Balance board
Encyclopedia
A balance board is a device used for recreation
Recreation
Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasure and are considered to be "fun"...

, balance training
Balance (ability)
In biomechanics, balance is an ability to maintain the center of gravity of a body within the base of support with minimal postural sway. When exercising the ability to balance, one is said to be balancing....

, athletic training
General Fitness Training
General fitness training works towards broad goals of overall health and well-being, rather than narrow goals of sport competition, larger muscles or concerns over appearance...

, brain development, therapy, musical training
Music education
Music education is a field of study associated with the teaching and learning of music. It touches on all domains of learning, including the psychomotor domain , the cognitive domain , and, in particular and significant ways,the affective domain, including music appreciation and sensitivity...

 and other kinds of personal development
Personal development
Personal development includes activities that improve awareness and identity, develop talents and potential, build human capital and facilitates employability, enhance quality of life and contribute to the realization of dreams and aspirations...

.

It is a lever
Lever
In physics, a lever is a rigid object that is used with an appropriate fulcrum or pivot point to either multiply the mechanical force that can be applied to another object or resistance force , or multiply the distance and speed at which the opposite end of the rigid object travels.This leverage...

 similar to a see-saw
See-Saw
See-Saw is a Japanese pop duo originally from Tokyo, Japan. Its members include Chiaki Ishikawa and Yuki Kajiura; former member left the group in April 1994 to pursue a writing career...

 that the user usually stands on, usually 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 edges from touching the ground and to keep from falling off the board.

A different challenge is presented by each of the four basic 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 steepness
Slope
In mathematics, the slope or gradient of a line describes its steepness, incline, or grade. A higher slope value indicates a steeper incline....

 and speed
Speed
In kinematics, the speed of an object is the magnitude of its velocity ; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as...

, are difficult and dangerous for professional athletes.

In their design, what differentiates the four types (and their subtypes) is how unstable
Newton's laws of motion
Newton's laws of motion are three physical laws that form the basis for classical mechanics. They describe the relationship between the forces acting on a body and its motion due to those forces...

 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
Lever
In physics, a lever is a rigid object that is used with an appropriate fulcrum or pivot point to either multiply the mechanical force that can be applied to another object or resistance force , or multiply the distance and speed at which the opposite end of the rigid object travels.This leverage...

 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
Martial arts
Martial arts are extensive systems of codified practices and traditions of combat, practiced for a variety of reasons, including self-defense, competition, physical health and fitness, as well as mental and spiritual development....

, for physical fitness
Physical fitness
Physical fitness comprises two related concepts: general fitness , and specific fitness...

 and for non-athletic purposes that are listed here.

It is used to develop balance
Balance disorder
A balance disorder is a disturbance that causes an individual to feel unsteady, for example when standing or walking. It may be accompanied by feelings of giddiness or wooziness, or having a sensation of movement, spinning, or floating...

, motor coordination
Motor coordination
thumb|right|Motor coordination is shown in this animated sequence by [[Eadweard Muybridge]] of himself throwing a diskMotor coordination is the combination of body movements created with the kinematic and kinetic parameters that result in intended actions. Such movements usually smoothly and...

 skills, weight distribution and core strength; to prepare people, before and after they reach old age
Old age
Old age consists of ages nearing or surpassing the average life span of human beings, and thus the end of the human life cycle...

, to avoid injurious falls; to prevent sports injuries, especially to the ankle
Ankle
The ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot...

  and knee
Knee
The knee joint joins the thigh with the leg and consists of two articulations: one between the fibula and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus , which permits flexion and extension as...

; and for rehabilitation
Healing
Physiological healing is the restoration of damaged living tissue, organs and biological system to normal function. It is the process by which the cells in the body regenerate and repair to reduce the size of a damaged or necrotic area....

 after injuries to several parts of the body.

Uses of a balance board that are distant from the athletic purpose of its origin have gradually become more common: to expand neural networks
Neural Networks
Neural Networks is the official journal of the three oldest societies dedicated to research in neural networks: International Neural Network Society, European Neural Network Society and Japanese Neural Network Society, published by Elsevier...

 that enable the left and right hemispheres of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

  to communicate with each other, thereby increasing its efficiency; to develop sensory integration
Sensory Integration Dysfunction
Sensory integration dysfunction is a neurological disorder characterized by a neurological sensory integration deficit. The more current diagnostic nosology uses the term sensory processing disorder to describe this condition....

 and cognitive skills in children with 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
Glamour (presentation)
Glamour originally was a magical-occult spell cast on somebody to make them believe that something or somebody was attractive. In the late 19th century terminology a non magical item used to help create a more attractive appearance gradually became 'a glamour'...

; to shake off writer's block
Writer's block
Writer's block is a condition, primarily associated with writing as a profession, in which an author loses the ability to produce new work. The condition varies widely in intensity. It can be trivial, a temporary difficulty in dealing with the task at hand. At the other extreme, some "blocked"...

 and other inhibitors of creativity; as an accessory to yoga
Yoga
Yoga is a physical, mental, and spiritual discipline, originating in ancient India. The goal of yoga, or of the person practicing yoga, is the attainment of a state of perfect spiritual insight and tranquility while meditating on Supersoul...

 and as a form of yoga, cultivating holistic health
Holistic health
Holistic health is a concept in medical practice upholding that all aspects of people's needs, psychological, physical and social should be taken into account and seen as a whole. As defined above, the holistic view on treatment is widely accepted in medicine...

, self-awareness and calm.

Users who may not be interested in any of those practical purposes use a balance board to entertain themselves; it is a game
Game
A game is structured playing, usually undertaken for enjoyment and sometimes used as an educational tool. Games are distinct from work, which is usually carried out for remuneration, and from art, which is more often an expression of aesthetic or ideological elements...

 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.

Skillful and dramatic balancing acts are presented by circus
Circus
A circus is commonly a travelling company of performers that may include clowns, acrobats, trained animals, trapeze acts, musicians, hoopers, tightrope walkers, jugglers, unicyclists and other stunt-oriented artists...

 performers who stack multiple boards on top of one another to increase the challenge, also combining this with other circus arts to create a more exciting spectacle.

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
Instability
In numerous fields of study, the component of instability within a system is generally characterized by some of the outputs or internal states growing without bounds...

, 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
Body
With regard to living things, a body is the physical body of an individual. "Body" often is used in connection with appearance, health issues and death...

 that implement the act of balancing (toes, soles, ankles, knees, hips, shoulders, arms and neck) and the parts of the body and brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 that create the sense of balance and that engineer the implementation of the act of balancing (inner ears, cerebellum
Cerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...

