|Movement Experience for Children|
|Instructor:||Dr. Shannon S.D. Bredin|
|Important Course Pages|
Balance is one of many identified abilities underlying motor performance in children (Clark & Watkins, 2010). In order to accomplish progression of other gross motor milestones such as walking to jumping and skipping, it is crucial to master the skill of balance (Roncesvalles, Woollacott, & Jensen, 2001). Essentially, balance provides the foundation to build other gross motor skills (Clark, 2007).Standing balance in particular is a necessary precursor to upright locomotor skills (Clarke, 2007). Balance reaches an adequate level during preschool years and the skill is mastered in later childhood (Venetsanou & Kambas, 2011).
- 1 Definition
- 2 Components of Balance
- 3 Types of Balance
- 4 Developing Balance
- 4.1 The Change of Centre of Pressure Throughout Childhood
- 4.2 Critical Age to Balance
- 4.3 The Childhood Changes in the Dependence of the Visual, Vestibular, and Somatosensory Systems on Balance
- 4.4 World Health Organization’s Window of Achievement for Six Gross Motor Milestones that Depend on Balance
- 5 Importance of Balance
- 6 Common Problems and Causes
- 7 Strategies to Maintain Balance
- 8 Functional Balance Assessment
- 9 Practical Applications in a Clinical Setting
- 10 References
According to the Oxford Dictionaries (2014), balance is defined as “an even distribution of weight enabling someone or something to remain upright and steady”. Simply put, balance is the ability to prevent the human body from falling (Pollock, Durward, & Rowe, 2000). Balance involves integral coordination between several systems which include the vestibular system, somatosensory system, and visual system (Redfern, Yardley, & Bronstein, 2001).
Components of Balance
Sensory inputs from the vestibular, visual, and somatosensory systems work together to maintain balance (Cumerworth et al., 2006).These three sensory systems have varying frequency ranges that affect their influence on balance control (Redfern et al., 2001). For example, very slow movements are characterized by extremely low frequencies and are best stabilized by sensory inputs from the visual system (Redfern et al., 2001). Faster movements are characterized by higher frequencies and are best stabilized by sensory inputs from the vestibular system (Redfern et al., 2001). The somatosensory system help assist balance in both fast and slow movements (Redfern et al., 2001). Damage or abnormality to any of these three systems can cause balance disorders (Casselbrant & Mandel, 2005).
The vestibular system coordinates and transforms information from the visual, proprioceptive, auditory, and tactile systems to maintain balance (Casselbrant & Mandel, 2005).This system is the last sensory system to mature and does not fully develop until late childhood (Cumerworth et al., 2006).
The visual system is the predominant system for the maintenance of balance especially for children (Gaerlan et al., 2011). The visual system detects motion to determine whether it is self-motion or movement of the environment (Redfern et al., 2001). When the visual system detects movement in the environment, the body responds with an increased sway (a back and forth motion of the body with the ankle joint as a pivot point, mimicking the motions of an inverted pendulum) to maintain balance (Redfern et al., 2001).
The somatosensory system is responsible for relaying proprioceptive information from the skin, muscles, and joints that are sensitive to stretch or pressure senses which provide information about the placement of body parts in space (Gaerlan et al., 2011). Mechanoreceptors, which detect pressure, are particularly important as they provide information about muscle length and velocity of contraction (Gaerlan et al., 2011). This information contributes to the ability to recognize joint movement and position (Gaerlan et al., 2011).
Types of Balance
The two main types of balance are static balance and dynamic balance (Venetsanou & Kambas, 2011).
Static balance is the ability to maintain control of posture in a stationary position (Venetsanou & Kambas, 2011). Static balance is important because it is required for many motor milestones of a child such as sitting or standing with no support (Cherng et al., 2003). Children can improve static balance through simple activities such as standing on one foot, balancing on both knees, standing on a narrow surface area such as a balance beam, or gently being pushed off balance while engaging the muscles at the waist and upper trunk to maintain an upright position (Lewis, Higham, & Cherry, 1985).
Dynamic balance is the ability to maintain postural control while performing functional tasks such as hopping, jumping, or riding a bike (Venetsanou & Kambas, 2011). Children can improve their dynamic balance through activities such as reaching for an object, walking up and down steps with a beanbag on their head, or walking up an inclined surface forward, backward, and sideways (Lewis, Higham, & Cherry, 1985). Walking is a more complex type of dynamic balance as it involves a balance between the body moving forward and the body maintaining lateral stability (Assiante, 1998). Due to the fact that the weight of the whole body must be supported by one leg during the swing phase, it is one of the more difficult balance tasks that infants experience when they learn to walk (Assaiante, 1998).
To achieve balance, the centre of gravity must remain within the base of support (Clark & Watkins, 2010). The centre of gravity is the point through which the vector of the body weight passes (Pollock, Durward, & Rowe, 2000).The base of support is the area of the body in contact with a support surface, such as the ground that exerts a counterforce against the body’s applied force (Pollock, Durward, & Rowe, 2000). The bigger or wider the base of support, the easier it is to maintain balance (Pollock, Durward, & Rowe, 2000). For example, when doing a hand stand, the base of support is the region bounded by the hands. In order to maintain balance while doing a hand stand, the head and body must be over the hands. This is a balanced position because the centre of gravity is within the base of support (Pollock, Durward, & Rowe, 2000). Balance can also be affected by changing the location of center of gravity. The higher the centre of gravity is within the body, the harder it is to maintain balance (Pollock, Durward, & Rowe, 2000). For example, standing on one leg and raising both arms redistributes the centre of gravity further up the body which result in less balance (Pollock, Durward, & Rowe, 2000).
The Change of Centre of Pressure Throughout Childhood
It is known that balance improves throughout childhood (Cumerworth et al., 2006). The improvement of balance throughout childhood is measured by the child’s ability to maintain their mean centre of pressure (COP) for a long period of time (Cumerworth et al., 2006). COP is the point of application of the vertical ground reaction force exerted on the foot or feet. Children with better balance are able to keep their COP in a smaller area when maintaining balance (Rival et al., 2005). Younger children have less balance because their COP moves at a faster velocity during balance assessments (Rival et al., 2005). As a consequence, younger children have less stability because they make larger and faster corrections to their COP in order to maintain balance (Rival et al., 2005). As a child gets older, their COP reduces in range and speed when maintaining balance (Rival et al., 2005). This means that older children are able to spend more time at the mean COP, thus indicating better stability (Rival et al., 2005).
Critical Age to Balance
The ages of 7-8 years old appears to be the critical age in balance development for a child (Gaetner et al., 2013). During this age period, balance begins to improve and resemble adult-like balance due to having better head-trunk coordination (Gaetner et al., 2013). During this transition period, children often have difficulty in maintaining the mean COP for a long period of time and minimizing movement of their COP (Rival et al., 2005). However, despite the increase in movement of their COP, they achieve better balance compared to before because their COP moves at a slower velocity (Rival et al., 2005). The decrease in velocity of the COP means that the child is learning to maintain the mean COP with accuracy for a longer period of time (Rival et al., 2005).
The Childhood Changes in the Dependence of the Visual, Vestibular, and Somatosensory Systems on Balance
The dependence of the visual, vestibular, and somatosensory systems changes as balance improves throughout childhood (Cumerworth et al., 2006). They change because these three input systems do not finish developing at the same time (Cumerworth et al., 2006). At an early age of 3-4 years old, the somatosensory system is the first system to fully develop like an adult (Cumerworth et al., 2006). Visual function is the second system to fully develop at the age of 15 (Cumerworth et al., 2006). The vestibular system does not develop until later in life and is the last system to be fully developed (Cumerworth et al., 2006). Since the input systems are not fully developed during early childhood, younger children have difficulty suppressing inappropriate visual and somatosensory inputs causing them to be less stable (Cumerworth et al., 2006).
The visual system is the main system that young children rely on for balance (Cumberworth et al., 2006). At 3 years of age, balance control is primarily dependent on the visual-vestibular system (Cumerworth et al., 2006). As a child gets older, their balance improves because there is a gradual maturation of the cerebellum which causes the child to depend less on visual input and increase their dependency on their vestibular system (Cumerworth et al., 2006). At 6 years of age, balance control primarily depends on the somatosensory-vestibular system (Cumerworth et al., 2006). Although children begin to rely on their somatosensory-vestibular system, up to the age of 10, they continue to be more visually dependent and have not fully developed their postural stability like adults (Rival et al., 2005). For example, when older children and adults are given a simple balance task, they show no difference in balance control (Cumerworth et al., 2006). However, when given a difficult balance task, studies demonstrated that adults have a significantly greater balance as compared to older children (Cumerworth et al., 2006).
World Health Organization’s Window of Achievement for Six Gross Motor Milestones that Depend on Balance
According to the World Health Organization, the following six gross motor milestones that depend on balance should be achieved within the following time frames (WHO, 2006). These six motor milestones were specifically selected because it was considered to be universal and fundamental to locomotion for development (WHO, 2006). They were also chosen because they are simple to test and evaluate (WHO, 2006).
|Motor Milestone||Age achieved|
|Sitting without support||4 – 9 months|
|Standing with assistance||5 – 11 months|
|Hands and knees crawling||5 – 14 months|
|Walking with assistance||6 – 14 months|
|Standing alone||7 – 17 months|
|Walking alone||8 – 18 months|
Importance of Balance
Balance plays a fundamental role in providing the foundation for gross motor skill development in children (Roncesvalles et al., 2001). Pre-school age is an important period for fundamental motor skill development and balance is a prerequisite for many skills. For example, when a child progresses from walking, to running, jumping, hopping, galloping, and skipping, strengthened ability to balance allows smooth transition from one motor skill to another. Appropriate balance control allows adjustment of muscle and joint position to maintain static balance (Venetsanou & Kambas, 2011). A dysfunctional balance control may indicate varying types of developmental deficits (Venetsanou & Kambas, 2011).
Common Problems and Causes
Balance disorders associated with dizziness in children are divided into three categories including acute non-recurring spontaneous vertigo, recurrent vertigo, and non-vertiginous dizziness (Casselbrant & Mandel, 2005). Acute non-recurring spontaneous vertigo is unusual in children and they typically recover from symptoms such as nausea and vomiting within days (Casselbrant & Mandel, 2005). Due to the short recovery time, parents may associate the symptoms to other health issues rather than a balance disorder (Casselbrant & Mandel, 2005). Recurrent vertigo can be due to disease of the peripheral or the vestibular system (Casselbrant & Mandel, 2005). Lastly, non-vertiginous dizziness is caused by vestibular disorders (Casselbrant & Mandel, 2005).
Head traumas and migraines are common causes of balance disorders in children (Casselbrant & Mandel, 2005). Although children usually recover fully from head traumas in a short period of time, even mild cases of head traumas can lead to abnormalities in balance testing (Casselbrant & Mandel, 2005). Symptoms include dizziness, sudden hearing loss, and clear or bloody drainage from the ear (Casselbrant & Mandel, 2005). Migraine is one of the most common causes of recurrent vertigo in children with symptoms ranging from nausea, vomiting, and agitation (Casselbrant & Mandel, 2005).
Strategies to Maintain Balance
The two main strategies used to control balance are the hip and ankle strategies (Colobert et al., 2006). These two strategies are basic motor programs from the nervous system which are used when the body is challenged with a task to maintain balance (Zhang et al., 2006).
The ankle strategy consists of a rotation in the ankle joint to assist the body to maintain balance (Creath et al., 2005). This strategy is when muscle activity starts in the ankle joint, and then travels to the muscles of the thigh and trunk respectively (Colobert et al., 2006). The body motion of this strategy is seen as a single-segment of an inverted pendulum produced by a force at the ankles (Colobert et al., 2006).
The hip strategy is the reverse of the ankle strategy where activity starts in a top-down sequence (Colobert et al., 2006). Therefore, activity starts from the trunk and travels toward the thigh and ankles respectively (Colobert et al., 2006). The body motion created by this strategy is associated as a double-segment inverted pendulum with counterphase rotations at the ankle and hip (Colobert et al., 2006). This means that the hip strategy is an inverted pendulum with another pendulum attached to its end, alternating in rotation at the hip and ankle joints (Colobert et al., 2006).
When is Each Strategy used for Balance?
The generally accepted idea is that the ankle strategy is used during quiet stance, which is standing with a stable support and surroundings (Zhang et al., 2006). The hip strategy is mainly used during a perturbed stance, which is standing with a brief disturbance of the support surface such as a moving surface (Zhang et al., 2006).
Different types of perturbation or disturbances determine whether the ankle or the hip strategy is used (Zhang et al., 2006). For example, an increase in weight by carrying a heavy object during quiet stance is more likely to increase the likelihood of utilizing the hip strategy (Zhang et al., 2006). Whereas the ankle strategy is more sensitive to sensory information such as standing with two feet naturally apart without any disturbances (Zhang et al., 2006).
During a quiet stance, the body sways forward and backward, as well as from side to side (Zhang et al., 2006). An anterior/posterior (forward/backward) sway is based on ankle control whereas a medial/lateral (side to side) sway is based on hip control (Zhang et al., 2006). Children experience more anterior/posterior sway compared to adults, however, they have a similar amount of medial/lateral sway (Cherng et al., 2003). This is because children do not resemble the same body structure as adults until they reach the age of 12-15 years old (Cherng et al., 2003). For example, children under 12 years old have more mass in the head, trunk, and upper extremities than in the lower extremities (Cherng et al., 2006). Another reason for this finding is because children have imperfect ankle control compared to adults, but has similar hip control of body sway (Cherng et al., 2006). This implies that children’s’ ankle strategies are still developing (Cherng et al., 2006).
Functional Balance Assessment
Developmental assessment instruments use various balance tasks such as static balance on one foot and walking heel-to-toe to evaluate balance skills in children (Venetsanou & Kambas, 2011). There are many clinical assessments to determine balance in children (Pollock, Durward, & Rowe, 2000). For example, the Rivermead Stroke Assessment can be used to determine the ability of a child to sit unsupported (Pollock, Durward, & Rowe, 2000). The Motor Assessment Scale can be used to determine the child’s ability to perform a voluntary movement after a disturbance and the ability to maintain balance from sitting to standing (Pollock, Durward, & Rowe, 2000). All of these clinical assessments measure different aspects of postural control but they are all valid in determining balance (Pollock, Durward, & Rowe, 2000).
Practical Applications in a Clinical Setting
Children with poor postural control are more likely to fall and be injured (Fong et al., 2012). Physiotherapists who aim to improve children’s balance in a clinical setting should focus on implementing exercises that incorporate skills acquired from Taekwondo. Research shows that children who practice Taekwondo have a better vestibular function compared to children who do not participate in Taekwondo classes (Fong et al., 2012). It is suggested that techniques used in Taekwondo help improve the effectiveness of the cerebrum to integrate somatosensory, visual, and vestibular inputs thus resulting in less body sway during one legged stance (Fong et al., 2012).
How does Taekwondo Improve Balance?
The vestibular system of children who have Taekwondo experience are comparable to adults, and they also demonstrate better stability while performing a one legged stance test (Fond et al., 2012). This suggests that the jumping and spinning techniques in Taekwondo help speed up the development of the vestibular system in children (Fong et al., 2012).
Why Choose Taekwondo?
Taekwondo is one of the most popular sports among children and adolescents (Fong et al., 2012). Children are most interested in the famous kicking techniques which requires a great amount of unilateral stance stability (Fong et al., 2012). Taekwondo is a great way to help improve balance in children because it is practical and enjoyable to children (Fong et al., 2012). Another reason to include Taekwondo related skills to improve balance is because the ability to stand and balance on one leg, which is crucial for executing high kicks in Taekwondo, is essential for many daily activities such as donning pants, climbing stairs, and walking (Fong et al., 2012). Taekwondo is a very effective method to improve balance because with only 3 months of training, children with a balance disorder improved on their single leg stance and their balance performance improved to the normal levels of healthy children (Fong et al., 2012).
Example Activities to Include
A fun way that physiotherapists can include Taekwondo related kicks in their physiotherapy session is to get the child to kick a moving ball (waist high) towards a target. This is one of the many activities physiotherapists can choose from to include Taekwondo related skills which involve a one legged stance while maintaining balance (Fong et al., 2012). Other Taekwondo techniques that help stimulate sensory and vestibular functions to improve balance include the roundhouse kick, side kick, and back kick (Fong et al., 2012). Physiotherapists can also incorporate any movement that involves quick spinning (which causes the head and trunk to rotate in an unstable body position) and jumping (which involves a vertical component) to target sensory and vestibular function improvement in children (Fong et al., 2012).
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