This section offers a simplified version of sweeping instruction.If you are a new curler, read this section before your Learn to Curl Session.All of these things will be covered in the session.
Sweeping makes the rock go farther and straighter.When it is your turn to sweep:
Put your slider in your pocket (or put a gripper on).
Stand to the side, on the tee line and take a position 45 degrees to the centerline.
Use an "open" stance (inside arm down).
Lower hand 18 inches from the broom head.
Upper hand should use an underhand grip.
Decide which sweeper will be closest to or "take" the rock.
As the rock is delivered, start moving forward and "meet" the rock at the hog line.
When called upon, sweep in front of the rock with as much head pressure AND head speed as possible.
Try to use a "skating" motion with your feet.
Finish your sweeping stroke to the side to not leave debris.
Move to the side and walk back.
In addition, with practice:
Always take your slider off for better grip with your feet.
Learn to sweep on both sides.This means switching arms to stay "open".
Put more and more pressure on the broom head.
Try to move the broom head at 2 strokes per second.
Try to judge draw weight.Is the rock moving too fast, too slow or just right for the shot?
Watch other sweepers time rocks to help judge weight.
The remainder of this section will cover the details of sweeping.
Sweeping affects the rock-ice interface.The running surface of the rock, which is about five inches in diameter (Figure 1) is in contact with the ice.Sweeping the ice in front of the running surface as the rock travels changes the ice surface by warming it slightly affecting the distance.The friction of the broom also creates small grooves in the ice, affecting direction.
In the early days of curling, when games were played outdoors on the lochs, snow and other debris was cleared from the path of the moving rocks.Bunches of sticks were used as debris clearing devices.However, as the sport evolved, it became clear that, in addition to clearing debris, vigorous sweeping affected the moving rocks.
Sweeping does several things:
Sweeping makes the rock travel farther.
Sweeping makes the rock travel straighter.
Directional sweeping, in some cases, makes the rock curl more.
Clears small debris from the running path.
All sweeping decreases the rock's rate of deceleration.
Sweeping Rule Summary
The World Curling Federation controls the rules of curling for most countries and all world championships.Rock manipulation through sweeping has been a difficult thing control and the rules have changed many times over the years.Today, there are no restrictions regarding the brush stroke.Sweeping in any direction and over any area is legal.However, the brush stroke must finish "away" from the running path as not to leave debris that may cause rock manipulation.Intentionally leaving debris (dumping) is a violation of the rules and may be punished by removing the rock in question.
Keeping the Ice Clean - the "Pick"
With today's ice maintenance and cleaning procedures, debris is kept to minimum and the only concerns are very small types of debris.Even something as small as a hair, fabric from clothing and dirt from shoes can cause the rock to change course.
"Pick" is the term curlers use when the rock is affected by debris.The term came from rocks "picking up" debris.Rocks are susceptible to picks, even on freshly scraped and swept ice.There's also an increased chance of picks as the game continues due to the pebble slowly eroding.As the ice gets "flat" there is more contact between the ice and the running surface.The condition of the rock's running surface also contributes to picking.Uneven or pitted surfaces are of particular concern.
There are a few things you can use to minimize picks since no team can ever afford a picked rock.Try the following.
Clean the running surface of the rock thoroughly before throwing.
One sweeper should "clean" the area in front of the rock as it travels.
Avoid crossing the sheet (walking from one side to the other), this may leave debris.
The "cleaning" stroke must have enough pressure to avoid debris "rolling" under the broom head but not enough to melt or scratch the ice.Teams must agree on how much pressure they will use.Pressure less than five lbs. could allow the roll under.If melting and scratching are an issue, a good team will always favor the short end of the weight window to allow cleaning.
Countless games have been determined by picks.Be aware, clean and enjoy good shots.
"Cleaning" the ice as the rock travels
Bullet #2 above refers to the active cleaning of the ice in front of a moving rock.Many "pick-conscious" teams do this.One sweeper lightly sweeps the area to remove debris.The amount of pressure necessary for this tricky.A very light sweep (one or two pounds of pressure) may be counterproductive.In this case, debris may "roll under" the broom head.By applying more pressure (10 pounds) will be much more effective in cleaning the area, however 10 pounds of pressure may actually make the rock travel farther and straighter.Your team should discuss this and decide how to proceed.
The most effective cleaning method is to use the 10 pounds of pressure and adjust the weights accordingly.If the ice is running 14.5, adjust to weight to something like 14.6 to compensate.