, 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
Pivot turn
The term pivot turn or simply pivot refers to certain turning dance steps which may differ in different dance styles, with common character that the turn is a rotational movement of the whole body around one's own vertical axis, as if around a pivot. During the turn the foot swivels on the floor...

, rotating, tilting, rolling
Rolling
Rolling is a combination of rotation and translation of that object with respect to a surface , such that the two are in contact with each other without sliding. This is achieved by a rotational speed at the cylinder or circle of contact which is equal to the translational speed...

 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 (to avoid landing or falling) 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 (an inflatable or solid 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) that are described below, in this article's "Rocker-Roller Boards" section.

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

For better foot traction, the stood-on surface of most models is manufactured with an unsmooth texture: for plastic models, in the molding; for wooden models, with grip tape or rubber. A smooth surface under the feet or shoes can cause a user to slip off a balance board and fall.

Wobble boards are the only type of balance board that is commonly made of plastic. Being no longer than their width, they don't need to be as strong and warp-resistant as other balance boards.

Classifying balance boards into four basic types

There are more than a hundred models of balance boards on the market in the United States. 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 the task
attached static balance
not attached dynamic balance

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. In some models the fulcrum is perpendicular to the board's length and in the other models the fulcrum is two rockers that are parallel to each other and parallel to the board's length, one in front of the person who is standing on the board and one behind. The ground-contacting edge of the fulcrum is curved in most models and is flat in some models.

With one foot placed at each end of the board, the user can tilt it from side to side until the balance point is found and can then either try to keep the board stationary or continue rocking.

Rocker boards offer only one degree of movement: part rotation about the longitudinal axis, i.e., banking (left-right tilting).

Most rocker boards are made by manufacturers of toys or of gym equipment.
Instability of the fulcrum

Rocker-roller boards add a degree of instability
Instability
In numerous fields of study, the component of instability within a system is generally characterized by some of the outputs or internal states growing without bounds...

 to the rocker board that makes them much more challenging for the rider than a rocker board is. Rather than on a fixed pivot, a rocker-roller's board is placed on a cylindrical roller; this fulcrum is a wheel
Wheel
A wheel is a device that allows heavy objects to be moved easily through rotating on an axle through its center, facilitating movement or transportation while supporting a load, or performing labor in machines. Common examples found in transport applications. A wheel, together with an axle,...

 that moves in relation to the ground and in relation to the board. The board's pivot point shifts back and forth as the cylinder rolls beneath it. 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).

The roller has a different form in different models. Some are a cylinder and some are a cylinder in their midsection that tapers
Cone (geometry)
A cone is an n-dimensional geometric shape that tapers smoothly from a base to a point called the apex or vertex. Formally, it is the solid figure formed by the locus of all straight line segments that join the apex to the base...

 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
Skateboarding trick
A skateboarding trick, or simply a trick is a maneuver performed on a skateboard while skateboarding. Learning and perfecting new tricks is the primary goal of many skateboarders, for whom most of the time spent skateboarding is spent on tricks....

 and simulating different boardsports. (One of those four is the roller at the top of the photograph to the side of this paragraph.) Vew-Do's patent gives information about the effect that its roller's shape has on the board's movement.

The diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...

 of the roller of almost all rocker-rollers is between 3.5 and 6 inches at its widest section. The rollers of the rola bolas that circus performers use are usually between 7 and 9 inches in diameter.

In the Bongo Balance Board, the roller (the second one from the top in the photograph to the side of this paragraph) is two wheels that rotate independently of each other on the same axle, each at its own speed according to the shifts of the rider's weight, allowing the board to roll and turn faster and more smoothly than other models when the rider's lean is not at exactly 90 degrees to the axle, which it hardly ever is. The ability of this model's two wheels to roll at different speeds includes each one's ability to stop while the other one is moving and their ability to roll in opposite directions at the same time. (The Bongo Balance Board, produced originally by KZT Sports in the 1990s and now produced by Fitterfirst, is not the same model as the Bongo Board, which was produced in the 1950s through the 1970s.)
Constraints on the fulcrum

The ways in which the roller is constrained by the board also vary:
  • Traditional rola bolas have no constraints (except the friction between the roller and board).
  • 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. This slide usually forces the user to fall. The end-stops are able to prevent this slide except when a careless lean by the rider causes the board to roll very fast.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. How the ridge fits into the groove is shown in a photo of the Bongo Board model in the "Structure" section of this article. This transverse guidance keeps the roller under the board and keeps the roller's axis parallel to the board's width. Without this feature, rocker-roller boards are not controllable enough or safe enough for unadvanced users to ride.


(Transverse guidance was introduced by the Bongo Board, which is the model whose movement is shown in the newsreel
Newsreel
A newsreel was a form of short documentary film prevalent in the first half of the 20th century, regularly released in a public presentation place and containing filmed news stories and items of topical interest. It was a source of news, current affairs and entertainment for millions of moviegoers...

 that appears at the top of this article's "Rocker-roller boards" section. Because the Bongo Board spread rocker-roller use beyond an elite of acrobats and circus performers to the general public, the Bongo Corporation's brand name "Bongo Board" is used loosely by some people as the generic term for a rocker-roller board of any type or model.)

  • If the roller has such a groove in its circumference, an elastic cord
    Elastomer
    An elastomer is a polymer with the property of viscoelasticity , generally having notably low Young's modulus and high yield strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, although the latter is preferred...

     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 (for the sake of safety) when gravity and friction do not.
  • At each of the two ends of a hollow roller (a pipe), a set-screw
    Set screw
    A set screw is a type of screw generally used to secure an object within or against another object. The most common examples are securing a pulley or gear to a shaft. Set screws are most often headless , meaning that the screw is fully threaded and has no head projecting past the major diameter of...

     from the board's end-stop(s) can be inserted horizontally into the hollow, a bit under the top of the roller. When the rolling in either direction makes the set-screws reach and press against the inside surface of the top of the roller, this contact makes the roller stop. This method of loosely locking the roller to the board is used by the models that are described in the next paragraph.


The models made by one company, Holoholo Board Sports, keep the roller locked loosely to the board when, instead of configuring the board for leftward-rightward riding, the user configures it for forward-backward riding. When locked, the roller can roll only a little further than one inch, which is more challenging to one's muscles and much more challenging to one's balancing skills than this short distance sounds. This lock makes riding forward-backward (which is more challenging than leftward-rightward) possible and safe for users who are not skilled enough for riding in that orientation on a board that is not locked to the roller. So, this lock enables a user to learn and practice toe/heel control, a fundamental boardsport skill. To make the Holoholo board suit users of a wide range of skill levels and to simulate features of a ride on a surfboard
Surfboard
A surfboard is an elongated platform used in the sport of surfing. Surfboards are relatively light, but are strong enough to support an individual standing on them while riding a breaking wave...

