain brush then who cares how much it cost? You should take good care of your sweeping equipment. Face it, you use the brush to keep debris from getting caught under the stone, you don’t want it to be the source of debris! For hair brooms, this mostly means keeping an eye out for loose hairs. They can be gently removed individually. Hair bristles are held in place with a drop of glue in small holes in the broom head. The bristles are actually in small clusters so if you jerk out a loose hair, you risk pulling out a whole cluster or at least loosening a larger bunch. When you start losing hairs repeatedly you need to replace the broom head (there’s a joke in there about bald people but I’ll refrain…). Every once in a while you should brush out the hairs with a fork as a way to get rid of debris and remove loose hairs. The synthetic brooms (non EQ heads!) are somewhat easier to keep in shape. They should be regularly cleaned to keep stuff from clinging to it. This is something you should do even during the game (but please, clean your brush over a garbage can and not over your opponents stones….). After a while the brush head will start to get shiny as it wears. When this happens you really need a good cleaning. The heads can be removed and cleaned in your dishwasher (no I’m not kidding…). Place the head of your brush face down on the top shelf of your dishwasher to rejuvenate it. Hand cleaning it with some laundry soap and a bristle brush is very effective too. Please don’t do this with the newer EQ heads however. Using a nail brush or dishwasher on your EQ head will ruin it.
Once your brush stops making that, well, brushing sound on the ice it’s time to replace the head. Brush heads should be replace as many times per season as you play per week. So, if you play three times per week, you should replace your broom heads three times a year. Sweeping requires co-ordination, balance and strength. It’s important for competitive teams to practice this. Good sweeping gives you more control over shots and may be all the difference between you and your competition.