Of course, there are times when is "pick" is needed.A rock thrown clearly too heavy may need that help.Many skips come up with a term to allow this.
Directional Sweeping
In 2015, because of the new information about why rocks curl, some elite curlers experimented with what is now called "directional sweeping".Directional sweeping is used to keep rocks straight as well as to increase the curl.The idea of creating additional scratches on the ice (with your broom) will help the natural action of tracking through the scratches.In order to get rocks to curl more, the "high side" sweeper (on the opposite side of the curl direction) sweeps/scratches the path at angle up to 45 degrees in the direction of the intended curl.Depending on the type of broom, this creates additional track scratches.It's important to understand that as the directional results will come from only one side.If two sweepers are scratching on opposite sides, they will counteract the results although two sweepers have always been used for weight sweeping.
Note: There are new WCF rules regarding the type of brooms (pads and fabric) that can be used in events leading to world play.Check the WCF website for more information and check your country's governing body for more local rules.
Most researchers will agree that we cannot completely discount either theory.Test for yourself.
The weight window was briefly mentioned in the Delivery Section.The amount of force necessary to propel a rock forward is known as "weight".Good sweepers can add an additional 4 - 8 feet to a rock's distance.This is important to know because, as you are throwing the rock, your throwing weight needs only to fall inside this 4 - 8 foot "weight window".This provides a fairly comfortable margin of error for a thrower with good sweepers.
Example: A rock thrown 8 feet short of the house without sweeping can easily be swept into the house by good sweepers.As a thrower, your responsibility was to hit the "window" and not the actual finished shot.This is what makes sweeping such a critical part of the game.
There are only a few types of sweeping devices being used today all using synthetic fabric.These synthetic brooms have a fabric, such as Cordura, stretched over a padded surface.Although introduced many years ago, these synthetic brooms became popular in the mid 1990's and are the standard sweeping device today.They are very effective and keep the ice clean.Some people argue that the synthetic brooms are so effective in polishing the ice that they erode the valuable pebble that the rocks ride on.This creates an undesirable "flat" surface with more area of contact on the running surface.
Carbon fiber handles were introduced around the year 2000.They are much lighter than the standard fiberglass handles.They do not offer much in additional sweeping performance other than perhaps some increased head speed due to the lighter weight.These handles are much more expensive.If money is not an issue, choose the carbon fiber.
CurlTech Choice for individual (league type) sweeping:
Any light weight, high-friction swivel type.
A note about broom regulations.The WCF has broom pad and fabric regulations for any games played that lead to world play.Only one fabric type (smoother, less-scratching) is allowed, and most broom manufacturers have a championship approved fabric pad.Check your local league rules as some more competitive leagues follow the WCF guidelines.Most club leagues do not use the use the WCF rule.In some cases, more competitive leagues have adopted it.
Let's talk about what makes a good sweeper.The best sweepers today are effective and efficient.Sweeping effectiveness has been the focus of much debate over the last thirty years or so.While many people argue that the most effective sweeping comes from rapid movement of the brush, others argue that effective sweeping is caused by increased pressure of the brush on the ice.CurlTech believes that a strong balance of both will achieve optimum results.Rapid movement with as much pressure as possible is what great sweepers strive for.
Sweeping efficiency refers to a sweeper's ability to be the most effective while using the least amount of energy.The sweeping style discussed in this section is the preferred method of most top teams.CurlTech teaches a sweeping style with the following main components:
Stance
To start sweeping properly, take a standing position that is 45 degrees to the rock's path, trying to face the rock and the skip at the same time.With the brush head on the ice, place the inside hand (the hand closest to the rock) on the brush handle half-way down using downward pressure.This is the bottom-hand, and it will be supporting much of your body weight during the sweeping stroke.The outside hand (top hand) should be placed underneath the handle (an underhand grip) about one foot from the top.The end of the handle will be tucked under the arm.
Two Types of Brush Motions
There are two types of brush motions:
The shoulder driven motion
The lower-hand motion
The should motion is more powerful since the lower arm can be used to hold your body weight over the broom.Right-handed players will feel more comfortable on the right side with the left arm down.The lower hand motion id driven by the lower hand pushing the head back and forth.This is not as effective since the body weight can not be support as well by a moving hand.To be as versatile as possible, learn the shoulder-drive from both sides.
