“Because you are only using one side of your body, you must keep tension in your core at the top of the swing to stay balanced,” says Carr. “The one-handed swing is slightly more difficult because you're being challenged to control the entire movement with one side.
As a result, it's best to start with a lighter weight and build up as you become more comfortable with the movement.” Stand with feet shoulder-width apart and a kettle bell on the floor about a foot in front of toes.
Hinging at the hips and keeping a neutral spine (no rounding your back), bend down and grab the kettle bell handle with both hands. C. Powering through the hips, exhale and quickly stand up and swing the kettle bell forward up to eye level.
At the top of the movement, your abdominal muscles and glutes should visibly contract. To help you do this, blow your breath out when the kettle bell reaches the top, which will create tension in your core.
Thomas Edison once said, “The doctor of the future will give no medicine; instead he will interest his patients in the care of the human frame, nutrition and the cause and prevention of disease.” 1 This is important because for those with lower back issues traditional posterior chain exercises such as dead lifts, good mornings, etc.
For those looking to strengthen the lower back and unable to use these traditional exercises the swing may be just the thing they’re looking for. Because of the dynamic nature of the swing the opportunity to overload or injure the body is quite low.
The rapid acceleration of the bell via the motion of the hips and knees is accompanied by substantial activation of muscles in both the posterior chain and the abdominal. They proposed the muscle flushing mechanism as an explanation for the reports of lower pain.
Now, sniff air into your belly through your nose and then exhale short and sharp like you’re trying to blow out a candle far away. But when you use forceful exhalation, known in ROC circles as power breathing, you are essentially creating a stiff wall around that flagpole to keep it stiffer.
Using the Cassava maneuver creates a dynamic internal pressure that I believe supercharges the cerebral-spinal fluid flow. The INTERCAL pressure is greatly increased when you add movement to the Cassava maneuver.
Cerebral-spinal fluid is pumped or controlled by respiration that causes movement in the sacrum and cranial bones. I believe that the spinal curves must be correctly maintained or the flow of information in the nervous system is compromised.
In order to do the Kettlebellswing correctly I really had to work on my form and this had an incredible influence on establishing the proper robotic and kyphotic curvatures of my spine. Set up as if you were doing a conventional two hand swing : hips back shoulders down, lats engaged, connected and linked to the bell.
The key principle of Hard style Kettle bell training is that, to quote Pavel, “We choose power over efficiency, choosing maximal acceleration in the quick lifts and maximum tension in the grinds.” If we’re looking to the swing to be our one size fits all solution to back care then we must recognize that, for many, swinging the bell overhead is impossible without hyper extending the lower back or jamming the neck or shoulders due to limitations in their thoracic mobility.
The swing is an expression of forward force projection such as found in boxing or martial arts, like a straight punch. If you’re an athlete with a vertical component to your sport such as in Olympic weightlifting, Highland Games, or even swimming, then try the snatch.
Picking the right tool for the job will go a long way to ensuring your back stays healthy and strong for years to come! A 16-kilogram (35 lb) “competition kettle bell Arthur Saxon with a kettle bell, cover of The Text Book of Weight-Lifting (1910)The Russian girl (, plural girl) was a type of metal weight, primarily used to weigh crops in the 18th century.
They began to be used for recreational and competition strength athletics in Russia and Europe in the late 19th century. The birth of competitive kettle bell lifting or Gregory sport ( ) is dated to 1885, with the founding of the “Circle for Amateur Athletics” ( ).
Russian girl are traditionally measured in weight by Food, corresponding to 16.38 kilograms (36.1 lb). The English term kettle bell has been in use since the early 20th century.
Similar weights used in Classical Greece were the halter, comparable to the modern kettle bell in terms of movements. Variants of the kettle bell include bags filled with sand, water, or steel shot.
By their nature, typical kettle bell exercises build strength and endurance, particularly in the lower back, legs, and shoulders, and increase grip strength. The basic movements, such as the swing, snatch, and the clean and jerk, engage the entire body at once, and in a way that mimics real world activities such as shoveling or farm work.
Unlike the exercises with dumbbells or barbells, kettle bell exercises involve large numbers of repetitions in the sport, and can also involve large reps in normal training. Kettle bell exercises are in their nature holistic; therefore they work several muscles simultaneously and may be repeated continuously for several minutes or with short breaks.
