CARDIFF SCHOOL OF SPORT
DEGREE OF BACHELOR OF SCIENCE
(HONOURS)
SPORT CONDITIONING REHABILITATION
AND MASSAGE
TITLE
Does fatigue affect balance and
proprioception
NAME
Reagan Crutchley
UNIVERSITY NUMBER
St09002368
NAME: REAGAN CRUTCHLEY
STUDENT NUMBER: ST09002368
SCHOOL OF SPORT
UNIVERSITY OF WALES INSTITUE CARDIFF
DOES FATIGUE AFFECT
BALANCE AND
PROPRIOCEPTION?
Table of Contents
Page
Acknowledgements..............................................................................................
i
Abstract..................................................................................................................
ii
CHAPTER ONE
- Introduction.........................................................................................................
1
CHAPTER TWO
- Literature Review...............................................................................................
3
- Fatigue.................................................................................................................
3
- What is Muscle Fatigue? ......................................................................
- How Muscle Fatigue Occurs? ..............................................................
- How Fatigue Affects Performance? ....................................................
- How Does Fatigue Relate to Injury? ...................................................
3
3
4
5
- Balance…………………………………………………………………………………………………………….
- What is Balance? ...................................................................................
- How is Balance Affected?......................................................................
6
6
6
- Proprioception…………………………………………………………………………………………………. 7
- What is Proprioception?.........................................................................
- How is Proprioception Affected?...........................................................
7
7
- Link between Proprioception and Balance…………………………………………..……….
8
- The Link between Balance, Proprioception and Fatigue…………………………….
8
- Testing and Research…………………………………………………………………………………….. 9
- Testing………………………………………………………………………………………………….. 9
- Previous Research………………………………………………………………………………. 10
Page
CHAPTER THREE
Method....................................................................................................................
12
- Subjects...............................................................................................................
12
- Instruments……………………………………………………………………………………………………….
12
- Procedure…………………………………………………………………………………………………………. 13
- Y- Balance Test....................................................................................... 13
- Romberg Test…………………………………………………………………………………….... 15
- Fatigue Protocol………………………………………………………………………………..…. 15
- Fatigue Assessment………………………………………………………………………..….. 16
- Data Collection....................................................................................................
17
- Data Analysis……………………………………………………………………………………………………. 18
CHAPTER FOUR
- Results……………………………………………………………………………………………………………….
19
- Y- Balance Test v Fatigue……………………………………………………………………………….
19
- Romberg Test v Fatigue………………………………………………………………………………….
22
CHAPTER FIVE
- Discussion………………………………………………………………………………………………………..
25
- Balance v Fatigue…………………………………………………………………………………………..
25
- The Romberg Test v Fatigue………………………………………………………………………….
28
- Balance and Proprioception……………………………………………………………………………
29
Page
- Future Research………………………………………………………………………………………………
31
- Limitations………………………………………………………………………………………………………..
31
CHAPTER SIX
- Conclusion……………………………………………………………………………………………………….
33
- Clinical Contributions………………………………………………………………………………………
34
REFERENCES…………………………………………………………………………………………………..
36
APPENDICIES
Appendix A…………………………………………………………………………………………………………..
49
Appendix B…………………………………………………………………………………………………………… 50
List of Tables
Page
Table 1. Guidelines for the Bruce treadmill test protocol……………………………..
16
Table 2. The Borg scale…………………………………………………………..........................
17
Table 3. Mean (and ±SD) characteristics of the subjects…………………………….
19
Table 4. Difference between the mean results of
the Y-Balance test for pre and post fatigue…………………………..........
20
Table 5. Paired samples t-test for the overall
results of the Y-Balance test…………………………………………………………….
21
Table 6. Paired sample t-test for the Y-Balance test…………………………………….
21
Table 7. Romberg test results of how many subjects
presented sway for both pre and post fatigue testing…………….......
23
Table 8. Percentage showing number of subjects
presenting a positive Romberg test after
presenting sway during the pre-fatigue test……………………………………
23
Table 9. Paired sample t-test for the Romberg test………………………................
24
List of Figures
Page
Figure 1. Performing the Y-Balance test in
the anterior direction…………………………………………………………………………
13
Figure 2. Performing the Y-Balance test in
the posterior medial direction ………………………………………..................
14
Figure 3. Performing the Y-Balance test in
the posterior lateral direction………………………………………….................
14
Figure 4. Pre and post mean scores of
the Y-Balance test……………………………………………………........................
19
Figure 5. Affect that pre and post fatigue
had on Proprioception……………………………………………….......................
22
Acknowledgements
I would like to thank Adeline Phillips for the guidance and support she has given
me over the last few months.
i
Abstract
Abstract
The purpose of this study was to examine the effect that fatigue had on
balance and proprioception and apply the study’s findings to previous
research in regards to injury
risk. Research has looked at the effect
fatigue has on balance and proprioception separately but no one has
researched them together. Seventeen sports students took part in the study
and underwent the Bruce’s protocol for fatigue. Pre and post balance
testing was conducted using the Y-balance test, and the Romberg test was
used to test for a decrease in proprioception.
Results showed that fatigue caused a decrease in balance, the mean score
for pre fatigue was 97cm and post fatigue was 94cm. The difference
between pre and post fatigue was significant as p value=0.000 and t
value= 4.6cm. The results also showed that fatigue had a negative effect
on proprioception as 76.5% of the subjects presented a positive Romberg
test post fatigue. The change in proprioception was significant as p value=
0.000 and t value= -7.2.
The principle finding from this study were that the negative effect fatigue
had on balance and proprioception is significant. The results from the study
showed that fatigue had a negative effect on balance and proprioception.
Alterations
within
postural
stabilization,
caused
by
fatigue,
altered
the
efficiency of the neuromuscular system. Supported by previous research the
alterations within the neuromuscular system can lead to an increase in
injury risk. Future research should look at whether increased balance and
proprioception training has an effect on the difference between pre and
post results, as well as looking at the effect training would have on injury
risk.
ii
CHAPTER ONE
INTRODUCTION
1
Introduction
When participating in sport an athlete places demands on their body that lead to
an increased risk of sustaining an injury (Bahr & Holme 2003). When diagnosing
an injury there are two classifications that an athlete may suffer from, they are
either an acute or chronic injury. An acute injury generally occurs from a one off
event, such as a blow to the shoulder or a twist to the ankle, (Bird et al. 1997),
whereas a chronic or overuse injury is the result of repeated exposure to a
generated force (Bird et al. 1997) that causes an athlete to suffer an injury.
Acute injuries are more common among high risk sports such as basketball,
football and rugby, whereas chronic injuries are more common in endurance
sports such as long distance running (Parkkari et al. 2001). Acute injuries are
more common than chronic injuries. A study by De Loes (1990) found that 10-19%
of all athletes attending hospital for emergency treatment was due to acute
injuries. Acute injuries can be classified as direct or indirect. A direct (or extrinsic)
acute injury is where an athlete sustains a direct blow and this is most common in
contact sports (Peterson & Renstrom 2001). An indirect or intrinsic acute injury is
caused by an excessive internal force within the musculoskeletal system. These
types of injury involve overload or a decrease in physical fitness when participating
in sport and can cause a sprain or tear injury (Peterson & Renstrom 2001). An
athlete is more likely to suffer from an acute injury in sports like football, rugby and
netball rather than a chronic injury. Unlike a direct acute injury that is caused by
contact from an object or opponent, indirect acute injuries offer greater knowledge
into how they are caused as coaches and sports therapists can create prevention
plans and correct treatment can be given (Slobounov 2008).
There are many factors that contribute towards an athlete suffering an acute
injury. These factors range from poor technique, not warming up properly, a
decrease in performance fitness whilst participating in sport or an alteration in the
muscles neurological system (NHS 2011).
A study by Hootman et al. (2007)
found that over a 16 year period injury trends were influenced by increased
participation in sport, changes in policies of National Collegiate Athletic
Association (NCAA), and the growing development of sports medicine. It is
believed that factors such as physical build, physical fitness and joint stability have
2
also been deemed important in the cause of injury (Renstrom 1994). Research by
Jones et al. (1993) found that the relationship between lower levels of physical
fitness and higher risk of injury was significant. Their research suggests that a
decrease in muscular strength and endurance fitness were the most common
factors associated with an increased risk of injury. Physical fitness has three major
components, aerobic fitness, muscular strength and muscular endurance. If any of
these factors are altered, it can have a negative effect on performance (Rayson et
al. 1999). Physical fitness when participating in sport decreases as the athlete
begins to fatigue and Neuberger et al. (1997) suggested that fatigue is a major
cause in the decrease of aerobic fitness in an athlete when participating in sport. If
an athlete takes part in an exhaustive or unfamiliar physical activity, that alters
physical fitness and causes fatigue, it can be known to induce temporary muscle
damage (Torres et al. 2010). Fatigue can cause alterations with the
somatosensory system and can lead to an effect on sporting performance
(Surenkok et al. 2008) as well as having an effect on muscle function leading to an
increase in injury (Neuberger et al. 1997).
Fatigue increases the risk of injury and does so by causing alterations within the
body’s neuromuscular control (Borotikar et al. 2008). Fatigue is a major factor that
causes a decrease in neuromuscular control that can lead to an acute reduction of
performance
during
exercise
or
sport
performance
(Vollestad
1997).
Neuromuscular control is where information is sent to the brain and then used to
create an accurate account of the body’s position and stability in space (Sandrey
& Kent 2008). Research by Surenkok et al. (2008) found that alterations within
neuromuscular control affected balance and Sandrey & Kent (2008) found that
alterations within neuromuscular control affected proprioception. Fatigue affects
neuromuscular control and causes the body to be unable to maintain efficient
muscle function as the muscles cannot generate enough force for the muscle to
contract (Surenkok et al. 2008). This can lead to both a decrease in performance
as coordination is impaired as well as well as a decrease in muscle function. This
is a major cause as to why the body is unable to keep participating in physical
activity and this increases the risk of injury (Ortiz et al. 2010).
3
CHAPTER TWO
LITERATURE REVIEW
4
Literature Review
Movement is an important aspect in not just daily activities, such as walking or
lifting but in sporting activities, such as kicking a ball or hitting a tennis ball. When
performing these different types of movement the body uses what is known as
motor skills that are learnt and developed throughout our lives (Dolon & Benali
2005). For an athlete to perform such motor skills there are neurological and
physiological factors that are essential to undertake a required movement. The
physiological aspects that aid during motor performance skills are muscular
strength and balance (Tveter & Holm 2010). Muscular strength (or postural
control) and balance are linked with stability and are a key function in the
efficiency of physical activities in humans (Pollock et al. 2000). Balance is not the
only key function during movement and keeping a good posture, proprioception is
also important (Surenkoka et al 2006) as it keeps the joint stable whilst moving
and aims to protect the joint from injury (Khayambashi et al. 2010).
Fatigue
What is muscle fatigue?
Muscular fatigue can occur during or after participating in exercise depending on
the nature of the activity and its intensity (MacIntosh & Rassier 2002). The
definition of muscular fatigue can sometimes be poorly defined, and this can be
down to the research conducted (Crowther et al. 2007). By looking into previous
research the best definition to describe muscular fatigue is ‘the reduction of force
development and power output during physical activity which leads to a decrease
in performance’ (Fitts 2004, 279-300).
How muscle fatigue occurs?
Muscle fatigue is related to a decrease in tension capacity and force output after
repetitive muscle contractions during physical activity (Powers & Howley 1990).
How fatigue occurs can be because of neurological or metabolic factors that are
5
controlled by either the central (location proximal to the motor neuron) or the
peripheral (involves the motor units) mechanism (Merton 1954), (Powers &
Howley 1990). Metabolic factors that affect fatigue occur due to a disturbance
within the events that take place between the CNS and muscle fibre. These
changes within the muscle occurs at the neuromuscular junction when the action
potential fails to cross from the motor neuron to the muscle fibre, this then results
in the nerve impulse not being transmitted to initiate muscle activation (McArdle et
al. 2007). The changes in the muscle’s metabolic status between the CNS and
muscle fibre is what can cause fatigue and then the muscle’s inability to generate
its normal force (Mannion & Dolan 1996). Disturbances within the metabolic status
of the muscles are the main contributor to fatigue (Athletic Performance
Revolution 2010). The depletion of the metabolic substrates that are needed for
muscle contraction, such as adenosine triphosphate (ATP), creatine phosphate
and glycogen as well as the build-up of metabolites, that include lactic acid,
hydrogen ions (H⁺) and phosphocreatine (PCr), causes the inability to maintain
muscle force that causes fatigue (Rozzi et al. 2000).
How fatigue affects performance?
Fatigue can have an effect on the body, both physical and mentally and together
can have an effect on an athlete’s performance. Due to the affect fatigue has on
the neuromuscular system it can affect performance physically (Halil et al. 2009).
In a study conducted by Wilkins et al. 2004, it was found that the fatigue group
scored considerably more total errors on the post-test than pre-test of the balance
error scoring system, as well as more errors than the control group at the posttest. The testing concludes that fatigue causes a decrease in postural instability
that can have a negative effect on performance. Fatigue can also mentally affect a
person’s ability to make judgements (Sagberg 1999). Bol et al. (2010) looked into
the effects fatigue has on cognitive complaints and the research suggests that
fatigue and cognitive complaints are highly correlated (r = 0.72, P ‹ 0.01). The
effect fatigue has mentally on the body can cause a lack in concentration during
performance, and this can lead to an athlete to make decisions during their
performance which may have a negative effect on performance e.g. going in for a
6
tackle you would not usually attempt and to push your body further than it is willing
to go.
How does fatigue relate to injury?
Injuries can occur due to the effects muscular fatigue has on the body. Absorption
of energy into the muscles is decreased during fatigue and this can cause injury
as the muscles are unable to reach their full degree of stretch forcing the athlete to
apply a greater amount of force to stretch the muscle fully (Mair et al. 1996).
Fisman et al. (2007) researched the effect fatigue plays on injuries caused by
sharp instruments in medical training. Although the research does not look into
muscular injuries as such, it was found that fatigue caused a decrease in memory
and cognition during a multistep task. This finding can be supported and related to
sports injuries on the basis that a study by Youngs et al. (2006) found that it is
specifically believed that delayed commands of psychological perception and a
decrease in motor unit recruitment can reduce muscular effort and performance
thus increasing injury. Both pieces of literature show that fatigue may have an
effect on the body’s neurological system and comprise neuromuscular control.
Acute effects of fatigue can cause impairment in motor performance and account
for a decline in performance. Motor performance is affected due to a decrease in
the release of motor neurons that slows the rate of muscle relaxation and
accompanies the decline in force during continued maximal muscle contractions
(Enoka and Stuart 1992). Other research has found that fatigue can lead to injury
and the occurrence of suffering an injury in sport can depend on the nature of the
activity or the stage of training/match. Research conducted by Hawkins and Fuller
(1999) stated that the time in a match in which injuries occurred were usually in
the last 15 minutes of each half. Whereas, Calderwell et al. (2003) reported
excessive lumbar flexion and fatigue within the erector spinae muscles has been
linked to lower back pain due to the load that endurance activities, such as rowing,
places on the lower back.
7
Balance
What is Balance?
Control and maintenance of posture and balance, either in dynamic or static
conditions, is a vital necessity for daily and physical activities (Lepers et al. 1997).
Balance is the body’s ability to maintain static posture in relation to centre of mass
and base of support or to create and maintain a stable posture during dynamic
movement patterns is what we know of balance (Guskiewicz 2001). To maintain
balance, external and internal factors are required. External factors such as
gravity, is required to help maintain posture, and acceleration forces, that help
maintain equilibrium, are needed (Massion & Woollacott 1996). The internal
factors that are involved in the maintenance of balance are the central nervous
system (CNS). The CNS controls the postural muscles by encouraging their usage
and engaging them when needed. By maintaining balance and postural control
whilst moving it can prevent an athlete from losing balance and falling over, thus
minimising injury. This is due to the acceleration forces creating an equilibrium and
the CNS controlling the postural muscles to prevent a loss in stability during
different activities (Erkmen et al. 2009) (Massion & Woollacott 1996).
How is balance affected?
Balance can be affected in different ways varying from the nature of the activity an
athlete undertakes, to factors that affect the CNS. Input factors that are related to
the CNS when maintaining balance, involve the somatosensory, visual and
vestibular system as well as coordination, joint range and motor responses that
affect strength (Palmieri et al. 2003). If any of the above input factors are disturbed
or damaged by physiological mechanisms that occur at the central or peripheral
level, fatigue is caused that leads to a decrease in motor control (Noakes 2000).
Other factors that can affect balance are the characteristics of different
movements as they may increase or decrease the amount of balance required to
execute balance efficiency (Huxham et al. 2001). A factor that can affect the
amount of balance required to perform a movement is the base of support (Horak
2006). The environment can also have an effect on balance due to the information
8
obtained from the somatosensory, visual and vestibular systems and motor
response as they can affect coordination, strength and the range of movement at
a joint (Lewis et al. 1982).
Proprioception
What is proprioception?
Proprioception can be defined as the specialized variation of the sensory modality
of touch that incorporates the perception of joint movement (kinesthesia) and
position (Lephart et al. 1994, 371-380). Proprioception is a key element in
maintaining good balance and it is essential in injury prevention. For this to
happen proprioception needs to detects impulses that are transmitted by
mechanoreceptors to the CNS and relay information about joint and body
positioning and movement direction and speed (Myers et al.1999) (Vathrakokilis
2008). Mechanoreceptors are found in the skin and within the ligaments, muscles
and tendons of a joint. These impulses transmitted by the mechanoreceptors are
then processed by the CNS along with information from the sensory systems such
as, vision and sound. They are then used by the CNS in relation to the activity or
movement undertaken (Grigg 1994). Proprioception’s main focus is to control
where body parts are in relation to each other, the space they are in and the base
of support (Hobeika 1999).
How is proprioception affected?
As proprioception is a process that uses neuromuscular responses due to the use
of the mechanoreceptors that transmits information to the joint it is understood that
as a muscle fatigues, proprioceptive feedback is affected (Voight et al. 1996).
Fatigue and injury are the main factors that can affect proprioception and can
cause a decrease in motor control, this is due to an interruption in the
neuromuscular feedback mechanism (Scott et al. 1997).
9
Link between proprioception and balance
As mentioned previously proprioception is required for balance to be
executed efficiently and also maintained. Proprioception is used in postural
control as it sends messages via the CNS to the postural muscles telling
them to engage as balance is required
(Rogers et al. 1985). Joint
movement is controlled by sensorimotor functions within the muscles, of
pain is present it can either effect motor (movement, strength) or sensory
(proprioception, balance) components of muscle function (Hassan et al.
2002). An example of how balance and proprioception are linked together
can be found in a study conducted by Hassan 1999 where subjects with
knee osteoarthritis have increased static postural sway through the lateral
and anteroposterior directions. This increase in static postural sway was
found to be the cause of a reduction in knee proprioception and activation
of the lower postural muscles that decreased balance, showing that balance
and proprioception are linked together. Other research by Hertel et al. (1996)
found that lateral ankle joint anethesia affects the centre of balance in
static and dynamic single-leg stance. It was also identified that the subjects
showed a shift in the centre of balance, this shift was to compensate for
loss of proprioceptive feedback to the joint. Blackburn et al. (2000) research
showed
that
the
relationship
between
balance
and
proprioception
is
significant and the two components are related. Their research concluded
that the enhancement of proprioception are effective in promoting joint
stability and balance maintenance. Blackburn et al. (2000) and the other
research
supports
that
there
is
a
relationship
between
balance
and
proprioception and that if a factor affects balance, proprioception will be
affected also.
The link between balance, proprioception and fatigue?
From previous research it is apparent that there is a relationship between balance,
proprioception and fatigue. Gioftsidou et al. 2011 found that the relevant systems,
that include the muscular and especially the proprioceptive systems, that mediate
balance (postural control) are important to be maintained to reduce injury during
10
soccer training. The research also found that muscle fatigue has an effect on the
body to maintain balance, although more testing needs to be conducted to make
the results substantial. As muscle fatigue causes impairments at numerous sites
within the neuromuscular system it creates a decline in the maximum force
generating capacity of the muscle and leads to a decrease in the ability to
maintain balance and a decrease in proprioception (Allman and Rice 2002) (Fulco
et al. 2001).
Testing and research:
Testing:
When testing for balance, previous research shows the most common tests used
are the balance error scoring system (BESS) (Bell et al. 2001) and the star
balance excursion test (SEBT) (Kinzey and Armstrong 1998). The BESS is based
on three stances: double leg stance, single leg stance (using non dominant leg),
and a tandem stance (one foot behind the other). The test is measured counting
how many errors (guided list to define error) a subject makes in 20 seconds in
each stance. The use of the test is common, mainly due to the lack of equipment
needed, the easy testing protocol and the fact the test incorporates aspects of
proprioception (Bell et al. 2011). However, Riemann et al.(1999) found that the
test was not able to be assessed as reliable due to the fact that there were no
errors made during double leg stance. Bell et al. 2011 concludes that due to its
range of reliability within the literature found the researcher should participate in
training to see if the BESS is reliable enough for their testing although the test is
valid for use to assess the effects of fatigue.
The SEBT measures dynamic balance but in a stable position and requires the
subject to stand on one leg and to try and stretch the leg as far as possible along
eight directional lines marked out. The reliability of the SEBT is an issue in that it is
necessary to clarify the simplest and practical number of trials due to the physical
burden on the subject. The test also needs to have rationalized measurement
method so that the test can be considered reliable (Demura and Yamada 2010).
Taking into account literature from previous research the Y-balance test has been
11
established as a reliable test to use. The Y-balance test measures balance on a
more dynamic base as it uses movements that can be seen in day to day activity,
the test is also more accurate and a developed version of the SEBT (Hosseini
2011).
The main way to test for proprioception is the Romberg test as it can identify if
there is a disturbance within the CNS that can affect a subject’s joint sense and
position (Lephart et al.1997). It is a simple test to asses if the subject present
excessive sway.
It is the most common way to test for proprioception as it
requires no equipment and can be conducted just via vision and a positive
Romberg test is easily identified (Lanska and Goetz 2000).
Bruce’s protocol for fatigue is a measurement of cardiovascular function and aims
to fatigue the body rather than put it through a physical fitness test that the
multistage shuttle run or cooper 12 minute run are used for (Froelicher et al. 1974)
and is a
recognised fatiguing protocol (Halil et al. 2009). With current research
one problem is that researchers often use repeated isokinetic exercise to fatigue
the muscle. Although this is an easier test to administer and bring about fatigue
the activities are not functional or sport related (Costill et al. 1979).
Previous research:
There has been a wide amount of research conducted that looks into the effects
fatigue has on balance but this research has looked into features such as the
accumulation of lactic acid (Surenkoka et al. 2006), effects of multiple sclerosisrelated fatigue and upright postural control (Herbert et al. 2011) or gender effects
on balance and fatigue (Gribble et al. 2009). By looking at previous research there
is a gap within literature that solely looks at the effects fatigue has on balance in
people that participate in regular physical activity but not at an elite level. Halil et
al. 2009 found that previous research shows fatigue has a negative effect on
balance but there is a greater need to look into this area of research but
incorporating proprioception as well. As research has not been conducted on
people that participate in regular physical activity, there is also currently no
research that looks at the effect fatigue plays on balance and proprioception
12
simultaneously after participating in physical activity. Proprioception is a key factor
in maintaining balance due to the connection they share with the CNS.
Proprioception also identifies joint positioning and movement to an athlete in
relation to the movement patterns or activity they are performing (Lephart et al.
1997). To support that research should be conducted in both the effects fatigue
plays on balance and proprioception Jua et al. 2010 found that by participating in
balance training after suffering an anterior cruciate ligament (ACL) injury
proprioception was increased and proves there is a relationship between balance
and proprioception and gives a bases for research to be conducted in this area.
Kynsburg et al. (2006) used proprioception training as a treatment to decrease
functional instability and found that training can have a positive affect on functional
stability. Linking the two studies together research by Holm et al. (2004) studied
the effects neuromuscular training had on balance and proprioception. Holm et al.
(2004) found that there was a significant improvement in balance and
proprioception after training and improved dynamic balance decreasing the risk of
ACL injury within women handball players.
The Hypothesis of this study is that fatigue will have a negative affect on balance
and prorpioception Therefore, the purpose of this research is to look at the affects
fatigue has on balance and proprioception.
13
CHAPTER THREE
METHODOLOGY
14
Method
Subjects
Subjects tested consisted of 17 sports students (11 females and 6 males) from the
University of Wales Institute Cardiff (UWIC) School of Sport. The subjects mean
(±SD) characteristics were age 20 (±1), height 171.1 (±7.7), body mass 71.3
(±7.7) and limb length 110 (±8). Volunteers taking part initially completed a
Physical Activity Readiness Questionnaire (PAR-Q) (see appendix A) to assess
their suitability for participation in the study. All subjects that participate should:

Participate in regular exercise (training at least 2-3 times a week)

Not suffered from a musculoskeletal injury on the lower limb during the
past six months.

Free from any respiratory diseases such as asthma, bronchitis or
emphysema.

Does not suffer from any neurological disease, motor problems or
vestibular impairment that could affect the balance testing.
All subjects gave consent to participate and ethical approval to conduct the
research was given by the UWIC School of Sport ethics committee.
Instruments
Equipment used for the testing consisted of a motorised treadmill (Cosmos
h/p/cosmos sports and medical, quasar 4.0, Nussdorf-Traunstein, Germany) for
the fatiguing protocol, as it was an incline treadmill required in the specifications
when performing the Bruce’s protocol. A stopwatch (Fast time 5 dual display
stopwatch, Ashby-de-la-Zouch, England) was required as well so that the tester
knew when to increase the speed and incline for each stage of the fatigue
protocol. A heart rate monitor was also used to help indicate when the subjects
reached the required target heart rate (Polar Electro, RS400, Kemple, Finland).
When measuring the subjects balance, a Y-Balance test kit was used as it is a
reliable and accurate way of testing for balance (Plisky et al. 2009). For the
15
Romberg test, two one metre rulers where used to indicate any excessive sway
from the subject.
Procedure
Y-Balance Test:
Subjects performed the Y-Balance test as it measures dynamic balance in the
anterior, posterior medial and posterior lateral direction, and has been reported as
being more accurate and developed version of the star execution balance test
(Hosseini 2011). The test was performed both pre and post fatigue, and each
subject had time to familiarise themselves with the test protocols before the official
testing started. The test was performed bear footed and one foot was placed on
the centre plate, with the distal part of their toes behind the centre plates red line.
Using one leg to balance, the subject then used their free foot to push the reach
indicator with their toes. When testing in the anterior direction, the subject used
their free foot to push the reach indicator forwards as figure 1 show.
Figure 1. Performing the Y-Balance test in the anterior direction.
16
For testing the posterior medial direction, the subject used their free foot to push
the reach indicator backwards, figure 2 shows this.
Figure 2. Performing the Y-Balance test in the posterior medial direction.
Posterior lateral was the last direction to test; this was done by crossing the free
foot behind the balancing leg and pushing the reach indicator backwards as figure
3 shows.
Figure 3. Performing the Y-Balance test in the posterior lateral direction.
Each subject performed the test three times in each direction so an average result
was gained. As well as this each direction was performed by alternate legs so that
there is consistency within the testing protocol. Each result was taken at the most
distal part that the foot pushed the reach indicator. If the subject failed to maintain
17
balance when pushing the reach indicator, failed maintain contact with the reach
indicator or used the reach indicator as a balance aid, the score was deemed to
be immeasurable and the subject repeated the test.
Romberg Test:
Subjects performed the Romberg test as it assesses proprioception and identified
any deficits of sensory dysfunction (Steffen & Seney 2008). As with the Y-Balance
test the Romberg test was performed both pre and post fatigue. Subjects
performed the test bare footed and on a hard surface floor, they then stood in the
middle of two one metre rulers that had been placed fifty centimetres apart, this
was to help measure any sway the subject presented. When the subject was in
place they stood with their feet together and eyes open for 15 seconds, and then
with their eyes closed for 15 seconds, this was repeated three times to get an
accurate measure of any sway presented. The subject presented a positive
Romberg test if they started to sway with their eyes shut showing a deficit in
proprioception.
Fatiguing Protocol:
Each subject participated in the recognised Bruce protocol for fatiguing on an
incline treadmill (Spies et al.2005) (treadmill). The first stage of the protocol began
with the treadmill at a speed of 1.7mph and a 10% gradient. After three minutes
the speed and gradient was increased by 2.5mph and 2%. This was then repeated
for every three minutes, until the subject reached 90% of their maximum heart rate
or equivalent to level 17 on the Borg scale (see table 1.) or were too fatigued to
continue. Each subject wore running trainers during the fatiguing protocol but
removed them directly after to perform the post testing measurement for the YBalance test and the Romberg test.
18
Table 1. Guidelines for the Bruce treadmill test protocol.
Level
Time (mins)
Speed (m/hr)
Grade (%)
1
0
1.7
10
2
3
2.5
12
3
6
3.4
14
4
9
4.2
16
5
12
5.0
18
6
15
5.8
20
7
18
6.6
22
Fatigue Assessment:
To measure the subject’s ratings of perceived exertion (RPE) the Borg 15 point
scale (6-20) was used when estimating the subjects fatigue level. When the
subject reached level 17 on the scale, they then repeated the Y-Balance test and
Romberg test. To help indicate when the subject had reached the required level
on the Borg scale, they wore a heart rate monitor to indicate when the subject had
reached 90% of their maximum heart rate (220 - age). Reaching 90% of their
maximum heart rate indicated that the subjects were at level 17 on the Borg scale
for rate of perceived exertion (see table 2.).
19
Table 2. The Borg scale
Level
6
% of maximum heart rate
20
Effort level
7
30
Very, very light effort (rest)
8
40
9
50
10
55
11
60
12
65
13
70
14
75
15
80
16
85
17
90
18
95
19
100
20
exhaustion
Very light (easy walking)
Fairly light
Somewhat hard, steady
pace. Close to anaerobic
threshold
Just under anaerobic
threshold
Hard effort
Very hard
Very, very hard. Exercising
all out
Data Collection
Testing was collected over a five week period, where the subjects choose a single
session they were able to attend. The average test time was approximately 25
minutes per subject and once they had completed the procedure they were free to
leave and did not have to return for any more testing. When collecting data, both
20
pre and post fatigue Y-Balance test scores were written down and recorded in
centre metres (see appendix B). To aid in the analysis of the Y-balance scores the
results are grouped into the different movement patterns so they can be compared
as well as an overall score for all three movements.
For the Romberg test it was a simple statement of either, no sway or sway
present. All raw data from the subjects was written down and recorded on the
back of the sheet used for the Y-balance test.
Data Analysis
The mean and standard deviation (±SD) were calculated for both pre and post
fatigue balance and pre and post fatigue proprioception tests using Microsoft excel
2010. When analysing the results a significant value (p value) of 2 centimetre (cm)
difference between pre and post balance test and for the Romberg test a
significant value of 75% that showed a positive Romberg test was used. As well as
these significant values the paired samples t-test was conducted to test for
differences between pre and post fatigue results. This was conducted by finding
an average score for each direction both pre and post fatigue as well as an overall
average score for all of the directions combined for both pre and post fatigue.
SPSS19.0 for windows was the software used to generate the statistical analysis,
and a significant value of 0.05 was used for all analyse conducted.
21
CHAPTER FOUR
RESULTS
22
Results
The subject’s mean (and ±SD) characteristics can be found in table 3. 17 subjects
that gave consent to participate completed the testing procedure.
Table 3. Mean (and ±SD) characteristics of the subjects
Age
Weight
Height
Limb Length
Mean
20
71.3
171.1
110
SD
1.4
7.7
9.2
7.8
Y-balance test v Fatigue
Figure 4 shows that there was a significant decrease in difference between the pre
and post fatigue results of the Y-balance test in the anterior, posterior medial and
posterior lateral directions. The difference between pre and post is classed as
significant as the results in table 4 showed that the significant value of difference
is p value≤ 2 cm.
100
98
96
94
92
Pre
90
Post
88
86
84
Anterior
Posterior
Medial
Posterior
Lateral
Figure 4. Pre and post mean scores of the Y-balance test
23
Table 4 reiterates what figure 4 shows in that there is a significant decrease in the
difference between pre and post fatigue results (p value≤ 2 cm). This significant
difference applies to all three of the directions (anterior, posterior medial and
posterior lateral) that are used in the Y-balance test and means that fatigue has a
significant effect on balance.
Table 4. Difference between the mean results of the Y-balance test for pre and
post fatigue
Pre Fatigue
Post Fatigue
Mean
Mean
Difference
Anterior
92
89
3
Posterior Medial
99
96.5
2.5
Posterior Lateral
99
96.5
2.5
Table 5 shows the results that were produced when using the paired samples ttest to analyse the results. From the average results of all three directions of the
Y-balance test the p value= 0.00 (t= 4.6) (p≤ 0.05) meaning that the difference in
results for pre and post fatigue are significant.
24
Table 5. Paired samples t-test for the overall results of the Y-balance test
Pre Fatigue
Overall
Post Fatigue
M
SD
M
SD
n
t
p
97
7.8
94
8.8
17
4.6
0.000
Table 5 looks at the mean (and ±SD) as well as the paired samples t-test results
for the individual directions of the Y-balance test.
Table 6. Paired sample t-test for the Y-balance test
Pre Fatigue
Post Fatigue
M
SD
M
SD
df
t
p
92
9.7
89
10.6
17
3.7
0.002
Posterior Medial 99
7.4
96.5
8.6
17
4.1
0.001
Posterior Lateral 99
7.4
96.5
7.9
17
3.3
0.004
Anterior
25
Table 5 as mentioned shows that the overall average results for the anterior,
posterior medial and posterior lateral directions and that the difference between
pre and post fatigue testing is significant. Table 6 shows that the difference
between pre and post fatigue testing is significant for each direction as an
individual. The p value= 0.002 (t= 3.7) for the anterior direction, p= 0.001 (t= 4.1)
for the posterior medial direction and p= 0.004 (t= 3.3) for the posterior lateral
direction. As each direction tested has a p≤ 0.05 the difference between pre and
post fatigue results can be deemed significant. In summary, the results that are
presented in table 4 and 6 show that there is a significant difference between pre
and post fatigue results on the Y-balance test.
Romberg test v Fatigue
Figure 5 shows if sway became present after the fatigue protocol. On the graph, 1
represents no sway and 2 represents sway present. Figure 5 shows that out of the
17 subjects that participated in the testing 13 of them showed a positive Romberg
test after the fatigue protocol. Table 7 shows more specifically when and how
many subjects presented sway during pre and post fatigue testing of the Romberg
test.
2.5
2
1.5
Pre Sway
Post Sway
1
0.5
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17
Figure 2. Effects that pre and post fatigue had on proprioception
26
Table 7. Romberg test results of how many subjects presented sway for both pre
and post fatigue testing
Pre Fatigue
%
Post Fatigue
No Sway
Sway
No Sway
Sway
15
2
4
15
88.2
11.8
11.8
88.2
Table 8 shows the percentage of how many subjects presented a positive
Romberg test
after participating in the fatigue protocol. The results obtained for
the Romberg test can be deemed significant as the percentage of subjects that
presented a positive Romberg test after the fatigue protocol was 76.5% (significant
value≤ 75%).
Table 8. Percentage showing number of subjects presenting a positive Romberg
test after presenting sway during the pre-fatigue test
Subjects
%
13
76.5
27
Table 9 shows the results from the paired samples t-test and the mean (±SD)
results from the Romberg test.
Table 9. Paired sample t-test for the Romberg test
Pre Fatigue
Sway
Post Fatigue
M
SD
M
SD
df
t
p
1(ns)
0.3
2(s)
0.3
16
-7.2
0.000
Key 1= no sway, 2= sway
From table 9 the paired samples t-test results shows that there is a significant
difference in the pre and post fatigue results for the Romberg test. This is shown
as the p value= 0.000 (t=-7.2) meaning that the results can be deemed significant
as p≤ 0.05. Table 7 also shows the mean score for pre and post fatigue testing
showing that sway became present after the fatigue protocol.
28
CHAPTER FIVE
DISCUSSION
29
Discussion
The purpose of this study was to look at the effects that balance has on balance
and fatigue. The main finding from the results obtained is that there is a significant
difference between pre and post fatigue results (Y-balance p=0.000, t= 4.6 &
Romberg test p= 0.000, t= -7.2). The effects that fatigue has are indicated in the
results as there is a significant decrease in the Y-Balance test scores and a
significant increase in sway in the Romberg test. These results obtained in the
study support the hypothesis that fatigue has a negative effect on balance and
proprioception.
Balance v Fatigue
The results showed that there was a significant decrease in the Y-balance test
results after the fatigue protocol. Although the results show that fatigue does have
a significant negative effect on balance, there was one subject whose results did
not follow the rest and increased after the fatigue protocol. However this did not
affect the end results in that fatigue decreased the dynamic balance of the
subjects that participated. The result of the study follows other studies conducted
by Halil et al. (2009) who when using the BESS found after fatigue there was an
increase in balance errors, and Erkmen et al. (2009) who conducted a study that
also found that more errors where scored on the BESS after a fatigue protocol
was conducted.
The Y-balance test looks at assessing dynamic balance when moving as well as
assessing an athlete’s risk of injury (Move2Perform 2009-2012). The results show
that fatigue had a different effect on each of the directions tested. The results for
the anterior direction showed a greater difference of 3cm between pre and post
fatigue results, whereas the difference between pre and post fatigue results for the
posterior medial and lateral direction was 2.5cm. However from a statistical
analysis the paired samples t-test showed that the difference between pre and
post fatigue results in the posterior medial direction was more significant than the
results for the anterior and posterior lateral directions. The posterior medial
30
direction p value= 0.001 this means that there is a 99.99% chance that the
results did not occur by chance and if the test was to be repeated similar results
would be obtained. Although the posterior medial direction’s p value is lower, the
results for the other two directions were still significant. By gaining information and
testing the effects fatigue has can help identify if an athlete is more susceptible to
injury and by using the Y-balance test we can assess the movement direction that
is more likely to cause and injury (Plisky et al. 2009) to the body when fatigued.
The results found within this study shows that fatigue has a negative effect on
balance. Research has found that a decrease in balance can put an athlete at a
higher risk of injury (Ireland 2002). Balance ability has been found to be
significantly related to ankle sprain injuries (Hrysomallis 2007) as well as valgus
angulation of the lower limb and ligament strains of the knee (Zazulak et al.
2007). As the Y-balance test looks at functional and dynamic stability in the lower
limb a decrease in balance, with respect to the lower limb, suggests that the knee
is most vulnerable during exercise (Borghuis et al. 2008). Ireland (2002) describes
a so called position of no return, in reference to an Anterior Cruciate Ligament
(ACL) injury, in which the neuromuscular factors are unable to function correctly
and balance is compromised. In a study by Olsen et al. 2004 they discovered that
ACL injuries occurred in two situations, a plant and cut faking movement (change
direction) and a one leg landing jump. The injury mechanism seemed to be a
forceful valgus collapse when the knee was close to full extension with slight
rotation of the tibia. The ACL’s main function is to stabilize the knee, when fatigue
affects the neuromuscular system the body is unable to stabilize the knee due to a
decrease of balance. When applying the results of this study, sports such as
football, basketball or rugby that have a high risk of ACL injuries and females, who
have a greater ACL injury risk (Swanik et al. 1999), a decrease in balance due to
fatigue can increase the risk of suffering, in particular, and ACL injury.
Other injuries to the lower limb such as, Lateral Ankle Sprains (LAS) are another
common injury in sport (Hosseinimehr et al. 2010) and deficits within balance have
been found to cause LAS as well as a decrease in the function of the lower limb
(Bernier & Perrin 1998). A study conducted by Forestier et al. (2002) found that
fatigue caused an increase in error when performing movements that used the
ankle in plantaflexion and dorsiflexion. From Forestier et al. (2002) study it was
31
concluded that fatigue had a damaging effect on balance and that when using
balance in sports the positioning of the ankle may be impaired. This leads to
believe that fatigue can increase the risk of injuries when participating in sport and
that muscle fatigue can lead to ligamentous injuries due to compensation in the
muscles firing pattern. Ross et al. (2010) reviewed research in that deficits within
the sensorimotor system are associated with Functional Ankle Stability (FAI) due
to impairment in balance. Ross et al. (2010) found that impairments within a
subjects balance can lead to an FAI injury and believe that balance assessments
should be used to identify a FAI injury. This in mind, places greater significance on
the effects that fatigue has on balance and it relation to injury. By applying the
results of the current study to what previous research has found it can indicate that
a decrease in balance can lead to an increase in risk of injury to the lower limb.
Putting what literature and the results in this current study show, a study by Rad et
al. (2010) looked at the effects dynamic balance had on knee extensor and ankle
plantar flexor muscles after undergoing a fatigue protocol. The main finding within
Rad et al. (2010) research was that fatigue had a meaningful negative effect of
knee extensor and ankle plantar flexor muscles on dynamic balance. Although
Rad et al. (2010) applied their study to elderly people this can be transferred to
athletes as previous research within this current study supports their findings. As
knee and ankle injuries are most commonly caused with a decrease in balance
Rad et al. (2010) research shows that athletes are at a high risk of injury when
fatigue starts to set in during physical activity. The findings within Rad et al. (2010)
research combined with the results gained in this study supports the findings that
fatigue has a negative effect on dynamic balance and can lead to an increase risk
of injury within athletes.
The Romberg Test v Fatigue
The results for the Romberg test showed that the amount of subjects that
displayed a positive Romberg test after the fatigue testing was significant as p≤
0.05. This significance in results showed that fatigue does have a negative effect
on the subject’s proprioception. Joint sense and position that requires
proprioceptive feedback for the body to remain stable is due to the
32
mechanoreceptors that are present in joint structures and muscles (Myers et al.
1999). It is believed by Pederson et al. (1999) that after fatiguing contractions
occur, intramuscular contractions of lactic acid may affect the muscle spindles.
Therefore this may cause a decrease in the accuracy of information that is sent to
the working joint and cause a decrease in the efficiency of proprioception. It
appears reasonable to suggest that this process is what increased the subjects
sway in the Romberg test after they underwent the fatigue testing. While fatigue
caused an increase in sway in over three quarter of the subjects, some did not
present sway after undergoing the fatigue protocol, while others presented sway
before the fatigue protocol. These anomalies within the results did not affect the
overall results and showed that fatigue can affect an athlete’s proprioceptive
feedback. This finding follows studies by Myers et al. (1999) who found clinical
relevance in their study as their findings showed that subjects were unable to
recognise joint position after participating in exercises that caused isokinetic
fatigue. Another study by Lattanzio et al. (1997) concluded that their findings
suggest that fatigue may produce a change in an athlete’s ability in the
reproduction of knee joint angles, which may have a decline in proprioceptive
function. Research shows that the same outcome as the research in this study
provides support in that fatigue has a negative effect on proprioception.
A study by Hiemstra et al. 2001 suggests that fatigue may contribute to altered
neuromuscular control in the lower limb due to altered joint stabilization that was
possibly caused by an alteration in proprioception. This theory gives reason to
believe that an alteration in proprioception due to fatigue can cause a higher
incidence of injury rate. Another study conducted by Payne et al. 1997 found that
deficits within proprioception of the ankle joint could be used to predict ankle
injuries. While the study suggests that further research is needed, the research
conducted in the study shows that the alterations in proprioception caused by
fatigue can possibly lead to injury. The research conducted by Payne et al. (1997)
supported research conducted by Tropp et al. (1984) in that instability and
proprioception deficits can increase the risk of ankle joint injuries.
A more recent study by Zazulak et al. (2007) found that there was an increase in
error within proprioception of the core was associated with an increase in the risk
of knee injuries. This research lead on to state that a decrease in proprioception of
33
the core could alter dynamic knee stability that could increase the chances of
injury risk during sports that require a high amount of knee stability. Zazulak et al.
(2007) study’s main finding for proprioception was that fatigue causes a deficit in
proprioception, due to mechanoreceptors being unable to detect a change in joint
position and having a negative effect on proprioceptive feedback. Relating this to
previous research it can give us reason to believe that any alterations in an
athlete’s proprioceptive feedback can leave them exposed to a higher chance of
sustaining an injury when participating in sport.
Balance and Proprioception
Although the study looked into the effects fatigue had on balance and
proprioception as separate themes, research has shown that they are linked. The
study by Yaggie & Armstrong (2004) found that the effects of muscle fatigue
seemed to provoke instability as well as postural control. It is important that
balance and proprioception work together so that postural stability is maintained.
Research by Rozzi et al. (1999) found that muscular fatigue may alter the
proprioceptive feedback system as well as altering the awareness of joint
awareness as well as having a direct and indirect effect on neuromuscular control
that affects balance. The effect found on neuromuscular control was that there
was impairment in the expected learning of joint position as well as an increase in
joint laxity. Fatigue affected joint laxity as it caused alterations within the joint
kinesthesia and sensors within joint position as the joint was unable to identify an
end point (Panics et al. 2008). as the joint was unable to maintain proper function
it leads to a decrease in the subject’s ability to maintain balance. More recent
research has supported the relationship between balance and proprioception in a
study conducted by Vuilleme et al. (2002) found that subjects presented more
sway post fatigue testing, as did the subjects in the current study. The results in
the study by Vuilleme et al. (2002) study showed that lower limb muscular fatigue
affects the body’s ability to maintain balance as well as an increase in postural
sway being observed. While most studies seem to suggest that if there is a
decrease in balance then postural control will also be affected and an
athlete will show an increase in sway. A study by Davidson et al. (2004)
34
disagrees with research conducted by Vuilleme et al. (2002), Rozzi et al. (1999)
and Yaggie & Armstrong (2004). Davidson et al. (2004) research found that
fatigue rate did not affect balance but did affect postural sway. Their main finding
within their research was that lumbar extensor fatigue did increase postural sway
and can contribute to an athlete falling over.
By combining the results that fatigue had on balance and proprioception from the
current study and applying the knowledge from previous research, it can be seen
that as fatigue effects balance, proprioception is also affected. This relationship is
a key contributor in maintaining postural stability and can stop an athlete from
falling over, as the research by Davidson et al. (2004) found that fatigue can
cause an increase in falls. Each set of results show that if balance or
proprioception is decreased athletes expose themselves to a higher chance of
sustaining a minor or major injury. Gribble et al. (2004) researched the effects
fatigue has on chronic ankle instability on dynamic postural control. Chronic Ankle
Instability (CAI) is a common ankle injury that is caused by impairments within the
sensorimotor feedback system (Wikstrom & Cordova 2009). Repeated LAS
(caused by a decrease in balance (Bernier & Perrin 1998)) occurs due to
impairment in proprioception that is caused by the initial sprain. A disruption to the
joint ligament and capsule causes a reduction in proprioception and therefore
predisposes the ankle to further injury resulting in CAI (Refshauge et al. 2000).
The main findings of Gribble et al. (2004) was that a decrease in reach distance in
the star execution balance test (SEDT) post fatigue testing caused a decrease in
knee flexion and hip flexion. They also found that chronic ankle instability not only
creates a decrease in dynamic postural control but fatigue also disrupts normal
muscle activation and this seems to be amplified and affects the unaffected limb
also. The information and theory that the damage caused to joint receptors can
lead to a delay in the recruitment of the required muscles,
leaves the body
exposed to an alteration within joint stability. This can then increase the chances
of an injury being caused (Willems et al. 2002).
The results obtained in the current study and the research that supports them
shows that when looking into the effects fatigue has on balance, the effects fatigue
has on proprioception should also be researched. The body needs both efficient
balance and proprioceptive feedback to maintain a good stable posture when
35
performing a specific movement, playing sport or in the prevention of injury
Kynsburg et al. (2006).
Future research
This study’s main aim was to look at the effects fatigue has on balance and
proprioception, the results gained showed that balance and proprioception are
negatively affected by fatigue. As a decrease in balance and proprioception can
lead to an increase in the risk of injury future research would be beneficial by
looking at whether introducing specific training can have a positive effect on injury
risk. As the demand for sports medicine increases (Paterno et al. 2004) research
has started to look at adding exercises to increase an athlete’s balance as well as
decrease injury rate (McGuine & Keele 2006) (Wilkstrom et al. 2009). Similar
research has been conducted for proprioception in that Verhagen et al. (2004)
found that the use of a balance board program was effective in the prevention of
ankle sprain reoccurrence. By conducting further research that applies training
programmes that use both proprioception and balance exercise may show a
decrease in the risk of injury.
Limitations
Although the current study’s results agree with the set hypothesis, changes within
the study could be made to make the results more specific in regards to an
athlete. The Bruce protocol for fatigue was used within the study as a maximal
exercise test as it works the subject to complete exhaustion (Wilmore & Costill
2005). Although the protocol can and did cause the subjects to fatigue the test
does not represent the movement patterns that an athlete may go through when
training or competing in sport. As the protocol was conducted using a treadmill the
subjects were unable to produce different movement patterns other than running
straight forward. For future studies, it is recommended that the fatigue protocol
incorporates different movement patterns so that the study is more realistic in how
an athlete would move during performance. As the testing was conducted in a
laboratory, this caused the results to be generalized to this type of environment.
36
The laboratory environment does not represent the same environment that an
athlete would usually take part in sport, for instance different types of ground
surface, temperatures, weather, and venue. When conducting future research the
testing environment should be taken in to account as research has found that
different ground surfaces can have an effect on the impact forces generated
(Dixon et al. 2000) as well as an increase in the rate of injury (Ekstrand & Nigg
1989). Therefore is important that the environment represents the athletes usual
surroundings when they participate in sport and to accommodate for this it may be
more beneficial to focus on a particular sport so that testing can be specific to the
effects fatigue has on balance and proprioception.
37
CHAPTER SIX
CONCLUSION
38
Conclusion
This study aimed to look at the effects fatigue had on balance and proprioception
within university sports students. The principle findings of the study showed that
fatigue caused a decrease in balance and proprioception. Statistical analysis
showed that for the Y-balance test p= 0.000 (t=) and Romberg test p= 0.000 (t=)
making the results significant. The implications of these shows that as fatigue
decreases balance and proprioception, an athlete is put at greater risk of injury
(Willems et al. 2002).
Use of the Y-balance test showed how fatigue affected dynamic balance and can
be applied to directional movements performed in physical activity (Move2Perform
2009-2012). As well as this the results gained in this study could be applied to
previous literature and used to determine injuries that an athlete is most likely to
suffer from in relation to the directions that the Y-balance test uses (Plisky et al.
2009). The results of the Romberg test were also applied to previous literature and
the effects proprioception had on joint sense and position could be used and
applied into the information generated in regards to injuries that may be sustained
by an athlete. The relationship between balance and proprioception was a key
factor in this study and previous research supports the results found within the
study in that if balance is affected by fatigue proprioception may be affected to.
Balance and proprioception are key factors when performing in sporting activities.
For an athlete to have success in sporting activities it is important that they stay fit
and free from injury. If an injury is sustained it means that an athlete has to spend
time out of training to recover, this can then lead to a decrease in fitness as well
as effecting the athletes technique within the sport they participate in. A decrease
in balance and proprioception when participating in sport has been shown to
increase the risk of injury (Yaggie & Armstrong 2004). The significance of the
results found within this study, can be presented to a coach and athlete and show
them how injuries may be sustained when training or competing in sport.
39
Clinical contributions
As physical activity is becoming more popular, the risk of injury within athletes is
increased (Bahr & Holme 2003). The increase in injury risk has placed more
emphasis in sports medicine and the development of training programmes specific
to decrease the risk of injury in performance (Paterno et al. 2004). Injury
prevention programmes tend to include a combination of strengthening, flexibility,
plyometric and most important to the current study, balance exercises (Olsen et al,
2005). Research by McGuine & Keene (2006) looked at the effects balance
training had on the risk of ankle sprains and found that the simple inclusion of
balance exercises such as, single leg stance and balancing on a wobble board
reduced the rate of ankle sprains by 38% in male and female high school athletes.
Further research by Wilkstrom et al. (2009) found that balance scores improved in
subjects that had suffered from an LAS and CAI after undergoing balance training.
Wilkstrom et al. (2009) also found through relevant literature that subjects who
participated in balance training reduced the risk of them sustaining a LAS. As
research supports the use of balance training to reduce the risk in an athlete
suffering an injury, proprioception training has the same results. It is widely
accepted that proprioception training is a conservative treatment method for
chronic functional lateral ankle instability, as concluded in research by Kynsburg et
al. (2006).Kynsburg et al. (2006) research findings showed that proprioception
training can be used as a treatment to decrease functional instability that an
athlete may show due to CAI. Kynsburg et al. 2006 also suggests that
proprioceptive training can be used as a prevention strategy to decrease the risk
of injury. Panics et al. (2008) found that proprioception training can improve joint
position sense in a study that looked at the effects proprioception had on knee
joint position in female handball players. Panics et al. (2008) also suggest that this
may explain the effect neuromuscular training has on reducing injury rate. In terms
of clinical reference, applying or increasing balance and proprioception training in
an athlete’s current training programme can aid in the decrease of risk of injury. As
the research suggests it has been proven that adding balance and proprioception
exercises to a training programme does in fact decrease the risk of injury.
40
In conclusion the research within this study proves the hypothesis in that fatigue
does have an effect on balance and proprioception. With the support of previous
research, the deficit caused by fatigue increases the chance in risk of injury.
Further research into such findings and applying the effects that balance and
proprioception training decreases the rate of injury can provide athletes and
coaches with a greater knowledge on how to prevent injuries caused by fatigue.
41
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APPENDICIES
56
Appendix A
PAR-Q & YOU
This questionnaire should be completed before taking part in any of the testing
procedures to see if you are eligible to take part.
1. Has your doctor ever said that you have a heart condition and that you should only do
physical activity recommended by a doctor?
YES
NO
2. Do you feel pain in your chest when you do physical activity?
YES
NO
3. In the past month, have you had chest pain when you were not doing physical activity?
YES
NO
Y
E
S or do you ever lose consciousness?
4. Do you lose your balance because of dizziness
Y
YES
NO
Y
E
E
S could be made
S
5. Do you have a bone or joint problem (for example,
back, knee or hip) that
N
worse by a change in your physical activity?
OY
Y
E
E
YES
NO
S
S
N
N
Y
Y
O
O
6. Is your doctor currently prescribing drugs (for example, water pills) for your blood
E
E
pressure or heart condition?
S
S
N
N
YES
NO
O
O
Y
Y
7. Have you suffered a lower limb injury in the past
6 months?
E
E
N
N
S
S
O YES
O
NO
8. Is there anything else that may stop you participating
in this research?
Y
Y
N
N
E
E
…………………………………………………………………………………………
O
O
S
S
…………………………………………………………………………………………
…………………………………………………………………………………………
Y
Y
E
E
………
S
N
O
S
N
O
I have read and understand the following questionnaire and answered to
my best ability.
N
N
O
O
Name: _________________________________
Date:
______________
Signature: ___________________________________________
Witness: ____________________________________________
57
Appendix B
Score Sheet for Y Balance TestT & Limb Length
Athlete Name: ________________________________________ Date: _________________
RIGHT Limb Length: _________________________
58