High vs. Low
Figure 2 shows the sweeper with the lower hand grip about 18 inches from the broom head.A grip any lower than that REDUCES the amount of potential head pressure.For a short period of time (a few years) it was thought that the lower the hand, the better the head pressure.This turned out to be false.A higher grip allows you to move more of your body weight over the head.This means a more upright stance will allow your entire body to stay closer to the weight point.The lower the grip and stance forces the body to stretch out horizontally, taking body weight and spreading it out.
Broom Motion
The most effective sweeping motion is approximately up to 45 degrees to the rock's path and covers an area just wider than the running surface (remember it's only five inches).A motion greater than this is waste of energy (not efficient).The stroke should be away from your body, and then back toward your body.Keep your top arm tight to your body.By staying tight, you will begin to put more and more pressure on the head as you begin to move your weight over the top of the brush.
Stroke Power
Experience shows that the push (away) stroke is much more powerful that pull stroke.This is important when it comes to directional sweeping.With experience, you will gradually place more of your body's weight over the head of the broom.The power of the sweeping stroke comes from the top shoulder (shoulder driven).The shoulder "drives" the brush head out and your core strength pulls it back.Because of this, most right-handed curlers (strong right side) will feel more comfortable sweeping on the right side of the rock.
Your dominant arm may dictate your preferred side to sweep.A good, shoulder-driven sweeping stroke will feel more comfortable with the non-dominant arm down.Since the power in the stroke comes from shoulder and the body weight is held by the lower arm, the dominant side will feel more natural.In some cases, the other side will feel more comfortable.This is usually because the dominant arm (lower arm) is doing the sweeping.This is not correct since the head pressure will decrease without the driving shoulder and the body weight on the broom.This is called a "jiggle arm" and is not very effective.This why some sweepers feel more comfortable in a closed stance.
For best results, place the strongest sweeper about 4 to 5 inches in front of the traveling rock.This is called "taking the rock".With the brush head perpendicular to the path, move the head back and forth with a clear and visible motion.Most adjustable brush heads are at least five inches long, so the running surface is automatically covered by simply placing the broom head in front of the rock.Any clear and visible movement at this point is acceptable.The second sweeper should be as close as possible to the inside sweeper without risking contact with the brushes.As a beginner, you may want to stay well clear of the rock to avoid hitting it with the brush. The most effective team sweeping is with the sweepers on opposite sides because the brushes can easily stay close together.Eighty percent of team sweeping effectiveness on draws comes from the inside sweeper, the outside sweeper representing the other twenty percent.However, the only way the inside sweeper can achieve this eighty percent is with the second sweeper present.The lead sweeper (farthest away) prepares the ice for the inside sweeper.They work together to create great sweeping.Sweeping with only one person will reduce the effectiveness by forty percent.
Note:Adding a third sweeper accomplishes almost nothing.As a skip or a thrower, avoid "jumping in" to help.This is a waste of time and only increases the chances of you or a teammate burning a rock.
In the Delivery Section, the use of a slider was discussed.Proper sweeping must be done without a slider.If you throw with a slider, remove it for sweeping.If your slider is built into your shoe, cover it with a gripper.Sweeping effectiveness requires a solid platform to sweep from.The proper sweeping motion, when moving with the rock, looks like a skating motion.Walking fast or jogging next to the rock is not very effective or efficient.As you move with the rock, your inside foot should be skating forward.Your outside foot should also be skating forward, but it will lead the body.The outside foot will extend much farther than the inside.The inside foot should also never cross the outside foot during the motion.The most pressure is created when the body weight is over the top of the brush.This can only happen using the tripod method with two feet and a brush head.In the beginning, you will have to support your weight on your feet.When you become more comfortable, begin to shift more and more weight onto the brush head.
To have the greatest degree of flexibility with your teammates, learn to sweep effectively on both sides of the rock.This will allow you to sweep with anyone at any time.
View the following video to see strong, effective, and efficient sweeping:
View the short video of proper sweeping mechanics.She uses good head pressure and good head movement.
Sweeping with a Slider
You may have seen good curlers sweep without covering their sliders.This is a personal preference.It does not benefit you as a sweeper although some say weight judgement is better while you're sliding.It does take less energy to sweep this way which is why it's so popular.You cannot apply as much head pressure when sweeping with a slider.For this reason, we recommend you keep your gripper on when you sweep.
Of course, there are different standards for Mixed Doubles curling.If the thrower will also sweep, they have no time to put a gripper on.