When training with high repetitions, kettle bell progression should start out slowly to build muscle endurance, support the joints and prevent injury. Like movements performed with any exercise tool, they can be dangerous to those who have back or shoulder problems, or a weak core, when performed without proper education and progression.
They can offer improved mobility, range of motion, agility, cardio vascular endurance, mental toughness and increased strength. The following is a list of common exercises that are uniquely suited to the kettle bell for one reason or another.
A kettle bell exercise that combines the lunge, bridge and side plank in a slow, controlled movement. Keeping the arm holding the bell extended vertically, the athlete transitions from lying supine on the floor to standing, and back again.
As with the other slow exercises (the windmill, get-up, and halo), this drill improves shoulder mobility and stabilization. It starts lying on the ground with the kettle bell over the shoulder in a straight arm position, as in the top of a floor press, but with the other arm along the floor straight overhead.
The trainee then gradually turns their body away from the kettle bell until they are lying partially on their front. The kettle bell is held hanging in one arm and moved smoothly around the body, switching hands in front and behind.
Also called a front leg pass, this is a backward lunge, circling the bell around the front leg, returning to the standing position, and repeating. Like the slingshot, but the bell is swung forward until the arms are parallel to the ground.
Starting with the bell in the rack, the bell is pushed away to the side slightly, the swung down to the other side in front of the body, and reversed back up into the rack. A variation of the press where the other arm assists by pushing open palm against the ball.
Stand on one leg and hold the kettle bell with the opposite arm. By then lowering and raising the kettle bell you can work stabilization and power.
A press utilizing a bent-leg windmill position to lift heavier weight than is otherwise possible. One bell is rowed to the chest while maintaining the plank position, then returned to the ground and repeated with the other arm.
Alternatively performed with a single kettle bell, one arm at a time. This requires more control than an ordinary push up and results in a greater range of motion.
Feet may be elevated to increase the difficulty, until the trainee is performing a handstand push-up on the kettle bells. In any movement involving the rack or overhead position, the kettle bell can be held with the ball in an open palm (sometimes called the waiter hold) for a greater stabilization challenge, or for even more precise control and added grip challenge, the bottom-up hold, squeezing the kettle bell by the handle upside-down.
Holding a single kettle bell in the rack position bottom-up with two hands (“by the horns”) makes for goblet exercise variants. Conventional swing : The kettle bell is swung from just below the groin to somewhere between the upper abdomen and shoulders, with arms straight or slightly bent, the degree of flexion depends on the trajectory of the kettle bell.
Hang clean: The kettle bell is held in the rack position (resting on the forearm in the crook of the elbow, with the elbow against the chest), lowered to below the knees, and then thrust back up in to the rack. The kettle bell is held in one hand, lowered to behind the knees via hip hinge, swung to an overhead position and held stable, before repeating the movement.
Jerk: As a push press, but with two dips, for more leg assistance (as in the barbell clean and jerk) Thruster: A rack squat with a press at the top using momentum from the squat. Pistol squat: A single-leg squat with one leg held straight in front parallel to the ground, holding the bell in the goblet or rack position.
An easier variant for those with less hip mobility is to perform the squat parallel to a step or ledge, so that the foot of the free leg can dip beneath the pushing leg at the bottom. Carry: Walking with the kettle bell held in various positions, such as suitcase, rack, goblet, or overhead.
Row: While bent over anywhere from 45 degrees to parallel with the ground, the kettle bell is held hanging from a straight arm, pulled up to the hips or laterally, and lowered again. Keeping the bell arm vertical, the upper body is bent to one side and rotated until the other hand is touching the floor.
The single kettle bell version is called the suitcase walk. These build grip strength while challenging your core, hips, back and traps.
The kettle bell is swung from just below the groin to somewhere between the upper abdomen and shoulders, with arms straight or slightly bent, the degree of flexion depends on the trajectory of the kettle bell. The key to a good kettlebellswing is effectively thrusting the hips, not bending too much at the knees, and sending the weight forwards, as opposed to squatting the weight up, or lifting with the arms.
The one-arm swing presents a significant anti-twisting challenge, and can be used with an alternating catch switching between arms. Within those variations there are plenty more variations, some are, but not limited to: pace, movement, speed, power, grip, the direction of thumb, elbow flexion, knee flexion.
The kettle bell has more than 25 grips that can be employed, to provide variety, challenge different muscles, increase or decrease complexity, and work on proprioception. Competitive lifter (Greek) performing jerk with 32 kg kettle bells (rack position). Contemporary kettle bell training is represented basically by five styles.
Hard style has its roots in powerlifting and Gj-rykarate training, particularly hobo undo concepts. With emphasis on the “hard” component and borrowing the concept of time, the Hard style focuses on strength and power and duality of relaxation and tension.
Gregory, sometimes referred to as the fluid style in comparison to the Hard style, represents the training regimen for the competitive sport of kettle bell lifting, focusing on strength endurance. Juggling is a training style where the practitioner releases and catches the kettle bell with all manner of spins and flips around the body.
Kettle bell training is extremely broad and caters to many goals, some being, but not limited to: mobility, flexibility, cardiovascular endurance, strength, speed and power. The sport can be compared to what the CrossFit Games is to CrossFit, however, the sport has been much longer in existence, and is only recently gaining more popularity worldwide, with women participating as well.
One such example being Valerie Wazowski, who at age 52, was the first US female lifter in the veteran age category to achieve Master of Sport in 24 kg Kettle bell Long Cycle. ^ , «» .
« » “ ”, 22 August 2016 (with period photographs). 21 (1908), p. 505: “PEOPLE ALL OVER THE WORLD ARE USING SCHMIDT'S Celebrated 'MONARCH' DUMB-BELL, BAR BELL AND KETTLE BELL SYSTEM”; also spelled KETTLE-BELLS (with hyphen) in a 1910 advertisement for the “Automatic Exerciser”) ^ a b c Rathbone, Andy (2009-01-04).
Journal of Bodywork & Movement Therapies 15 (2011): 542-544 ^ a b Iv ill, Laura (2008-11-22). “Exclusive ACE research examines the fitness benefits of kettle bells” (PDF).
Journal of Bodywork & Movement Therapies 15 (2011): 125-127 ^ Kettle bell Swing Vs. High Pull”. ^ “The Kettle bell Clean, Stop Banging Your Wrists | The Complete Guide”.
Our patented Dark Iron Fitness lifting straps are made of durable cowhide suede and are the perfect accompaniment to kettle bells. Their numerous benefits include strength gain, endurance, flexibility and weight loss.
Many of the movements and skills required in CrossFit focus on learning to have fast and effective hips. Dumbbells have a tight center of gravity and mainly utilize the major muscle groups.
A kettle bell ’s odd shape and off-center mass forces you to use muscles that mimic real-life activities. Its odd center of gravity forces you to do more work involving your stabilizing muscles to create explosive movements with the bell.
Enjoy the ease of use and appreciate that such a unique weight can help streamline other exercises you already do. Always practice correct form and safety in all exercises, but be content in the fact the kettle bell is one of the safer weights to work with.
If you have previously been avoiding barbell exercises due to safety concerns, look into the kettle bell alternatives. The kettle bell alternates periods of intense contraction and controlled relaxation, to give you a superior workout that combines strength, as well as endurance.
Other exercises such as the windmill, and single leg dead lift, also build flexible strength. The kettle bell stimulates tremendous abdominal contraction because of the explosive conditioning movements.
The fact you can work your core indirectly, just through the dynamic aspect of kettle bells, is truly amazing. Kettle bells are so effective because they stimulate the muscles and surpass standard cardio exercises.
They enable you to increase your strength, build up speed as well as your endurance level at the same time. This gives you a great strength and endurance workout in a shorter amount of time.
So rather than moving on to a heavier kettle bell you simply complete more reps or change the exercise to a more difficult option. Killer strength and endurance work can be achieved without necessarily having to use the heaviest weight you can find.
This is especially valued by physical therapists because kettle bells actually teach you to move in a way that is better, stronger, and safer. Unfortunately, many of us today lose some of our basic movements as a result of sedentary occupations and lifestyles.
That’s what happens when we don’t move our bodies with the full range of motion or become used to certain unhealthy postures (like sitting in front of a computer all day). They are terrific for overall fat loss, improving lean body mass, and helping teach proper use of the hips (important for speed and power sports).
It is unclear as to when kettle bells officially became a recognized tool for strength and conditioning, however it's estimated their history dates back over 300 years. Known as a “girl” in Russia, kettle bells were originally used to help balance scales while weighing crops.
The man most notable for Westernizing the kettle bell is Pavel Tsatsouline, chairman of Strongest Inc. and former PT drill instructor for Smetana. Tsatsouline's authored several books that outline simple but effective kettle bell training programs.
Entire workouts can be executed with nothing more than a single kettle bell, whether the aim is strength, hypertrophy, power or endurance. A kettle bell is relatively small (though I dare not say it's “light,” as that all depends on the weight you select) and relatively affordable in comparison to most other gym equipment.
Compared to training with machines or even dumbbells, the kettle bell provides variability and offsets the load so that no one rep is ever truly the same. Kettle bell exercises can at times be the biggest bang for your fitness buck, targeting numerous muscle groups and moving you through multiple planes of motion.
As Tsatouline writes in his book Simple & Sinister, “the kettle bell is an ancient Russian weapon against weakness.” Every piece of equipment brings something unique to the table, and every person is different, so it's foolish to speak in definitive.
Barbells make it easy for a newbie to load a movement heavier than they can handle in a fixed position. A perfect example is that of a Barbell Bench Press, where the hands are pronated and the shoulders are inherently placed in an internally rotated position.
Kettle bells are a great option to keep an individual's load lower while growing their movement competency. It targets the posterior chain and teaches individuals how to hip hinge properly with some force.
This exercise involves holding the kettle bell with both hands (although single-arm and double-bell variations do exist) and using the hip hinge to forcefully drive it out in front of yourself. Your gripping muscles may eventually burn if the set is long or enough or the weight's heavy enough, but your arms and shoulders should essentially contribute no power to the movement.
Once the KettlebellSwing is mastered, it is an excellent addition to any program or a convenient stand-alone option for a conditioning day. Its goal is simple: Stand from a supine position while keeping a weight over your head.
However, that simple act requires a lot of technique, shoulder stability, core strength, hip mobility and focus to execute effectively. There are also many scenarios where replacing a classic barbell or dumbbell exercise with a kettle bell version can make sense.
It might seem like an insignificant swap, but kettle bells naturally lead to better scapular position, making the move more effective and reducing wear and tear on your body. Undoubtedly the kettle bell is an extraordinary tool with a long history of producing excellent results.
After I earned my first kettle bell certification, I heard about a challenge that Dan John had people go through. Of course, I turned this into a challenge; sadly, only 1 person accepted.
As I was trying figure out what has hurting more -my hands, by erectors, my lungs, or my pride- at minute 46 I didn’t want to touch another kettle bell EVER again. Pavel gave our challenge a mention in his most recent book, Simple and Sinister (page 85).
Anyone that wants to increase their vertical jump will get very familiar with swings. The definition of Mastery is comprehensive knowledge or skill in a subject or accomplishment.
At a maximum, a full overhead swing is one end of the continuum. The minimum height of your swing is determined by arm length.
To find this stand up and let your arms hang straight down to your thighs, this is the minimum height you can swing the bell to while hitting full hip extension. Those 3 are expressions of the swing that you need to be able to do to display mastery of the 2 arm kettlebellswing.
If you look at all the various ways the swing is taught, we can reverse engineer it back to some very simple non-negotiable characteristics that EVERY organization includes in their instruction. There will be some degree of knee flexion, but the hips dominate the force production of the swing.
How you breathe, where you look, your arm position, feet position, and other key points all are details that have an impact on the actual performance of the swing, but each lag behind the spine and hips. If the spine is flexing/extending while someone is swinging a bell, having a discussion about their bent elbows is misplaced precision.
Not only do you need to be able to maintain a stable spine and use your hips to generate the force you need to show that you can do that over an extended period of time. Depends on whom you talk to, but since I’m writing this, I’ll tell you my minimum expectation: 25 swings with 25% of your body weight.
I write and explain this in a lot of detail in Volume 3 of our New Language of Movement Series. For the purposes of this article, the point that I need to make is that asymmetry isn’t a bad thing.
If you are thinking of all the times you have heard asymmetry leads to injury,” let me address that. Second, asymmetry is the wrong word to describe the real risk factors for injuries (compensations, irregularities, and not meeting minimum human movement standards).
Sport (and life as well as occupation) occurs in asymmetrical postures. We do need to strive to keep the irregularities between these asymmetrical postures as minimal as possible, but the human body is not designed for perfect symmetry.
That being said, for us to see a transfer of training effect from the gym to the real-world we need to better address the needs of our athletes/clients/patients. Doing 2-arm swings (symmetrical stance, coordinated weight shift) is a great starting point, but this version of a swing has very little direct transfer over to anything other than powerlifting, Olympic lifting, the standing long jump test, and the vertical jump test.
Because those are the only expressions of symmetrical power creation in sports. I’m sure I missed one or two on this list, but the bulk of athletics require the ability to generate and control power asymmetrically.
Once we have established a 2-arm, 1- kettlebellswing, we have displayed a symmetrical, but simple, ballistic (fast) expression of hip extension That begins with a 2-arm, 1- kettle bell dead lift. Every progression of swing we utilize for athlete begins with the slower and even simpler variation in the form of a dead lift.
You will notice that I omitted single leg stance. We don’t believe “single leg” is actually a developmental stance.
We do believe that people can stand on one leg and do all kinds of things, but when you look at the development of human movement competency where to we see a static single leg stance? When we see the expression of people being on one leg during work, life, and sport it is as a transition.
In the upper body, we follow a similar but different progression. The most basic attribute that we can discuss is the ability to asymmetrically generate and absorb force.
Posted in: Kettle bells, Neurodevelopmental Continuum, Strength, Swing, Training Filed under: #Ban, 25k, athlete, athleticism, Correlate, kettle bell, movement, MovementOutlaws, purpose, running, Science, swings Kettle bell training is the latest trend in town that is taking the world of fitness by a storm.
These simple exercises boost endurance, power and increase strength while reducing body fat. The kettlebellswing features a dead lift movement pattern that targets almost every muscle in the body.
The kettlebellswing is great for people who have time to only perform one exercise because of their busy schedule. The kettlebellswing is a fine choice as it targets a variety of movements and is not difficult to perform once you get the hang of it.
However, be warned not to swing too hard as the deceleration can lead to muscle soreness and make it difficult for you to walk for a couple of days. This exercise features dynamic movement and utilizes more force which is why you should always read the guidelines and abide by safety measures.
A kettle bell swings works wonders on your hamstrings, glutes, core, hips and back. However, the kettlebellswing helps maintain an upright position, improving your posture by pulling your shoulders back.
Everyone, starting from a professional bodybuilder to a casual fitness enthusiast, can benefit from a kettlebellswing. If you want to lose body fat and are dreaming of a leaner physique, perhaps kettle bell training is a good option for you.
Kettle bell training incorporates many high-intensity workouts that allow you to burn fat. Moderate to high repetitions will give your heart and lungs the ideal workout, causing you to feel rejuvenated and alive.
Big strength comes from performing eccentric movements and workouts that a beginner might be too intimidated to try. These eccentric movements will make your muscles sore the next day but the results will be worth it.
This means it only takes between 30 and 60 seconds before your lungs and heart are pushed to their maximum capacity. This means you really have to fight it to keep your joints in place, resulting in exceptional benefits for your stabilizing muscles.
Most women who work out have a common desire to build strength without achieving the bulky appearance of a bodybuilder. Kettle bell exercises incorporate full body functional movements that target several muscle groups at the same time.
Talk to your trainer about your special needs, and they will be happy to design a workout routine that meets all your specified requirements. Stand with your feet around 6 to 12 inches outside shoulder width, with each side of your foot positioned slightly outward.
Next, brush your arms on the inner thighs, extending your knees and hips while accelerating the kettle bell upwards. Some people advise the kettle bell should be facing completely skyward, but it could cause you to lose control.
Swinging the bell with one hand requires you to put in extra effort and can be twice as much demanding for the shoulders. Quickly, reverse the direction, driving the kettle bell with your hips, moving the bell straight out.
Two-handed kettlebellswing offers low impact training that is also easy on the joints, making it a terrific vertical jumping exercise. In today’s world we spend the majority of our days doing things in front of us with terrible posture.
This overuse of the muscles on the front side of our bodies is called “anterior dominance” and it is plaguing our society. Anterior dominance results in imbalances in our muscles causing us to move and perform at sub-optimal levels.
It will allow you to loosen your tight hips and strengthen your butt so that you’ll develop the rear end of an athlete. It will bulletproof your low back by creating an armored brace around your midsection, and it will get rid of that paunchy gut.
Push your hips back keeping your butt high and bend your knees slightly. Always making sure your shoulders stay above the level of your hips, “hike pass” the kettle bell through your knees by contracting your lats.
When you push your hips back keeping your butt high and your shins vertical, you are hinging. This is good because most people today are hip flexor and quad dominant (your anterior muscles), so learning how to load and use your posterior chain creates a natural balance between front and back that will help in preventing knee and hip issues.
Imagine that you are growing roots through your feet and grab the ground with your entire foot. Getting proper instruction from an expert so that you can MASTER THE KETTLEBELLSWING is the best thing that you can do for your training regardless of your goal.
If you want to build strength, kettle bell swings will forge a grip of steel and will add pounds to your dead lift & squat. If you want to boost your athleticism, kettle bell swings will make you more powerful and add height to your jump and shave seconds off your sprints.
If you want to pack on muscle, swinging a heavy kettle bell will build an intimidating upper back & set of shoulders. And if you want to shed body fat, swings will incinerate blubber like butter melting in an iron pan.
The classic kettlebellswing, the Russian swing, is a fundamental exercise that every guy should do. It’s an explosive and natural expression of hip extension, a key portion of your vertical leap and your sprinter’s stride, too.
You stand grasping a kettle bell with both hands, core tight, toes pointed ever-so-slightly outward, knees slightly bent. From there, you push your butt back slightly and hinge at the waist, letting momentum take the kettle bell behind your thighs.
Momentum carries the kettle bell upwards and in front of you, and your arms drive forward, typically until they’re parallel to the ground, in the process. In practice, the American swing frequently takes the emphasis off your mammies and glutes, and average gym-goers over-involve muscles that aren't meant for the job, such as the shoulders and lower back.
In general, you always want to choose exercises that minimize risk and maximize the benefits that’ll push you to your goals. You should evaluate all exercises this way (and not be afraid to question your group fitness trainer either -- it’s their job to answer you).
American swing fans have two key arguments that fail to account for the way the general population actually moves. It’s a demonstration of true shoulder flexion at the top of each rep, that your mid- and upper-back muscles will fire.
In this way, it’s a total body exercise, and superior and more “complete” than the Russian kettlebellswing. So that means, by default, they’re destined to perform the American swing incorrectly (and I've seen “fit” folks wreck this move, too).
Targeting muscles is important, even if “all-workouts-should-be-total-body” nation doesn't understand that, because it's a key method of correcting weaknesses in both your mechanics and your physique. Quick test: Lie with your belly on the ground, arms and legs long in front of you.
The basic swing lets you move a fairly heavy weight, since it relies on two of your body’s most powerful muscle groups, the legs and glutes, to generate the majority of the force. If those muscle groups can’t power the bell to the dumb American standard, the shoulders and lower back do the brunt of the extra work -- except they’re not meant to move the same load as the glutes and mammies.
So the shoulder muscles and smaller upper-body stabilizers take over that large load. The American swing crowd might contend that this isn’t all that different from a snatch anyway, hamstrings and glutes firing.
Thing is, both the barbell and single-arm snatch versions let you drive weights overhead while rotating and spreading your shoulders more freely to create joint space for your rotator cuff tendons. That can’t happen when both hands are grasping a kettle bell handle with a close grip.
They rely on high rep loads, and, eventually, fatigue piles on. Station-to-station randomness makes things worse: if the American swing ’s your first move, your mind and your shoulder blades aren’t fatigued.
You could go “lighter” on the weight with the American swing, both in a class setting and in your own workouts, focusing on form. Except then, your hamstrings and glutes, the targets of the classic swing, simply don’t get to move as much weight.
Unless you compete in CrossFit (where the American swing sometimes shows up in competition), the wildest part about the stupidity of the American kettlebellswing is that there’s a much simpler way to achieve the super-aggressive hip extension and explosive glute contraction that it is supposed to bring. There’s a smarter, less injury-inducing way to push your glutes and hamstrings to “pop” more than they do on your average Russian swing.
Ebenezer Samuel, C.S.C.S., is the fitness director of Men's Health and a certified trainer with more than 10 years of training experience. This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses.