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The Role of Core Stability in Athletic Function


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The importance of function of the central core of the body for stabilisation and force generation in all sports activities is being increasingly recognised. ‘Core stability’ is seen as being pivotal for efficient biomechanical function to maximise force generation and minimise joint loads in all types of activities ranging from running to throwing. However, there is less clarity about what exactly constitutes ‘the core’, either anatomically or physiologically, and physical evaluation of core function is also variable. ‘Core stability’ is defined as the ability to control the position and motion of the trunk over the pelvis to allow optimum production, transfer and control of force and motion to the terminal segment in integrated athletic activities. Core muscle activity is best understood as the pre-programmed integration of local, single-joint muscles and multi-joint muscles to provide stability and produce motion. This results in proximal stability for distal mobility, a proximal to distal patterning of generation of force, and the creation of interactive moments that move and protect distal joints. Evaluation of the core should be dynamic, and include evaluation of the specific functions (trunk control over the planted leg) and directions of motions (three-planar activity). Rehabilitation should include the restoring of the core itself, but also include the core as the base for extremity function.
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Sports Med 2006; 36 (3): 189-198
2006 Adis Data Information BV. All rights reserved.
The Role of Core Stability in
Athletic Function
W. Ben Kibler,
Joel Press
and Aaron Sciascia
1 Lexington Clinic Sports Medicine Center, Lexington, Kentucky, USA
2 Rehabilitation Institute of Chicago, Chicago, Illinois, USA
The importance of function of the central core of the body for stabilisation and
force generation in all sports activities is being increasingly recognised. ‘Core
stability’ is seen as being pivotal for efficient biomechanical function to maximise
force generation and minimise joint loads in all types of activities ranging from
running to throwing. However, there is less clarity about what exactly constitutes
‘the core’, either anatomically or physiologically, and physical evaluation of core
function is also variable.
‘Core stability’ is defined as the ability to control the position and motion of
the trunk over the pelvis to allow optimum production, transfer and control of
force and motion to the terminal segment in integrated athletic activities. Core
muscle activity is best understood as the pre-programmed integration of local,
single-joint muscles and multi-joint muscles to provide stability and produce
motion. This results in proximal stability for distal mobility, a proximal to distal
patterning of generation of force, and the creation of interactive moments that
move and protect distal joints. Evaluation of the core should be dynamic, and
include evaluation of the specific functions (trunk control over the planted leg)
and directions of motions (three-planar activity). Rehabilitation should include the
restoring of the core itself, but also include the core as the base for extremity
1. What is the Core? to its local functions of stability and force genera-
tion, core activity is involved with almost all ex-
The musculoskeletal core of the body includes
tremity activities such as running, kicking and
the spine, hips and pelvis, proximal lower limb and
throwing. Therefore, the position, motion and con-
abdominal structures. The core musculature in-
tributions of the core must be evaluated and treated
cludes the muscles of the trunk and pelvis that are
as part of the evaluation and treatment of extremity
responsible for the maintenance of stability of the
spine and pelvis and help in the generation and
transfer of energy from large to small body parts
This article provides a general functional defini-
during many sports activities.
The muscles and
tion of core stability, describes the anatomy and
joints of the hip, pelvis and spine are centrally
physiology of core muscles, discusses core stability
located to be able to perform many of the stabilising
in function and dysfunction, provides principles of
functions that the body will require in order for the
clinical evaluation of core stability, and describes
distal segments (e.g. the limbs) to do their specific
rehabilitation and conditioning programmes to max-
function, providing the proximal stability for the
imise the effect of core stability on athletic function.
distal mobility and function of the limbs. In addition
190 Kibler et al.
2. Definition of Core Stability single-joint segmental stabilisation that allow the
longer, multi-joint muscles to work more efficiently
Core stability is an important component max-
to control spine motions.
This combination of
imising efficient athletic function. Function is most
muscle activations helps create the ‘neutral zone’
often produced by the kinetic chain, the coordinated,
control of the spinal segments. In this ‘neutral zone’
sequenced activation of body segments that places
the ligaments see minimal tension.
the distal segment in the optimum position at the
The abdominal muscles consist of the transverse
optimum velocity with the optimum timing to pro-
abdominus, the internal and external obliques, and
duce the desired athletic task.
The core is impor-
rectus abdominus. Contracting the transverse ab-
tant to provide local strength and balance and to
dominus increases intra-abdominal pressure and
decrease back injury. In addition, since the core is
tensions the thoracolumbar fascia. The transverse
central to almost all kinetic chains of sports activi-
abdominals have been shown to be critical in
ties, control of core strength, balance and motion
stabilisation of the lumbar spine.
will maximise all kinetic chains of upper and lower
muscle contractions help create a rigid cylinder,
extremity function.
enhancing stiffness of the lumbar spine.
It is
There is no single universally accepted definition
important to note that the rectus abdominus and
of core stability. A general definition of core stabili-
oblique abdominals are activated in direction-spe-
ty that will be used in this article is the ability to
cific patterns with respect to limb movements, thus
control the position and motion of the trunk over the
providing postural support before limb move-
pelvis and leg to allow optimum production, transfer
Contractions that increase intra-ab-
and control of force and motion to the terminal
dominal pressure occur before initiation of large
segment in integrated kinetic chain activities.
segment movement of the upper limbs.
In this
manner, the spine (and core of the body) is stabilised
3. Anatomy, Physiology
before limb movements occur to allow the limbs to
and Biomechanics
have a stable base for motion and muscle activa-
Clinically, it has been shown that only a very
3.1 Anatomy
small increase in activation of the multifidi and
abdominal muscles is required to stiffen the spinal
The core acts as an anatomical base for motion of
segments (5% of maximal voluntary contraction for
the distal segments. This can be considered ‘proxi-
activities of daily living and 10% of maximal volun-
mal stability for distal mobility’ for throwing, kick-
tary contraction for rigorous activity).
ing or running activities.
