Balance board

For the Wii video game accessory, see Wii Balance Board.

A wobble board. The black piece is the edge of a disk seen from its side.

A rocker-roller board.

A balance board is a device used for recreation, athletic training, brain development, therapy, musical training and other kinds of personal development.

It is a lever, similar to a see-saw, that the user usually stands on with the left and right foot at opposite ends of the board. The user's body must stay balanced enough to keep the board's edge from touching the ground.

A sphere-and-ring board

A different challenge is presented by each of the four types of balance boards and their subtypes. Some of them can be attempted successfully by three-year-olds and elderly people, and some, because of their speed and incline, are difficult and dangerous for professional athletes.

In their design, what differentiates the four types (and their subtypes) is how unstable each of them is, i.e., in how many and in which of the three dimensions of space each board turns and/or sways and how freely its fulcrum contacts the board and the ground.

Uses and users

Originally produced for skiers and then surfers to practice their skills in the off season and at night, a balance board is a device that has come to be used for training in all sports and martial arts, for physical fitness and for non-athletic purposes that are listed here.

It is used to develop balance, motor coordination skills, weight distribution and core strength; to prepare people, before they reach old age, to avoid injurious falls in old age; to prevent sports injuries, especially to the ankle; and for rehabilitation after injuries to several parts of the body.

Common uses of a balance board that are more distant from the athletic purpose of its origin are: to expand neural networks that enable the left and right hemispheres of the brain to communicate with each other, thereby increasing its efficiency; to develop sensory integration and cognitive skills in blind people, in children with autism and in children with other developmental disorders; to make dancers lighter on their feet; to teach singers optimal posture for the control of air-flow; to teach musicians how to hold their instrument; to look glamorous; to shake off writer's block and other inhibitors of creativity; as an accessory to yoga and as a form of yoga, cultivating holistic health, self-awareness and calm.

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A rolla bolla, which is one type of rocker-roller board.

Users who may not be interested in any of those practical purposes use a balance board to entertain themselves; it is a game of thrills that is somewhat frightening because of the almost constant sensation of being at risk of falling in the next moment if one does not adjust carefully enough before then.

Videos online: where to find them

The rest of this article will be made more vivid by pausing to look first at some online video clips of balance boards being ridden, in order to see the movements of the board, of the rider's body and of the rider's face. Hundreds of amateur and professional video clips are online. Among them are balance board videos showing fitness exercises, exercises for specific sports, skateboard-like tricks, accidental falls, handstands, musical performances, teen-agers fooling around, toddlers and acrobats.

There are videos at the websites of balance board manufacturers, most of them about ten or fifteen seconds long. The URLs of manufacturers' websites are listed in A Guide to Balance Boards That Roll in its "Catalog" section.

The URLs of 75 video clips are listed in A Guide to Balance Boards That Roll in its "Videos" section, but many of those URLs are outdated.

To find videos at YouTube or at some other videos search engine, type any of these terms in the search box: "balance-board -wii" or "balanceboard -wii" or "bongo-board" or "wobble-board" or "rolla-bolla" or "rola-bola" or the plural of any of those terms (except "wii"). Advice for keyword searches that is more specific is in A Guide to Balance Boards That Roll in its "To Search Online" section.

Structure

The user/rider/player stands on a board or other platform which is on top of an unstable ground-contacting member, the fulcrum. The height of the fulcrum of most models is between 3 and 6 inches (i.e., the top of the fulcrum is that distance above the ground). Due to the fulcrum's instability, all of a user's balance skills must be activated and coordinated in order to prevent the board from touching the ground.

Thus, the rider stimulates, exercises and teaches the parts of the body that implement the act of balancing (toes, soles, ankles, knees, hips, shoulders, arms and neck) and the parts of the body and brain that create the sense of balance and that engineer the implementation of the act of balancing (inner ears, cerebellum, proprioceptors [nerve receptors in muscles, tendons and ligaments around joints that let a person visualize a bone's changing location] and eyes).

The degrees of movement through which the board can move–-sliding, pivoting, rotating, tilting, rolling or some combination of those–-and the speed of the board differ in different types and subtypes of models, depending on the shape and size of the fulcrum, whether it is attached to the board and, if it isn't attached, the method(s) by which it is constrained by the board, if any. With an increase of speed and with each additional degree of movement through which one model or another can move, the need to avoid losing control of the board increases the level of fun and the danger of falling and forces the rider to exercise considerably more skill.

In rocker boards and wobble boards, the fulcrum is attached to the board. In rocker-roller boards and sphere-and-ring boards, the fulcrum is a separate piece. In sphere-and-ring boards, the fulcrum (a rubber ball) is constrained by a ring on the board's underside. In some rocker-roller boards, the fulcrum (a cylinder or mainly a cylinder) isn't constrained by the board (except by their friction), and in most rocker-rollers the cylinder is constrained by the board in any of five ways (a different number and combination of those ways in each type of rocker-roller).

Positions other than standing are also used, in order to work on particular muscles and skills. See below, under the heading "Fitness Exercises."

Playing the game: its tension

The opponents in the game are the person (standing at one end of the "see-saw") who made the most recent lean and the person (standing at the other end of it) who will need to make the next lean, in the opposite direction, to fight against the previous one's excess. Because the two opponents weigh about the same and are of about equal strength, neither of them has an easy time of it and neither of them is cowed, though it seems to each of them, about half the time or maybe a bit more than half the time, that the other is winning or is about to. They are as evenly matched as long-time sparring partners. Those two fighters are not actually two different people. They are the left and right (or front and back) halves of the same player, to each of whose halves the other feels like an opponent and troublemaker who can't be shaken off.

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Another illusion is the balancer's belief that the activity is play and not arduous exercise. Physical education teachers of young children make use of this confusion to get them to work out for 30 or 40 minutes without the usual resisting and faking. It is only when the activity ends that they realize, from how their bodies feel, that what they had been doing was, approximately, calisthenics and stretching. Although the balancing effort at each moment demands much less energy than outright calisthenics and stretching (except in the occasional moment when the need to recover from an extreme imbalance forces a student to throw a lot of weight fast), it adds up to a workout because the work is constant. In each minute there are about 55 seconds during which the body is too unbalanced to stop pushing.

On a board that can roll (i.e., a rocker-roller or a sphere-and-ring board), the player is almost always too clumsy to win (i.e., to stay balanced for as long as was hoped for) and therefore accepts defeat by landing, i.e., letting one end of the board come to rest on the ground. Until that defeat or until losing the game by the more unpleasant experience of bailing out, i.e., hastily hopping off the board in order to avoid the worst defeat, which is accidentally falling off the board (thereby possibly getting hurt), the player is a human pendulum caught up in a vicious cycle of over-compensations toward the left and right or front and back.

That cycle is too fast for comfort, especially on a board that can roll, except in occasional moments when the player "finds a groove" (as musicians sometimes do in rhythm) or "catches a wave" (as surfers do when their timing is perfect) and learns to relax enough to make the board stand still. Those moments of grace usually last for a fraction of a second and sometimes for as long as a few seconds. The ineffable satisfaction that is felt in those delicate moments can be communicated only through the eyes and fully appreciated only in the inner ears of the player/rider, where the vestibular system tries all day to calculate where the horizon is with absolute precision in order to achieve balance adequate for standing, walking, turning, sitting, aiming a fork or a spoon, swallowing, gesturing, handling objects and feeling safe. (If that constant navigational neuro-musculo-skeletal effort and achievement seem like something that can be done on automatic pilot or like anything less than rocket science and magic, close your eyes at the end of this sentence and try standing on one foot or writing or open your eyes and try brushing your teeth while standing on one foot.)

In those seconds when a balance board's rider is balanced enough to feel calm and calm enough to keep the board balanced, i.e., stationary, the sensation is not the kind of relaxation that comes of leaning back in one's favorite chair, getting ready to do nothing for an hour and slowly exhaling. It's a relaxation (if that word can be used for a mode of experience and effort that is more dynamic than a person's usual modes) that comes of having three systems--vestibular, visual and proprioceptive--operating and cooperating at high alert in rare perfect efficiency, in sync and humming like an expensive car's engine. It's a peaceful feeling: power.

On a board that can roll backward-forward (as opposed to left-right), the experience of maintaining that stationary mode, when the rider is successful enough to be able to maintain it for any number of seconds, is a state of trance. When the trance ends (when the rider feels the board land or move), the rider suddenly becomes aware of having until then been off the ground. (A thin carpet is the surface on which this rare experience is most likely to occur.) From soles and ankles to neck, it feels during this mode as if each nerve, muscle and joint has become aligned with the direction of the magnetic pull toward the center of the flat spinning planet. Some speculation on the transcendental effect of backward-forward rocking and balancing is in the third and fourth paragraphs below.

The player on a balance board constantly faces difficult choices. When an imbalance makes the board seem about to land, the player must decide whether to let the board land or to attempt recovering balance by throwing weight in the opposite direction, which often causes a worse imbalance that necessitates hopping off the board. When hopping off (to avoid a fall) seems advisable or necessary, the player must decide whether to accept that defeat or to "go for it" by throwing enough weight to recover balance and stay up on the board. Going for it can result in a worse imbalance that forces a fall, especially on a board that can roll. If there is someone watching the player, that choice between prudence and heroics becomes skewed toward risk, especially if there is more than one person or an important person watching. A player who feels about to fall must decide whether to adjust posture in order to soften the fall's impact or make a last-ditch effort to stay on the board (either to avoid defeat or to avoid a fall) by going for broke: throwing a lot of weight to recover balance, which can propel the player up into the air, causing a worse fall than the one that was originally impending.

A factor that complicates the choice between prudence and heroics is that their results can be the opposite of the intention if the rider is not realistic enough: A lean that was intended for safety may go too far, and a brave thrust that is successful (at keeping the board from landing) obviates the need to bail out (i.e., hop off the board to avoid a fall) when a hurried hop's impact could be hard on the ankle. After gaining some experience, a rider becomes more realistic-- though also more ambitious because of the new agility. An experienced rider seldom needs to hop off and hardly ever falls, unless attempting to do tricks.

As described above, how it feels when a board that can roll backward-forward stands still is a state of trance in which every piece of the body feels aligned with gravity's direction. What kind of effect this experience has on a person's mood is suggested by reference to a somewhat related non-sports exercise. The prolonged practice of swaying forward and back on the balls of the feet while pressing the inside of each foot against the other, thereby providing only the narrowest base of support for the constant swaying (a challenge that activates balance mechanisms of the body that would not need to operate if the feet were a normal distance apart), is the posture of a traditional Hebrew prayer, the Amidah, which lasts as long as it takes to whisper its more than 1,000 words and is performed three times a day. The Amidah induces a sharper focus, a more "plugged in" sensation and a more meditative detachment than other Jewish prayers, even though its text is less poetic, visual, religious and evocative than most Jewish prayers. The word "amidah" is the noun form of the Hebrew word that means "to stand," and probably the Amidah's dynamic kind of standing is what mainly captivates the person who recites it. The kinesthetic experience of this long prayer is a parallel to the attempt to stand still on a balance board that can roll backward and forward-- a safer and more readily available parallel to that.

A yoga teacher or biologist could probably explain why the inner ears, the soles and many nerves, muscles and joints between them are more thoroughly stimulated and lulled by backward-forward rocking than by the sideways kind and, for example, why rocking horses and rocking chairs do not rock sideways. One apparent reason is that the human body is not symmetrical front to back, which might make balancing in that orientation more challenging than sideways. The cause of the difference is more likely to be found in the inner ears or the eyes (or their connections to the brain). Each of the three semicircular canals (in each of the inner ears) is perpendicular to the other two. Maybe the canal whose orientation senses backward-forward tilt doesn't have the same sensitivity as the one that senses sideways tilt. Or maybe the sight of backward-forward tilt, i.e., the eyes' recognition of that tilt by the head they are in, doesn't have the same sensitivity as the sight of sideways tilt.

A rocker-roller board

The interior duel of a person's attempt to balance sideways on a rocker-roller board could be depicted by the staccato of a radio announcer's live report, e.g.:

"They come out cautious. They trade jabs. Joe takes a 1-2 on the inside. A right hook. A straight left. A hard left upstairs. They trade jabs again. Swings left. Swings right. Leans left. Two hard rights to the body. He's wobbling now. He's almost down. He answers him with a left hook. Leaping left hook to the right. "Is that all you got? Let me have it!" growls LaMotta. Hard body shot. The ref separates them. He's coming back. He's weaving from the right. He lands a left, sneering. He lands a left down the pipe. Heavier moves now from the right. He's reeling now. But he leans fast and comes back. A straight left. Stiff upper cut to LaMotta. He tries a sharp right but misses. Two jabs from the right. A vicious left. A wild right. Left-right, left-right, left-left-right. He works the body. A confident stance. Left feints. Right blocks. Nudges him to the center of the ring. Now the boys are dancing. A long right. A double left. 1-2 left, 1-2 right, 1-2 left. But now he sneaks in a right and a left of his own. Big left where it counts. The right pushes, pushes him to his corner. A left and a right and a left and another right. Bam. This could be it for him. He rocks backwards. He drops to his knees. He's on the ropes now. How much more can he take? He's down. He's down to the ground. The ref has seen enough and doesn't even bother to count. That's it."

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So, a person's normal assumption (i.e., gut perception) of what the sources of the aggression, conflict and frustration that s/he is currently encountering are becomes exposed, clarified, complicated and sometimes dissolved by the shoving match that a balance board incites. The question of who is doing what to whom becomes difficult to answer, unanswerable or irrelevant and forgotten.

Types

There are about a hundred models of balance boards on the market. Each of them is a version of one of about fifteen types of balance board. Each of these models and types can be classified as one of four basic types of balance board according to two binary parameters: whether its fulcrum is attached to the board and whether the board tilts in only two opposite directions (left and right or forward and back) or in every direction (360 degrees).

More specifically:

	bipolar	360 degrees
attached	Rocker	Wobble
not attached	Rocker-Roller	Sphere-and-Ring

In other words:

• A rocker-roller board is a rocker board whose fulcrum is a separate piece.
• A sphere-and-ring board is a wobble board whose fulcrum is a separate piece.
• A wobble board is a rocker board that tilts toward 360 degrees.
• A sphere-and-ring board is a rocker-roller board that tilts toward 360 degrees.

Those four analogies are not precise definitions. They ignore some details of models' structure.

Rocker boards

A rocker board is the most basic and least challenging type of balance board. It is a flat board with a fulcrum attached to the board's underside, perpendicular to the board's length. Thus, with one foot placed at each end, the person who is standing on the board can tilt it from side to side until the balance point is found. The fulcrum's shape differs in different models; five common shapes are a rectangular block, a rectangular block whose bottom is beveled, a semi-cylinder, a three-quarter cylinder and a gradual arc along a long section of the board's underside.

Rocker boards offer only one degree of movement– part rotation about the transverse axis.

These are made by manufacturers of toys and gym and sports equipment.

Wobble boards

video clip of a wobble board after it is flicked once

Wobble boards are widely used in child development, gymnasiums, sport training, rehabilitation after injury and physiotherapy. They are used on their own and in conjunction with other exercises and equipment.

The fulcrum of a wobble board is commonly a semi-sphere whose flat side is attached to the center of the board's underside. This allows the board to pivot in all directions during the same ride: forward-backward, left-right and anywhere in between. Standing on it exercises muscles that are not exercised by standing on boards that tilt in only two (opposite) directions. In almost all models, the board's length and width are about the same size. A circle is a common shape.

A version of the fulcrum that is easier to make and that facilitates improvising fulcrums of alternative sizes and shapes is made by replacing the semi-sphere with two semi-circular or approximately semi-circular flat pieces (of wood or some other rigid material) that are perpendicular to each other.

A wobble board offers full rotation about the vertical axis (i.e., spinning), part rotation about the transverse axis (i.e., backward-forward tilting) and part rotation about the longitudinal axis (left-right tilting), therefore having three degrees of movement.

Shopping: The challenge level of a particular wobble board is determined by the height of the fulcrum, by how gradual or sharp the fulcrum's curve that touches the ground is and by the length of the board (i.e., how close to each other the user's feet must be). Those three factors combine to determine the steepness of a board's incline, which is the angle its flat surface makes with the ground when its edge and the fulcrum are touching the ground. That angle is specified in almost all online and printed catalogs' descriptions of their wobble boards. The range of the incline of products on the market is 10 to 20 degrees.

Without the blue fulcrum that appears in the neighboring photo, this wobble board's incline is 10 degrees when any point along the board's circumference touches the ground.

When the blue fulcrum is attached by the user, the same board's incline becomes 18 degrees when any point along the board's circumference touches the ground.

A 4-year-old and a 70-year-old can manage a 10-degree board. A fast downhill skier and an experienced yoga practitioner can manage 20 degrees. It takes many hours of practice to be ready for an increase of one degree. When that happens, the incline that has already been mastered becomes boring. So, you will need to buy another board then and probably a third one after a while. You can save money by buying the later sizes in advance: either a set of boards that each have a different incline or one board that can be adjusted for three different inclines. Online sellers of several adjustable boards are listed near the end of the "Models That Don't Roll" section of A Guide to Balance Boards That Roll.

Extreme Balance Board, a well-known brand, is a highly versatile model. It is a combination of wobble board and rocker board that can be configured in various ways for different levels and kinds of challenge.

Wobble boards are made by manufacturers of gym, sports and physical therapy equipment.

Rocker-Roller boards

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A rocker-roller board

Rocker-roller boards add a degree of instability to the rocker board that makes them much more challenging for the rider than a rocker board is. (The photo of a wooden model at the top of this article shows the design of a common type of rocker-roller.) Rather than on a fixed pivot, a rocker-roller's board is placed on a cylindrical roller; this fulcrum is a wheel that moves in relation to the ground and in relation to the board. In almost all models the two flat ends of the wheel/roller are about as far from each other as the width of the board. In most models the axis of the roller is perpendicular to the board's length. Thus, as the rider's weight moves over the roller, the board both tilts from side to side and also slides sideways. In models whose roller can be placed with its axis parallel to the board's length, the board slides and tilts toward the front and back (if the rider's feet are oriented accordingly).

Acrobats, jugglers and other circus performers do stunts on a rocker-roller, which is called a rolla bolla (other spellings: rola bola, rolo bolo, roly boly and each of those four as a single word) in the circus world. Videos of such performances are online, findable via the Videos link at Google, which is accessible via the "More" link at the top of Google's window. A photo of a rolla bolla being balanced on by a performer supporting herself on it with her hands instead of her feet is above, at the bottom of this article's "Uses and Users" section. A photo of another rolla bolla stunt is below.

The roller has a different form in different models. Some are a cylinder and some are a cylinder in their midsection that tapers toward the two ends. That tapering enables tricky moves by the rider. Four of the models produced by Vew-Do Balance Boards each have a roller whose shape has a different taper, designed for doing different tricks and simulating different boardsports. In almost all rocker-rollers, the roller's diameter is between 3.5 and 6 inches at its widest section. The rollers of the rolla bollas that circus performers use are usually 8 or 9 inches in diameter. In one non-rolla-bolla model, the Bongo Balance Board, the roller is two wheels that rotate independently of each other on the same axle, allowing the board to roll and turn faster than other models when the rider's lean is not at exactly 90 degrees to the axle, which it hardly ever is. (The Bongo Balance Board, produced originally by KZT Sports and now produced by FitterFirst, is not the same model as the Bongo Board, which is no longer produced.)

Every few minutes into their act, many acrobats who perform on a rolla bolla add another roller on top of the one that was until then directly under the board, alternating the orientation of the rollers (curved side down vs. flat side down). Some performers stack five rollers.
The photographer's own caption notes that this acrobat did "180's" (moves in which he turned about-face while his feet were briefly off the board).

The ways in which the roller is constrained by the board also vary. Traditional rolla bollas have no constraints. Some boards have only a stop (a guard rail) at each end of their underside to stop the board from sliding off of the roller. Most models supplement that safety feature with another one that keeps the roller lined up with the board: a ridge on the board's underside, centered on the board's width, that runs between the two end-stops, parallel to the board's length, which (ridge) fits into a radial groove in the roller's center. This transverse guidance keeps the roller under the board and keeps the roller's axis parallel to the board's width.

For the rider's safety: If the roller has such a groove, an elastic cord can be stretched tight from one end-stop of the board to the other, passing under the roller's axle, to hold the bottom of the board to the roller when gravity does not.

A pivoting rocker-roller board created in 2007 by Holoholo Board Sports gives a rider the ability to ride and pivot or spin the board, making the experience more similar to riding a surfboard or skateboard than the ride on other models is.

If the rider of a Holoholo board positions the roller for backward-forward riding, which is more difficult than leftward-rightward riding, the roller is kept within a 1.25-inch range by end-stops and set-screws. This feature enables non-experts to ride in that orientation safely and to seek the state of trance that is described above, under the heading "Playing the Game: Its Tension."

Another feature that constrains the roller of some rocker-roller models to the board (and the floor) is winding a strip of rubberized grip tape around each of the roller's two ends, to slow it down. This kind of tape is sold in skateboard stores.

Rocker-roller boards offer two of the three degrees of rotation that wobble boards offer: full rotation about the vertical axis, i.e., spinning, and part rotation about either the longitudinal axis (in a model whose roller's axis is parallel to the board's width) or the transverse axis (in a model whose roller's axis is parallel to the board's length). Models that lack the transverse guidance (of a matching ridge and groove) offer either of those degrees of part rotation, depending on the roller's orientation, but not both at the same time. Unlike wobble boards, rocker-rollers offer a degree of translation (sliding) along the longitudinal axis, thus totalling four degrees of movement of which three are possible at any one time.

By combining different shapes of board with different forms of roller, constrained in different ways, a rocker-roller board can be given many different characteristics, leading to it being ridden in many different ways. This has made them popular with other board riders (e.g., skateboarders, surfers, snowboarders, etc.) and has made them a sport in their own right. Tricks can be done on these boards, and competitions are held.

They are also used in child development, gymnasiums, sport training and physiotherapy. They are used on their own and in conjunction with other exercises and equipment.

Getting the knack: Many people who try to learn to ride a rocker-roller board give up after less than 1 minute, convinced by a fall or a near fall that only an acrobat could manage it. But anyone who is under 50 years old who can ride a bicycle without training wheels can learn how to ride a rocker-roller board leftward-rightward if its roller has a groove for crosswise guidance. It takes between 10 and 20 minutes to learn, as long as the rider remembers the 4 numbers that are mentioned in the 3 tips about starting a ride that are on the 1st page of tips in A Guide to Balance Boards That Roll. Toward the end of that 1st 10 or 20 minutes, most people begin to feel that they are acrobats, Olympic athletes or Batman. Learning to ride a rocker-roller board backward-forward should not be attempted before becoming experienced riding one leftward-rightward.

Customizing a rocker-roller board for a beginner: The piece on the right whose end is outlined in blue (1.5 inches square) and the matching piece at the left end of the board are training blocks.

To keep a beginner from giving up, a board can be customized by screwing training blocks into it through the end-stops (the left and right guardrails on the underside of the board that stop the roller). The training blocks are attached for a beginner's first five minutes of riding and are then removed (until another beginner uses the board). The first five minutes on a rocker-roller board that doesn't have training blocks are like trying to ride a bicycle for the first time without ever having been on one that has training wheels and with a seat whose height precludes kicking against the ground. Without training blocks, the first tilt of each ride by a beginner is almost always too fast, which immediately forces a desperate opposite lean whose excess causes a fall or a near fall that permanently scares many beginners away from balance boards. When a rider is about to start a ride, the training block that is at the low end of the board (the training block that is resting on the ground) lowers the height of the board's high end and the height of the rider's higher foot (the foot that will start the ride by being leaned on); this reduces the speed of the board and the roller during a ride's first tilt. Many rocker-roller boards get left in an attic on the day they are taken out of their carton. With training blocks, they get people lining up at parties to wait for a turn.

The leading rocker-roller brands are Vew-Do Balance Boards (7 models), Indo Board Balance Trainer (6 models), Holoholo Board Sports (3 models), Bongo Balance Board (the only rocker-roller made by FitterFirst, maker of several other balance boards and many other balance products), Scrub (the name under which the Bongo Balance Board is sold in the United Kingdom) and Lush Balance Board (the only balance board made by Lush Longboards, maker of skateboards).

Sphere-and-Ring boards

The underside of a sphere-and-ring board

A sphere, usually an inflated rubber ball that is similar to a basketball or is an actual basketball, is the fulcrum on which the board is balanced. Diameters of different models' balls range from 4.5 to 12 inches. By redistributing his/her weight across the board, the rider can move the board in any direction other than vertically. It can also be tilted in any direction and fully rotated. Thus, sphere-and-ring boards give the greatest freedom of movement (and, therefore, challenge) of any type of balance board. They, like wobble boards, exercise muscles that are not exercised by use of boards that tilt in only two (opposite) directions.

For safety, the ball needs a stop, so that the board will remain on the ball. This stop is a ring (or other shape of wall) on the underside of the board. The ball is placed inside the ring, so that if the board is moved too far in any direction during a ride, the ball hits the ring, prompting the rider to lean in the opposite direction.

Thus, the area within the ring is the play area for the board. The bigger the ring, the more the board can be moved around. However, if the ball can move beyond where the rider can place his/her weight, control may be lost and the rider fall. Therefore, there is a maximum size the ring can safely be for a given size of rider. The ring can be simply circular or oblong in shape or more complicated to use more of the potential play area, while keeping the rider within his/her safety zone.

These boards are increasingly being used by other board riders as the freedom of movement makes them a more realistic trainer than other types of balance boards are (other than for skateboarding, which is mimicked more closely by a rocker-roller board with a tapered roller). They are also being seen as an activity in their own right, with tricks being adapted for them.

Sphere-and-ring boards also have application in child development, gymnasiums, sport training and physiotherapy.

Sphere-and-ring boards give the most degrees of movement of any type of balance board, allowing rotation about all axes and translation in both longitudinal and transverse direction. The only degree missing is translation in the vertical direction. Thus, they have five degrees of movement.

For safety, riding a sphere-and-ring board should not be attempted before becoming experienced riding a rocker-roller board leftward-rightward and backward-forward.

CoolBoard, Si-Boards and SurfBall are producers of sphere-and-ring boards.

Although the concept has been around for years, sphere-and-ring boards were not produced for marketing until 2005, when the Balance 360 Board (the model whose underside is shown in the above photo) was released. It appears that that model's manufacturer is no longer doing business. Information about that manufacturer and that model is displayed when that above photo is clicked on.

Injury risk and prevention

An adult-size wrist-guard whose hard plastic splint is six inches long, which enables the forearm and palm to absorb the impact of a fast fall. Only the splint's middle segment (its angled segment, which is white in the photo and which spans the underside of the wrist) is visible because the rest of it stays inside the black pad.

Balance boards are dangerous. Falling off one can tear your cartilage and break your bones, due to the force with which you throw your weight when attempting to prevent the board from landing or to prevent yourself from falling in the opposite direction. The most dangerous are rocker-roller boards and sphere-and-ring boards; due to their speed, "falling off" one of them can mean diving onto the floor or flying into a wall.

Wrist-guards of the kind that are sold in skateboard, snowboard and sporting goods stores and a helmet that blocks the skull and nose are recommended and for beginners are urgently recommended. Knee-pads and elbow-pads of the kind that are sold in those kinds of stores are recommended for beginners. The space within six feet of the board in every direction should be clear of furniture, walls, glass and hard or pointy stationary objects. The floor should not be concrete or stone, even if the concrete or stone is covered with wood, linoleum or carpet. Riding a rocker-roller or sphere-and-ring board while under the influence of alcohol or drugs is not as dangerous as driving under those conditions for the people passing by, but for the rider it is more likely to cause injury than driving because there is no airbag.

For the first two or three minutes of learning to ride a rocker-roller board or sphere-and-ring board, a rider should hold onto (or be held by) another person, more lightly in each next ride. If no person is available, for the first two or three minutes a rocker-roller board's rider should stand inside a doorway, facing its frame, and grasp, push against or touch the frame, more lightly in each next ride. Being that close to a hard object could be unsafe, but it is less unsafe than riding for the first time without any support. It should be a doorway that does not have a threshold and whose door does not have a door knob. A sphere-and-ring board needs more room around it than a doorway gives.

Fitness exercises

For particular muscles and skills, there are exercises that are done either while standing on a balance board (e.g., squats) or while contacting it in positions other than standing. For example, a user can lie face-down, with only the toes or knees contacting the ground, and press down on the board with the hands to do challenging pushups.

Other exercises and positions are shown in photos, videos and instructions at the websites of some balance-board manufacturers. The URLs of such videos and of manufacturers' websites are listed in the online PDF file A Guide to Balance Boards That Roll in its Videos section and its Catalog section. The Variations section of that PDF guide lists some exercises and some online sources of exercises.

The maneuvers for rocker-roller-board riding that are listed in Wikipedia's Rola Bola article under the heading "Rolla Bolla Skills" are more complex and challenging and less muscle-drilling than fitness exercises. They are performers' tricks and stunts. Diagrams, photos and videos of tricks and instructions for learning them are at some manufacturers' websites.

Iraq, 2003: a U.S. Air Force team in a game of tug of war

A contest for two opponents standing on balance boards: facing each other in a tug of war. Winning means the other player landed or let go of the rope. Besides pulling hard on the rope, two ways to try to win are faking the intention to pull or suddenly loosening the grip while the other player is pulling hard. This exercise is used by the U.S. Ski Team, with players standing on unspecified balance devices, according to the 2007 book Balance: In search of the lost sense by Scott McCredie. (The book is described at the end of this article, under the heading "External Links.") In the book's appendix, McCredie lists this tug-of-war among several one-person exercises provided to him by the ski team's trainer, Per Lundstam. If a tug of war is played on balance boards that roll, players are likely to fall and should wear the four kinds of safety equipment that are mentioned above, under the heading "Injury Risk and Prevention."

Two books of exercises that are illustrated by about three photos for each exercise:

Potvin, Andre Noel & Benson, Chad (2003). The Great Balance and Stability Handbook. Surrey, British Columbia: Productive Fitness Products.

Karter, Karon (2007). Balance Training: Stability workouts for core strength and a sculpted body. Berkeley, California: Ulysses Press.

Most of the exercises in those two books are for doing on balance devices other than balance boards: foam roller, balance cushion, balance ball or BOSU. The exercises there that are done on a balance board are shown being done only on a rocker board or a wobble board. Most of them can be done also on a board that rolls if the user is experienced enough and willing to risk injury.

Video game complements

A conventional (i.e., non-electronic) balance board can be connected to the Wii video game console, which was released by Nintendo in 2006. The movements of the board affect the video action when the wireless Wii Remote controller is attached to the board. The screen displays a live (i.e., simultaneous) representation of a ride, viewable by the rider and any other people in the room, that is more sophisticated than a realistic video of a ride. The display uses psychedelic animation effects. A 40-second online video of a rider watching a Wii screen's representation of his ride while he rides a balance board is at the homepage of Holoholo Board Sports, above a caption that mentions the wireless remote.

That feature (video representation of a non-electronic balance board's movement) is unrelated to the Wii Balance Board, which is an electronic accessory to the Wii. The Wii Balance Board, which was released by Nintendo in 2007, is not a balance board in the sense that that term is used in in the world of English-speaking sports equipment makers and users. It is a stationary platform that lies flat on the floor that translates the shifts of a user's bodyweight into psychedelic animation effects on the screen. This device is combined with the Wii Fit software for physical fitness exercises.

A simple homemade video game, BongoPong, connects a conventional (non-electronic) balance board by wire to a video screen which displays a simultaneous representation of the ride, viewable by the rider and any other people in the room. The display translates the movement and pressure of the rider's left and right feet (via their effects on the board) into the movement of paddles hitting a ball to each other. Clicking on the BongoPong link leads to a webpage that near its bottom has a 90-second video of a rider watching a video screen's BongoPong representation of his ride while he is riding. That webpage has links to three blog posts that give narration of the creation of BongoPong (with about twelve dollars' worth of materials, not counting what it cost to build a conventional balance board), but they don't give instructions for building the device. That narration and the accompanying photos might be enough to let an electronics person know how to build it. Its creator can be emailed from a link there.

External links

• A Guide to Balance Boards That Roll is a 30-page PDF text that includes the URLs of sellers of 40 models, the URLs of 75 video clips, tips for training and safety and explanations of why using a balance board develops athletic, cognitive and artistic skills and a less impetuous relationship with gravity and other forces that can't be controlled.

• the Bongo Board of the 1950's-1970's, shown in photos, a Newsreel video and official patent drawings, with information about its origin and inventor and about other devices that were based on its design. The groove in the Bongo Board's roller gave it the crosswise guiding that made it the first rocker-roller board controllable enough and safe enough for non-circus performers to ride. (The wooden model in a photo at the top of this article is a Bongo Board.)

• McCredie, Scott (2007). Balance: In search of the lost sense. New York: Little, Brown. This book's contents: a survey of scientific discoveries about the sense of balance in the 19th through 21st centuries; descriptions of people (e.g., pilots, toddlers, patients, acrobats) and animals whose normal or abnormal sense of balance enables the reader to understand and feel what scientists have explained; analyses of the constant and mostly unconscious operations of the sense of balance in the management of many of a person's basic activities and functions; descriptions of how sophisticated, limited and precarious the normal human sense of balance is; current theories of the influence of the sense of balance on a child's cognitive development and on human evolution; a survey of prostheses and other bio-engineering solutions currently being developed to restore the ability to sense balance input in people whose injuries have damaged or destroyed that ability; and how-to information for the general public on improving one's balance skills. The last words of the book's subtitle allude to three phenomena that are sketched in the next-to-last paragraph of the "Brains and Music" section of A Guide to Balance Boards That Roll.