, skateboard
Skateboard
A skateboard is typically a specially designed plywood board combined with a polyurethane coating used for making smoother slides and stronger durability, used primarily for the activity of skateboarding. The first skateboards to reach public notice came out of the surfing craze of the early 1960s,...

, snowboard
Snowboard
Snowboards are boards, usually with a width the length of one's foot, with the ability to glide on snow. Snowboards are differentiated from monoskis by the stance of the user...

 or wakeboard, the user can configure the roller and/or an optional semi-cylindrical roller in any of nine ways, so that the user can merely roll or else do tricks by pivoting the board or spinning it.
Specifications

The degrees of movement offered by rocker-roller boards are one degree of translation
Translation (geometry)
In Euclidean geometry, a translation moves every point a constant distance in a specified direction. A translation can be described as a rigid motion, other rigid motions include rotations and reflections. A translation can also be interpreted as the addition of a constant vector to every point, or...

 (sliding, either left-right or forward-backward, depending on the roller's orientation, but not both at the same time), full rotation about the vertical axis, i.e., yawing (twisting) and part rotation about either the longitudinal axis, i.e., banking (in a model whose roller's axis is parallel to the board's width) or the transverse/lateral axis, i.e., pitching (in a model whose roller's axis is parallel to the board's length). Models that lack a transverse track offer either of those degrees of part rotation, depending on the roller's orientation, but not both at the same time. Thus, the total is 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, rocker-roller boards can be given many different characteristics, leading to their being ridden in many different ways. This has made them popular with other board-sporters (e.g., skateboarders, surfers, snowboarders, etc.) and has made riding them a sport in its own right. Tricks can be done on rocker-roller boards, and competitions are held. Tricks that do not need a tapered roller or a board shaped like a skateboard or snowboard (unflat or non-rectangular) are listed in the section about rola-bola tricks below.

Rocker-roller boards 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.

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 and fitness 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).
Novices' obstacle and solutions

Many people who try to learn to ride a rocker-roller board give up after several seconds, convinced by a fall or a near fall that only a gymnast 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 get the knack, 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, people begin to feel that they are gymnasts or acrobats.

Attempting to ride a rocker-roller board backward-forward before becoming experienced riding one leftward-rightward could cause a hard fall.

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 for the first time to ride a bicycle
Bicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....

 whose seat’s height precludes kicking against the ground without ever having been on a bicycle that had training wheels
Training wheels
Training wheels are an additional wheel or wheels mounted parallel to the rear wheel of a bicycle that assist learners until they have developed a usable sense of balance on the bicycle. Typically they are used in teaching very young children to ride a bike, although versions for adults exist...

 and without ever having been on one whose seat was low enough to enable kicking against the ground
Balance bicycle
A balance bicycle, or run bike is a training bicycle that helps children learn balance and steering. It has no pedals, no crankset and chain, and no training wheels.-Designs:Balance bikes have been made out of both metal and wood...

. Without training blocks, the first tilt of each ride on a balance board 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
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....

 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.

Rola-bola skills and tricks

In the circus
Circus
A circus is commonly a travelling company of performers that may include clowns, acrobats, trained animals, trapeze acts, musicians, hoopers, tightrope walkers, jugglers, unicyclists and other stunt-oriented artists...

, a variety of acts are performed on a rudimentary rocker-roller board, which is called a rola bola in the circus world. A rola bola lacks the transverse track that makes other rocker-roller boards easier to control and safer. A traditional rola bola lacks also another fall-preventing feature: a rocker-roller board's end-stops (the two guardrails on the board's underside at the opposite ends of the board's length, which are usually able to prevent the roller from scooting out from under the board). In the circus, multiple boards and cylinders are often stacked on top of one another in several alternative configurations, some of which are shown in photos in this article (not only in this section of the article). Some performers ride a rola bola or a stack of them while simultaneously performing one of these other circus arts: juggling, fire twirling (fire staff, fire poi
Poi (juggling)
Poi refers to both a style of performance art and the equipment used for engaging in poi performance. As a performance art, poi involves swinging tethered weights through a variety of rhythmical and geometric patterns. Poi artists may also sing or dance while swinging their poi...

 and fire devil sticks), hula-hooping and even acrobalance
Acrobalance
Acrobalance is an acrobatic art that combines elements of two other arts: adagio and hand balancing.Adagio consists of partner lifts, usually performed by a man and a woman, where the male lifts his female partner in many different poses and positions...

 and adagio.
Adagio (circus skill)
Adagio is the performance of partner acrobalance poses and associated movements that involve stationary balances by a pair of performers. It is performed in professional circus, in various dance disciplines including acro dance and ballet, in pair skating, and as a hobby in university circus...



Photos or videos of tricks are at the websites of many manufacturers of rola bolas and of other rocker-roller boards. Some of those websites include diagrams or instructions for learning the tricks.

Alternative spellings that are common: rolla bolla, rolo bolo, roly boly and each of these as a single word or hyphenated.

Skills and tricks on a rola bola:
  • balancing on one foot and the other knee (simultaneously)
  • balancing on one hand and one foot (simultaneously)
  • a bowling ball instead of a cylinder as the roller
  • center stand (in the center of the board, feet parallel to each other and together without space between them)
  • doing it in a dark (but not absolutely dark) room
  • doing it with eyes closed or—dangerous even for experts—blindfolded
  • free mount and ride for 30 seconds
  • free ride for 3 minutes
  • the Frog Stand (slowly squatting down while riding the board)
  • full jumping turns: 360°
  • half jumping turns: 180°
  • handstand
  • headstand
  • jump mount
  • jump mount with additional boards stacked for height in layers that alternate a board and two cylinders whose flat side faces down
  • pausing (suddenly stopping a roll, without reversing direction, when the cylinder reaches one end of the board)
  • the Penguin Stand (feet together in the center of the board with feet facing one of the long ends of the board)
  • quarter jumping turns: 90°
  • riding a board above two cylinders that roll in different directions
  • skipping rope
  • the Three-Stack (riding a board above three cylinders stacked in a column– the bottom one's flat side facing down, the middle one's curved side facing down and the top one's flat side facing down)
  • the Five-Stack (an extension of the Three-Stack)
  • standing on one foot
  • surfing (riding with the feet facing one of the ends of the board's length)
  • the Surf Hop (while surfing, standing on one foot and then hopping to the other foot)
  • two people on the board
  • walking the board (walking the board on the roller from one end to the other)

Wobble boards

The fulcrum of almost all wobble boards is a semi-sphere or smaller spherical cap
Spherical cap
In geometry, a spherical cap is a portion of a sphere cut off by a plane. If the plane passes through the center of the sphere, so that the height of the cap is equal to the radius of the sphere, the spherical cap is called a hemisphere....

 (or a shape that is approximately such) 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, i.e., toward 360 degrees. Standing on a wobble board 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 the usual shape.

Wobble boards are widely used in child development
Child development
Child development stages describe theoretical milestones of child development. Many stage models of development have been proposed, used as working concepts and in some cases asserted as nativist theories....

, gymnasiums, sport training, prevention of injuries to the ankle and knee, rehabilitation after ankle, knee and hip injuries and physiotherapy.

The basic exercise is standing on the wobble board with both feet and tilting in any direction without letting the board tilt so far that its edge touches the ground. Some of the many other common exercises are squats
Squat (exercise)
In strength training, the squat is a compound, full body exercise that trains primarily the muscles of the thighs, hips and buttocks, quads , hamstrings, as well as strengthening the bones, ligaments and insertion of the tendons throughout the lower body...

; standing on the board with one foot while keeping the other foot off the ground; push-ups (pressing down on the board with the hands while lying face-down with only the knees or toes contacting the ground); and sit-ups
Sit-up (exercise)
The sit-up is a strength training exercise commonly performed with the aim of strengthening the hip flexors and abdominal muscles. It begins with lying with the back on the floor, typically with the arms across the chest or hands behind the head and the knees bent in an attempt to reduce stress on...

 (with the board under one's rear end). Any exercise is much more work when a person's weight is on a wobble board than when s/he is supported by a stable and level base such as a floor.

For additional muscle exercise while wobbling, some models can be attached to an elastic stretch band
Resistance training
Resistance training has two different meanings. A broader meaning that refers to any training that uses a resistance to the force of muscular contraction , and elastic or hydraulic resistance, which refers to a specific type of strength training that uses elastic or hydraulic tension to provide...

. Each hand pulls up one of the band's two ends. Each end of the band fits through one of two opposed holes near the rim of the board, for quick attachment and detachment.

A wobble board offers full rotation about the vertical axis (i.e., yawing, i.e., twisting), part rotation about the transverse/lateral axis (i.e., pitching, i.e., backward-forward tilting) and part rotation about the longitudinal axis (i.e., banking, i.e., left-right tilting). A fourth and fifth degree of movement, translation
Translation (geometry)
In Euclidean geometry, a translation moves every point a constant distance in a specified direction. A translation can be described as a rigid motion, other rigid motions include rotations and reflections. A translation can also be interpreted as the addition of a constant vector to every point, or...

  (i.e., sliding) in the dimensions of the two horizontal axes, are possible for almost all wobble boards, i.e., all models except ones that have a stationary base. This sliding occurs much less often and usually across a shorter distance than in the case of a rocker-roller board and sphere-and-ring board. It is usually unintended and unwanted by a wobble board user and, presumably, also by the manufacturer and might more accurately be called skidding than sliding.

Plastic is the material that most wobble boards are made of. Wooden models are better able than plastic ones to withstand long use, such as in a gym. Among plastic models, how heavy-duty the plastic is varies.

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

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 maximum incline
Slope
In mathematics, the slope or gradient of a line describes its steepness, incline, or grade. A higher slope value indicates a steeper incline....

, which is the angle
Angle
In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...

 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 maximum incline of products on the market is 10 to 24 degrees.




A 3-year-old and many people in their 80's can manage a 10-degree board. A fast downhill skier and a yoga teacher can manage 24 degrees. To go from 10 to 16 degrees takes about seven months of daily practice; to go from 16 to 22 degrees takes about two and a half years of practicing several times a day. Above 22 degrees, the rate of progress and possibility of progress are unpredictable. Above 15 degrees, skipping any next degree (e.g., going from a 17-degree board to a 19-degree board) is very difficult and can cause repeated falls. All of these numbers and all other estimates here for challenge-level parameters assume averages for people who are physically developed and active and reasonably fit. In actual cases, the numbers vary widely.

Another reason that users need to buy a new board every so often (if they don't have access to several at a gym or health club) is that an incline that has already been mastered becomes boring for many users. To save money
Frugality
Frugality is the quality of being frugal, sparing, thrifty, prudent or economical in the use of consumable resources such as food, time or money, and avoiding waste, lavishness or extravagance....

, future inclines can be bought in advance: either a set of boards that each have a different incline or one board that can be adjusted for different inclines.

In the previous paragraph and the rest of this section, the noun "incline"
Slope
In mathematics, the slope or gradient of a line describes its steepness, incline, or grade. A higher slope value indicates a steeper incline....

 is used as a convenient replacement for "maximum possible incline."

A beginner's wobble board is shown in the following three side-by-side photos, which show the three alternative inclines to which this model can be adjusted. The shape of this model's two alternative fulcrums makes a beginner much less likely to fall off it or to quickly swear off ever again mounting a wobble board for fear of falling than happens with other models. The increase in challenge between this model’s low and medium settings and between its medium and high settings is small enough for a user to be comfortable with the increase after practice on the previous setting, which is not the case with most other adjustable models. It takes about one week of daily practice on the low setting for a user to be ready for the medium setting and about two weeks of daily practice on the medium setting to be ready for the high setting. A month of daily practice on the high setting prepares a user for a wobble board whose incline is 15 degrees. The grey fulcrum's bottom face might look flat in these small photos, but its gradual convexity (i.e., its arc) is noticeable in the closeup photo that appears in the margin of the paragraph that is under the small photos' captions.




What causes the incline of the above wobble board (the model shown in the three side-by-side photos and in the closeup of its attachable alternative fulcrum in the margin of this paragraph) to be much steeper than the incline of other models that have a similar level of challenge (or, to put it differently, what causes this model to be much less challenging than other models whose incline is the same as this model’s) is that the upper part of both of this model’s fulcrums is a cylinder. (Other models’ fulcrums are a spherical cap
Spherical cap
In geometry, a spherical cap is a portion of a sphere cut off by a plane. If the plane passes through the center of the sphere, so that the height of the cap is equal to the radius of the sphere, the spherical cap is called a hemisphere....

 or a shape that is approximately a spherical cap.) Because the convexity of the bottom face of this model's fulcrum is gradual enough (i.e., close enough to being flat) to enable a user to avoid leaning too fast (too fast to be able to correct an imbalance soon enough to avoid landing or falling), the increase in the board’s incline that is caused by the cylinder’s increase of the fulcrum’s height increases the board’s instability to a degree that is much less crucial (to a user who is trying to stay balanced) than the degree to which an increase in the incline of a model that has a non-cylindrical fulcrum increases the board’s instability. With this model, there is a much bigger difference (than with other models) between the maximum possible incline and the inclines that the user usually maintains during use. A user who wants a little stimulation can decide to keep the board approximately level, but the cylinder enables extra leaning when a user wants excitement or a workout.
It takes about four months of dialing a daily increase in the height of the above-pictured model's screwable fulcrum to go from being able to stand with difficulty on its least steep setting to standing on its steepest setting. ("To stand" here means to stand without letting the board's edge touch the ground.) To be ready to attempt standing on the least steep setting of this model takes having mastered either a 13-degree board whose entire fulcrum is curved like a spherical cap
Spherical cap
In geometry, a spherical cap is a portion of a sphere cut off by a plane. If the plane passes through the center of the sphere, so that the height of the cap is equal to the radius of the sphere, the spherical cap is called a hemisphere....

 or another board of that level of challenge, such as the model with an alternative grey fulcrum that is shown in the three side-by-side photos above.

Physical therapy
Physical therapy
Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...

 for injured joints is a wobble-board use for which the infinite variability of the above-pictured screwable model's incline is particularly useful. This feature makes it possible for a therapist or patient to dial to the currently optimal incline with absolute precision.

The range of the above-pictured screwable model's inclines (the range of its maximum possible inclines) is 16.5 degrees to 21 degrees, but because its fulcrum's bottom face is less convex than other models', the challenge level of its least steep setting is similar to that of a 14-degree model whose fulcrum is typically convex and the challenge level of its steepest setting is similar to that of a 16-degree model whose fulcrum is typically convex. What accounts for this discrepancy between the maximum incline and the felt incline and challenge, i.e., what makes the maximum incline steeper than would be expected for a model whose fulcrum's bottom face is more gradually curved than that of other models whose maximum incline is the same, is that this model's fulcrum has two upper parts—a cylinder and a slice of a cone—that are much steeper than the curve of the bottom face; this issue is explained in more detail above, in the paragraph under the captions of the three side-by-side photos of a wobble board with an alternative grey fulcrum.
Boards with springy fulcrums

These are not boards that have springs in them but rather boards whose fulcrum's material has some springiness to it (rubber, elastic, dense foam or inflated plastic). This springiness makes the stretching of the muscles, tendons and ligaments of the ankles and knees more smooth and thorough than it is on a wobble board whose fulcrum is wood or hard plastic.

Springy-fulcrum wobble boards are popular with both experienced board-sporters and non-athletes. They are used for training for board-sport tricks, for improving muscle tone and coordination and for rehabilitation of injured ankles and knees.

Two models, Fitterfirst's Soft Board Intermediate and Soft Board Advanced, have an unusually gradual impact on the ankles and knees and present a beginner's level of balance challenge because the ground-contacting surface of their fulcrum is unusually broad (seven inches in diameter) and entirely flat.

The fulcrum of two models, Vew-Do's Progression Trainer and Progression Fit, is a ball-and-socket joint that is mounted to a stationary base. The joint's elastic bushing can be adjusted (infinitely, by screwing) to increase or decrease the board's resistance to a user's tilt. This makes the board adjustable for how much the user weighs and for a broad range of balance-challenge levels without the board's maximum possible incline being changeable. Having a stationary base greatly reduces the risk of falling.

There are models that a user can configure, by inserting and/or removing some part(s), to make them move like either a rocker board or a springy-fulcrum wobble board. Two such models: Chango's Chango R4 and Chango S2000.

Another model, Twist Sport Conditioning's Smart Muscle Board (which was originally produced by Best Sport Toy Canada Co. under the name "Extreme Balance Board"), moves like a rocker board and somewhat like a wobble board at the same time (during the same ride) because the rubbery part of the fulcrum is springy enough to enable the board to tilt around a second axis (the lateral/transverse axis, for pitching, i.e., forward-backward tilting) in addition to tilting around the rocker's longitudinal axis (for banking, i.e., left-right tilting).

Because the rotation mode can be locked or slowed down in the Smart Muscle Board and the Chango models, a user can control the speed and instability of the equipment as desired.

Reebok's Core Board was produced from 2000 until 2008. Because many were sold, it is often still available from online sellers of used goods. Its fulcrum was attached to a stationary base. The board's resistance to a user's tilting was adjustable to three levels. It also recoiled against a user's twisting movement (around the vertical axis).
Improvising fulcrums


A testable prototype of a wobble board's fulcrum that is easier for a designer to make than a semi-sphere or other spherical cap
Spherical cap
In geometry, a spherical cap is a portion of a sphere cut off by a plane. If the plane passes through the center of the sphere, so that the height of the cap is equal to the radius of the sphere, the spherical cap is called a hemisphere....

 and that facilitates improvising fulcrums of alternative sizes and shapes is made by replacing the spherical cap with two identical flat pieces (of wood or some other rigid material) which are each in the shape of a semicircle or other circle segment (or a shape that is approximately such) in which a slot (whose width is the size of the material's thickness) is cut out of the top half of one piece and the bottom half of the other so that they can fit into each other perpendicular to each other, i.e., together forming an object that when seen from above is the shape of a plus sign (+).

This skeletal version of a fulcrum was intended also for the finished product in a design that was the first wobble board that is known to have been patented. The three drawings on the right are from its patent.

Two alternative variations (of the two flat fulcrum pieces' shape) that have potential for usefulness to a balancing person are a short vertical straight line above each of the ends (left and right) of the ground-contacting curve and a pair of short straight lines there that taper downward. Even small changes in that line's length and in the angle of its taper significantly vary the balance challenge. The three-dimensional results of those short lines (a cylinder and a conical section) in non-skeletal fulcrums are in the three side‑by‑side photos of a wobble board and in the five side‑by‑side photos of a wobble board in the "Levels of Challenge" section of this article's "Wobble Boards" section.

Excessive friction (friction between the floor and the skeletal fulcrum's two pieces that prevents the board from being responsive enough to shifts of the user's weight) can be eliminated by beveling the ground-contacting edge of each piece from the center of the edge toward each of the piece's two faces (or else rounding the edges).

Sphere-and-ring boards

A sphere, either an inflatable
Inflatable
An inflatable is an object that can be inflated with a gas, usually with air, but hydrogen, helium and nitrogen are also used. One of several advantages of an inflatable is that it can be stored in a small space when not inflated, since inflatables depend on the presence of a gas to maintain their...

 rubber ball (such as a basketball) or a solid polyurethane
Polyurethane
A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...

 ball, is the fulcrum on which the board is balanced. By redistributing his/her weight across the board, the rider can move the board in any direction– side to side, forward and backward, twisting, diagonal, and full rotations or any combination of these movements. A rider can move the board vertically by doing an advanced maneuver called an ollie
Ollie (skateboarding trick)
The ollie is a skateboarding trick where the rider and board leap into the air without the use of the rider's hands. Particularly on flat ground, it is not intuitively obvious how the liftoff is achieved, making the trick visually striking....

. It can also be tilted in any direction and fully rotated. Sphere-and-ring boards provide the greatest freedom of movement
Freedom of movement
Freedom of movement, mobility rights or the right to travel is a human right concept that the constitutions of numerous states respect...

 of any type of balance board, allowing rotation about all axes (yawing, pitching and banking) and translation (i.e., sliding) in both transverse (i.e., lateral) and longitudinal directions. They, like wobble boards, simultaneously exercise muscles that are not exercised by use of boards that tilt about only one axis (in two opposite directions).

When balancing or riding on a sphere-and-ring board, the difficulty and ride speed, which is how fast the rider can move the board on the ball, are determined by the following:
Ring's shape and size

For safety, sphere-and-ring boards use a stop so that the board will remain on the ball. This stop is a ring or railing (or other shape of wall
Wall
A wall is a usually solid structure that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into rooms, or protects or delineates a space in the open air...

) on the underside of the board. The ball is placed inside the rail, so that if the board is moved too far in any direction during a ride, the ball hits the rail, prompting the rider to shift weight and lean in the opposite direction. The rail can be simply circular or oblong
Rectangle
In Euclidean plane geometry, a rectangle is any quadrilateral with four right angles. The term "oblong" is occasionally used to refer to a non-square rectangle...

 in shape or more complicated to use more of the potential play area, while keeping the rider within his/her safety zone. Current manufacturers produce rings or rails made from steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

, polyurethane
Polyurethane
A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...

 or wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

.

Thus, the area within the rail is the play area for the board. If the rail is centered under the middle of the board, the rider's weight is evenly distributed when standing equidistant from the rail. If the rail is offset (closer to the tail or nose of the board), the weight distribution is uneven. An uneven weight distribution causes one leg to contract more than the other.

The larger the area inside the rail, the more the board can be moved around in all directions. The longer the rail, the wider the stance of the rider. The wider the stance, the greater adductor and quadriceps muscle strength required. However, if the ball can move beyond where the rider can place his/her weight or foot, control may be lost and the rider will fall. Therefore, there is a maximum size the ring can safely be for a given size of rider.

Depending on the size of the rail, the rider may be able to place more than one fulcrum under the board. This transforms the board from having one moving fulcrum point to having two of them. While the board is more stable with two fulcrum points, it is more challenging than a roller/tube because each fulcrum point can move independently.

A variation of the sphere-and-ring board is the SurfBall, which does not come with a ring. Instead of a ring, what keeps (or usually keeps) the board on the ball is a one-inch-deep concave recess in the board's underside. An optional ring can be purchased for the SurfBall for attaching to the board's underside. It can be configured for two alternative diameters.

Si-Boards produces polyurethane rails in varying size that can be attached to the bottom of a skateboard or other board top, allowing the user to create their own balance trainer.
Fulcrum's (Sphere's) size, weight and rigidity

Diameters of different models' balls range from 3 to 12 inches. A small fulcrum has less surface area contacting the board and ground, thus producing less friction. A small ball will roll faster than a larger ball. A smaller ball keeps the board closer to the ground, which is usually advantageous for beginners because it makes it easier to ground the board and stop quickly. A larger ball keeps the rider higher off the ground and usually lets the rider carve and tilt the board at greater angles.

Weights of different models' balls range from 0.5 to 20.5 pounds. A light-weight fulcrum requires less leg strength to move the board on the ball than a heavier ball does. Respectively, when momentum is gained it takes more strength and coordination to control the board on a heavier ball. Currently produced solid polyurethane balls by Si-Boards increase in weight as the ball diameter increases.

Fulcrum/sphere rigidity depends on the construction of the ball. A more rigid sphere (such as a solid polyurethane ball) that resists deformation has a smaller fulcrum point than a sphere that deforms (such as an inflatable ball). A smaller fulcrum point creates a faster ride, requiring faster reflexive response. Thus, a rigid sphere provides more challenge than a ball that deforms when weight is applied.
Board's shape and size

The board can be either flat or concave (the board curved upward at the nose and tail). A board with a concave shape moves with the natural motion of the hips (a ball and socket joint) like a pendulum. A board that is flat requires the hips to slide in each direction.

Secondly, the shape of the board impacts the way the board rides. Current board shapes are elliptical, rounded rectangular, butterfly, skimboard-shaped, surfboard-shaped and snowboard-shaped. If the board is narrow at the nose compared to a square or rectangular nose, the narrow nose has less weight and is easier to move. This make carving turns faster and easier. If the tail of the board is wide and rectangular, it is stable on the end.

The length of different models' boards ranges from 18 to 58 inches.

In summary, a rigid, small and light ball with a smaller board and railing size will ride faster, requiring more reflexive coordination. A rigid, large and heavy ball with a larger board and railing size will ride slower and will require greater leg strength to move the board.
Uses

Sphere-and-ring 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.

They have application in child development, gymnasiums, sport training and physiotherapy.

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. Learning how to ride a sphere-and-ring board can be quite challenging. The key point is to initially keep your upper body stable while moving your lower body. While holding onto a stable surface, such as a counter top, move the board left and right, forward and backward, twist side to side, then move the board top clockwise and counterclockwise. This provides a neurological wake-up to your lower body while integrating the core stability
Core stability
Core stability relates to the bodily region bounded by the abdominal wall, the pelvis, the lower back and the diaphragm and its ability to stabilise the body during movement. The main muscles involved include the transversus abdominus, the internal and external obliques, the quadratus lumborum and...

 of your upper body. Then try to stay centered and slowly let go of the stable surface. Let your body react to the movements of the board. Over time, you will be able to actively move and control the board.
Models and patents

The original concept of a balance board using a loose sphere for its fulcrum was patented in 1975 by Will Clarke England. Sphere-and-ring boards were not produced for marketing until 2005, when the Balance 360 Board (the model whose underside is shown in a photo in this article's "Structure" section), developed by Kevin Curran and granted a patent in 2007, was released. Si-Boards, developed by Elysia Tsai, became available on the market in 2007 and received a patent in 2008. CoolBoard was developed by Nic Smith.

Current producers of sphere-and-ring boards include Si-Boards (10 board models, 5 solid polyurethane balls), CoolBoard (3 models, 2 adjustable inflatable balls), SurfBall (3 models, 1 adjustable inflatable ball) and Balance 360 (2 models, 3 adjustable inflatable balls).