Open vs. Closed Stance
There are two types of sweeping stances, open and closed.An open stance is one where the down-hand is on the inside near the rock.A right-side sweeper would have the left arm down.A closed stance on the same side would have the right arm down.Since most people have a stronger side, this position allows some people to switch sides without switching strokes.The advantage of an outside arm down position (closed) is a more perpendicular sweeping stroke.This helps two sweepers stay close.The disadvantage is the body position.The head travels in a more backward style.This results in poorer visual communication with the skip and poorer weight judgment (the field of play is moving sideways across the body instead of into it).
Head pressure and head speed can be produced equally with both stances so as an individual with no other sweeping responsibilities, it makes no difference which stance you choose.However, sweeping with an open stance will produce a stronger stroke due to the pushing action of the shoulder.The broom head is pushed away from the body by the shoulder.A closed stance will generate the same pressure but not the same power stroke.See the section on team sweeping for other important considerations when deciding which stance is right for you.
As the shooter prepares to throw the rock, the sweepers must take a position near the tee line and the side lines.This allows the shooter to view the skip.As the shooter begins to come out of the hack, the sweepers slowly meet the delivery at or near the hog line.One sweeper will always "take the rock" which means sweep closest to the rock.As a general rule, the person taking the rock will "clean" the surface in front of the rock to avoid the rock picking up small debris.Clean by slowly moving the brush head across the surface.The pressure should be light as not to create too much friction.This cleaning should be done in a position ready for sweeping if the skip calls.
Quick Tip:
When a right-handed player throws the rock, their broom is extended out to the left.This interferes with the left side sweeper at the beginning of the shot.If directional sweeping is not part of your team plan, have the right-side sweeper take the rock, since there is no extended delivery broom.This allows the sweeper to clean or sweep at a much earlier point.
When finished, move immediately to the sides and walk back in a non-distracting manner.It is not necessary to stop completely.
Since 2015 when the theory of sweep-scratching was introduced, advanced curlers have been experimenting with different sweep styles.This is an ongoing effort.The new theory opened the door to lots of speculation, additional theories, many spirited discussions, and strong beliefs.CurlTech is monitoring the sweeping issue and will stay as current as possible with new ideas.
Studies have shown that the most effective sweeping style is the one that adds the most pressure and repetition (sweeping over the same area).So how do you get the most pressure?A test using a simple bathroom scale will show that more pressure can be applied to the head of the broom if the body position is higher (lower hand on the broom 12-18 inches from the head).As the lower hand move closer to the head, less pressure will be applied because the lower position spreads the body weight horizontally.As your body bends over, more weight is distributed back to the feet.Higher hands spread the body weight vertically over the head.
The remainder of this section will cover some advance sweeping concepts and techniques that can be used by teams.The topics are:
Team Sweeping
Sweeping Communication
Corner and Directional Sweeping
Timing shots - Interval (split) Timing
Judging Weight
Team Sweeping
Most of the discussion so far has been about why we sweep and how we sweep.Those of you who curl mostly in leagues as an individual contributor will benefit greatly from the basic mechanics.If you play on a team that plays together regularly, you have the opportunity to take sweeping to next level by applying some team sweeping techniques.
Rule #2Team Control Factor (TCF)
Team sweeping comes in twos.The perfect draw shot is thrown two feet short and the draw broom is two inches more than needed.The perfect takeout broom is two inches less than needed.
Once the rock has been delivered, the sweepers are responsible for judging the weight.Is it moving too fast, too slow, or just right?It is not realistic to expect the skip to judge the weight from 120 feet away.After the rock has been thrown, the sweepers place the rock.By understanding the shot called, the sweepers can determine if the called spot is possible.If it is, the sweepers complete the shot.If the weight is heavy or light, the sweepers must communicate to the skip the new location.The skip then makes a line sweeping decision based on whether or not the rocks curl needs to be straightened-out.
Judging the weight of the rock is very difficult and takes lots of practice.You can increase your ability to judge rocks with a few sweeping techniques.
Sweep more upright than low, this allows you to visualize the entire field of play and judging motion and speed becomes easier.The fluids in the inner ear must remain as stable as possible for accurate motion judgment.By dipping the head down (leaning over too much) you change the orientation of the fluids.This not only decreases motion judgment, but it also causes a slight bit of vertigo (spatial disorientation) when the head is returned to the upright position.
Take a sweeping position that faces the skip (open stance).This also helps view the entire field of play and allows you to view the skip at all times.Curling clubs can be very loud at times and visual contact with the skip may be the only means of communication.This can be done by placing the inside hand in the lower position.This will naturally put you in a "forward facing" position.
Team sweeping refers to teams striving for similar sweeping styles.This continuity will make all sweeping calls more consistent.For example, the most effective sweeping is two sweepers sweeping from opposite sides of the rock.This allows the brushes to be as close as possible to each other, limiting the amount of cool down that happens after the brush passes over the surface.
For the most part, sweepers judge weight and skips judge line.It is very important for both parties to understand each other.For example, a skip judges line based on how the rock was delivered and how he or she thinks the rocks will curl.Since rocks curl less with more weight, the skip must know any weight deviations as soon as possible.
Judging the weight of a rock and communicating properly takes time and practice.Weight judgement is best when your spatial and proprioception skills are good.
Spatial Skills
Spatial skills are the ones that sense your body position in relation to your surroundings.The better your spatial skills, the more likely you will judge the weight of the rock properly.These skills are difficult to develop but practice will help.
Proprioception Skills
These skills are the ability to sense your body's position within its own space.Balancing and sweeping over the broom head is a good example (a perfectly balanced delivery is a better example).
With both skills, it is important that you put your body in a position that does not compromise the senses.Keep your head as upright as possible and face your target since the inner ear fluids will change your perception if disturbed.An open stance will help keep your head in a good position.The closed stance, although not incorrect, will put your head in a tilted position and moving slightly sideways.Since your weight judgement is mostly spatial (judging the rock from where you are to where you want it) an upright forward position is best.Remember, we are judging where it will stop and not how fast it is going.
Draw Weight and Rock Position Systems
Teams can use any weight and position system they desire.Many teams use a numbered system to communicate draw weight and rock position.The 1-11 system works well.
Long guard
Mid guard
Close guard
Top twelve-foot
Top eight-foot
Top four-foot
Button/tee line
Back four-foot
Back eight-foot
Back twelve-foot
Just through
Another system is house position system.In this system sweepers call out the house position such as top twelve, back eight, etc.This may be easier for some teams.
More intuitive House System:
High
Mid
Close
Top 12
Top 8
Top 4
Tee
Back 4
Back 8
Back 12
Through
Hack
Board
This is a more intuitive system since no conversion is necessary in the language.It works well with shots played in the middle of the sheet.It does have a drawback, however.Shots played to the sides are difficult to place since a rock in the top four (6 on the 1-11 system) on the centerline will be in the twelve foot near the side-line.
Using the 1-11 system or the house system, try the following:
Before the rock is thrown, make sure the sweepers know the exact shot and weight called.If throwing a draw for example, the sweepers should communicate any weight differences to the skip halfway down the sheet.Commit to an area of the house such "top four" or "back twelve".This can be verbal or visual depending on the circumstances.As the rock travels down the ice, the sweepers must continuously report the weight differences to the skip.To simplify matters, only communicate weight if it is different than what the skip expects.Over-communicating such as screaming "the weight is good" is not necessary.Effective communication is not necessarily constant communication. In fact, a better use of sweepings is to have them communicate between each other and not the skip.
Sweepers should communicate these numbers to the skip as soon as possible.It is not necessary to communicate detailed weight positions at the release point.At the halfway point, the sweepers must commit to something.At the hog line the sweepers must be certain.Keep in mind, these are swept weights.The system will get very confusing if teams don't understand the "swept verses unswept" numbers.
The Perfect Weight Communication System
A better system that incorporates this numbering system is the "quiet system".Using this system, the sweepers say nothing if the weight is correct.This is difficult for most skips, particularly the ones that require constant updates.This system only works on established teams with a high degree of trust.This has three benefits:
Less chance of miscommunication.
No over-communication.
Swept vs. unswept problem is eliminated.
This "by exception" system works well because it keeps the noise to a minimum especially in loud arenas and clubs.This system represents the highest level of team development since it requires trust and skill.
Example of the Perfect System
The skip calls a draw to the top four-foot (6), the sweepers say nothing until they know (or think) it's not in the six position.If they can get it to the four-foot with sweeping, they still say nothing and sweep.If the weight is heavy, they immediately communicate the heavy weight resting position, such as 8 or 9.The skip can then decide if an alternate is necessary.If the weight is light, the sweepers communicate the swept weight such as 3 or 4.
It is always necessary to confirm the shot with the sweepers and thrower before the shot is thrown.
When learning this system, teams can start by using a less complex numbering system.The following can be used when just starting out.
In support of the frictional melting theory of why rocks curl, a new sweeping concept became popular in the 1990's called corner sweeping.This refers to sweeping across one side of the running surface instead of sweeping across the entire running surface.This was done to gain even greater control over the rocks curl.For example, by sweeping the inside edge of a takeout (the slow side), friction is reduced on the slow side only, reducing the pivot action discussed earlier in this section.Because of this the rock runs straighter.Sweeping the outside edge of a draw could make it curl more but seems to be much less effective.Corner sweeping results in more manipulative sweeping.This could result in less predictable shots.CurlTech suggests you leave corner sweeping for emergencies only.Our staff members have seen corner sweeping in action and work very well.We've also seen disastrous results from corner sweeping every shot.If you really need to get around that guard, use it.Even though corner sweeping may be more effective, most good teams prefer to concentrate on good overall sweeping skills.
Corner sweeping does not appear to help rocks curl.Use it as a straightening tool.
Fixed Head Differential Pressure
The most effective way to corner sweep is to use differential pressure.This can only be achieved using a fixed-head broom.Swivel types don't work as well and are covered in the next paragraph.Start by covering the five-inch running surface with the head of the broom.This will give you good coverage to begin with (and is a good overall technique).Once you hear a panic call from your skip, "twist" the handle to apply pressure only on the desired side.We suggest you use good, solid sweeping most of the time and twist in the extreme cases.Working the edge is nearly impossible with a swivel type broom.
Forward Stroke Corner Sweeping
Most curlers today use some type of swivel head broom.Swivel head brooms offer maximum head contact with the ice at almost any angle.The downside to the swivel is that you cannot use differential pressure.The weight applied to the head (through the handle) is dissipated through the entire head with somewhat more pressure in the center by the handle/head intersection.Since differential pressure is not an option, the inside edge of the rock can be swept by using a stronger forward stroke than return stroke.This happens naturally since it's easier to drive the broom away from the body rather than back toward the body.Sweepers must identify the inside edge on each shot and the person "taking the rock" changes.
Note:To straighten a rock, corner sweeping and directional sweeping use roughly the same stroke.So far, no studies have been done on which mechanism is dominant.
In 2015, a new fabric type was introduced to broom technology.Instead of the standard weave that had been used for decades, a "bi-directional" weave was created.Immediately, curlers protested the design as being inconsistent with the principles of the sport.Apparently, the new fabric scratched the ice surface and allowed much more control of the curl.Similar to the corner sweeping principle, sweepers could target the area to scratch (one side to keep straight, the other to curl more) with greater, almost unnatural results.
It did not take long for the new fabric to be outlawed.The WCF, citing too much control over the rock and possible ice surface damage, instituted a moratorium on the use of this fabric.
The idea of directional sweeping, the millennial version of corner sweeping, evolved from the new fabric controversy.Sweepers argue that the brush stroke, which is more powerful on the forward stroke than the return stroke, could effectively reduce friction on the inside edge.This is slightly different than the old corner sweeping because it focuses on the direction of the outward stroke instead of the result of the pressure.Since there is no way to change the pressure on a swivel head broom (as opposed to the fixed head), the direction of the stroke causes scratches in the ice that the rock tracks on.
In addition, sweepers argue that a second sweeper on the opposite side would "counter" the work of the inside sweeper.As a result, you will see only one sweeper working the inside edge of a rock that needs to be straightened.
Mechanics of Directional Sweeping
Straightening To keep a rock straight, take a position on the inside of the curl (right side on an in-turn for example) with your body at a 45-degree angle to the line of delivery.Drive the broom away from your body at a starting at a point on the inside of the running surface.This will create scratch grooves in the ice up to 45 degrees to the line or path.Since rocks, in part, curl (see the Why Rocks Curl Section) by channeling the natural rock scratching, the rock will stay straighter trying to move over the grooves and not with them.Be sure to cover the entire running surface area of approx. five inches.
Shaping/Carving/Pushing - More Curl
To add curl, take a position on the outside of the curl (left side on an in-turn for example) with your body at a 45-degree angle to the line of delivery.Drive the broom away from your body at a starting at a point on the inside of the running surface.This will create scratch grooves in the ice near 45 degrees to the line.In theory, the rock will curl as it moves with the grooves and not over them. Be sure to cover the entire running surface area of approximately five inches.
Parallel scratching on draws
Consider this... In theory, our brooms create scratches and grooves that effect the rock.On draws that do not need straightening or more curl, try sweeping more "with" the rock, near parallel to the natural scratches created by the rock.This could create grooves that rock can move with and not against.
You Decide:
Creating parallel grooves requires one sweeper to sweep parallel to the natural scratch, the brush stroke prevents the second sweeper from staying close.Is it better for two sweepers to sweep at opposite 45-degree angles?This would create a "neutral" scratch condition allowing the rock to travel farther.
Multiple studies have shown that the WCF compliant brush head does not scratch enough to be effective. Do not expect any directional results with this head. Straightening can occur but not as a result of scratching.
The dominant mechanism here is differential melting and NOT scratching.
In the Delivery Section, rotating the rock at release is discussed in depth.Many curlers at all levels target 3-4 rotations.In the "Why Rocks Curl" Section, the natural scratching of the running surface over the ice is explained.It is suggested that the ice is scratched by the leading edge of the running surface as it decelerates.This creates a scratch 90 degrees to the path of the rock.Since the rock is also moving forward, the natural scratch will get shallower as the rock travels faster (see the hart below).To summarize, the scratches created by the rock itself are dependent on how hard the rock is thrown and how fast it is rotating.Because the variability of the natural scratches, the speed and rotation change the angles needed for directional sweeping.For carving, the broom scratch angle should be just outside the natural scratch angle (45-degree natural scratches would require a broom scratch angle of 50 degrees).This not only compliments the natural scratch action, but it also helps the rock curl beyond its natural (non-swept) ability.
Consider the following chart for directional sweeping.Not for distance.
Draw Time
14.0
14.0
14.0
Rotations
2
3-4
5
Scratch Angle to Path
20
40
70
Takeout Time
9.5
9.5
9.5
Rotations*
2
3-4
5
Scratch Angle to Path
5
20
45
To complicate matters further, the rock will decelerate in speed faster than it will in rotation.This means the sweeping scratch angle will sharpen as the rock approaches the house.
*Rotating the same speed as the draw, roughly ten RPM's.
It's important for teams to agree on a rotation standard for the sweeping angles to match each player.A team member who throws 2 draw rotations will need a shallow angle (20) while the team member throwing 5 rotations will need a deeper angle (70).
Most curlers associate sweeping with rocks traveling farther and straighter.This is true for most shots.There is a case though when sweeping will cause a rock to appear to curl more.As a draw is coming to rest, many newer curlers continue to sweep the rock in an attempt to keep it straight.Sweeping will keep the rock moving, which means it continues on its path.Imagine the arc of a rock that is curling.It begins straight then starts to curl (see The Curl Profile).If the rock could move forever, it would eventually leave the sheet of ice across the sideline.Sweeping rocks after the curl begins does two things:
It reduces the amount of additional curl.
It keeps the rock moving on its current path.
Finishing the rock refers to keeping it moving on its arc.This pulls the rock even deeper behind a guard because the rock is still moving on its curl path.This is important to know since many come-around shots can be "finished", meaning the rocks can be swept under the guard.The mistake many new skips and vices make is to stop sweeping.This only makes the rock stop short and not continue to curl under.On the other hand, if a rock is curling too much at the end, stop sweeping.Additional sweeping here will only continue the rock's path.Directional sweeping can help here.Not only will it keep the rock moving, but it may also help the rock curl more.Directional sweeping can offer something never seen before when it comes to finishing the draw.Directional sweeping on the inside of a finishing draw may keep it from curling.Be careful and test this theory yourself.
The sweepers are responsible for split-timing shots.Split timing (short times) is an excellent sweeping tool to help manage weight judgement and distance.
See a full write up on timing rocks in the "Timing Rocks" section.
As mentioned earlier in this section, sweeping can dramatically affect any given shot.Whether it's a takeout thrown narrow or a draw that needs help, effective sweeping is essential.
Like many systems, sweeping effectiveness is measurable.Brush head pressure and head speed are the two quantifiably measured components.Head speed is measured by the number of brush strokes per second.Out and back equals one stroke.Head pressure is measured by pressure sensors in the head of a special test broom.Since curlers are different sizes, the standard is measured in percent of body weight applied to the head.Coverage is measured by sustained coverage of the running surface, approximately five inches.
Below are the CurlTech sweeping standards for sustained pressure and speed over 10-15 second sweep:
Speed
Pressure
Coverage
Ineffective
2 sps
Under 40 lbs.
5 inches
Somewhat Effective
2 sps
40-75 lbs.
5 inches
Effective
3 sps
75-110 lbs.
5 inches
High Performance
4 sps
110-135 lbs.
5 inches
sps = strokes per second, one stroke is out and back
Of course, these standards must be maintained for the entire sweeping session, sometimes the entire length of the shot.Do not expect to achieve the high-performance standard without being in top physical shape.Strength, particularly in the arms, shoulders and core is required to maintain the high-performance standard.The shoulder drives the brush out and the core pulls it back.
A sweeping system is an interrelated group of sweeping activities.Teams should design their own system by compiling known and proven components.In any sweeping system, you will have the following components:
The best team brooms are the ones that create the most friction with the least effort and allow the two sweepers to sweep in close proximity.Lighter, carbon fiber handles dramatically reduce the weight of any broom reducing fatigue, particularly over longer competitions.The carbon fiber handle brooms are slightly harder to control due to the lack of weight.Head "float", meaning the head of the broom drifts off the line, may result during the transition to these brooms.As the head grabs the ice, the friction pulls the head toward the rock causing an oval pattern to the sweeping stroke.Many teams, however, will agree that the advantages outweigh the disadvantages of these brooms.For team sweeping, where the players are in fixed positions for each shot, swivel-head brooms provide the best coverage.
If using fixed angles, it will be necessary to switch brooms for different players.A team switching system is simple if the players are in proper position after each shot.A team can own four broom types for efficiency.A straight broom for sliding and skipping and angles for sweeping.
CurlTech Choice for team sweeping equipment:
8" or 10" light weight swivel
Sweeping Style
The same sweeping style described earlier in this section should be used by the advanced players.The sweeping stroke must be short, vigorous and with as much pressure as possible.
Positioning
Positioning refers to where and when each team members place themselves during the game.Competitive games are timed, and effective positioning helps play quickly without rushing.Select a position for each player that can be replicated each end.
The "Ready Position"
Those of you that coach or play baseball or softball understand the "ready position" concept.This refers to the position of the players as the ball is put into play.In curling, the sweepers take a ready position just before they need to sweep (or are called on to sweep).The person taking the rock (closest to the rock), must be in the ready position AND cleaning the path at all times.Cleaning the path helps prevent "picks" and allows the sweeper to sweep immediately when the skip calls.The outside sweeper (not on the rock) needs a ready position that is upright and facing the skip.This sweeper communicates weight information to the skip.
Clean in front of the rock at all times unless you want a pick.Create a skip's signal to stop cleaning.There are times when a pick may help.
Who Takes the Rock?
If your team uses directional sweeping in any way, use what's called the "control" system.On each shot, the sweeper on the inside of the curl (right side on an in-turn) is the "control" or primary sweeper.The control sweeper takes the rock and cleans the entire time.The other sweeper will take split times and communicate to the skip as necessary.The default sweeping on draws is to add distance and on takeouts to keep the rock straight.The inside sweeper always has a better directional stroke for straightness.The outside sweeper may or may not sweep at all.On draws, as the rock is crossing the hog line and is most susceptible to directional sweeping, the communicator will switch and act as the control sweeper to possibly finish the draw.
Determining who is the control sweeper is based on the shot called.Good team sweepers never need to confirm this.
Unless your team uses directional sweeping, the "throwing arm" side sweeper should always take the rock.When a right-handed player throws the rock, their broom is extended out to the left.This interferes with the left side sweeper at the beginning of the shot.Since there is no extending delivery broom, the right-side sweeper can clean or sweep at a much earlier point.
Sweeping Quick Reference
Stand upright, facing the skip, angled 45 degrees to the rock
Inside/lower arm down with overhand grip
Lower arm grips broom half- way down (18") or slightly lower
Sweeping affects the rock-ice interface.The running surface of the rock, which is about five inches in diameter (Figure 1) is in contact with the ice.Sweeping the ice in front of the running surface as the rock travels changes the ice surface by warming it slightly affecting the distance.The friction of the broom also creates small grooves in the ice, affecting direction.
Stance
Stroke Power