Most of the prime mov-
Core stability requires control of trunk motion in
er muscles for the distal segments (latissimus dorsi,
all three planes. In order to provide stability in all
pectoralis major, hamstrings, quadriceps and iliop-
planes of motions, muscles may be activated in
soas) attach to the core of the pelvis and spine. Most
patterns that are different from their primary func-
of the major stabilising muscles for the extremities
tions. For example, the quadratus lumborum (QL)
(upper and lower trapezius, hip rotators and glutei)
muscle functions mainly as a stabiliser of frontal
also attach to the core.
plane flexion and extension activities. However, the
Numerous muscles make up the complex known
QL is attached from the transverse processes of the
as core muscles. Some are small, short muscles with
spine and the 12th rib to the iliac crests. This orien-
small lever arms to span single joints. These are
tation allows QL muscle activation that occurs in
activated in ‘length dependent’ muscle activation
association with flexion, extension and lateral bend-
Others span numerous spinal segments
ing activities to buttress shearing of the spine in the
and function as prime mover muscles to integrate
plane of movement, making it more than just a
several joints and produce force. They are activated
frontal plane stabilising muscle.
in ‘force dependent’ activation patterns.
tion of both activation patterns is required in the The roof of the core muscle structures is the
multi-segmented structure like the spine. The mul- diaphragm. Simultaneous contraction of the dia-
tifidi are an example of short muscles that provide phragm, the pelvic floor muscles, and the abdominal
2006 Adis Data Information BV. All rights reserved. Sports Med 2006; 36 (3)
The Role of Core Stability in Athletic Function 191
muscles, is required to increase intra-abdominal 3.2 Physiology
pressure, providing a more rigid cylinder for trunk
support, decreasing the load on the spine muscles
Muscle activation in kinetic chain function is
based on pre-programmed patterns of muscle activa-
and allowing increased trunk stability.
tion that are task oriented, specific for the athletic
diaphragm contributes to intra-abdominal pressure
activity, and are improved by repetition. These pat-
before the initiation of limb movements, thereby
terns are grouped into the following two classes:
assisting spine/trunk stability. This activation occurs
length-dependent patterns, which confer stability
independently of the respiratory actions.
around one joint, are mediated by gamma affer-
At the opposite end of the trunk component of the
ent input and involve reciprocal inhibition of
core muscles are the pelvic floor muscles. Because
muscle to provide stiffness around a joint;
of the difficulty in directly assessing these muscles,
force-dependent patterns integrate activation of
they are also often neglected or ignored with respect
multiple muscles to move several joints and de-
to musculoskeletal rehabilitation. Synergistic acti-
velop force, and are mediated by Golgi tendon
vation patterns exist involving the transverse
Force-dependent patterns of activation are
abdominus, abdominals, multifidi and pelvic floor
demonstrated in many aspects of core-related activi-
muscles that provide a base of support for all the
ties. Evaluation of muscle activation patterns in
trunk and spinal muscles.
association with rapid arm movement shows that the
The hips and pelvis and their associated struc-
first muscles to be activated are the contralateral
tures are the base of support for the core structures.
and that patterns of activa-
Critical to functioning of the hip and pelvis are the
tion proceed up to the arm through the trunk.
many major muscle groups in this area. These mus-
Maximum foot velocity in kicking is more highly
cles have large cross-sectional areas and, in addition
related to hip flexor muscle activation than knee
A study of baseball throwing demon-
to their stabilising role, can generate a great deal of
strated that in all levels of pitching there is a pattern
force and power for athletic activities. The glutei are
of muscle activation that starts from the contralateral
stabilisers of the trunk over the planted leg and
external oblique and proceeds to the arm.
provide power for forward leg movements.
These muscle activation patterns also result in
hip/trunk area also contributes around 50% of the
increased levels of muscle activation in the extremi-
kinetic energy and force to the entire throwing mo-
ties, improving their capability to support or move
the extremity. Maximum gastrocnemius plantarflex-
The thoracolumbar fascia is an important struc-
or power is generated by use of the hip muscles.
ture that connects the lower limbs (via the gluteus
Twenty-six percent more activation can occur in the
maximus) to the upper limbs (via the latissimus
ankle as a result of proximal muscle activation.
Similarly, a 23–24% increase in maximal rotator
dorsi). This allows the core to be included in inte-
cuff activation occurs when the scapula is stabilised
grated kinetic chain activities such as throwing.
by the trapezius and rhomboid muscles, either in
covers the deep muscles of the back and trunk
asymptomatic or symptomatic individuals.
including the multifidi. The thoracolumbar fascia
addition, the distal muscle activity can be more
also has attachments to the internal obliques and
directed towards precision and control, rather than
transverse abdominus muscles, thus providing
power generation, when proximal muscle activation
three-dimensional support to the lumbar spine and
is maximum. This can be seen in the function of the
aiding core stability.
It helps to form a ‘hoop’
elbow muscles in throwing.
around the abdomen, consisting of the fascia poste-
Core muscle activation is used to generate rota-
riorly, the abdominal fascia anteriorly, and the ob-
tional torques around the spine. Most studies of
lique muscles laterally, which creates a stabilising
muscle activation demonstrate a differential pattern
corset effect.
of intensity and timing of muscle activation, starting
2006 Adis Data Information BV. All rights reserved. Sports Med 2006; 36 (3)
192 Kibler et al.
that minimise internal loads at the joint. There are
many examples of proximal core activation provid-
ing interactive moments that allow efficient distal
segment function. They either provide maximal
force at the distal end, similar to the cracking of a
whip, or they provide precision and stability to the
distal end. Maximum force at the foot segment in
kicking is developed by the interactive moment re-
sulting from hip flexion.
Maximum shoulder inter-
nal rotation force to rotate the arm is developed by
the interactive moment developed by trunk rota-
Maximum elbow varus torque to protect
against elbow valgus strain is produced by the inter-
active moment resulting from shoulder internal rota-
Maximal fast ball speed is correlated with the
interactive moment from the shoulder that stabilises
elbow and shoulder distraction
and produces el-
bow angular velocity.
Accuracy of ball throwing
is related to the interactive moment at the wrist
produced by shoulder movement.
As a result of the activations and interactive
moments, there is a proximal to distal development
Fig. 1. One-leg stance. No verbal cues are given. Attention should
be paid to alterations in posture or arm position.
of force and motion, according to the ‘summation of
speed’ principle
that includes core activation. This
on the contralateral side, that creates rotation as well
is not always a purely linear development strictly
as force generation.
from one segment to the next. In the tennis serve,
Finally, core muscle activation provides stiffness
to the entire central mass, making a rigid cylinder
that confers a long lever arm around which rotation
can occur and against which muscles can be
stabilised as they contract.
3.3 Biomechanics
Physiological muscle activation results in several
biomechanical effects that allow efficient local and
distal function. The pre-programmed muscle activa-
tions result in anticipatory postural adjustments
(APAs), which position the body to withstand the
perturbations to balance created by the forces of
kicking, throwing, or running.
The APAs create
the proximal stability for distal mobility.
The muscle activations also create the interactive
moments that develop and control forces and loads
at joints. Interactive moments are moments at joints
that are created by motion and position of adjacent
They are developed in the central body
segments and are key to developing proper force at
distal joints and for creating relative bony positions
. 2. Trendelenbur
position, with the contralateral hip dropped.
2006 Adis Data Information BV. All rights reserved. Sports Med 2006; 36 (3)
The Role of Core Stability in Athletic Function 193
the moment of inertia in these distal areas is less,
allowing the summation of higher velocities. Final-
ly, by allowing joint force control to be largely
influenced and controlled by pre-programmed mus-
cle activation patterns and interactive moments de-
veloped through core activation, instead of being
based on local ligament size or feedback-based local
muscle activation, the ligaments can be smaller in
size, and the smaller local muscles can be activated
for precision and control of performance variables.
5. Examples of Failure of Core Stability
Associated with Dysfunction
Weak hip muscles and resulting alteration of hip/
trunk position are a common finding associated with
knee injury. Weak hip abductors and tight hip flex-
ors are seen in association with anterior knee pain
and chondromalacia.
Alterations in hip muscle
Fig. 3. ‘Corkscrewing’ – using hip rotators to stabilise the trunk over
the planted le
in the presence of hip abductor weakness.
activity are associated with increased hip varus and
hip flexion positioning and increased knee valgus
elbow maximal velocity is developed before maxi-
positioning in squatting or landing manoeuvres, all
mal shoulder velocity. However, this general pattern
of which increase load on the anterior cruciate liga-
of force development from the ground through the
ment. A recent longitudinal study looked at core
core to the distal segment has been demonstrated in
stability parameters and found that weakness in hip
the tennis serve,
baseball throw
and kick.
external rotation was correlated with incidence of
Force control is also maximised through the core.
knee injury.
Based on these associations, most
The trunk is essential in re-acquiring the forward
rehabilitation and conditioning programmes for the
momentum in throwing,
and approximately 85%
knee now emphasise core stabilisation and hip
of the muscle activation to slow the forward-moving
arm is generated in the periscapular and trunk mus-
cles, rather than the rotator cuff.
4. Advantages of Core Stability
in Function
Core stability creates several advantages for inte-
gration of proximal and distal segments in generat-
ing and controlling forces to maximise athletic func-
tion. The larger, bulkier muscles in the central core
create a rigid cylinder and a large moment of inertia
against body perturbation while still allowing a sta-
ble base for distal mobility. In addition, it places
most of the ‘engine’ of force development in the
central core, allowing small changes in rotation
around the central core to effect large changes in
rotation in the distal segments, similar to the crack-
ing of the end of a whip. Because of the need for
relatively smaller mass in the peripheral segments,
Fig. 4. Sagittal plane evaluation. The shoulders should barely touch
the wall.
2006 Adis Data Information BV. All rights reserved. Sports Med 2006; 36 (3)
194 Kibler et al.
muscles to be tested should be tested in functional
positions when possible. If the muscle is mainly
used in a closed chain manner, it should be tested in
a closed chain manner. If the muscle is activated in
different planes of motion, it should be tested in
various planes of motion. If muscles are used prima-
rily in an eccentric manner, they need to be tested in
an eccentric manner. Often, to assess all of the
different muscles that function together to provide
core strength, evaluation of specific motion patterns
and quality of movement may be done.
method of analysis is harder to quantify, but is more
similar to actual three-planar core function. There is
no consensus regarding the most reliable or repro-
ducible evaluation system.
One option to assess core strength that incorpo-
. 5. Frontal plane evaluation.
rates many of these variables is to look at one-leg
standing balance ability, a one-leg squat, and a
Alteration of knee flexion has also been associat-
standing, three-plane core strength test. In a standing
ed with increased stresses in the arm. Tennis players
balance test, the patient is asked to stand on one leg
who did not have adequate bend in the knees, break-
with no other verbal cue (figure 1). Deviations such
ing the kinetic chain and decreasing the contribution
as a Trendelenburg posture or internally or external-
by the hip and trunk, had 23–27% increased loads in
ly rotating the weightbearing limb indicates inability
horizontal adduction and rotation at the shoulder and
to control the posture and suggests proximal core
valgus load at the elbow.
A mathematical analy-
weakness (figure 2).
sis of the tennis serve showed that a decrease in 20%
of the kinetic energy developed by the trunk resulted
A one-leg squat would be the next progressive
in a requirement of 34% more arm velocity or 80%
evaluation if the standing balance test is done well.
more shoulder mass to deliver the same energy to
Assuming the same starting point as the standing
the ball.
balance test, the patient is asked to do repetitive
Weakness or tightness at the hip can also affect
the arm. Decreased hip flexibility in rotation or
strength in abduction (positive Trendelenburg) was
seen in 49% of athletes with arthroscopically proven
posterior-superior labral tears.
6. How is Core Strength Evaluated?
There is no standard way that has been described
to measure core strength. Different investigators
have used different techniques to try to gauge the
relative strengths of specific core muscles via elec-
tromyogram data
and isometric dynamometer
These data can give an approximate
estimate of core strength. Firing of numerous mus-
cles in task-specific patterns to provide core strength
makes evaluation of any specific single muscle as a
reference point questionable. Any evaluation tech-
nique will need to take into consideration that the
. 6. Transverse plane evaluation.
2006 Adis Data Information BV. All rights reserved. Sports Med 2006; 36 (3)
The Role of Core Stability in Athletic Function 195
patient stand 8cm away from the wall, and progress
like the sagittal plane test from bilateral weightbear-
ing to single-leg stance and alternately touch one
shoulder then the other just barely against the wall
(figure 6). Quality of motion and speed can be
assessed. With lesser degrees of core strength, there
is a greater breakdown in the ability to maintain
single-leg stance and the ability to just barely touch
. 7. Horizontal side support exercises.
the wall. This test will assess transverse plane mo-
tions that incorporate abdominal muscles, hip rota-
partial quarter to half squats with no other verbal
tors and spine extensors. Therapy can then be insti-
cues. Similar deviations in the quality of the move-
tuted based on the muscles and planes of motion that
ment are assessed as in the standing balance test. A
are found to be deficient.
Trendelenburg posture, which may not be noted on
standing balance, may be brought out with a single-
7. Principles of Core Rehabilitation
leg squat. The patient may use their arms for balance
Rehabilitation of the core should concentrate on
or may go into an exaggerated flexed or rotated
both the intrinsic needs of the core for flexibility,
posture (‘corkscrewing’) in order to put the gluteal
strength, balance and endurance, and on the function
or short rotator muscles on greater tension to com-
of the core in relation to its role in extremity func-
pensate for other muscular weakness (figure 3).
tion and dysfunction. A thorough pre-rehabilitation
Three-plane core testing is an attempt to quantify
examination including the core and the extremity is
core control in the different planes of spine and core
required prior to rehabilitation.
motion. Reliability and validity studies have not
The early focus is on the deficiencies discovered
been done on specific tests. Clinical experience has
during the pre-rehabilitation examination. These
demonstrated that this battery of tests does give
usually include both altered patterns of motion of
useful information that allows specific rehabilitation
the hip, trunk and shoulder, and actual weakness or
protocols to be instituted for increased core func-
inflexibilities of muscles, and may be seen locally or
tion. Testing is done with the patient standing a
distantly. Specific inflexibilities and weaknesses
given distance (usually 8cm) away from a wall. In
may be addressed locally by specific exercises, but
sagittal plane testing, they will be facing away from
motion patterns should be addressed on a global
the wall. They are asked to slowly move their body
level involving the entire kinetic chain motion. Re-
backwards, keeping their feet flat on the floor, to just
barely touch their head against the wall (figure 4).
Initially, this can be done with both legs on the
ground, then progressed to partial weightbearing on
each side and ultimately to single-leg standing. Sag-
ittal plane core strength testing creates eccentric
activation in the abdominals, the quadriceps and hip
flexor muscles, and concentric activation in the hip
and spine extensors. Frontal plane testing is done by
having the patient standing with one side then the
other 8cm away from the wall (figure 5). While
standing on the inside leg, they are asked to barely
touch their inside shoulder to the wall. This test
evaluates eccentric strength of the quadratus
lumborum, hip abductors, and some long spinal
muscles that are working in a frontal plane. Finally,
transverse plane motion is tested by having the
. 8. Isometric trunk rotation.
2006 Adis Data Information BV. All rights reserved. Sports Med 2006; 36 (3)
196 Kibler et al.
of rehabilitation is not only to restore core function
by itself, but also is the first stage of extremity
Progressions for lower extremity rehabilitation
include forward and side lunges, integrated trunk
rotation/hip rotations, and knee flexion/extensions
with trunk rotations.
The frequency and intensi-
ty of each of the exercises will depend on the indi-
vidual response to the exercises.
Shoulder and upper extremity rehabilitation may
begin with a posture of bilateral leg stance, hip
extension and trunk extension.
Activation pat-
terns may start with ipsilateral muscles and proceed
to contralateral activations. Diagonal patterns in-
Fig. 9. Diagonal trunk rotation around a stable base: starting posi-
volving trunk rotation around a stable base imitate
the throwing motion (figure 9, figure 10, figure 11).
habilitation for extremity injury should start with
The lower extremity activation drives the scapular
core emphasis.
and shoulder activation. All upper extremity exer-
In order to create a stable base, the rehabilitation
cises should end in the same position of trunk/hip
protocols start with the primary stabilising muscula-
extension. One method to assure this posture is to
ture such as the transverse abdominus, multifidus,
ask the patients to end with ‘the elbows in the back
and the quadratus lumborum. Due to their direct
pockets’. Progression for upper extremity rehabilita-
tion include integrated scapular retraction/arm ab-
attachment to the spine and pelvis, they are responsi-
duction/external rotation and ‘low rows’, integrated
ble for the most central portion of the core stability.
trunk extension/scapular retraction/arm extension
Exercises include the horizontal side support (figure
(figure 12) and hip/trunk rotation with scapular re-
7) and isometric trunk rotation (figure 8). This stage
traction (figure 13).
Core stabilisation should avoid emphasising the
use of single planar exercises that isolate specific
muscles or specific joints. They may be used at
times during the rehabilitation protocol, but empha-
sis should be on early progression to functional
. 10. Dia
onal trunk rotation: maximal external rotation. Fi
. 11. Dia
onal trunk rotation: cross bod
2006 Adis Data Information BV. All rights reserved. Sports Med 2006; 36 (3)
The Role of Core Stability in Athletic Function 197
positions, motions and muscle activation sequences.
In this manner, normal physiological activations are
restored, which lead to restoration of normal biome-
chanical motions. Exercises may be started with the
extremity close to the body, decreasing the moment
arm, then progressing to more abducted positions,
increasing the forces and loads. The goal is to
achieve coordination of activation of the segments
throughout the entire kinetic chain.
Rehabilitation should be viewed as a ‘flow’ of
exercises that build a base of stability and force
generation, and then proceed distally to establish
control of the forces while allowing maximal mobil-
ity of the distal segment.
The core is the central
part of this flow. It acts as the base of stability and
the ‘engine’ of force generation, and also acts as the
controller to regulate the forces. Since it is involved
in many aspects of all athletic activities, it should be
evaluated as part of the workup of any extremity
injury, and should be rehabilitated prior to rehabili-
tation of the injured extremity.
Fig. 13. Hip/trunk rotation with scapular retraction. These may be
done in various planes of arm elevation.
8. Conclusion
be approximated by evaluations that reproduce the
three-planar motions that are used by the core to
Core stability is a pivotal component in normal
accomplish its functions. Better understanding of
athletic activities. It is best understood as a highly
the complex biomechanics and muscle activations
integrated activation of multiple segments that pro-
will allow more detailed evaluations and more spe-
vides force generation, proximal stability for distal
cific rehabilitation protocols.
mobility, and generates interactive moments. It is
difficult to accurately quantify by isolating individu-
al components, but its function or dysfunction can
No sources of funding were used to assist in the prepara-
tion of this review. The authors have no conflicts of interest
that are directly relevant to the content of this review.
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2006 Adis Data Information BV. All rights reserved. Sports Med 2006; 36 (3)
... All movements and forces of the body are linked through the myofascia surrounding the trunk, pelvic area, and lower extremities [1,2]. These structures interact and act as stabilizers that play an important role in maximizing performance [1]. ...
... All movements and forces of the body are linked through the myofascia surrounding the trunk, pelvic area, and lower extremities [1,2]. These structures interact and act as stabilizers that play an important role in maximizing performance [1]. In particular, effective mobilization of the trunk muscles is associated with optimal generation of muscle strength and precise control of hip motion through the lumbar spine and pelvis [3,4]. ...
... This is thought to assist force or power generation of the limbs during kinetic chain activity [52,53]. A strong and stable trunk and its rapid activation are potentially the foundation for limb force generation and achieving improved sports performance [1]. A 4 kPa increase in the IAP results in a 25% improvement in spinal stability [54]. ...
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Abdominal pressure is vital in protecting the lumbar spine and controlling postural balance. Dynamic balance is associated with movement stability, adaptation to load, and reduced injury risk. Although trunk stability has been examined using belts and braces, the effects of external abdominal pressure support (APS) on balance control remain unknown. In this study, we aimed to determine the effects of external APS on dynamic balance. Overall, 31 young adults participated in this randomized crossover study. External APS was provided using a device that could be pressurized and decompressed by inflating a cuff belt wrapped around the trunk. The modified Star Excursion Balance Test was performed under external APS and non-APS conditions. The maximum anterior, posterolateral, and posteromedial values normalized to the spinal malleolar distance and their respective composite values were compared between the two conditions with and without APS. Posterolateral, posteromedial, and composite values were significantly higher in the APS condition than in the non-APS condition (p < 0.001). The external APS was effective in immediately improving dynamic balance. Furthermore, APS was effective in dynamic balance control as it improved stability during anterior trunk tilt, which displaces the center of gravity forward.
... By being located in the middle of the kinetic chain system as a box, (65) (35) (66) optimal functioning of the core is required for the production of strong, functional movements of the extremities. (67) KIBLER AND MCMULLEN frequently referred to a proximal stability method, also known as a kinetic chain approach, in the literature when discussing shoulder rehabilitation. (68) (60,69) This protocol is primarily concerned with driving the scapula and shoulder during the rehabilitation process using distal segments, such as the trunk and legs. ...
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Background: Periarthritis shoulder has an incidence of 3%-5% in the general population and up to 20% in those with diabetes. Greater core stability benefits performance by providing a foundation for greater force production in the upper and lower extremities. Thus, core muscle exercises have a theoretical basis in rehabilitating various musculoskeletal disorders. Method: After obtaining approval from the institutional ethics committee out of 68 participants, 20 were excluded. Pre-data of pain, range of motion (ROM), and functional ability score were taken before intervention. Participants were randomly divided into two groups. Group A (control group) received Conventional therapy and Group B (experimental group) received Conventional therapy plus core stability exercise (5 sessions/week) for 4 weeks. Post-intervention data on pain, ROM and functional ability scores were collected for both groups. Pre-data and post-data were compared within group and between groups statistically. Results: Within Group A and Group B pain, shoulder ROM, and functional ability score post-4-week showed significant improvement compared to pre-data (p<0.00). Between groups (Group A and Group B) analysis of pain, shoulder ROM and functional ability score post 4 weeks of intervention did not show a significant difference (p>0.05). Thus, statistically between Group A and Group B there was no significant difference after 4 weeks of intervention on pain, shoulder ROM and functional ability score. Conclusion: Group B showed statistically no significant effect compared to Group A on pain, shoulder ROM and functional ability score in the peri-arthritis shoulder.
... During pedaling, breathing muscles act as a crucial postural function, where optimal relation between the diaphragm, abdominal wall, parasternal, and pelvic floor provides production, transfer, and control of the active force [26]. In particular, the bike sitting posture may induce physical constraints to THA expansion and could affect respiratory mechanics. ...
Thoracoabdominal breathing motion pattern is being considered in sports training because of its contribution, along with other physiological adaptations, to overall performance. We examined whether and how experience with cycling training modifies the thoracoabdominal motion patterns. We utilized optoelectronic plethysmography to monitor ten trained male cyclists and compared them to ten physically active male participants performing breathing maneuvers. Cyclists then participated in a self-paced time trial to explore the similarity between that observed during resting breathing. From the 3D coordinates of 32 markers positioned on each participant’s trunk, we calculated the percentage of contribution of the superior thorax, inferior thorax, and abdomen and the correlation coefficient among these compartments. During the rest maneuvers, the cyclists showed a thoracoabdominal motion pattern characterized by an increased role of the inferior thorax relative to the superior thorax (26.69±5.88%, 34.93±5.03%; p = 0.002, respectively), in contrast to the control group (26.69±5.88%; 25.71±6.04%, p = 0.4, respectively). In addition, the inferior thorax showed higher coordination in phase with the abdomen. Furthermore, the results of the time trial test underscored the same pattern found in cyclists breathing at rest, suggesting that the development of a permanent modification in respiratory mechanics may be associated with cycling practice.
... Core strength leads to better balance and stability, that important for most sports and other physical activities depend on stable core muscles, leads to better balance and stability. Core strengthening increases the performance of spiker by transferring the power from the lower body to the upper body 16 , whereas these abdominal and pelvic muscles are acts as a fulcrum, where the upper and lower body acts a movable lever 5,11,16 . In volleyball, vertical jump is a critical aspect for a spiker 13 . ...
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Background and Purpose:-Spiking is the central element to score a point which need maximum force to hit the ball. Where as the power transfer from the core muscles of the body. The purpose of the study is to evaluate the effect of yoga (Angamardhana) on core strength among volleyball spikers.
... Trunk stabilization is explained according to the principle of proximal stability for distal mobility (18). Good trunk stabilization is required for football-specific technical skills such as dribbling, passing, shooting, tackling, and defending. ...
Objective: This study was designed to investigate the effect of participation in sports on the functional capacity of a person with an amputation. Material and Method: The study included a sports group of 29 male football players with unilateral lower limb loss aged between 18-45 years and a control group of 11 sedentary persons with an amputation. Body composition, postural stability, and trunk muscle strength were measured with a skinfold, Biodex Stability System, and dynamometer. A pulmonary function test and cardiopulmonary exercise test were performed. Aerobic capacity was evaluated by cardiopulmonary exercise test using the breath-by-breath method. Result: Skinfold thickness measurements performed at the triceps, thigh, and calf regions were higher in the sports group (p<0.05), whereas body fat percentage indicated no significant difference among both groups (p>0.05). The sports group had higher postural stability, trunk muscle strength, and endurance (p<0.05). Predicted maximum voluntary ventilation (MVV%) and peak expiratory flow (PEF%) values were significantly higher in the sports group (p<0.05). The sports group had higher heart rates corresponding to the anaerobic threshold (p<0.05). At the same time, no significant difference was observed between the two groups concerning resting and maximum heart rate (p>0.05). The sports group had longer exercise times and higher gas exchange values (p<0.05). ÖZET Amaç: Bu çalışma, ampütasyonu olan kişilerin spora katılımının fonksiyonel kapasiteleri üzerindeki etkisini araştırmak için yapıl-mıştır. Gereç ve Yöntem: Çalışmaya 18-45 yaş arası tek taraflı alt eks-tremite kaybı olan 29 erkek futbolcudan oluşan spor grubu ve ampütasyonu olan sedanter 11 kişiden oluşan kontrol grubu da-hil edildi. Vücut kompozisyonu, postural stabilite ve gövde kas kuvveti sırasıyla skinfold, Biodex Stabilite Sistemi ve izokinetik dinamometre ile ölçüldü. Solunum fonksiyon testi ve kardiyopul-moner egzersiz testi yapıldı. Aerobik kapasite, breath-by-breath (her nefeste) yöntemi kullanılarak kardiyopulmoner egzersiz testi ile değerlendirildi. Bulgular: Triseps, uyluk ve baldır bölgelerinden yapılan deri kıvrım kalınlığı ölçümleri spor yapan grupta daha yüksek bu-lundu (p<0,05), vücut yağ yüzdesi ise her iki grup arasında an-lamlı bir fark göstermedi (p>0,05). Postural stabilite, gövde kas kuvveti ve dayanıklılığı spor yapan grupta anlamlı olarak yüksekti (p<0,05). Tahmin edilen maksimum istemli ventilas-yon (%MVV) ve tepe ekspiratuar akış (%PEF) değerleri spor yapan grupta anlamlı olarak yüksekti (p<0,05). Anaerobik eşiğe karşılık gelen kalp hızları spor grubunda daha yüksek bulu-nurken (p<0,05), istirahat ve maksimum kalp hızı açısından iki grup arasında anlamlı bir fark gözlemlenmedi (p>0,05). Spor yapan grubun egzersiz süreleri ve gaz değişim değerleri daha yüksekti (p<0,05).
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Background Acetabular dysplasia (AD) is defined as a structurally deficient acetabulum and is a well-recognized cause of hip pain in young adults. While treatment of severe AD with a periacetabular osteotomy has demonstrated good long-term outcomes, a trial of non-operative management is often recommended in this population. This may be especially true in patients with milder deformities. Currently, there is a paucity of research pertaining to non-operative management of individuals with AD. Purpose To present expert-driven non-operative rehabilitation guidelines for use in individuals with AD. Study Design Delphi study Methods A panel of 15 physiotherapists from North America who were identified as experts in non-operative rehabilitation of individuals with AD by a high-volume hip preservation surgeon participated in this Delphi study. Panelists were presented with 16 questions regarding evaluation and treatment principles of individuals with AD. A three-step Delphi method was utilized to establish consensus on non-operative rehabilitation principles for individuals presenting with AD. Results Total (100%) participation was achieved for all three survey rounds. Consensus, defined a piori as > 75%, was reached for 16/16 questions regarding evaluation principles, activity modifications, appropriate therapeutic exercise progression, return to activity/sport criteria, and indications for physician referral. Conclusion This North American based Delphi study presents expert-based consensus on non-operative rehabilitation principles for use in individuals with AD. Establishing guidelines for non-operative management in this population will help reduce practice variation and is the first step in stratifying individuals who would benefit from non-operative management. Future research should focus on patient-reported outcomes and rate of subsequent surgical intervention to determine the success of the guidelines reported in this study. Level of Evidence Level V
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The aim of this study is to compare the effects of 5-week core training without equipment and with bosu-swiss ball on body composition, trunk extensor endurance, anaerobic power and some blood parameters. A total of 30 volunteers participated in the study. The research group was randomly divided into 3 groups of 10 people. These groups are named as the Equipment-Free Training Group (EAG), the Bosu-Swiss Ball Group (BSG), and the Control Group (KG). EAG applied the core training program, which was determined as 3 days a week, without using any auxiliary equipment for 5 weeks. BSG applied the core training program, which was determined as 3 days a week, using idle-swiss ball-based exercises for 5 weeks. KG did not use any training program. Height, body weight and body fat percentage of the research group were measured before and after the training protocol was applied. In addition, anaerobic strength test and trunk extensor endurance test were applied to the participants. In addition, blood samples were taken and Leptin, Insulin, Testosterone and Growth Hormones were evaluated. The obtained data were analyzed with Wilcoxson and Kruskal Wallis statistics. As a result, it was determined that the applied training programs had a positive effect on body composition. Trunk extension test and anaerobic power values of the study groups increased. As a result of the study, while Leptin and Insulin values of EAG and BSG groups decreased, Growth Hormone values increased, but there was no significant change in Testosterone values.
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The purpose of this study was to compare the shoulder and elbow joint loads during the tennis serve. Two synchronised 200 Hz video cameras were used to record the service action of 20 male and female players at the Sydney 2000 Olympics. The displacement histories of 20 selected landmarks, were calculated using the direct linear transformation approach. Ball speed was recorded from the stadium radar gun. The Peak Motus system was used to smooth displacements, while a customised inverse-dynamics program was used to calculate 3D shoulder and elbow joint kinematics and kinetics. Male players, who recorded significantly higher service speeds (male = 183 km hr(-1): female = 149 km hr(-1)) recorded significantly higher normalised and absolute internal rotation shoulder torque at the position when the arm was maximally externally rotated (MER) (male = 4.6% and 64.9 Nm: female = 3.5% and 37.5 Nm). A higher absolute elbow varus torque (67.6 Nm) was also recorded at MER, when compared with the female players (41.3 Nm). Peak normalised horizontal adduction torque (male = 7.6%: female = 6.5%), normalised shoulder compressive force (male = 79.6%: female = 59.1%) and absolute compressive force (male = 608.3 N: female = 363.7 N), were higher for the male players. Players who flexed at the front knee by 7.6 degrees, in the backswing phase of the serve, recorded a similar speed (162 km hr(-1)), and an increased normalised internal rotation torque at MER (5.0%), when compared with those who flexed by 14.7 degrees. They also recorded a larger normalised varus torque at MER (5.3% v 3.9%) and peak value (6.3% v 5.2%). Players who recorded a larger knee flexion also recorded less normalised and absolute (4.3%, 55.6 Nm) peak internal rotation torque compared with those with less flexion (5.6%, 63.9 Nm). Those players who used an abbreviated backswing were able to serve with a similar speed and recorded similar kinetic values. Loading on the shoulder and elbow joints is higher for the male than female players, which is a reason for the significantly higher service speed by the males. The higher kinetic measures for the group with the lower knee flexion means that all players should be encouraged to flex their knees during the backswing phase of the service action. The type of backswing was shown to have minimal influence on service velocity or loading of the shoulder and elbow joints.
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The neutral zone is a region of intervertebral motion around the neutral posture where little resistance is offered by the passive spinal column. Several studies--in vitro cadaveric, in vivo animal, and mathematical simulations--have shown that the neutral zone is a parameter that correlates well with other parameters indicative of instability of the spinal system. It has been found to increase with injury, and possibly with degeneration, to decrease with muscle force increase across the spanned level, and also to decrease with instrumented spinal fixation. In most of these studies, the change in the neutral zone was found to be more sensitive than the change in the corresponding range of motion. The neutral zone appears to be a clinically important measure of spinal stability function. It may increase with injury to the spinal column or with weakness of the muscles, which in turn may result in spinal instability or a low-back problem. It may decrease, and may be brought within the physiological limits, by osteophyte formation, surgical fixation/fusion, and muscle strengthening. The spinal stabilizing system adjusts so that the neutral zone remains within certain physiological thresholds to avoid clinical instability.
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The relatively large mass of the upper body and its elevated position in relation to the area of support during standing accentuate the importance of an accurate control of trunk movements for the maintenance of equilibrium. This fact has often been emphasized but never studied in detail. In this thesis the kinematics and motor patterns of simple voluntary trunk movements are investigated during standing. The analysis integrates neurophysiology and biomechanics using electromyographic (EMG) and optoelectronic techniques. Both the voluntary (primary movement) and the involuntary (associated postural adjustment) components of the movement are considered. The results demonstrate how the central nervous system (CNS) in its control of equilibrium utilizes biomechanical principles such as mechanical leverage of the different muscles and the interaction of active (muscle force) and passive forces (e.g. gravity and forces in stretched ligaments and/or muscles). Both primary and associated movements were found to be controlled by task specific and flexible muscle synergies which adapt to the mechanical demands of the situation. These task specific synergies were related to the amplitude, velocity and direction of the movement. Slow movements were often initiated through the action of gravity after a decrease or cessation of activity in postural muscles. Fast movements, however, were always initiated by a marked burst of activity in the agonist muscles. Significant relationships were observed between kinematical parameters (amplitude, duration and velocity) of fast trunk movements and temporal aspects of the EMG pattern. Multiple regression analysis indicated that the time to onset of muscle activity braking the ongoing trunk movement contained more information regarding the amplitude of the movement than did the duration of the initiating burst of activity in the prime mover. This supports the view that the initiating agonist burst is preprogrammed, whereas the braking antagonist burst may be influenced by peripheral feedback such as from muscle stretch receptors. In the early phase of a fast trunk flexion an unexpected flexion of the knees was observed. It is suggested that this knee flexion is a fast postural adjustment passively initiated as a mechanical consequence of the activation of muscles controlling the primary movement. This mechanism, which for anatomical reasons cannot act during an extension of the trunk, simplifies the feed-forward control of equilibrium during voluntary trunk flexion movements. For fast trunk extension movements a preactivation of ankle muscles occurred which resulted in a delay in the onset of the prime mover muscles when measured during a simple reaction time task.(ABSTRACT TRUNCATED AT 400 WORDS)
Study design: This study investigated the influence of five different muscle groups on the monosegmental motion (L4-L5) during pure flexion/extension, lateral bending, and axial rotation moments. Objectives. The results showed and compared the effect of different muscle groups acting in different directions on the stability of a single motion segment to find loading conditions of in vitro experiments that simulate more physiologically reasonable loads. Summary of Background Data. In spine biomechanics research, most in vitro experiments have been carried out without applying muscle forces, even though these forces stabilize the spinal column in vivo. Methods. Seven human lumbosacral spines were tested in a spine tester that allows simulation of up to five symmetrical muscle forces. Changing pure flexion/extention, lateral binding, and axial rotation moments up to +/-3.75 Nm were applied without muscle forces, with different muscle groups and combinations. The three-dimensional monosegmental motion was determined using an instrumented spatial linkage system. Results. Simulated muscle forces were found to strongly influence load-deformation characteristics. Muscle action generally increased the range of motion and the natural zone of the motion segments. This was most evident for flexion and extension. After five pairs of symmetrical, constant muscle forces were applied (80 N per pair) the range of motion decreased about 93% in flexion and 85% in extension. The total natural zone for flexion and extension was decreased by 83% muscle action. The multifluids muscle group had the strongest influence. Conclusion. This experiment showed the important of including at least some of the most important muscle groups in invitro experiments in lumbar spine specimens.
Analysis of shoulder dysfunction in throwing and overhead athletes can no longer be restricted to evaluation of the glenohumeral joint alone. The isolated shoulder is incapable of generating the force necessary to hurl a baseball at velocities of 90-100 miles per hour or serve a tennis ball in excess of 120 miles per hour. The purpose of this paper is to provide a literature based theoretical framework for the role of the spine during these activities. The spine is a pivotal component of the kinematic chain which functions as a transfer link between the lower and upper limbs, a force generator capable of accelerating the arm, and a force attenuator which dampens shear forces at the glenohumeral joint during the deceleration phase of the pitching motion. Side bending and rotation of the cervical spine facilitates visual acquisition of the intended target. Inflexibility of the hip musculature and weakness of the muscles which attach to the thoracolumbar fascia have profound effects upon spine function which secondarily places greater stress upon the glenohumeral joint and rotator cuff. Shoulder rehabilitation and injury prevention programs should include evaluation of and exercise regimens for the lumbar, thoracic and cervical spine.
From the mechanical point of view the spinal system is highly complex, containing a multitude of components, passive and active. In fact, even if the active components (the muscles) were exchanged by passive springs, the total number of elements considerably exceeds the minimum needed to maintain static equilibrium. In other words, the system is statically highly indeterminate. The particular role of the active components at static equilibrium is to enable a virtually arbitrary choice of posture, independent of the distribution and magnitude of the outer load albeit within physiological limits. Simultaneously this implies that ordinary procedures known from the analysis of mechanical systems with passive components cannot be applied. Hence the distribution of the forces over the different elements is not uniquely determined. Consequently nervous control of the force distribution over the muscles is needed, but little is known about how this achieved. This lack of knowledge implies great difficulties at numerical simulation of equilibrium states of the spinal system. These difficulties remain even if considerable reductions are made, such as the assumption that the thoracic cage behaves like a rigid body. A particularly useful point of view about the main principles of the force distributions appears to be the distinction between a local and a global system of muscles engaged in the equilibrium of the lumbar spine. The local system consists of muscles with insertion or origin (or both) at lumbar vertebrae, whereas the global system consists of muscles with origin on the pelvis and insertions on the thoracic cage. Given the posture of the lumbar spine, the force distribution over the local system appears to be essentially independent of the outer load of the body (though the force magnitudes are, of course, dependent on the magnitude of this load). Instead different distributions of the outer load on the body are met by different distributions of the forces in the global system. Thus, roughly speaking, the global system appears to take care of different distributions of outer forces on the body, whereas the local system performs an action, which is essentially locally determined (i.e. by the posture of the lumbar spine). The present work focuses on the upright standing posture with different degree of lumbar lordosis. The outer load is assumed to consist of weights carried on the shoulders. By reduction of the number of unknown forces, which is done by using a few different principles, a unique determination of the total force distributions at static equilibrium is obtained.(ABSTRACT TRUNCATED AT 400 WORDS)