Aquatic balance boards

These are underwater balance boards. They were developed for physical therapy
Physical therapy
Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...

 and are used also for recreation. Besides the general advantages of aquatic therapy
Aquatic therapy
Definition of Aquatic Therapy: A therapeutic procedure which attempts to improve function through the application of aquatic therapeutic exercises. These procedures require constant attendance of a therapist educated in performing aquatic therapeutic exercises. [1, 2] Common synonyms: Aquatic...

 over non-aquatic therapy (the use of the smooth resistance of water instead of the jerky resistance of weights and the avoidance of burdening an injured joint with excessive weight– in this case, the weight of the patient's own body), aquatic balance boards have the specific advantage over non-aquatic balance boards of saving a patient who slips off of a board from the impact of falling and crashing into a floor. Slipping off of an aquatic balance board is safe as long as the user knows to avoid inhaling while underwater and knows how to tread water.

Three models are produced by Theraquatics Australia: The Theraquatics Balance Board is a V-shaped rocker board that a user stands, kneels or sits on. The Wonder Board is a V-shaped rocker board that a user kneels or sits on. The Aquatic Balance Board (a.k.a. the Aquafit Balance Board) is a wobble board. The holes in it allow water to fill it, making it neutrally buoyant (i.e., neither sinking on its own nor floating up to the water's surface) so that it is easier to control and safer than it would be if this wobble board were more buoyant.
Two products that Theraquatics Australia calls balance boards, its Star Balance Board and its Theraquatics Balance Board with Straps, are not balance boards in the familiar sense of the term, though they can be used for practicing balance skills.

Playing the game: its tension

The opponents in the game are the person (standing at one end of the "see-saw
See-Saw
See-Saw is a Japanese pop duo originally from Tokyo, Japan. Its members include Chiaki Ishikawa and Yuki Kajiura; former member left the group in April 1994 to pursue a writing career...

") 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
Boxing
Boxing, also called pugilism, is a combat sport in which two people fight each other using their fists. Boxing is supervised by a referee over a series of between one to three minute intervals called rounds...

. 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.

Another illusion is the balancer's belief that the activity is play and not arduous exercise. Physical education teachers
Physical education
Physical education or gymnastics is a course taken during primary and secondary education that encourages psychomotor learning in a play or movement exploration setting....

 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
Force
In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...

.

People who for the first time are seeing a young child of theirs on a balance board commonly make a similar remark, more commonly when the board is one of the types that roll: that they have never before seen such a degree of some specified attitude
Attitude (psychology)
An attitude is a hypothetical construct that represents an individual's degree of like or dislike for something. Attitudes are generally positive or negative views of a person, place, thing, or event— this is often referred to as the attitude object...

 in that child's face. The attitude specified by different parents is one of these: seriousness, fear, hope, concentration, alertness, aggressiveness, desperation, self-reliance, self-confidence, cautiousness, toughness, vigilance, meticulousness, frustration, determination, cunning, ambition, perseverance or poise. Some parents' version of that remark includes the modification that the only times they have seen such a degree of that attitude in the child's face were during a temper tantrum.

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
Landing
thumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...

, 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
Falling (accident)
Falling is a major cause of personal injury, especially for the elderly. Builders, electricians, miners, and painters represent worker categories representing high rates of fall injuries. The WHO estimate that 392,000 people die in falls every year...

 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
Relaxation (psychology)
In psychology, relaxation is the emotional state of low tension, in which there is an absence of arousal that could come from sources such as anger, anxiety, or fear. Relaxation is a form of mild ecstasy coming from the frontal lobe of the brain in which the backward cortex sends signals, or...

 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
Contentment
"Contentment" seems realistically defined as "enjoyment of whatever may be desired". That definition is realistic because the more contented an individual or community becomes the less extreme so more acceptable their desires will be...

 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
Vestibular system
The vestibular system, which contributes to balance in most mammals and to the sense of spatial orientation, is the sensory system that provides the leading contribution about movement and sense of balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of...

 tries all day to calculate where the horizon
Horizon
The horizon is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting...

 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.

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
Vestibular system
The vestibular system, which contributes to balance in most mammals and to the sense of spatial orientation, is the sensory system that provides the leading contribution about movement and sense of balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of...

, visual and proprioceptive--operating and cooperating at high alert in rare perfect efficiency
Energy conversion efficiency
Energy conversion efficiency is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The useful output may be electric power, mechanical work, or heat.-Overview:...

, in sync and humming like an expensive car's engine
Engine
An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...

. 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
Trance
Trance denotes a variety of processes, ecstasy, techniques, modalities and states of mind, awareness and consciousness. Trance states may occur involuntarily and unbidden.The term trance may be associated with meditation, magic, flow, and prayer...

. 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
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...

. 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
Prudence
Prudence is the ability to govern and discipline oneself by the use of reason. It is classically considered to be a virtue, and in particular one of the four Cardinal virtues .The word comes from Old French prudence , from Latin...

 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
Realism (arts)
Realism in the visual arts and literature refers to the general attempt to depict subjects "in accordance with secular, empirical rules", as they are considered to exist in third person objective reality, without embellishment or interpretation...

 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
Ankle
The ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot...

. 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
Skateboarding trick
A skateboarding trick, or simply a trick is a maneuver performed on a skateboard while skateboarding. Learning and perfecting new tricks is the primary goal of many skateboarders, for whom most of the time spent skateboarding is spent on tricks....

.

As described above, how it feels when a board that can roll backward-forward stands still is a state of trance
Trance
Trance denotes a variety of processes, ecstasy, techniques, modalities and states of mind, awareness and consciousness. Trance states may occur involuntarily and unbidden.The term trance may be associated with meditation, magic, flow, and prayer...

 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
Prayer
Prayer is a form of religious practice that seeks to activate a volitional rapport to a deity through deliberate practice. Prayer may be either individual or communal and take place in public or in private. It may involve the use of words or song. When language is used, prayer may take the form of...

, 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
Vestibular system
The vestibular system, which contributes to balance in most mammals and to the sense of spatial orientation, is the sensory system that provides the leading contribution about movement and sense of balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of...

 (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.

Injury risk and prevention

Balance boards can break bones and tear tendons, ligaments and cartilage. These risks can be diminished by preparing the space, wearing protective gear and following manufacturers' other safety recommendations.

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
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

 or stone
STONe
is a Japanese manga written and illustrated by Sin-Ichi Hiromoto. Kodansha released the two bound volumes of the manga on April 23, 2002 and August 23, 2002, respectively.The manga is licensed for an English-languague released in North America be Tokyopop...

, even if it is covered with a softer material, such as wood, linoleum or matting. Surfaces that are slick should be avoided. For a beginner, the surface of the floor or ground should be a material that provides traction, such as thin carpet, rubber matting, grass or turf.

Standing on a balance board is extremely dangerous for a person who is prone to dizziness
Dizziness
Dizziness refers to an impairment in spatial perception and stability. The term is somewhat imprecise. It can be used to mean vertigo, presyncope, disequilibrium, or a non-specific feeling such as giddiness or foolishness....

 and for a person who is tired or under the influence of alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....

 or another drug
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...

. Those four conditions compromise the reflexes, coordination
Motor coordination
thumb|right|Motor coordination is shown in this animated sequence by [[Eadweard Muybridge]] of himself throwing a diskMotor coordination is the combination of body movements created with the kinematic and kinetic parameters that result in intended actions. Such movements usually smoothly and...

 and focus that protect a person from accidentally falling off a balance board. Alcohol or another drug can give a user the impression that the opposite is the actual case– that being under its strong influence strengthens those three defenses. After or upon mounting a balance board, this grandiose sensation does not last long.

Standing on a balance board can be dangerous for all people, even when sober and alert. All types of balance boards can cause injury because standing on a moving and tilting surface can make a person fall or twist a joint. Manufacturers' guidelines, instructions and precautions detail how to use a balance board safely. With proper training and practice, the rider will learn how to safely stop the momentum of the board and of his or her body. Ignoring safety precautions and riding instructions without having proper body mechanics can result in a harder fall than would be expected from a height of only four to twelve inches above the ground. What makes the fall hard enough to cause injury is the force with which a user sometimes throws his or her weight when attempting to prevent the board from landing or to prevent falling in the opposite direction.

Wrist-guards of the kind that are sold in skateboard, snowboard and sporting goods stores and a helmet
Helmet
A helmet is a form of protective gear worn on the head to protect it from injuries.Ceremonial or symbolic helmets without protective function are sometimes used. The oldest known use of helmets was by Assyrian soldiers in 900BC, who wore thick leather or bronze helmets to protect the head from...

 that blocks the skull
Human skull
The human skull is a bony structure, skeleton, that is in the human head and which supports the structures of the face and forms a cavity for the brain.In humans, the adult skull is normally made up of 22 bones...

 and nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...

 are recommended and for beginners are urgently recommended. The helmet should not be a baseball batting-practice helmet because the thinness of its bottom edge makes it sharp enough to hurt the clavicle's area in a fall. For a small child, a hockey helmet
Hockey helmet
A hockey helmet is worn by players of ice hockey and inline hockey to help protect the head from potential injury when hit by the puck, sticks, skates, boards, other players, or the ice.-Construction:...

 or goalie mask
Goalie mask
A goaltender mask, commonly referred to as a goalie mask or a hockey mask, is a mask worn by ice hockey, inline hockey, and field hockey goaltenders to protect the head from injury. Jacques Plante was the first goaltender to create and use a practical mask in 1959. Plante's mask was a piece of...

 is safer than a U.S. football helmet because a small child’s neck is not strong enough to withstand the strain that a heavy helmet adds to the impact of some falls. Knee-pads and elbow-pads of the kind that are sold in skateboard, snowboard and sporting goods stores are recommended for beginners. Even without a fall or any other collision, sprains of the ankle and knee are a risk because of how fast, how suddenly and (for someone who is new to a particular board, even if experienced with other models) how unfamiliarly a rider needs to pivot. Ankle braces
Sprained ankle
A sprained ankle, also known as an ankle sprain, twisted ankle, rolled ankle, ankle injury or ankle ligament injury, is a common medical condition where one or more of the ligaments of the ankle is torn or partially torn.-Cause:...

 and knee braces
Anterior cruciate ligament injury
An injury to the anterior cruciate ligament can be a debilitating musculoskeletal injury to the knee, seen most often in athletes. Non-contact tears and ruptures are the most common causes of ACL injury....

 of the soft and flexible kind can prevent injuries without constraining those joints to a degree that would prevent necessary pivoting. Such braces are sold in sporting goods stores, medical supply stores and pharmacies.

Wobble boards whose base is not stationary can skid, which can cause the user to fall.

Because rocker-roller boards and sphere-and-ring boards have two surfaces that move in relation to each other, they are faster and more unstable than rocker boards and wobble boards. Although their greater instability and speed makes rocker-roller boards and sphere-and-ring boards more effective than rocker boards and wobble boards are in training a user to prevent an accidental fall and to soften the impact of a fall during non-balance-board use (while walking, turning, playing and running on the ground), rocker-roller and sphere-and-ring boards are much riskier than rocker and wobble boards while they are being ridden, especially for beginners. Some falls from a rocker-roller or sphere-and-ring board amount to throwing oneself at a floor or wall.

The first time learning to use any balance board, a user, no matter of what age and athletic ability, should hold onto or be held by a spotter (another person), more lightly in each next ride as coordination and skill are developed. If no person is available, the user should hold onto a stable surface such as a counter top, back of a couch, or plyometric box. Another option is to 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
Squat (exercise)
In strength training, the squat is a compound, full body exercise that trains primarily the muscles of the thighs, hips and buttocks, quads , hamstrings, as well as strengthening the bones, ligaments and insertion of the tendons throughout the lower body...

) 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 competitions and entertainment that are listed in the section about rola-bola tricks in this article's "Rocker-Roller Boards" section are more complex and challenging and less muscle-drilling than basic fitness exercises are.

A contest for two opponents standing on balance boards: facing each other in a tug of war
Tug of war
Tug of war, also known as tug o' war, tug war, rope war or rope pulling, is a sport that directly pits two teams against each other in a test of strength. The term may also be used as a metaphor to describe a demonstration of brute strength by two opposing groups, such as a rivalry between two...

. 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 unstable balance-training devices, according to the 2007 book Balance: In search of the lost sense by science journalist Scott McCredie. 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
Tug of war
Tug of war, also known as tug o' war, tug war, rope war or rope pulling, is a sport that directly pits two teams against each other in a test of strength. The term may also be used as a metaphor to describe a demonstration of brute strength by two opposing groups, such as a rivalry between two...

 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: a balance cushion, a foam roller, a balance ball or the BOSU
BOSU
A BOSU Balance Trainer, or BOSU ball as it is often called, is a fitness training device, invented in 1999 by David Weck, consisting of an inflated rubber hemisphere attached to a rigid platform. It is also referred to as the "blue half-ball", because it looks like a stability ball cut in half...

. 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.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK