i
Abstract
Balance is a crucial component of daily activity. It is a simplistic concept but the
mechanisms involved in monitoring, adjusting and percieving balance are highly complex. The
three systems associated with balance work together to maintain the body’s centre of mass over
the base of support. This report will discuss the physiology and responsibilities of the vestibular,
visual and the somatosensory systems and their role in balance. This report will also discuss
closed kinetic chain exercises and their progressions to retrain balance in individuals with lower
extremity injuries. The visual system is responsible for percieving movement, locating objects in
space and differentiating between exafferent and reafferent information. The vestibular system is
responsible for monitoring gravity changes and acceleration associated with head movement.
The somatosensory system monitors many bodily changes, but this report will focus on
proprioception. Proprioception is the ability to monitor and percieve the location of body parts
in space with the feedback of muscle spindles and golgi tendon organs. It is concluded that
closed kinetic chain exercises that progress to challenge the visual and somatosensory systems
are successful in retraining balance. It is recommended that the vestibular system be challenged
with rotational and lateral head movements to incorporate all three balance systems.
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Table of Contents
1.0 Introduction...........................................................................................................................1
1.1. Balance...........................................................................................................................1
1.1.1. Visual and Vestibular Systems.............................................................................2
1.1.2. Somatosensory System.........................................................................................4
1.2. Open vs. Closed Kinetic Chain Exercises......................................................................6
2.0 Methods and Findings...........................................................................................................7
2.1. Physical Therapy for the Vestibular System..................................................................7
2.2. Rehabiliation of the Visual System................................................................................8
2.3. Balance Exercises and the Somatosensory System.....................................................10
3.0 Conclusion..........................................................................................................................11
4.0 Recommendations...............................................................................................................12
5.0 Glossary..............................................................................................................................13
6.0 References...........................................................................................................................15
7.0 Appendix.............................................................................................................................17
8.0 Evaluation...........................................................................................................................19
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List of Tables and Figures
Figure 1.0. Anatomical structures of the vestibular labyrinth.....................................................2
Figure 2.0. Diagram of the ampulla within semicircular canals.................................................2
Figure 3.0. Otolith organs at rest and displaced..........................................................................3
Figure 4.0. GTO response to over contraction of bicep muscle..................................................4
Figure 5.0. Patellar reflex depicting muscle spindle activity......................................................5
Figure 6.0. OKC lat pull down vs. CKC pull up.........................................................................6
Figure 7.0. Ankle strategy (left) vs. Hip strategy (right)............................................................9
Table 1.0. Level progression for 26 participants at the end of a 6-week test period................10
1
1.0 Introduction
[name of clinic here] is a multi-disciplinary clinic that deals with a wide range of personal
and motor vehicle injuries to help promote and increase the rate of recovery. The role of the
kinesiology department is to implement the correct stretches and exercises for each individual
and progress accordingly based on therapists’ guidelines and assessment of injuries. A wide
range of injuries are present throughout the clinic, however, those involving the lower
extremities are often associated with one’s inability to maintain one’s balance. There are many
factors that can affect one’s balance, these include tramautic brain injuries, muscle or nerve
damage, concussions, age or visual acuity.
1.1 Balance
It is now understood that balance is maintained by three sensory systems, the vestibular,
visual and somatosensory system (Mohapatra, Krishnan & Aruin, 2011). The stimulation of
either of these systems evokes a deviation in balance and increases body sway. We are able to
depress or remove the systems while training for balance by closing the eyes to remove vision,
standing on a foam pad, one leg or uneven surface to hinder the somatosensory and vestibular
system. Proprioception* can be altered in many ways. Vibration introduced to the muscle
tendons will activate muscle spindles, producing a feeling of instability causing postural tilt in
the direction of the muscle vibrated, also known as vibration-induced falling (Van Ooteghem,
2010). This phenomena only occurs when the individual is not looking at the vibrated limb.
When vision is introduced, the sensation ceases and negates the vibrating effect (Van Ooteghem,
2010). This reflects how much one relies on the visual system for proprioceptive feedback. The
vestibular system is a highly complex system that monitors head movement through a labyrinth
of organs in the inner ear (Gray, n.d.). It works together with the visual system to differentiate
objects moving in our visual space and the movement of one’s own head. When working
optimally, the three components of balance work collectively to produce a stable body,
minimizing deviations from the central base of support by postural sway and reducing the risk of
injury from falls and instability.
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1.1.1 Vestibular and Visual Systems
One cannot describe the visual system and vestibular system individually without
referencing the other. This section will discuss the vestibulo-ocular pathway and its relationship
with balance. The vestibular system
is located in the inner ear and is
made of 3 semicircular canals
(SCCs) and 2 otolith organs, the
saccule and utricle, making up a
structure called the vestibular
labyrinth, shown in Figure 1.0
(Gray, n.d.). The semicircular
canals are responsible for detecting
angular acceleration and are
oriented 90° to each other (Gray, n.d.). Their orientation allows angular acceleration of the head
to be detected in the roll*, pitch* and yaw* directions, corresponding to the x,y,z axes (Gray,
n.d.). See Appendix A for a diagramatic view of each direction. Otolith organs oriented 90° from
one another detect linear changes in head movement, the utricles measure mostly horizontal
acceleration (ie. deceleration) while the saccules responds primarily to vertical acceleration (ie.
gravity) (Gray, n.d.). All 3 SCCs and both otolith organs innervate the vestibulocochlear nerve
(VIIIth CN) (Gray, n.d.).
At the entrance (ampulla) of each semicircular canal there is a gelatinous liquid called cupula
(Rutka, n.d.). Embedded in the cupula are
stereocilia, tiny hairs that extend out from
the vestibulocochlear nerve that respond to
mechanical shearing* in different directions
causing a chemical depolarization* or
hyperpolarization* of the nerve (Rutka,
n.d.). As the head moves, the cupula lags
behind and bends the hairs, resulting in a
reafferant* signal to the brain indicating that
Figure 1.0. Anatomical structures of the vestibular labyrinth.
Figure 2.0. Diagram of the ampulla within semicircular canals
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the head has moved (Rutka, n.d.). In relation to vision, each SCC innervates two ipsi-lateral* and
two contra-lateral* muscles of each eye, with six extraocular muscles in each eye, corresponding
to each of the three SCCs there is an innervation ratio of 2:1 (Rutka, n.d.). This level of control
allows for a fine response in eye movement, keeping a stable retina image (Rutka, n.d.).
Importantly, this allows us to differentiate between subjective and objective movements. This
phenomena can be demonstrated by placing your finger infront of your face and shaking your
head up and down, and left and right while fixing your gaze upon your finger (Clopton, 2007).
Your finger stays stationary while your head moves, but by shaking your finger while your head
is fixed, the finger appears blurry (Clopton, 2007). This is an example of the SCC portion of the
vestibulo-ocular pathway (Clopton, 2007).
Otolith organs lie between the semicircular canals and the cochlea within the vestibular
labyrinth (Rutka, n.d.). Responsible for gravitational movement, the saccule and utricle are
oriented at 90° from each other, detecting linear changes in the horizontal and vertical directions
(Rutka, n.d.). Otolith organs contain a gelatinous matrix* with cilia* projecting from the afferent
nerve endings, similar to the SCCs (Rutka, n.d.). However, the surface of the gelatinous matrix
contains a membrane with a layer of calcium carbonate crystals ontop, increasing the weight of
the membrane (Rutka, n.d.). Otolith mean’s “ear stones” in Greek (Rutka, n.d.). This blanket of
crystals causes drag on the top of the gelatinous matrix when the head is moved causing a
displacement of the matrix resulting in the hairs within the matrix to bend, similar to the function
of the SCCs (Rutka, n.d.). In turn, the otolith organs also stimulate the vestibulocochlear nerve
(Rutka, n.d.).
Figure 3.0 Otolith organs at rest and displaced
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1.1.2 Somatosensory System
The somatosensory* system is a collection of unnamed senses which includes vibration,
temperature, pain and proprioception (Arezzo, Schaumburg & Spencer, 1982). This report will
focus on proprioception and its involvement in balance and reafferent sensory feedback.
Proprioception is termed as the ability to perceive the location of our own body in space
(Van Ooteghem, 2010). It is part of the somatic division, or voluntary division, of the peripheral
nervous system, which includes the sensory neurons of the skin, joints, tendons and muscles
(Van Ooteghem, 2010). During balance rehabilitation there are two structures that are being
targeted and are responsible for fall prevention and limiting postural sway. These are golgi
tendon organs (GTOs) and muscle spindle fibers (Van Ooteghem, 2010).
Golgi tendon organs are innervated by encapsulated 1B nerve endings located at the muscle-
tendon junction and are arranged in series with the muscle and its tendon (Van Ooteghem, 2010).
Since muscles contract towards the muscles belly, the
most tension occurs at the tendons thus stimulating the
GTOs (Van Ooteghem, 2010). Response to tension
prevents the muscle from over contraction and
overexertion that could cause muscular damage at its
origin and insertion points as well as the muscle itself
(Van Ooteghem, 2010). GTOs are associated with a
negative feedback loop where an over contraction felt at
an agonist muscle, the collagen fibrils of the tendons
press on the 1B afferent neurons which synapses at the
spinal cord shutting off the 1A motor neuron of the same
agonist muscle, preventing damage from over contraction
(Van Ooteghem, 2010). This feedback loop also
prevents the muscle from fatigue and therefore
maintains muscle force (Van Ooteghem, 2010).
Figure 4.0. GTO response to over contraction of the bicep muscle
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Opposite GTOs are muscle spindle fibers. Muscle spindles are intrafusal* fibers,
innervated by gamma motor neurons and are located within the muscle belly (Van Ooteghem,
2010). Intrafusal fibers are not to be confused with extrafusal* fibers which are innervated by
alpha motor neurons, as they are both arranged in parallel to each other within the muscle belly
(Van Ooteghem, 2010). Muscle spindle fibers contain 2 sensory components, primary
(annulospiral) endings and the secondary (flower spray) endings (Van Ooteghem, 2010). Primary
endings output signals to the spinal cord via 1A afferent neurons, secondary endings via Group II
afferent neurons (Van Ooteghem, 2010). These components respond to stretching of the muscle,
which is dependent on sarcomere* length. Muscle spindles are involved in a feedback loop, also
known as the “stretch reflex” (Van Ooteghem, 2010). The stretch reflex is activated when the
muscle spindle fibers have been stretched quickly in a short period of time (Van Ooteghem,
2010). This elicits a response of the intrafusal fibers signalling via 1A and Group II afferent
neurons to the spinal cord where they synapse with alpha motor neurons of the agonist and
antagonist muscles (Van Ooteghem, 2010). The “stretch reflex” elicits a contraction of the
stretched agonist muscle and a relaxation of the antagonist muscle. A prime example is the
patellar reflex. The patellar tendon is struck with a reflex hammer, causing a stretch in the
muscle. This sudden stretch in the muscle causes the spindle fibers to respond. Information is
sent to through the stretch reflex loop and the quadriceps contract causing the leg to rise.
Figure 5.0. Patellar reflex depicting muscle spindle activity
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1.2 Open vs. Closed Kinetic Chain Exercises
Exercises can be broken down into two components, open kinetic chain (OKC) and
closed kinetic chain (CKC) exercises. OKC exercises are defined as an exercise where the distal*
segment of a limb (ie. hands, feet) is moving freely (Hooper, Morrissey, Morrissey & King,
2001). Straight leg raise, leg press, lat pull down and knee extension are examples of OKC
exercises. During CKC exercises, the distal end of the segment is fixed throughout the exercise
(Hooper, Morrissey, Morrissey & King, 2001). Isometric shoulder exercises, squats, pull-ups and
push ups are examples of CKC exercises.
Studies have shown that CKC exercises may be more beneficial
in the early rehabilitation stages because of its involvement in
activating more muscle groups in a more functional way rather
than isolating a single muscle group with OKC exercises
(Hooper, Morrissey, Morrissey & King, 2001). CKC exercises
are also conceived at better enhancing functional performance,
more than OKC excercises (Hooper, Morrissey, Morrissey &
King, 2001). For example, a CKC exercise such as a squat recruits twice as much hamstring
activity, greatest activation of quadriceps at full knee flexion as well as more vasti muscle
activation than an OKC leg press exercise (Escamilla, Fleisig, Zheng, Barrentine, Wilk &
Andrews, 1998). However, proper discretion must be taken into consideration when
implementing primarily CKC or OKC exercises to an individual’s routine. For anterior cruciate
ligament injuries, studies have found that greater strain was placed on the ligament with OKC
exercises than CKC exercises (Escamilla, Fleisig, Zheng, Barrentine, Wilk & Andrews, 1998).
However, many studies have concluded that although CKC exercises promotes greater functional
capabilities, OKC exercises must be incorporated to increase torque* in the lever muscle (ie.
tricep, quadriceps) (Escamilla, Fleisig, Zheng, Barrentine, Wilk & Andrews, 1998). This report
will focus on CKC exercises and their implementation in balance rehabilitation.
[The name of your hometown] Physiotherapy and Rehabilitation Centre caters to a large
demographic and a multitude of injuries. Treatments prescribed by the clinicians incorporate
Figure 6.0. OKC lat pull down vs CKC pull up
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many rehabilitation techniques and modalities to promote the healing of musculoskeletal
structures and systems. The role as a kinesiologist is to prescribe exercises and stretches based on
the clinician’s program requests and make changes if necessary. Many individuals at the clinic
experience issues with balance, whether from muscular or neural issues. This report will discuss
the utilization of CKC exercises and other methods to challenge the three balance systems. This
is a non-empirical report where formal reasoning and research of implemented CKC exercises
and rehabilitation methods for balance will be discussed and supplemented with critical analysis.
2.0 Methods and Findings
Balance rehabilitation must incorporate many areas of expertise and treatment to be able
to fully diagnose the root cause of an individual’s balance disorder. At [nonames] Physiotherapy
and Rehabilitation Centre there are a large majority of individuals with balance disorders
stemming from musculoskeletal issues such as lower extremity fractures*, ligament* and
muscular tendon* tears. Therefore, there is greater application of proprioceptive balance training.
This section will discuss methods of vestibular, visual and proprioceptive rehabilitation for
balance with most emphasis on proprioception through CKC exercises.
2.1 Physical Therapy for the Vestibular System
There are two branches of the vestibular system, central and peripheral. Physical therapy
is one method for treating vestibular system dysfunctions. Other forms of intervention include
pharmacological therapy and surgical intervention. This section will discuss the physical therapy
methods for treating the vestibular system. Imbalance in the peripheral vestibular system, which
consists of the inner ear organs, can cause mild to severe vertigo*, nausea and gait*
abnormalities which can be treated in multiple ways in the clinical setting (Brown, Whitney,
Marchetti, Wristley & Furman, 2006). Central vestibular dysfunctions are more difficult to treat
through physical therapy and must address the neurological issues involving the central nervous
system (Brown, Whitney, Marchetti, Wristley & Furman, 2006). Those with peripheral
vestibular dysfunction can benefit most from physical therapy (Brown, Whitney, Marchetti,
Wristley & Furman, 2006).
In a study by Brown et al, patients performed the Dynamic Gait Index (DGI), Timed Up
& Go(TUG) and Five Times Sit-to-Stand (FTSTS). The DGI is composed of 8 gait tasks;
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walking, walking at varying speeds, walking with head movements in the yaw and pitch
directions, walking over and around objects, pivoting and stair climbing (Brown, Whitney,
Marchetti, Wristley & Furman, 2006). TUG is a timed sitting, walking and standing examination
where the patient is asked to stand up from a chair, walk 3 metres and return back to their chair
and sit down (Brown, Whitney, Marchetti, Wristley & Furman, 2006). The FTSTS test measures
balance and lower extremity strength and it requires individuals to rise from a seated position
and sit back down without the aid of their arms (Brown, Whitney, Marchetti, Wristley &
Furman, 2006). The tests cause angular and linear accelerations of the head, exposing the
individual to movements that may cause discomfort and rehabilitating the issue. Significant
improvements in gait and balance were present at patient discharge after vestibular physical
therapy (Brown, Whitney, Marchetti, Wristley & Furman, 2006).
Benign paroxysmal positional vertigo (BPPV) is a common issue in vestibular
dysfunctions and can be treated more intensively with positional exercises and liberatory
maneuvers proposed by Semont et al and Epley (Brandt, 2000). This physical therapy treatment
involves rapid lateral head and trunk tilts to induce the feeling of vertigo. The patient is to remain
in the tilted position until vertigo subsides or duration of 30 seconds (Brandt, 2000). This process
can be repeated in different planes of the head and trunk to stimulate the different SSCs. The
purpose of these maneuvers is to loosen and break down clots that have accumulated in the
endolymph* of the inner ear (Brandt, 2000). The clot decreases the fluidity of the gelatinous
matrix, which lags behind causing nystagmus* and vertigo (Brandt, 2000). These maneuvers can
be performed in home without assistance from a clinician (Brandt, 2000). See Appendix B for a
schematic of the Semont maneuvers.
2.2 Balance and the Visual System
Vision is a crucial component in balance. Not only does vision allow us to detect hazards
and uneven surfaces, it also communicates with the vestibular system and perceive spatial
relationships with respect to objects in the environment (Lord, 2003). Without visual feedback to
the vestibular system, when standing with eyes closed there is a 20-70% increase in postural
sway (Lord, 2003). Impaired visual acuity also causes increases in postural sway and is
associated most with decreased near-visual acuity (Lord, 2003). Decreased peripheral vision is
also a cause of imbalance (Lord, 2003). People are limited in the ways they are able to increase
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the acuity of their eye sight, therefore must compensate
with greater demand on the vestibular and
somatosensory systems (Lord, 2003).
Those who are visually impaired put more
emphasis on vestibular and somatosensory information
to adjust and monitor balance (Ray, Horvat, Croce,
Mason & Wolf, 2008). Older adults with adverse
vestibular affects and lessened visual acuity place more
priority on their proprioception (Ray, Horvat, Croce,
Mason & Wolf, 2008). It is reported that both
adolescent children and adults who are blind exhibit fear of falling and have decreased postural
stability (Ray, Horvat, Croce, Mason & Wolf, 2008). In a mixed trial where individuals with full
vision closed their eyes and balanced, and blind individuals closed their eyes, imbalance was
similar (Ray, Horvat, Croce, Mason & Wolf, 2008). However, with eyes open, blind individuals
demonstrated similar amounts of imbalance (Ray, Horvat, Croce, Mason & Wolf, 2008). This
indicates that those with vision absent do not fully adapt to vision loss (Ray, Horvat, Croce,
Mason & Wolf, 2008). The greater increase in postural sway was correlated to an increase in hip
shifting strategy, where the individuals reacted with the hip instead of through the ankles and
knees (Ray, Horvat, Croce, Mason & Wolf, 2008). Increased hip strategy can lead to an
increased chance of falls (Ray, Horvat, Croce, Mason & Wolf, 2008).
Therefore, greater emphasis of vestibular and somatosensory training must be implemented to
adapt for an individual’s visual impairment. A study by King et al proposed that rapid upper limb
movement can be beneficial in fall prevention, absorption and protect against head injury and hip
fractures for the visually impaired (King, McKay, Cheng & Maki, 2010). Training individuals to
use their peripheral vision to grasp for stable fixtures such as a handrail can reduce the chance of
falls (King, McKay, Cheng & Maki, 2010). A study was done to determine if there was a delay
in timing and accuracy of central and peripheral vision. Although it is surely advantageous to
reach and grasp with central vision, peripheral vision provides adequate information for balance
recovery for a fall (King, McKay, Cheng & Maki, 2010).
Figure 7.0. Ankle strategy (left) vs. Hip strategy (right)
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2.3 Balance Exercises and the Somatosensory System
Postural control can be described as the attempt to maintain coordination of body
segments without loss of balance for the facilitation of other actions (Strang, Haworth,
Hieronymus, Walsh & Smart, 2010). Postural sway is the continuous movement the body
undergoes to maintain this control (Strang, Haworth, Hieronymus, Walsh & Smart, 2010). Thus,
it can be interpreted that minimum postural sway is required to achieve significant postural
control. Balance can be improved in all demographics by training with balance-specific
exercises. Balance exercises have been shown to strengthen the lower extremities as well as
reduce recurring injuries (Strang, Haworth, Hieronymus, Walsh & Smart, 2010).
Holistic and progressive balance exercises can be prescribed in the clinical and
rehabilitative setting to improve postural control of individuals with balance issues (Strang,
Haworth, Hieronymus, Walsh & Smart, 2010). It has been noted by researchers that a healthy
postural sway reflects the individual’s flexibility, adaptability and automaticity of postural
control(Strang, Haworth, Hieronymus, Walsh & Smart, 2010). A limited, rigid postural sway
indicates a less-adaptable, attention-demanding control of posture (Strang, Haworth,
Hieronymus, Walsh & Smart, 2010).
In a study by Strang et al,
the following holistic balance
exercises were prescribed, within
each exercises were 4 progressive
stages increasing in difficulty.
Single leg stance, balance path,
double leg BOSU, single leg
squat and reach, Bongo Board, 4-
way tube resist and balance,
forward hop, side hop. The
descriptions and progressions of each exercise are illustrated in Appendix C. Vestibular, vision
and proprioception is tested in each of the exercises within their progressive stages. Trials with
eyes closed tested reliance on vision. Squats, forward and lateral hops and the balance path
would stimulate the vestibular system in both linear and angular directions. Proprioception is
Table 1.0. Level progression for 26 participants at the end of a 6-week test period
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tested in each of the trials by progression of exercises from a hard surface to foam surfaces,
inflatable discs, BOSU balls and Bongo Boards (Strang, Haworth, Hieronymus, Walsh & Smart,
2010). There were improvements in balance for each of the balance trials for each individual.
Table 1.0 illustrates the progression of each of the 26 individuals, and the number of successful
individuals to complete each task at the end of the trial period (Strang, Haworth, Hieronymus,
Walsh & Smart, 2010). Findings lead to the understanding that by training with restricted vision
and diminished proprioceptive feedback, a change in postural sway in the normal stance position
and improved postural control was observed (Strang, Haworth, Hieronymus, Walsh & Smart,
2010).
3.0 Conclusions
In a physical rehabilitation setting balance is a featured component in most injuries,
especially those regarding the lower extremities. Composed of an elaborate system of
interconnected feedback pathways, balance is a complex but crucial component in everyday life.
The vestibular labyrinth within the inner ear is continuously monitoring head movement
and can be manipulated and rehabilitated with simple head and trunk movements. Treating for
vertigo and addressing balance issues, exercises can be administered to the individual and be
self-treated in-home or more intensive physical therapy maneuvers can be performed by a
clinician. The SSCs, Utricles and Saccules are targeted with these maneuvers and by reproducing
the symptoms, vertigo and balance issues can be resolved.
Closely linked to the vestibular system, slight alterations in vision can cause imbalance,
increased postural sway by 20-70%, and issues with fall control and fall prevention. By training
reach-and-grasp for the peripheral vision, one can decrease their chance of falling by increasing
the accuracy of their grasp and speed at which they reached. Reducing the amount of hip strategy
used by those visually impaired and instructing the use of the ankle strategy one can also reduce
the chance of falls.
Progressive proprioceptive balance training is an important area to train because it
incorporates all components of balance as well as training the somatosensory system with
perturbations, uneven and unsteady surfaces. Golgi tendons and muscle spindles are active in all
movements but are specifically triggered during high velocity movements and those involved in
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re-establishing balance such as falls, wobble board training, BOSU stance and forward and
lateral hops.
4.0 Recommendations
With extensive research of the physiology of each system and their corresponding
methods of training, [The Cool People Rehab Clinic] should implement a balance training
protocol that incorporates the vestibular as a major component of training. Removal of vision by
performing exercises with eyes closed and the addition of an unstable surface to challenge the
proprioceptive system is commonplace in a rehabilitative setting. However, vestibular training
can be implemented to further challenge vision and the somatosensory system. By having
individuals stand on one leg with eyes closed on an unstable surface while moving their head in
the yaw and pitch directions, all systems are included in one exercise. There are a lot of clinical
based exercises for balance focused on proprioception, by introducing a wobble board, foam mat
or BOSU ball and progressing to eyes closed but few have considered introducing head
movement to stimulate the vestibular system in addition to the other components. Begin with
vestibular movements similar to those mentioned in Section 2.1 and progress to standing and one
foot balance positions to challenge proprioception, then finally removing vision. This
progression will allow for extensive balance training and incorporate all three areas of balance.
5.0 Glossary
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Cilia – minute hairlike organelles lining the surface of cells
Contra-lateral – pertaining to the opposite side
Depolarization – the influx of sodium ions across a membrane, causing an action potential
stimulating the nerve
Distal – situated away from the point of origin
Endolymph – fluid within the labyrinth of the inner ear
Extrafusal – situated outside of a muscle spindle
Fracture – a break in the continuity of the bone
Gait – a pattern of movements for walking or moving on foot
Hyperpolarization – efflux of potassium ions across a membrane preventing or inhibiting an
action potential
Intrafusal – situated within a muscle spindle
Ipsi-lateral – pertaining to the same side
Ligament – fibrous tissue that connects bones to bones
Matrix – a material or substance that specialized structures are embedded
Nystagmus – fast, uncontrollable movement of the eyes
Pitch – forwards and backwards movement of the head on the y-axis
Proprioception – the body’s awareness of the position of its limbs in space
Reafferent – stimulation as a result of one’s own body movements
Roll – lateral movement of the head side to side on the x-axis
Sarcomere – basic unit of striated muscle fibers
Shear – force acting parallel to the transverse plane
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Somatosensory – sensations pertaining to the skin and deep tissues of the body
Tendon – fibrous tissue that connects muscle to bone
Torque – a moment of force to produce rotation about an axis
Vertigo – a feeling of motion, dizziness or confusion
Yaw – rotational movement of the head side to side on the z-axis
6.0 References
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1. Arezzo, J. C., Schaumburg, H. H., & Spencer, P. S. (1982). Structure and function of the somatosensory system: A neurotoxicological perspective. Environmental Health Perspective, 44, 23-30. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1568957/pdf/envhper00461-0029.pdf
2. Brown, K. E., Whitney, S. L., Marchetti, G. F., Wrisley, D. M., & Furman, J. M. (2006). Physical therapy for central vestibular dysfunction. American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation, 87(87), 76-81. doi: 10.1016/j.apmr.2005.08.003
3. Brandt, T. (2000). Management of vestibular disorders. 491-499.
4. Clopton, J. (2007). Balanced vision: How the visual and vestibular system interact. Unpublished manuscript, Retrieved from http://www.sifocus.com/files/Balanced Vision- How the Visual and Vestibular Systems Int….pdf
5. Escamilla, R., Fleisig, G., Zheng, N., Barrentine, S., Wilk, K., & Andrews, J. (1998). Biomechanics of the knee during closed kinetic chain and open kinetic chain exercises. Medicine and science in sports and exercise, doi: 10.1097/00005768-199804000-00014
6. Gray, L. (n.d.). Chapter 10: Vestibular system: Structure and function. Informally published manuscript, Department of Communication Sciences and Disorders, James Madison University, Houston, Tx, Retrieved from http://neuroscience.uth.tmc.edu/s2/chapter10.html
7. Hooper, D. M., Morrissey, M. C., Drechsler, W., Morrissey, D., & King, J. (2001). Open and closed kinetic chain exercises in the early period after anterior cruciate ligament reconstruction. The american journal of sports medicine, 29(2), 167-174.
8. King , E. C., McKay, S. M., Cheng, K. C., & Maki, B. E. (2010). The use of peripheral vision to guide perturbation-evoked reach-to-grasp balance-recovery reactions. 105-118. doi: 10.1007/s00221-010-2434-9
9. Lord, S. R. (2003). Vision, balance and falls in the elderly. Informally published manuscript, Retrieved from http://www.cmellc.com/geriatrictimes/g031209.html
10. Mohapatra, S., Krishnan, V., & Aruin, A. (2011). Postural control in response to an external perturbation: effect of altered proprioceptive information. doi: 10.1007/s00221-011-2986-3
11. Purves D, Augustine GJ, Fitzpatrick D, et al., editors. Neuroscience. 2nd edition. Sunderland (MA): Sinauer Associates; 2001. Other Afferent Feedback that Affects Motor Performance. Retrieved from: http://www.ncbi.nlm.nih.gov/books/NBK10986/
12. Purves D, Augustine GJ, Fitzpatrick D, et al., editors. Neuroscience. 2nd edition. Sunderland (MA): Sinauer Associates; 2001. The Otolith Organs: The Utricle and Sacculus. Retrieved from: http://www.ncbi.nlm.nih.gov/books/NBK10792/
13. Ray, C. T., Horvat, M., Croce, R., Mason, R. C., & Wolf, S. L. (2008). The impact of vision loss on postural stability and balance strategies in individuals with profound vision loss. Gait & Posture, 28, 58-61.
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14. Rutka, J. A. (n.d.). Physiology of the vestibular system. Informally published manuscript, Retrieved from http://www.bcdecker.com/SampleOfChapter/1550092634.pdf
15. Strang, A. J., Haworth, J., Hieronymus, M., Walsh, M., & Smart Jr, L. J. (2010). Structural changes in postural sway lend insight into effects of balance training, vision, and support surface on postural control in a healthy population. 1485-1495. doi: 10.1007/s00421-010-1770-6
16. Van Ooteghem, K. (2010). An Introduction to Psychomotor Behaviour. University of Waterloo.
17. Vestibular exercises. Unpublished raw data, University of Mississippi, Jackson, MS, Retrieved from http://www.umc.edu/uploadedfiles/umcedu/content/education/schools/medicine/clinical_science/otolaryngology__communicative_sciences/handouts/vestibularexercise.pdf
7.0 Appendix
A. Diagrammatic view of Roll, Pitch and Yaw directions
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B. Schematic of the Semont maneuvers
C. Description of holistic exercises and their progressions
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