Introduction

Techniques and Ending Info

Attachment and Innervation

Relative Location

Palpation

Actions

Arthrokinematics

Fascial Integration

Subsystems

Behavior in Postural Dysfunction

External Obliques

REPSI

WITS

PTAGlobal

NASM

AUSactive

REPS

ISSA

AFAA

ACSM

AOTA

PACE

TPTA

CIMSPA

YOGA

NCBTMB

NYPT

CanFitPro

This course describes the anatomy and <a id="integration" data-tip="1473" target="_blank" href="/glossary-term/integration" class="glossary">integrated</a> function of the external oblique muscles (a.k.a. the obliques, external abdominal oblique, oblique <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>). The external oblique muscles originate on ribs 5-12 and insert into the abdominal fascia, linea alba, iliac crest, and inguinal ligament. This is the most superficial <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> on the <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> abdominal wall; the internal obliques and transverse abdominis lay beneath this <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>. Research is not available on the fiber type composition of the oblique muscles; however, it may be reasonable to suggest that the proportion of type I <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> fibers and type II <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> fibers is similar to the rectus abdominis and fairly even. The external oblique muscles cross the torso and pelvis, influencing motion of the pelvis, thoracic spine, lumbar spine, and ribs. The obliques are the primary rotators of the lumbar spine, will contribute to flexion and <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> flexion of the spine, as well as a <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> pelvic tilt, a <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> pelvic tilt, and increasing intra-abdominal pressure and spine/pelvis <a id="stability" data-tip="1191" target="_blank" href="/glossary-term/stability" class="glossary">stability</a>. This course also describes the role of the external obliques in facet joint <a id="arthrokinematics" data-tip="1859" target="_blank" href="/glossary-term/arthrokinematics" class="glossary">arthrokinematics</a>, fascial <a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a> (<a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a> of abdominal wall muscles), <a id="posture" data-tip="1659" target="_blank" href="/glossary-term/posture" class="glossary">postural</a> dysfunction, and subsystem <a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a>. Sports medicine professionals (personal trainers, fitness instructors, physical therapists, massage therapists, chiropractors, occupational therapists, athletic trainers, etc.) must be aware of the <a id="integration" data-tip="1473" target="_blank" href="/glossary-term/integration" class="glossary">integrated</a> function of the oblique muscles for the detailed analysis of human movement, and the development of sophisticated exercise programs and therapeutic (rehabilitation) interventions. Further, this course is essential knowledge for future courses discussing injury prevention and physical rehabilitation/physical therapy (e.g. &#x201C;weak core,&#x201D; abdominal wall pain, diastasis recti, hip flexor strain, sports hernias, groin injury, <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> pubic ligament injury, low back pain), the synergistic function of the external obliques (e.g. increased intra-abdominal pressure with the transverse abdominis, internal obliques, rectus abdominis, diaphragm, and pelvic floor muscles) and oblique <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> <a id="specificity" data-tip="1224" target="_blank" href="/glossary-term/specificity" class="glossary">specific</a> exercises and techniques for enhancing sports performance (e.g. ensuring ideal oblique length for <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> core <a id="stability" data-tip="1191" target="_blank" href="/glossary-term/stability" class="glossary">stability</a>, strength, <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, hypertrophy, etc.).
<h4>Brookbush Institute&#x2019;s most recommended techniques for the External Obliques (see videos below):</h4>
<ul>
 <li>Activation: <a href="https://brookbushinstitute.com/videos/plank-progressions-with-elbows-on-ball">Ball Plank</a></li>
 <li>Activation:&#xA0;<a href="https://brookbushinstitute.com/videos/static-standing-chop-pattern">Static Standing Chop</a></li>
 <li>Reactive Activation: <a href="https://brookbushinstitute.com/videos/modified-mountain-climbers-for-core-reactive-stabilization">Mountain Climbers</a></li>
</ul>
<img alt="The external oblique muscle on the lateral side of the body" title="The attachments of the external oblique muscles" src="https://www.datocms-assets.com/25800/1638276949-screen-shot-2016-10-18-at-10-33-51-pm.png">

 Course Description: External Oblique

<h3>What&#x2019;s in a name?</h3>
<ul>
 <li><a href="https://www.etymonline.com/word/external#etymonline_v_14117" target="_blank" rel="noopener">External (adj.)</a> - early 15c., from Middle French externe or directly from Latin externus &quot;outside, outward&quot; (<a href="https://www.etymonline.com/word/external#etymonline_v_14117" target="_blank" rel="noopener">Etymology Online</a>)</li>
 <li><a href="https://www.etymonline.com/word/oblique#etymonline_v_2430" target="_blank" rel="noopener">Oblique (adj.)</a> - early 15c., from Middle French oblique (14c.) and directly from Latin obliquus &quot;slanting, sidelong, indirect,&quot; from ob &quot;against&quot; (see <a href="https://www.etymonline.com/word/ob-#etymonline_v_2404" target="_blank" rel="noopener">ob-</a>) + root of licinus &quot;bent upward&quot; (see <a href="https://www.etymonline.com/word/limb#etymonline_v_9522" target="_blank" rel="noopener">limb</a> (n.1)). As a type of <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>, in reference to the axis of the body, 1610s (adj.), 1800 (n.). (<a href="https://www.etymonline.com/word/oblique#etymonline_v_2430" target="_blank" rel="noopener">Etymology Online</a>)
 <ul>
 <li>&quot;the most external <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> that runs slanting&quot;</li>
 </ul>
 </li>
</ul>
<img src="https://www.datocms-assets.com/25800/1645299278-abdominal-fascia.png" title="The attachment of the external oblique muscles" alt="The diagonal direction of the external obliques on the torso">
External Obliques - By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (Image: Bartleby.com: Gray&apos;s Anatomy, Plate 392, Public Domain, https://commons.wikimedia.org/w/index.php?curid=287550)

Introduction to the External Obliques

<ul>
 <li>Origin:&#xA0;The external surfaces of ribs 5 - 9, interdigitating with the&#xA0;<a href="https://brookbushinstitute.com/courses/serratus-anterior" target="_blank" rel="noopener">serratus anterior</a>, and the external surfaces of ribs 10 - 12 interdigitating with the&#xA0;<a href="https://brookbushinstitute.com/courses/latissimus-dorsi" target="_blank" rel="noopener">latissimus dorsi</a>&#xA0;(1-3).</li>
 <li>Insertion:&#xA0;The <a id="medial" data-tip="1568" target="_blank" href="/glossary-term/medial" class="glossary">medial</a> fibers invest in the abdominal fascia (running superficial to the&#xA0;<a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>) terminating at the linea alba (a tendinous raphe that extends from the xiphoid process to pubis) (1-5). The more <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> fibers invest in the inguinal ligament from the pubic tubercle to the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> iliac spine (ASIS), and the external lip of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> half of the iliac crest (1-5). The insertion of the external obliques is primarily tendinous and is known as the aponeurosis of the external obliques (4).</li>
 <li>Nerve:&#xA0;Segmentally innervated by branches of the intercostal nerves from T7 - T11, with potential contribution from the intercostal nerves of T5, T6, and/or T12, the subcostal <a id="nerve-cell" data-tip="1361" target="_blank" href="/glossary-term/nerve-cell" class="glossary">nerve</a>, and iliohypogastric (L1) <a id="nerve-cell" data-tip="1361" target="_blank" href="/glossary-term/nerve-cell" class="glossary">nerve</a> and/or the ilioinguinal (L1) nerves (1-2, 4-5).</li>
</ul>

Attachments & Innervations: External Obliques

<ul>
 <li>Depth:&#xA0;The external obliques are the most superficial <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> of the <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> abdominal wall, lying just beneath a thin layer of skin, <a id="connective-tissue-cell" data-tip="1776" target="_blank" href="/glossary-term/connective-tissue-cell" class="glossary">adipose tissue</a>, and fascia (5). The <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> fibers are oriented from superior/lateral to inferior/medial; the direction your fingers would face if your hands were placed in your front pockets (5).</li>
 <li>Lateral (and <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a>):&#xA0;The external obliques invest in the external surfaces of ribs five through twelve (1-3). Starting <a id="cephalad" data-tip="1560" target="_blank" href="/glossary-term/cephalad" class="glossary">cranially</a>, the origin progresses with each successive rib from anterior/medial at the <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> border of the&#xA0;<a href="https://brookbushinstitute.com/courses/pectoralis-major" target="_blank" rel="noopener">pectoralis major</a>&#xA0;on rib 5, to posterior/lateral near the insertion of the&#xA0;<a href="https://brookbushinstitute.com/courses/latissimus-dorsi" target="_blank" rel="noopener">latissimus dorsi</a>&#xA0;and serratus <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> on rib 12. Fascia from the&#xA0;<a href="https://brookbushinstitute.com/courses/serratus-anterior" target="_blank" rel="noopener">serratus anterior</a>,&#xA0;<a href="https://brookbushinstitute.com/courses/latissimus-dorsi" target="_blank" rel="noopener">latissimus dorsi</a>,&#xA0;and sternal fibers of the&#xA0;<a href="https://brookbushinstitute.com/courses/pectoralis-major" target="_blank" rel="noopener">pectoralis major</a>&#xA0;invest in the superficial fascia of the external oblique, resulting in one continuous fascial sheath. This fascial sheath may serve to link the muscles of the upper extremity and core (1-2, 6). Studies have demonstrated that force imparted from trunk muscles will be transmitted through all layers of the abdominal fascial network (7-8), which may also imply that force from the abdominal muscles or upper extremity muscles may transmit force through this network.</li>
 <li>Medial:&#xA0;From the costal cartilage to the arcuate line (the level of the umbilicus), the fascia of the external obliques and&#xA0;<a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>&#xA0;converge at the semilunar lines, and then continue <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> to the&#xA0;<a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>, to <a id="posture" data-tip="1660" target="_blank" href="/glossary-term/posture" class="glossary">form</a> the superficial layer of the rectus sheath before investing in the linea alba (9-10). Below the arcuate line, the fascia of the obliques and&#xA0;transverse abdominis&#xA0;converge and run <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> to the&#xA0;<a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>. (9-10). The crisscross of fibers from the fascia of the external obliques,&#xA0;<a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>,&#xA0;transverse abdominis,&#xA0;and&#xA0;<a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>&#xA0;from both sides converge at the tendon-like structure known as the linea alba, which adds strength to the abdominal wall (5). This implies that the external obliques on one side invest into the external obliques on the other side; however, the way these fibers are organized suggests it would be an exaggeration to say that the fibers from the external oblique fascia on one side continue specifically into the fascia of the external obliques on the other side.</li>
 <li>Inferior:&#xA0;The portion of the <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> border of the external oblique aponeurosis that runs from pubic tubercle to <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> iliac spine (ASIS) develops into a thickened band of <a id="connective-tissue-cell" data-tip="1368" target="_blank" href="/glossary-term/connective-tissue-cell" class="glossary">connective tissue</a> known as the inguinal ligament (11). This thickened band also folds under itself and plays an important role in forming the inguinal canal; in which arteries, veins, nerves, and lymphatic vessels pass (11). The more <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> fibers of the external obliques invest in the external lip of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> half of the iliac crest and may have some continuity with the iliotibial band of the fascia lata (1-5).</li>
 <li>Deep:&#xA0;Deep to the external obliques lay the&#xA0;<a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>&#xA0;and their fascial sheath, with a near perpendicular fiber direction (5, 10). Deep to the internal obliques lies the horizontal fibers of the&#xA0;transverse abdominis&#xA0;and their fascial sheath, comprising the majority of the <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> rectus sheath and the deepest layer of abdominal fascia. Deep to the&#xA0;transverse abdominis&#xA0;is the peritoneum and <a id="viscera" data-tip="1278" target="_blank" href="/glossary-term/viscera" class="glossary">viscera</a>.</li>
</ul>
<img alt="Connective tissue brining together the external obliques and the inguinal ligament" title="Attachment of the external obliques on the pelvis" src="https://www.datocms-assets.com/25800/1645299666-gray393.png" width="408" height="385">

Where are the External Obliques Located?

<ol>
 <li>Start with your partner in a hook-lying position (<a id="supine" data-tip="1562" target="_blank" href="/glossary-term/supine" class="glossary">supine</a> with knees flexed to 90&#xB0;). A bolster can be placed under the knees to aid in reducing hip flexor activity.</li>
 <li>Both hands can be used to palpate the external obliques, or one hand can be placed on the <a id="ipsilateral" data-tip="1550" target="_blank" href="/glossary-term/ipsilateral" class="glossary">ipsilateral</a> shoulder to aid in applying manual resistance, while the other hand is used to palpate.</li>
 <li>Locate the tips of ribs 5 -12, outlining the end of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> rib cage from xiphoid process down to the floating ribs (11th and 12th rib).</li>
 <li>Then locate the iliac crest and the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> iliac spine (ASIS) by tracing the &quot;top of the pelvis&quot; to the angle formed at the <a id="medial" data-tip="1568" target="_blank" href="/glossary-term/medial" class="glossary">medial</a> end.</li>
 <li>Place your fingertips between the bottom of the rib cage and the iliac crest, and try to visualize the fiber direction of the external obliques based on the discussion of external oblique anatomy above.</li>
 <li>Attempt to feel fibers running in that direction by strumming perpendicular to them. The fibers of the external obliques course from superior/lateral to inferior/medial. Run your fingers from superior/medial to inferior/lateral in an attempt to strum the fibers like the strings of a guitar.
 <ul>
 <li>Helpful tips
 <ul>
 <li>The easiest fibers to identify of the external obliques are located on the lower border of the rib cage, and/or near the attachment on the iliac crest.</li>
 <li>If you are having difficulty feeling the thick fascicles of the external oblique, have your partner perform a crunch with rotation away from you, while resisting the same side shoulder with one hand (this does not require a maximal effort from your partner). Try to feel for the fibers contract (becoming dense/taut) under your fingertips.</li>
 <li>Alternatively, you may have your partner take a deep breath using diaphragmatic breathing, and hold that breath, passively stretching the abdominal muscles and making it easier to identify the separation between fascicles.</li>
 </ul>
 </li>
 </ul>
 </li>
</ol>
<a href="https://www.datocms-assets.com/25800/1645299731-external-obliques-2.jpeg"><img src="https://www.datocms-assets.com/25800/1645299731-external-obliques-2.jpeg" title="The attachment of the oblique muscles on the posterior side of the body" alt="Attachment of the external obliques, latissimus dorsi, erector spinae, nd internal obliques"></a>
By Zyryab at English Wikipedia, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=22698733

Palpating the External Obliques

<ul>
 <li>Spine: Flexion, <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> rotation (<a id="prime-mover" data-tip="1662" target="_blank" href="/glossary-term/prime-mover" class="glossary">prime mover</a>), <a id="ipsilateral" data-tip="1550" target="_blank" href="/glossary-term/ipsilateral" class="glossary">ipsilateral</a> flexion
 <ul>
 <li>The external obliques behave like <a id="prime-mover" data-tip="1663" target="_blank" href="/glossary-term/prime-mover" class="glossary">prime movers</a>. That is, they are often recruited unilaterally, in a direction-specific manner, activity may not increase during low-intensity functional tasks, only increasing in activity when needed to accommodate larger external loads (22, 33) (similar to the <a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>). They do not exhibit the behavior associated with stabilizing muscles like the <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a> and transverse abdominis; including &quot;bilateral co-activation&quot; during motion regardless of direction or load (19, 32).</li>
 </ul>
 </li>
 <li>Pelvis: <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">Posterior</a> tilt, <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> tilt</li>
 <li>Respiration: Forceful exhalation</li>
 <li>Intra-abdominal Pressure: May contribute to bracing during heavy lifting.</li>
</ul>
<h3>Integrated Function:</h3>
<ul>
 <li>Stabilization:
 <ul>
 <li>Stabilization of the lumbar spine, thorax, sacroiliac joint, and pubic symphysis during &quot;bracing&quot;.</li>
 </ul>
 </li>
 <li>Eccentric Deceleration:
 <ul>
 <li>Eccentric deceleration of <a id="ipsilateral" data-tip="1550" target="_blank" href="/glossary-term/ipsilateral" class="glossary">ipsilateral</a> rotation of the spine (33).
 <ul>
 <li>This has been referred to as &quot;anti-rotation&quot;, and may be the most important function of the external oblique. The ability to decelerate and stabilize the spine against rotation, and/or rotation and extension forces is paramount to preventing injury.</li>
 </ul>
 </li>
 <li>Eccentric deceleration of extension of the spine.</li>
 <li>Eccentric deceleration of <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> flexion of the spine.</li>
 <li>Eccentric deceleration of <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> tilting, sacral extension, and sacroiliac <a id="counter-nutation" data-tip="1214" target="_blank" href="/glossary-term/counter-nutation" class="glossary">counter-nutation</a>.</li>
 </ul>
 </li>
 <li>Synergists:
 <ul>
 <li>Trunk Rotation
 <ul>
 <li>The external obliques are the primary rotators of the spine, assisted by <a id="synergists" data-tip="1650" target="_blank" href="/glossary-term/synergists" class="glossary">synergists</a> including the <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal oblique</a>, <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> <a href="https://brookbushinstitute.com/courses/erector-spinae" target="_blank" rel="noopener">erector spinae</a>, and <a id="ipsilateral" data-tip="1550" target="_blank" href="/glossary-term/ipsilateral" class="glossary">ipsilateral</a> multifidus (1-2, 4-5, 15-16, 19-21).</li>
 </ul>
 </li>
 <li>Lumbar Flexion and <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">Posterior</a> Pelvic Tilting
 <ul>
 <li>The <a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a> is the <a id="prime-mover" data-tip="1662" target="_blank" href="/glossary-term/prime-mover" class="glossary">prime mover</a> of lumbar flexion and posteriorly tilting of the pelvis (1, 4-5, 15-18). The external obliques are <a id="synergists" data-tip="1650" target="_blank" href="/glossary-term/synergists" class="glossary">synergists</a> along with the <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>.</li>
 </ul>
 </li>
 <li>Lateral Flexion of the Spine and <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">Lateral</a> Tilt of the Pelvis
 <ul>
 <li>The external obliques may be the <a id="prime-mover" data-tip="1662" target="_blank" href="/glossary-term/prime-mover" class="glossary">prime mover</a> of <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">Lateral</a> flexion of the spine and <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">Lateral</a> tilting of the pelvis, assisted by <a id="synergists" data-tip="1650" target="_blank" href="/glossary-term/synergists" class="glossary">synergists</a> including the quadratus lumborum, <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>, and <a href="https://brookbushinstitute.com/courses/erector-spinae" target="_blank" rel="noopener">erector spinae</a> (1, 16, 19-21).</li>
 </ul>
 </li>
 <li>Bracing
 <ul>
 <li>Activity of the external obliques is not necessary to increase intra-abdominal pressure (<a id="drawing-in" data-tip="1580" target="_blank" href="/glossary-term/drawing-in" class="glossary">drawing-in</a>) (35); this is likely attributable to a lack of attachment to the thoracolumbar fascia (36). However, the external obliques may become an important <a id="stabilizers" data-tip="1653" target="_blank" href="/glossary-term/stabilizers" class="glossary">stabilizer</a> when the body resists significant external load (2, 22). The use of global trunk musculature to stabilize the spine is often termed &quot;bracing&quot;, and includes isometric contractions from all stabilizers and <a id="prime-mover" data-tip="1663" target="_blank" href="/glossary-term/prime-mover" class="glossary">prime movers</a> of the spine.</li>
 </ul>
 </li>
 <li>Forceful Exhalation
 <ul>
 <li>During forceful exhalation, the external obliques may contribute to increasing intra-abdominal pressure along with the transverse abdominis, <a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>, and <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>; and further, aid in depressing the ribs and costocartilage aiding in decreasing intrathoracic space (1-2, 15-18). The external oblique&apos;s contribution to forceful expiration may also imply that these muscles are part of a motor synergy that includes the <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">Posterior</a> serratus <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> and the external intercostals.</li>
 </ul>
 </li>
 </ul>
 </li>
</ul>
<a href="https://www.datocms-assets.com/25800/1645299786-external-obliques-3.png"><img src="https://www.datocms-assets.com/25800/1645299786-external-obliques-3.png" title="A cross-sectional view of the abdominal core muscles of the trunk" alt="External Oblique, Internal Oblique and Transverse Abdominis Muscles"></a>
By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See &quot;Book&quot; section below) Bartleby.com: Gray&apos;s Anatomy, Plate 545, Public Domain, https://commons.wikimedia.org/w/index.php?curid=541410

External Oblique Actions

Spine: Motion of the spine could be described as <a id="arthrokinematics" data-tip="1701" target="_blank" href="/glossary-term/arthrokinematics" class="glossary">arthrokinematic motion</a> at each facet (<a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a>, <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a>, <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a>, and <a id="medial" data-tip="1568" target="_blank" href="/glossary-term/medial" class="glossary">medial</a> <a id="glide" data-tip="1598" target="_blank" href="/glossary-term/glide" class="glossary">glide</a>), which results in <a id="osteokinematic-motion" data-tip="1518" target="_blank" href="/glossary-term/osteokinematic-motion" class="glossary">osteokinematic motion</a> (flexion, extension, <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> flexion, and rotation) when the movement at each facet is combined. Extension is the combined <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> <a id="glide" data-tip="1598" target="_blank" href="/glossary-term/glide" class="glossary">glide</a> of the facets at several segments of the spine, and flexion is the combined <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> <a id="glide" data-tip="1598" target="_blank" href="/glossary-term/glide" class="glossary">glide</a> of the facets at several segments of the spine (5). Like the <a href="https://brookbushinstitute.com/courses/rectus-abdominis" target="_blank" rel="noopener">rectus abdominis</a>, the external obliques produce <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> <a id="glide" data-tip="1817" target="_blank" href="/glossary-term/glide" class="glossary">shear</a> and <a id="compression" data-tip="1595" target="_blank" href="/glossary-term/compression" class="glossary">compression</a> on the vertebral column, facet joint <a id="distraction" data-tip="1589" target="_blank" href="/glossary-term/distraction" class="glossary">distraction</a>, <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> <a id="glide" data-tip="1598" target="_blank" href="/glossary-term/glide" class="glossary">glide</a>, and <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> <a id="glide" data-tip="1598" target="_blank" href="/glossary-term/glide" class="glossary">glide</a> (<a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> on <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> facet), all of which are synonymous with forward bending of the spine (40). The forces of <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> <a id="glide" data-tip="1817" target="_blank" href="/glossary-term/glide" class="glossary">shear</a> (<a id="glide" data-tip="1598" target="_blank" href="/glossary-term/glide" class="glossary">glide</a>) and <a id="compression" data-tip="1595" target="_blank" href="/glossary-term/compression" class="glossary">compression</a> may be correlated with pathologies including <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> and posterior-lateral herniation of lumbar discs, degenerative joint and disc disease (DJD and DDD) of the lumbar spine, and <a id="compression" data-tip="1595" target="_blank" href="/glossary-term/compression" class="glossary">compression</a> fractures in those with osteoporosis (5). A <a id="unilateral" data-tip="1551" target="_blank" href="/glossary-term/unilateral" class="glossary">unilateral</a> contraction of the external obliques may laterally flex the spine contributing to facet joint <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> <a id="glide" data-tip="1598" target="_blank" href="/glossary-term/glide" class="glossary">glide</a> and compression; however, a <a id="unilateral" data-tip="1551" target="_blank" href="/glossary-term/unilateral" class="glossary">unilateral</a> contraction resulting in the <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> rotation would result in <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> <a id="glide" data-tip="1598" target="_blank" href="/glossary-term/glide" class="glossary">glide</a> and <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> <a id="glide" data-tip="1817" target="_blank" href="/glossary-term/glide" class="glossary">shear</a>. Considering the mechanisms of herniation, DJD or DDD, and the opposing <a id="arthrokinematics" data-tip="1702" target="_blank" href="/glossary-term/arthrokinematics" class="glossary">arthrokinematic motions</a> that may result from <a id="unilateral" data-tip="1551" target="_blank" href="/glossary-term/unilateral" class="glossary">unilateral</a> contraction of the obliques, it seems unlikely that asymmetrical over-activity of the external obliques would be a significant contributor to dysfunction of the lumbar facets.
Rib Cage: The rib cage forms a closed chain comprised of the sternum, ribs, and thoracic vertebrae (15). The costovertebral joints are synovial joints formed by the head of a rib, the two adjacent vertebral bodies (<a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> and <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> to the rib), and the intervertebral disc (15). The costotransverse joints are synovial joints formed between the costal tubercle of the rib and the costal facet of the transverse process of the corresponding vertebrae (15). The slightly <a id="convex" data-tip="1284" target="_blank" href="/glossary-term/convex" class="glossary">convex</a> demifacets of the ribs on the <a id="concave" data-tip="1281" target="_blank" href="/glossary-term/concave" class="glossary">concave</a> facets of the vertebral body results in the rib facets <a id="gliding-joint" data-tip="1835" target="_blank" href="/glossary-term/gliding-joint" class="glossary">gliding</a> superiorly on the vertebral facets as they role anteriorly during spinal flexion (and consequently external oblique activity) (41). The motion of the costotransverse joints of ribs 1-6 is similar to the costovertebral joints; however, the facets on ribs 7-10 are planar and oriented in the anterolateroinferior to posteromediosuperior plane leading to a posteromediosuperior <a id="glide" data-tip="1598" target="_blank" href="/glossary-term/glide" class="glossary">glide</a> during flexion and external oblique activation (42). Costovertebral and costotransverse joint pain can be quite debilitating, resulting in transversospinalis and intercostal <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spasms and pain during inhalation. Considering the research discussed below under &quot;postural dysfunction&quot;, it seems plausible that a relationship may exist between <a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">Upper Body Dysfunction (UBD)</a>, <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a> subsystem dominance, over-activity of the external obliques, and costovertebral/costotransverse joint dysfunction.
<a href="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2020/02/Costovertebral-joints.png" target="_blank" rel="noopener"><img src="https://www.datocms-assets.com/25800/1645299896-costovertebral-joints.png" title="The attachment points of the obliques on the spine" alt="The facet joints of the spine with attachments of the ligaments and boney landmarks highlighted"></a>
By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See &quot;Book&quot; section below)Bartleby.com: Gray&apos;s Anatomy, Plate 313, Public Domain, https://commons.wikimedia.org/w/index.php?curid=85402

The superficial and deep layers of the external oblique fascia continue to become the superficial layers of the rectus sheath coursing over the two <a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a> muscles (5, 9). All layers of the rectus sheath converge at the linea alba and continue into an identical fascial sheath on the opposite side (5). The transverse inscriptions that run horizontally through the <a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>&#xA0;are also continuations of the oblique fascia (37). In addition, the <a id="caudal" data-tip="1557" target="_blank" href="/glossary-term/caudal" class="glossary">caudal</a> fascia of the sternal fibers of the <a href="https://brookbushinstitute.com/courses/pectoralis-major" target="_blank" rel="noopener">pectoralis major</a>, and superficial fascia of the <a href="https://brookbushinstitute.com/courses/serratus-anterior" target="_blank" rel="noopener">serratus anterior</a> are continuous with the <a id="cephalad" data-tip="1559" target="_blank" href="/glossary-term/cephalad" class="glossary">cranial</a> portion of the superficial fascia of the <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external obliques</a> (and sometimes <a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>) (2, 6, 9, 38-39). It is unknown if the <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> edge of the external oblique fascia continues to invest in the fascia of the <a href="https://brookbushinstitute.com/courses/latissimus-dorsi" target="_blank" rel="noopener">latissimus dorsi</a>, serratus <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a>, and/or the external intercostals. However, research investigating the existence of a myofascial synergy that included the external obliques, serratus <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> and the external intercostals may have implications related to breathing and forceful exhalation.
<img title="Image of the fascial system of the body connecting muscles" src="https://www.datocms-assets.com/25800/1649100927-fascia-web-in-body.jpg" alt="The fascial web connecting two muscle fascicles">

The external obliques are part of the&#xA0;<a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">Anterior Oblique Subsystem (AOS)</a>. The&#xA0;<a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a>&#xA0;is a myofascial synergy that is connected by the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">Anterior</a> layer of the abdominal fascia; integrating the&#xA0;<a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis and pyramidalis</a>, external obliques,&#xA0;<a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">anterior adductors</a>,&#xA0;and potentially the&#xA0;<a href="https://brookbushinstitute.com/courses/pectoralis-major" target="_blank" rel="noopener">pectoralis major</a>&#xA0;and&#xA0;<a href="https://brookbushinstitute.com/courses/serratus-anterior" target="_blank" rel="noopener">serratus anterior</a>&#xA0;(1-2, 6, 9). The muscles of the&#xA0;<a href="https://brookbushinstitute.com/course/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a>&#xA0;include the <a id="prime-mover" data-tip="1663" target="_blank" href="/glossary-term/prime-mover" class="glossary">prime movers</a> of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">Anterior</a> trunk and the&#xA0;<a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">adductors</a>&#xA0;(19, 22, 32-33). This subsystem plays a significant role in stabilizing the thoracic and lumbar spine, sacroiliac joint (SIJ), pubic symphysis, and hip, especially in opposition to anterior-to-posterior forces, as well as contributing to the transfer of force between lower and upper extremities (5, 9). The&#xA0;<a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a>&#xA0;plays an active role in all pushing patterns, rotational movement patterns (especially &quot;turning in&quot;), and multi-segmental flexion patterns. Further, this subsystem aids in eccentrically decelerating spinal extension and rotation, as well as&#xA0;<a href="https://brookbushinstitute.com/article/hip-joint" target="_blank" rel="noopener">hip</a>&#xA0;extension, abduction, and external rotation (<a href="https://brookbushinstitute.com/video/overhead-squat-assessment-6-knees-bow-in-breakdown/" target="_blank" rel="noopener">knees bow in</a>&#xA0;and&#xA0;<a href="https://brookbushinstitute.com/video/overhead-squat-assessment-8-excessive-forward-lean/" target="_blank" rel="noopener">excessive forward lean</a>). The&#xA0;<a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a>&#xA0;is the functional <a id="antagonists" data-tip="1705" target="_blank" href="/glossary-term/antagonists" class="glossary">antagonist</a> of the&#xA0;<a href="https://brookbushinstitute.com/courses/posterior-oblique-subsystem-pos" target="_blank" rel="noopener">Posterior Oblique Subsystems (POS)</a>.
<h4>For additional information:</h4>
<ul>
 <li><a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">Anterior Oblique Subsystem (AOS)</a></li>
</ul>
<a href="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2013/05/Rectus-Sheath.png" target="_blank" rel="noopener"><img src="https://www.datocms-assets.com/25800/1645300039-rectus-sheath.png" title="An image of the rectus sheath " alt="The rectus sheath with rectus abdominis, external oblique, peritoneum, and linea alba"></a>
Rectus Sheath - By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body. (Image: Bartleby.com: Gray&apos;s Anatomy, Plate 399, Public Domain, https://commons.wikimedia.org/w/index.php?curid=561473)

The external obliques are <a id="prone" data-tip="1561" target="_blank" href="/glossary-term/prone" class="glossary">prone</a> to over-activity and an increase in length, which is a behavior often exhibited by muscles acting as over-active synergists. <a id="synergistic-dominance" data-tip="1647" target="_blank" href="/glossary-term/synergistic-dominance" class="glossary">over-active synergists</a> are usually addressed with <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> techniques but not lengthening techniques; <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> techniques for the external obliques are generally ineffective. This is likely due to the external obliques rarely presenting with active <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger points</a>, the difficulty in attempting <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> techniques on a <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> that has nothing to press the <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> into (e.g. bone), and pincer <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> being difficult or impractical due to the closely packed layers of fascia and abdominal <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>. The external obliques do play a significant role in many of the recommended core strength and subsystem <a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a> techniques.
<ul>
 <li><a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">Upper Body Dysfunction (UBD)</a> may result in the external obliques exhibiting altered behavior relative to changes in core subsystem recruitment. In those exhibiting signs of <a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">UBD</a> and thoracic kyphosis, the <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">Anterior Oblique Subsystem (AOS)</a> may become over-active and <a id="synergistic-dominance" data-tip="1649" target="_blank" href="/glossary-term/synergistic-dominance" class="glossary">synergistically dominant</a> for relative inhibition of the <a href="https://brookbushinstitute.com/courses/posterior-oblique-subsystem-pos" target="_blank" rel="noopener">Posterior Oblique Subsystem (POS)</a> and <a href="https://brookbushinstitute.com/courses/intrinsic-stabilization-subsystem" target="_blank" rel="noopener">Intrinsic Stabilization Subsystem (ISS)</a>. The altered activity of these subsystems, in particular the inhibition of the <a href="https://brookbushinstitute.com/courses/intrinsic-stabilization-subsystem" target="_blank" rel="noopener">ISS</a>, leads to reliance on the <a id="prime-mover" data-tip="1663" target="_blank" href="/glossary-term/prime-mover" class="glossary">prime movers</a> for <a id="stability" data-tip="1191" target="_blank" href="/glossary-term/stability" class="glossary">stability</a>, including the <a href="https://brookbushinstitute.com/courses/latissimus-dorsi" target="_blank" rel="noopener">latissimus dorsi</a> and the <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a>. This can be illustrated using the Overhead Squat <a id="assessment" data-tip="1478" target="_blank" href="/glossary-term/assessment" class="glossary">Assessment</a> (OHSA). When an individual with <a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">UBD</a> performs the OHSA with hands overhead, the <a href="https://brookbushinstitute.com/video/overhead-squat-assessment-10-arms-fall/" target="_blank" rel="noopener">arms fall</a> forward or adduct, and the spine may stay relatively neutral as the over-activity of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">Anterior</a> trunk muscles are balanced by over-activity of the <a href="https://brookbushinstitute.com/courses/latissimus-dorsi" target="_blank" rel="noopener">latissimus dorsi</a>. If the OHSA is performed again with hands on the pelvis, the individual will usually exhibit signs of lumbar flexion or an <a href="https://brookbushinstitute.com/video/overhead-squat-assessment-8-excessive-forward-lean/" target="_blank" rel="noopener">excessive forward lean</a>, because the <a href="https://brookbushinstitute.com/courses/latissimus-dorsi" target="_blank" rel="noopener">latissimus dorsi</a> is no longer taut and resisting activity of the <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a>.</li>
 <li><a href="https://brookbushinstitute.com/courses/lumbo-pelvic-hip-complex-dysfunction-lphcd" target="_blank" rel="noopener">Lumbo Pelvic Hip Complex Dysfunction (LPHCD)</a> and low back pain are correlated with external oblique activity that resembles the altered activity of the <a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>. Individuals with low back pain, exhibit less external oblique activity in sway standing (24), more activity (bilaterally) to stabilize the spine (bracing) during functional tasks, and are more active during exercises requiring more <a id="stability" data-tip="1191" target="_blank" href="/glossary-term/stability" class="glossary">stability</a> (ex. <a href="https://brookbushinstitute.com/video/ball-bridge" target="_blank" rel="noopener">bridges on ball</a>) (24, 44-45). Further, studies demonstrate that low back pain and fatigue increase external oblique activity, relative to a decrease in <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a> and transverse abdominis activity (27-30, 43). These changes in behavior suggest the external obliques become <a id="synergistic-dominance" data-tip="1647" target="_blank" href="/glossary-term/synergistic-dominance" class="glossary">over-active synergists</a> (like the <a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>) to <a id="compensation-pattern" data-tip="1697" target="_blank" href="/glossary-term/compensation-pattern" class="glossary">compensate</a> for inhibition of the transverse abdominis and <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>.</li>
 <li>Sacroiliac Joint Dysfunction (SIJD)&#xA0;may result in the external obliques exhibiting more over-activity on the side of sacroiliac joint stiffness. This behavior may be attributed to the relative <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> tilt of the pelvis on the stiff side, or rotation of the lumbar spine in the opposite direction to align the shoulder girdle despite pelvic asymmetry. Rotation of the spine is predominately controlled by the global core musculature, including the <a href="https://brookbushinstitute.com/courses/latissimus-dorsi" target="_blank" rel="noopener">latissimus dorsi</a>, external obliques, and psoas (19, 22, 32-33); however, the activity of the external obliques is likely best addressed by addressing sacroiliac joint, lumbar spine and pubic symphysis stiffness, and activating under-active muscles. <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">Release</a> techniques for the external obliques are not particularly effective.</li>
 <li><a href="https://brookbushinstitute.com/courses/lower-leg-dysfunction" target="_blank" rel="noopener">Lower Extremity Dysfunction (LED)</a> similar to <a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">UBD</a>, altered behavior of the external obliques may result relative to changes in core subsystem recruitment. Again, the <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a> may become over-active and <a id="synergistic-dominance" data-tip="1649" target="_blank" href="/glossary-term/synergistic-dominance" class="glossary">synergistically dominant</a> for relative inhibition of the <a href="https://brookbushinstitute.com/courses/posterior-oblique-subsystem-pos" target="_blank" rel="noopener">POS</a> and <a href="https://brookbushinstitute.com/courses/intrinsic-stabilization-subsystem" target="_blank" rel="noopener">ISS</a>; however, in the case of <a href="https://brookbushinstitute.com/courses/lower-leg-dysfunction" target="_blank" rel="noopener">LED</a> this altered behavior contributes to, or is correlated with an <a href="https://brookbushinstitute.com/video/overhead-squat-assessment-8-excessive-forward-lean" target="_blank" rel="noopener">excessive forward lean</a>.</li>
</ul>
<h3>Signs of Altered Length/Tension:</h3>
<h4><a href="https://brookbushinstitute.com/courses/solutions-table-overhead-squat-assessment">Overhead Squat Assessment:</a><a href="https://brookbushinstitute.com/course/solutions-table-overhead-squat-assessment"></a></h4>
<ul>
 <li><a href="https://brookbushinstitute.com/video/overhead-squat-assessment-9-anterior-pelvic-tilt-excessive-lordosis/" target="_blank" rel="noopener">Anterior Pelvic Tilt</a>: Long/Under-active</li>
 <li><a href="https://brookbushinstitute.com/video/overhead-squat-assessment-8-excessive-forward-lean/" target="_blank" rel="noopener">Excessive Forward Lean</a>: Long/Over-active</li>
 <li><a href="https://brookbushinstitute.com/video/overhead-squat-assessment-15-sign-clusters-asymmetrical-weight-shift/" target="_blank" rel="noopener">Asymmetrical Weight Shift</a>: Long/Over-active on side opposite shift</li>
</ul>
<h4>Brookbush/Grieve (51) Sacroiliac Joint Dysfunction Movement Assessment Cluster:</h4>
<ul>
 <li><a href="https://brookbushinstitute.com/course/sign-clusters-compensation-patterns-overhead-squat-assessment" target="_blank" rel="noopener">Overhead Squat </a><a id="assessment" data-tip="1478" target="_blank" href="/glossary-term/assessment" class="glossary">Assessment</a> (OHSA): Stiff SIJ on the side opposite of an <a href="https://brookbushinstitute.com/video/overhead-squat-assessment-15-sign-clusters-asymmetrical-weight-shift" target="_blank" rel="noopener">asymmetrical shift with &quot;heel rise&quot;</a>
 <ul>
 <li>&quot;Top tier exam&quot; used to identify asymmetry and imply further SIJ assessment</li>
 </ul>
 </li>
 <li><a id="unilateral" data-tip="1551" target="_blank" href="/glossary-term/unilateral" class="glossary">Unilateral</a> Pelvic Tilt: <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">Posterior</a> tilted innominate correlated with stiffer side</li>
 <li><a href="https://brookbushinstitute.com/video/sacroiliac-joint-special-test-stork-gillet-test" target="_blank" rel="noopener">Gillet Test</a>: Less motion on the stiffer side</li>
 <li><a href="https://brookbushinstitute.com/article/lower-body-goniometry" target="_blank" rel="noopener">Hip Rotation Range of Motion</a>: Less motion on the stiffer side</li>
</ul>
<h4>Clinical Implications:</h4>
<ul>
 <li>Rectus abdominis tendonitis</li>
 <li>Sports Hernia</li>
 <li>Diastasis Recti</li>
 <li>Costovertebral and costotransverse joint pain</li>
 <li>Intercostal pain</li>
 <li>Low back pain</li>
 <li>Thoracic pain</li>
 <li>Sacroiliac joint dysfunction</li>
 <li>Pubic symphysis dyskinesis</li>
 <li>Groin pain</li>
</ul>
Trigger Points and <a id="referred-trigger-point-pain" data-tip="1709" target="_blank" href="/glossary-term/referred-trigger-point-pain" class="glossary">Referral Pain</a> Patterns: Active <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">Trigger Points</a> in the external and <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a> have the potential for <a id="referred-trigger-point-pain" data-tip="1709" target="_blank" href="/glossary-term/referred-trigger-point-pain" class="glossary">Referral Pain</a> patterns that extend into the chest, down toward the pelvis, obliquely across the <a href="https://brookbushinstitute.com/courses/rectus-abdominis-pyramidalis" target="_blank" rel="noopener">rectus abdominis</a>, and/or lower abdominal <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">Trigger Points</a> can refer pain to the groin and testicles (2). Further, active <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">Trigger Points</a> in the external obliques can produce symptoms similar to heartburn, abdominal hernia, and deep epigastric pain (2). These visceral-like symptoms can easily confound or be correlated with visceral dysfunction (2, 46-49). Careful <a id="assessment" data-tip="1478" target="_blank" href="/glossary-term/assessment" class="glossary">assessment</a> and referral to a physician should be considered when a clear delineation cannot be made between visceral dysfunction and <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">Trigger Points</a> in the abdomen.
As mentioned above, <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> techniques for the external obliques are generally ineffective. This is likely due to the external obliques rarely presenting with active <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger points</a>, the difficulty in attempting <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> techniques on a <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> that has nothing to press the <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> into (e.g. bone), and pincer <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> being difficult or impractical due to the closely packed layers of fascia and abdominal <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>.
The external obliques can be examined for <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger points</a> using the palpation techniques described above, with the intent of identifying acute points of increased tissue density, acute points of pain pressure <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>, or points that result in <a id="referred-trigger-point-pain" data-tip="1709" target="_blank" href="/glossary-term/referred-trigger-point-pain" class="glossary">referral pain</a> and replication of the patient&apos;s symptoms.

Postural Dysfunction and the External Obliques

Exercises and Techniques for the External Obliques

Static Standing Chop from Chop Progressions

Reactive Plank (Modified Mountain Climber) from Plank Progressions

<ol>
 <li>Peterson Kendall, F., Kendall McCreary, E., Geise Provance, P., McIntyre Rodgers, M., &amp; Anthony Romani, W. (2005). Muscles: Testing and Function with Posture and Pain (5th ed.). Baltimore, MD: Lippincott Williams &amp; Wilkins.</li>
 <li>Donnelly, J. M., Fern&aacute;ndez-de-las-Pe&ntilde;as, C., Finnegan, M., &amp; Freeman, J. L. (2019). Travell, Simons &amp; Simons' Myofascial Pain and Dysfunction: The Trigger Point Manual (3rd ed.). Philadelphia, PA: Wolters Kluwer.</li>
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 <li>Jenkins, D. B. (2009). Hollinshead's Functional Anatomy of the Limbs and Back (9th ed.). St. Louis, MO: Saunders/Elsevier.</li>
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 <li>Sanchez, E. R., Sanchez, R., &amp; Moliver, C. (2014). Anatomic relationship of the pectoralis major and minor muscles: a cadaveric study. Aesthetic surgery journal, 34(2), 258-263.</li>
 <li>Brown, S. H., &amp; McGill, S. M. (2009). Transmission of muscularly generated force and stiffness between layers of the rat abdominal wall. Spine, 34(2), E70-E75.</li>
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 <li>Cramer, G. D., &amp; Darby, S. A. (2014). Clinical anatomy of the spine, spinal cord, and Ans (3rd ed.). St. Louis, MO: Mosby.</li>
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 <li>Richardson, C., Hodges, P. W., &amp; Hides, J. (2004). Therapeutic Exercise for Lumbopelvic Stabilization: a Motor Control Approach for the Treatment and Prevention of Low Back Pain (2nd ed.). Edinburgh: Churchill Livingstone.</li>
 <li>Goodwin, J. (2013). Touch &amp; movement: Palpation and kinesiology for massage therapists (1st ed.). Clifton Park, NY: Delmar.</li>
 <li>Levangie, P. K., Norkin, C. C., &amp; Lewek, M. D. (2019). Joint Structure &amp; Function: A Comprehensive Analysis (6th ed.). Philadelphia, PA: F. A. Davis.</li>
 <li>McGill, S. M. (1992). A myoelectrically based dynamic three-dimensional model to predict loads on lumbar spine tissues during lateral bending. Journal of biomechanics, 25(4), 395-414.</li>
 <li>McGill, S. M. (1996). A revised anatomical model of the abdominal musculature for torso flexion efforts. Journal of biomechanics, 29(7), 973-977.</li>
 <li>De, A. T., &amp; Estenne, M. (1988). Functional anatomy of the respiratory muscles. Clinics in chest medicine, 9(2), 175-193.</li>
 <li>Andersson, E. A., Grundstr&ouml;m, H., &amp; Thorstensson, A. (2002). Diverging intramuscular activity patterns in back and abdominal muscles during trunk rotation. Spine, 27(6), E152-E160.</li>
 <li>McGill, S. M. (1991). Kinetic potential of the lumbar trunk musculature about three orthogonal orthopaedic axes in extreme postures. Spine, 16(7), 809-815.</li>
 <li>McGill, S. M. (1991). Electromyographic activity of the abdominal and low back musculature during the generation of isometric and dynamic axial trunk torque: implications for lumbar mechanics. Journal of Orthopaedic Research, 9(1), 91-103.</li>
 <li>Cholewicki, J., Panjabi, M. M., &amp; Khachatryan, A. (1997). Stabilizing function of trunk flexor‐extensor muscles around a neutral spine posture. Spine, 22(19), 2207-2212.</li>
 <li>Hodges, P. W., &amp; Richardson, C. A. (1997). Contraction of the abdominal muscles associated with movement of the lower limb. Physical therapy, 77(2), 132-142.</li>
 <li>O&rsquo;sullivan, P. B., Grahamslaw, K. M., Kendell, M., Lapenskie, S. C., M&ouml;ller, N. E., &amp; Richards, K. V. (2002). The effect of different standing and sitting postures on trunk muscle activity in a pain-free population. Spine, 27(11), 1238-1244.</li>
 <li>Fujitani, R., Jiromaru, T., Kida, N., &amp; Nomura, T. (2017). Effect of standing postural deviations on trunk and hip muscle activity. Journal of physical therapy science, 29(7), 1212-1215.</li>
 <li>Ng, J. K. F., Richardson, C. A., Parnianpour, M., &amp; Kippers, V. (2002). EMG activity of trunk muscles and torque output during isometric axial rotation exertion: a comparison between back pain patients and matched controls. Journal of Orthopaedic Research, 20(1), 112-121.</li>
 <li>Ng, J. K. F., Richardson, C. A., Parnianpour, M., &amp; Kippers, V. (2002). Fatigue-related changes in torque output and electromyographic parameters of trunk muscles during isometric axial rotation exertion: an investigation in patients with back pain and in healthy subjects. Spine, 27(6), 637-646</li>
 <li>Cholewicki, J., Silfies, S., Shah, R., Greene, H., Reeves, N. Alvi, K., Goldberg, B. (2005). Delayed trunk muscle reflex responses increase the risk of low back injuries. Spine. 30(23), 2614-2620</li>
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 <li>Rizk, N. N. (1980). A new description of the anterior abdominal wall in man and mammals. Journal of anatomy, 131(Pt 3), 373.</li>
 <li>Danneels, L. A., Vanderstraeten, G. G., Cambier, D. C., Witvrouw, E. E., Stevens, V. K., &amp; De Cuyper, H. J. (2001). A functional subdivision of hip, abdominal, and back muscles during asymmetric lifting. Spine, 26(6), E114-E121.</li>
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 <li>Drysdale, C. L., Earl, J. E., &amp; Hertel, J. (2004). Surface electromyographic activity of the abdominal muscles during pelvic-tilt and abdominal-hollowing exercises. Journal of athletic training, 39(1), 32.</li>
 <li>Cresswell, A. G., &amp; Thorstensson, A. (1989). The role of the abdominal musculature in the elevation of the intra-abdominal pressure during specified tasks. Ergonomics, 32(10), 1237-1246.</li>
 <li>Bogduk, N., &amp; Macintosh, J. E. (1984). The applied anatomy of the thoracolumbar fascia. Spine, 9(2), 164-170.</li>
 <li>Willard, F. H., Vleeming, A., Schuenke, M. D., Danneels, L., &amp; Schleip, R. (2012). The thoracolumbar fascia: anatomy, function and clinical considerations. Journal of anatomy, 221(6), 507-536.</li>
 <li>Porterfield, J., &amp; DeRosa, C. Mechanical Low Back Pain: Perspectives in Functional Anatomy. 1998.</li>
 <li>Juker, D., McGill, S., Kropf, P., &amp; Steffen, T. (1998). Quantitative intramuscular myoelectric activity of lumbar portions of psoas and the abdominal wall during a wide variety of tasks. Medicine and science in sports and exercise, 30(2), 301-310.</li>
 <li>White, A. A., &amp; Panjabi, M. M. (1990). Clinical biomechanics of the spine. Philadelphia: J. B. Lippincott.</li>
 <li>Lee, D. (2003). The thorax: an integrated approach. White Rock, British Columbia, Canada: Diane G. Lee Physiotherapist Corporation.</li>
 <li>Lee, D. G. (2015). Biomechanics of the thorax&ndash;research evidence and clinical expertise. Journal of Manual &amp; Manipulative Therapy, 23(3), 128-138.</li>
 <li>Richardson C, Jull G, Hodges P, Hides J. Therapeutic Exercise for Spinal Segmental Stabilization in Low Back Pain: Scientific Basis and Clinical Approach. Edinburgh: Churchill Livingstone: 1999.</li>
 <li>Granata, K. P., Slota, G. P., &amp; Wilson, S. E. (2004). Influence of fatigue in neuromuscular control of spinal stability. Human factors, 46(1), 81-91.</li>
 <li>Lehman, G. J., Hoda, W., &amp; Oliver, S. (2005). Trunk muscle activity during bridging exercises on and off a swissball. Chiropractic &amp; osteopathy, 13(1), 14.</li>
 <li>Aredo, J. V., Heyrana, K. J., Karp, B. I., Shah, J. P., &amp; Stratton, P. (2017, January). Relating chronic pelvic pain and endometriosis to signs of sensitization and myofascial pain and dysfunction. In Seminars in reproductive medicine (Vol. 35, No. 01, pp. 088-097). Thieme Medical Publishers.</li>
 <li>Jarrell, J. (2004). Myofascial dysfunction in the pelvis. Current pain and headache reports, 8(6), 452-456.</li>
 <li>Jarrell, J., Giamberardino, M. A., Robert, M., &amp; Nasr-Esfahani, M. (2011). Bedside testing for chronic pelvic pain: discriminating visceral from somatic pain. Pain research and treatment, 2011.</li>
 <li>Anderson, R. U., Sawyer, T., Wise, D., Morey, A., &amp; Nathanson, B. H. (2009). Painful myofascial trigger points and pain sites in men with chronic prostatitis/chronic pelvic pain syndrome. The Journal of urology, 182(6), 2753-2758.</li>
 <li>Brookbush, B. (2011). Fitness or Fiction: The Truth about Diet and Exercise. Brent Brookbush. http://www.amazon.com/Fitness-Fiction-Truth-About-Exercise/dp/0615503012</li>
 <li>Grieve, E. (2001). Diagnostic tests for mechanical dysfunction of the sacroiliac joints. Journal of Manual &amp; Manipulative Therapy, 9(4), 198-206.</li>
</ol>

Bibliography

© 2020 Brent Brookbush
Questions, comments and criticisms are welcome and encouraged

Copyright

A-Band - Refers to the part of the muscle cell that looks darker under a microscope.  This area of the cell is darker due to parallel arrangement of thicker filaments (myosin) and overlap with the thinner filaments (actin).
<ul>
 	<li>As a muscle contracts, the A-band is where actin and myosin interact.</li>
</ul>
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

Accuracy - the proportion of individuals correctly identified by the test results.
<ul>
 	<li>For example, a special test with perfect accuracy would imply a test has 100% specificity, 100% sensitivity, 100% positive predictive value and 100% negative predictive values.</li>
</ul>

Action Potential - A rapid change in voltage, resulting in a wave of excitation, that may result in stimulation of a nerve or muscle cell.
<ul>
 	<li>In order for an action potential to be initiated, the resting membrane voltage must exceed the excitation threshold, which then results in a cascade of depolarization and the "wave of excitation." Any stimulus below that threshold will not result in an action potential, and a stimulus greater than the threshold will not increase a single action potential, but may result in additional action potentials.  In this way, the action potential functions more like an on/off switch (all or none), and less like a dimmer switch.</li>
</ul>

A single-joint movement pattern (most often) designed to load a specific under-active muscle(s), while minimizing the contribution of over-active synergists via specific cues/joint motions.
<ul>
 	<li style="text-align: left;">Activation techniques/exercises are performed with the intent of addressing a muscle exhibiting a reduction in activity (tone) as a result of, or contributing to postural dysfunction.</li>
 	<li style="text-align: left;">Activation techniques/exercises cannot be multi-joint movement patterns due to relative flexibility, altered reciprocal inhibition, and synergistic dominance resulting in compensation patterns.</li>
</ul>
Example, <a href="https://brentbrookbush.com/articles/corrective-exercise-articles/activation/gluteus-medius-activation-progression/" target="_blank">gluteus medius activation</a> involves resisted hip abduction while minimizing the contribution of the TFL via hip extension.

Active stretching is a term used to describe a stretch that involves an active contraction of opposing musculature to lengthen a muscle to its end range. Generally these stretches are held for 2-5 seconds and repeated for 8-15 repetitions.

Adenosine triphosphatase (ATPase): is the enzyme responsible for catalyzing (initiating and accelerating) the decomposition of ATP to ADP.
<ul>
 	<li>This dephosphorylation (breakdown) reaction releases energy for processes like muscular contraction.</li>
</ul>

Adenosine triphosphate (ATP): The molecule that functions as a universal energy-transfer molecule, providing most of the energy associated with muscular contraction and human movement. ATP is composed of an adenine group, a ribose group, and three molecules of inorganic phosphates.
<ul>
 	<li>Energy is provided when hydrolysis results in the cleaving of a phophate group; resulting in adenosine diphosphate, an inorganigic phosphate group, and energy.</li>
</ul>

Algometry - measuring the amount of pressure to result in sensitivity or pain, using an algometer.
<ul>
 	<li>Generally, research uses algometry to establish a minimum pain pressure threshold (PPT), in which a lower PPT implies more sensitivity and pain, and a higher PPT implies less sensitivity and pain. PPT is a common outcome measure in trigger point research.</li>
</ul>
<a href="https://brentbrookbush.com/wp-content/uploads/2019/07/Algometer.jpg"><img class="aligncenter wp-image-140177" src="https://brentbrookbush.com/wp-content/uploads/2019/07/Algometer.jpg" alt="Image of an Algometer" width="500" height="333" /></a>

All-or-none principle - a nerve or muscle cell's response to a stimulus is independent of the strength of the stimulus. If that stimulus exceeds the threshold potential (threshold of an action potential), the nerve or muscle fiber will respond completely; otherwise, there is no response.

Example, when a motor unit in the biceps brachii is stimulated it contracts the same way whether a 10 lb or 50 lb dumbbell is lifted.  It is actually the number of muscle cells and the size of the motor unit that determines force output.

&nbsp;

The transition period between eccentric load and concentric contraction during a repetition of an exercise.  This term is most often used in reference to power/plyometric exercises, in which a shorter amortization phase is believed to be beneficial.  The shorter amortization phase may better use the stored energy from the elastic deformation of connective tissue and enhance synchronization of myotatic (stretch) reflex with maximum voluntary contraction.

Example, the athlete was cued to spend as little time as possible in the bottom of their squat stance (the amortization phase) during a set of box jumps.

Muscles that oppose the prime mover and synergists for a given joint action.

That is, all the muscles that can perform the opposing joint action.

Example: The triceps and anconeus are antagonists during elbow flexion.

An anatomical direction; toward the front

Example, the face is on the anterior aspect of the head

Appendicular Skeleton - referring to the bones the bones of the arms and legs, as well as the bones that support them. This includes the pelvis, clavicle and scapula. There are approximately 126 bones in the appendicular skeleton.
<ul>
 	<li>Etymology - Appendicular, as in appendage, "that which is appended to something as a proper part," 1640s, from <a class="crossreference" href="https://www.etymonline.com/word/append?ref=etymonline_crossreference">append</a> + <a class="crossreference" href="https://www.etymonline.com/word/-age?ref=etymonline_crossreference">-age</a>. - <a href="https://www.etymonline.com/word/appendage" target="_blank" rel="noopener">Etymology Online</a></li>
</ul>
"Appendicular skeleton" is a label referring to a set of bones whose function is distinct from the bones of the "<a href="https://brentbrookbush.com/glossary/axial-skeleton/" target="_blank" rel="noopener">axial skeleton</a>".

A reflexive decrease in muscle activity due to joint dyskinesis.
For example, a reduction in deep cervical flexor activity as a result of cervical spine dyskinesis.

Arthrokinematic Motion - Small amplitude motions between bone surfaces at a joint.  The arthrokinematic motions are roll, glide (slide or translation), spin, compression and distraction (traction). Arthrokinematic motions accompany osteokinematic motions to maintain joint congruence.
<ul>
 	<li>Example, arthrokinematic motion of the talus includes posterior glide on the tibia during ankle dorsiflexion.</li>
</ul>
Synonyms include: arthrokinematics, passive accessory motion, joint play and component motion

&nbsp;

Assessment - is the act of assessing, i.e. determining the importance, size, or value of -

In most cases, the results of an assessment are compared to normative data. If the individual exhibits values that are within normal parameters, it may be assumed that the aspect of health or motion assessed is not contributing to the patient's complaint, symptoms or movement impairment. If the results fall outside of normal parameters, it may indicate that the aspect of health or motion assessed is contributing to, or being affected by the patient/client's complaint, symptoms, or movement impairment. In some cases, the results of an assessment are compared to an "ideal model." In this case, deviations from the ideal are noted as potential issues. For example, deviations noted in the <a title="Introduction to the Overhead Squat Assessment" href="https://brentbrookbush.com/online-courses/articles/assessment/introduction-overhead-squat-assessment/" target="_blank">Overhead Squat Assessment</a> are compared to an "ideal model" of posture and motion.

Assessments used by human movement professionals can be divided into three broad categories:
<ul>
 	<li>"Clear" the Patient/Client for Intervention - These are tests, assessments and evaluations used to determine if a patient/client's issue may improve given the assessing professional's scope, skills, abilities and willingness to treat that individual.
<ul>
 	<li>For example, many of the special tests used in orthopedic medicine assist in determining the level of pathology or likelihood of a particular diagnosis. Certain issues and diagnoses are beyond the scope of the human movement professional, and are better treated by diagnostic professionals in the medical community (physicians, podiatrists, surgeons, etc.). A Calf Squeeze (Thompson) Test is one example, in which a positive sign may indicate a rupture of the Achilles tendon that may be better treated via surgical intervention.</li>
</ul>
</li>
 	<li>Highlight Contraindications - Tests, assessments and evaluations used to stratify risk or preclude a professional from addressing certain tissues, motions or using a particular technique.
<ul>
 	<li>For example, the Vertebral Artery Test (VBI) is often used to determine if high velocity thrust mobilizations (manipulations) are safe for a patient with cervical dysfunction.</li>
</ul>
</li>
 	<li>Refine Exercise/Intervention Selection: Tests, assessments and evaluations used to assist the professional in determining which techniques, modalities and exercises will best address a patient/client's complaints or desired goals.
<ul>
 	<li>Most movement assessments fall into this category. For example, a positive <a href="https://brentbrookbush.com/vimeo_videos/elys-test-rectus-femoris-flexibility-assessment/" target="_blank">Ely's Test</a> may indicate a need to release and/or lengthen the <a href="https://brentbrookbush.com/articles/anatomy-articles/muscular-anatomy/rectus-femoris/" target="_blank">rectus femoris</a>.</li>
</ul>
</li>
</ul>
Note: An assessment, or assessment result, may fall into more than one category. For example, although goniometry is an assessment most often used to Refine Exercise/Intervention Selection, if a range of motion is significantly altered, with an abnormal end-feel, and/or causes the patient or client/pain, the individual may need to be referred to a physician for further testing and Clearance to resume rehab activities.  Further, that same patient may return to the human movement professional with a list of Contraindicated Activities from the physician. - "When in doubt, refer out!"

Axial Skeleton - referring to the bones of the head, neck, trunk and spinal column (does not include pelvis). There are approximately 80 bones in the axial skeleton.
<ul>
 	<li>Etymology - Axial, as in "axis", referring to "imaginary motionless straight line around which a body (such as the Earth) rotates," from Latin axis "axle, pivot, axis of the earth or sky" - <a href="https://www.etymonline.com/word/axis" target="_blank" rel="noopener">Etymology Online</a></li>
</ul>
"Axial skeleton" is a label referring to a set of bones whose function is distinct from the bones of the "<a href="https://brentbrookbush.com/glossary/appendicular-skeleton/" target="_blank" rel="noopener">appendicular skeleton</a>".

Balance - The ability to maintain a body’s center of mass over its base of support. Balance can be static or dynamic.
<ul>
 	<li>For example, maintaining balance is harder on one leg because the center of mass must stay over a much smaller base of support.</li>
</ul>

A ball and socket joint (also called a spheroid joint or spheroidal joint) is a synovial joint in which the rounded or spherical end of one bone fits into a cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of axes, which have one common center. Examples include the hip and shoulder (glenohumeral joint)

Base of support (BoS) - refers to the area beneath an object or person, and the area within the perimeter created by every point of contact that the object or person makes with the supporting surface. This may include the <a href="https://brentbrookbush.com/articles/anatomy-articles/muscular-anatomy/gluteus-maximus/" target="_blank" rel="noopener">glutes</a> of someone sitting on a chair, or the back of someone leaning against a wall.
<ul>
 	<li>For example, during a single leg balance the BoS is the area of the foot in contact with the surface; however, when a person is standing on two feet, the BoS is the area of both feet and the surface between them.</li>
</ul>

Pertaining to both sides

Example, bilateral rows are performed with both arms at the same time.

Case-control Study - a particular form of retrospective study that samples a matched group of people who have, and do not have the outcome being studied. A case-control study is a quasi-experimental design, often used in medicine to aid in determining potential contributing factors (cannot determine causality). In this study type exposure is the dependent variable and outcome is independent.
<ul>
 	<li>Example, in this retrospective case-control, medical records were investigated for trends correlated with cervical pain (1).
<ol>
 	<li>Mäkela, M., Heliövaara, M., Sievers, K., Impivaara, O., Knekt, P., &amp; Aromaa, A. (1991). Prevalence, determinants, and consequences of chronic neck pain in Finland. American journal of epidemiology, 134(11), 1356-1367.</li>
</ol>
</li>
</ul>

An anatomical direction; toward the tail, relative to humans this term is often used to refer to "in the direction of the tale (toward the feet)".

Example, to release the trapezius muscle the therapist used a force directed caudally.

Center of mass (CoM) - an object's mean position of mass; that is, a point that is perfectly surrounded by an equal amount mass in all directions.

Center of gravity (CoG) - point where gravity appears to act. Since the human body is so small compared to the earth, we can assume gravity acts uniformly on the body, and that CoG and CoM are the same.
<ul>
 	<li>Example, the CoM of the human body while lying down or standing straight up is close to our navel. However, it is possible that during a resistance exercise, the combination of the body's weight and the weight of the resistance will place the combined CoM outside the body. For example, during the mid-portion of a <a href="https://brentbrookbush.com/vimeo_videos/back-squat/" target="_blank" rel="noopener">back squat</a> the CoM would be several anterior to the naval.</li>
</ul>

An anatomical direction; toward the head (synonym: cranial)

Example, hip pain was felt with any force directed cephalad.

Cohort Study - a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic), performing a cross-section at intervals through-out a period of time. A cohort study is a quasi-experimental design often used in medicine to aid in determining etiology or a cause-and-effect relationship. In this study type exposure is the independent variable and outcome is dependent.
<ul>
 	<li>Example, the study by Cholewicki et al. (1) investigated Yale Varsity Athletes (the cohort) with 2 and 3 year follow up (longitudinal design) and found that trunk muscle response time to off-loading was predictive of future low back injury.</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/core/increased-trunk-muscle-latency-may-cause-rather-than-result-from-low-back-pain/" target="_blank" rel="noopener noreferrer">Cholewicki, J., Silfies, S., Shah, R., Greene, H., Reeves, N. Alvi, K., Goldberg, B. (2005). Delayed trunk muscle reflex responses increase the risk of low back injuries. Spine. 30(23), 2614-2620</a></li>
</ol>

Comparable Sign: A combination of pain, stiffness and/or spasm during examination that is comparable to the patients symptoms.
<ul>
 	<li>One common error made during evaluation with special tests is attention given to any discomfort or pain, rather than attempting to identify the pain/discomfort related to the patient's complaint (concordant/comparable sign). Many special tests purposefully test tissue limits and are at least mildly uncomfortable in every individual. Basing your assessment on positive tests that resulted in "concordant/comparable signs" will improve your chances of arriving at the correct diagnosis.</li>
</ul>

An alternative movement pattern that has been adopted to compensate for dysfunction/impairment in the human movement system.
Example: A lack of calf extensibility may limit dorsiflexion, leading to the knees bowing inward (functional valgus) and excessive forward lean of the torso during a squat.

An arthrokinematic motion - the approximation of joint surfaces; that is, a force that directs one bone surface into another resulting in a reduction in intra-articular volume. Although widely thought of as a "destructive force", it is likely best to consider compression as a naturally occurring, stabilizing force. Any arthrokinematic force in excess (spin, glide, roll, traction) may be viewed as potentially deleterious.

For example, during a squat the femoral head is compressed into the acetabulum by muscular forces, bodyweight and any additional external load.

Concave (Concavity) - Having an outline or surface curved like the interior surface of a bowl or sphere - to cave-in or curve inward.
<ul>
 	<li>Example, the internal surfaces of the pelvis is concave, holding some of the bodies viscera.</li>
</ul>

Concordant Sign - The patient's specific pain, symptom or complaint. 
<ul>
 	<li>One common error made during evaluation with special tests is attention given to any discomfort or pain, rather than attempting to identify the pain/discomfort related to the patient's complaint (concordant/comparable sign). Many special tests purposefully test tissue limits and are at least mildly uncomfortable in every individual. Basing your assessment on positive tests that resulted in "concordant/comparable signs" will improve your chances of arriving at the correct diagnosis.</li>
</ul>

Conductivity: Stimulation results in more than a local effect (1).
<ul>
 	<li>For example, in a muscle cell the stimulation of a motor endplate results in a change in cell membrane polarity that rapidly propagates (is conducted) along the entire length of the muscle cell, stimulating all sacromere.</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

A condyloid joint (also called condylar, bicondylar, ellipsoid, or ellipsoidal) is an ovoid articular surface, or condyle, that is received into an elliptical cavity.  These joints permit movement in two planes.  Examples include the knee, metacarpophalangeal joints and metatarsophalangeal joints.

Connective Tissue Cell - One of the four basic types of animal tissue, consisting mostly fibers and ground substance.  These cells are specialized to binds organs together, holds them in place, protect them from external forces, and may fill space in the body's cavities.

Example, the body's muscles are enclosed in durable connective tissue sheets known as the "epimysium", "perimysium", and "endomysium," which and in support and transmitting force.
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

Contractility: The ability to shorten (1).
<ul>
 	<li>Contractility: Muscle cells are unique in the amount they can shorten when stimulated; this is this largerly due to the highly organized and unique arrangement of myofilaments (actin and myosin).</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

Pertaining to the opposite side

Example, the external oblique muscle performs contralateral rotation; rotation to the opposite side.

Convex (Convexity) - Having an outline or surface curved like the exterior of a circle or sphere - to bulge or curve outward.
<ul>
 	<li>Example, the top of your head is shaped by the convex exterior surface of your skull.</li>
</ul>

Correlational Research - Non-experimental <a href="https://www.questionpro.com/blog/what-is-research/">research</a> method in which the statistical relationship between two variables is investigated.
<ul>
 	<li>In this research by Kwon et al., a correlation was noted between a decrease in extensibility during a hamstring length test (goniometry) and current knee pain (1).</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/knee/correlation-patellofemoral-pain-syndrome-pfps-hamstring-activity/" target="_blank" rel="noopener">Kwon O, Yun M, and Lee W. (2014). Correlation between intrinsic patellofemoral pain syndrome in young adults and lower extremity biomechanics. J. Phys. Ther. Sci. 26: 961-964</a></li>
</ol>

Counter-nutation - posterior rotation of sacrum relative to ilium, and/or anterior rotation of ilium relative to sacrum.
<ul>
 	<li>The pelvic floor muscles are examples of muscle that may counter-nutate the sacrum.</li>
</ul>
[caption id="attachment_126335" align="aligncenter" width="400"]<a href="https://brentbrookbush.com/wp-content/uploads/2018/10/Nutation.png"><img class=" wp-image-126335" src="https://brentbrookbush.com/wp-content/uploads/2018/10/Nutation.png" alt="Nutation and Counter-nutation of the Sacroiliac Joint" width="400" height="967" /></a> Nutation and Counter-nutation of the Sacroiliac Joint[/caption]

&nbsp;

Crossover (Study) Design - A type of longitudinal, repeated measures quasi-experimental design in which each group receives both treatments, but at different times. It is named "crossover" due to the patients "crossing-over" to the other treatment or sham group after a specified period of time.
<ul>
 	<li>This type of study has the advantage of every individual serving as their own control, which may reduce the influence of confounding variables.</li>
 	<li>Unfortunately, the design itself introduces the chances that anyone receiving the experimental variable in the first period will continue to be effected in the second period.</li>
</ul>
In a study by Senna et al., a cross-over design was used to investigate the difference load made on inter-set rest intervals (1).
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/strength-training-research-corner/heavy-vs-light-load-single-joint-exercise-performance-with-different-rest-periods/" target="_blank" rel="noopener">Senna, G.W., Rodrigues, B.M., Sandy, Scudese, Bianco, A, &amp; Dantas, E.H.M. (2017). Heavy vs light load single-joint exercise performance with different intervals. Journal of Human Kinetics, 58, 197-206. </a></li>
</ol>

Cross-sectional Study - a research design that involves gathering data from a population or representative subset at a specific point in time.
<ul>
 	<li>Example, the study by Karimi-Mobarake et al.(1) investigated the prevalence of genu varum and genu valgum among school children 7-11 years old in Iran.</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/knee/low-prevalence-of-genu-varum-and-valgum-among-elementary-school-children/" target="_blank" rel="noopener noreferrer">Karimi-Mobarake, M., Kashefipour, A., Yousfnejad, Z. The prevalence of genu varum and genu valgum in primary school children in Iran 2003-2004. (2005) Journal of Medical Science 5(1). 52-54</a></li>
</ol>

Cytokine - A broad and loose category of small proteins that act through receptors, and are especially important to immune function (inflammation).
<ul>
 	<li>Cytokines include substances such as interferon, interleukin, and growth factors, which are secreted by certain cells of the immune system and have an effect on other cells. Their definite distinction from hormones is a topic of continued research.</li>
</ul>
&nbsp;

Dependent variable - in research, this is the variable that is changed by the independent variable, most often this is the "outcome" of the study.
<ul>
 	<li>Example, in the study by Cleland et al. (1), the independent variable is "thoracic manipulation," and the dependent variable is "lower trapezius muscle strength."</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/short-term-effects-lower-thoracic-manipulation-lower-trapezius-muscle-strength/" target="_blank" rel="noopener noreferrer">Cleland J, Selleck B, Stowell T, Brown L, Alberini S, St. Cyr H, Caron T. Short-term Effects of Thoracic Manipulation on Lower Trapezius Muscle Strength.  Journal of Manual &amp; Manipulative Therapy. 2004; 12(2): 82-90</a></li>
</ol>

An anatomical direction; further from the trunk or center of the body

Example, the foot is at the distal end of the leg.

An arthrokinematic motion - a force applied to a body part that may result in the separation of joint surfaces, a reduction in intra-articular pressure, and/or an increase in intra-articlar space.

For example, to hang from one's hands (i.g. in preparation for a pull-up) results in a traction force on the glenohumeral joint (shoulder).

An anatomical term of location; back or upper surface

Example, shoe laces may compress tissues on the dorsal surface of the foot

The "drawing-in" maneuver is a common cue used during exercise and rehabilitation programs. A light contraction of the <a href="https://brentbrookbush.com/articles/muscular-anatomy/transverse-abdominis/" target="_blank" rel="noopener">transverse abominis</a> (and potentially the entire <a href="https://brentbrookbush.com/articles/corrective-exercise-articles/core-subsystems/intrinsic-stabilization-subsystem/" target="_blank" rel="noopener">intrinsic stabilization subsystem</a>) achieved by gently pulling the lower abdominal region away from one's waist band. This should have minimal effect on breathing, and should not be confused with a maximal contraction of the <a href="https://brentbrookbush.com/articles/muscular-anatomy/transverse-abdominis/" target="_blank" rel="noopener">transverse abdominis</a> resulting in a "vacuum pose".
<ul>
 	<li>Research often refers to this maneuver as the "abdominal drawing-in maneuver"; abbreviated ADIM.</li>
</ul>
Development and introduction of this cue into practice is based on the pivotal research and resulting text:
<ol>
 	<li>Carolyn Richardson, Paul Hodges, Julie Hides. Therapeutic Exercise for Lumbo Pelvic Stabilization – A Motor Control Approach for the Treatment and Prevention of Low Back Pain: 2nd Edition (c) Elsevier Limited, 2004</li>
</ol>

Faulty or abnormal movement; an alteration of normal kinematics.

For example, joint stiffness or a reduction in arthrokinematics motion that results in limited osteokinematic range of motion - inadequate inferior glide of the femoral head resulting in limited abduction of the hip.

The seeping into, or abnormal collection of fluid in a body cavity.

For example, knee effusion describes swelling within the knee joint.

Note: the word "effusion" is used differently in medicine than it is used in reference to the movement (seeping out) of liquids and gases, for example in chemistry.

&nbsp;

A trait of body tissues that allows a tissue to return to its resting length or state after deformation or stretch.
Example:  Muscle is elastic tissue; many muscles will return to their resting length after being stretched to 150% of that length without any appreciable change in tissue quality.

Elasticity: Elasticity refers to the ability of a cell to return to its resting length after being stretched/lengthened.
<ul>
 	<li>Note: this term is often confused with extensibility. Elasticity is not the ability to stretch; it is the ability to return to normal length after being stretched. Muscle tissue, connective tissue and even nerve tissue have varying levels of elasticity.</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

Epithelial cell - One of the four basic cell types, found lining the body's cavities, blood vessels, organs and constitutes most gland tissue.  These cells are specialized to aid with absorption, secretion, or act as a barrier from foreign objects.
<ol>
 	<li>Saladin, K. S., &amp; Miller, L. (1998). Anatomy &amp; physiology. New York (NY): WCB/McGraw-Hill.</li>
</ol>

Equilibrium - a state in which opposing forces or influences are balanced.
<ul>
 	<li>For example, to maintain a neutral trunk while pushing or pulling a weight in one hand, your core musculature must balance the force by creating an equal amount of force in the opposite direction.</li>
</ul>

The study of causation, or origination. The word is commonly used in the medical professions, where it may refer to the study of why things occur, or the reason behind why things act a certain way.

For example, the etiology of low back pain is a complex subject, with multiple contributing factors and various structures implicated.

<div class="gs_citr" tabindex="0">Evidence-based medicine (practice) is the integration of best research evidence with clinical expertise and patient(client) values (2)."</div>
<ul>
 	<li class="gs_citr" tabindex="0">...the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients (clients).  It involves the integration of at least (a) clinical expertise/expert opinion, (b) external scientific evidence, and (c) client/patient/caregiver perspectives to provide high-quality services reflecting the interests, values, needs, and choices of the individuals we serve (1).</li>
</ul>
&nbsp;
<ol>
 	<li id="gs_cit1" class="gs_citr" tabindex="0">Sackett, D. L., Rosenberg, W. M., Gray, J. M., Haynes, R. B., &amp; Richardson, W. S. (1996). Evidence based medicine: what it is and what it isn't. Bmj, 312(7023), 71-72.</li>
 	<li class="gs_citr" tabindex="0">Sackett D et al. Evidence-Based Medicine: How to Practice and Teach EBM, 2nd edition. Churchill Livingstone, Edinburgh, 2000, p.1</li>
</ol>

Excitability: The ability of a cell to change in membrane conductance as a response to stimulation.

<ul>
 	<li>For example, muscle cells are specialized to react to a change in membrane potential with contraction, where as nerve cells are specialized to propagate a change in membrane potential along there axons and communicate that message to other tissues via neurotransmitters.
</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

Excitation threshold: The level that a depolarization must reach for an action potential to occur.
<ul>
 	<li>The excitation threshold is a contributing factor to the "all-or-none" response of muscle and nerves cells to a stimulus.</li>
</ul>

Exercise Progression - Modification of an exercise with the intent of promoting adaptation by increasing demand. This can be accomplished by increasing reps, load, tempo, range of motion, complexity, and/or challenge to an individual's stability.
<ul>
 	<li>Because load, reps, tempo and complexity are often explicitly noted, the term "exercise progression" is most often used throughout Brookbush Institute (BI) content to refer to an exercise, or series of exercises that make it harder to maintain stability with good form.
<ul>
 	<li>Sample Exercise Progression: <a href="https://brentbrookbush.com/vimeo_videos/kneeling-chop-pattern/" target="_blank" rel="noopener">Kneeling Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/static-standing-chop-pattern/" target="_blank" rel="noopener">Standing Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/single-leg-chop-pattern/" target="_blank" rel="noopener">Single-leg Chop</a></li>
</ul>
</li>
</ul>

Exercise regression - The opposite of progression; that is, modification of an exercise with the intent of reducing demand. This can be accomplished by decreasing reps, load, tempo, range of motion, complexity, and/or challenge to an individual's stability. Generally, regressions are used to modify an exercise to the client's current level of ability, with the intent of improving form, motor learning and retention.
<ul>
 	<li>Because load, reps, tempo and complexity are often explicitly noted, the term "exercise regression" is most often used throughout Brookbush Institute (BI) content to refer to an exercise or series of exercises that make it easier to maintain stability with good form.
<ul>
 	<li>Sample Exercise Regression: <a href="https://brentbrookbush.com/vimeo_videos/single-leg-chop-pattern/" target="_blank" rel="noopener">Single-leg Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/static-standing-chop-pattern/" target="_blank" rel="noopener">Standing Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/kneeling-chop-pattern/" target="_blank" rel="noopener">Kneeling Chop</a></li>
</ul>
</li>
</ul>

Experimental Research - Studies in which the researchers introduce the variable to be studied, with the intent of observing the outcome. This is different than observational research which observes the effect of a variable already present. Many texts also assert that experimental research should include randomization and ideally a control group, as is seen in Randomized Control Trials. Studies in which the variable is introduced by the researchers, but participants are not randomized may be considered Quasi-experimental research.
<ul>
 	<li>In this study by Esformes, the experimental variable was squat depth and the outcome measures observed were various performance measures related to power (1).</li>
</ul>
<ol>
 	<li><a href="https://brookbushinstitute.com/article/back-squat-depth-lower-body-post-activation-potentiation/" target="_blank" rel="noopener">Esformes, J., &amp; Bampouras, T. (2013). Effect of back squat depth on lower-body postactivation potentiation. Journal of Strength and Conditioning Research, 27(11), 2997-3000.</a></li>
</ol>
&nbsp;

Extensibility: The ability of a cell to be stretched or lengthened without damage (1).
<ul>
 	<li>For example, most cells would rupture with even a modest stretch, but muscles can stretch up to 3 times their contracted length.</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

False Negative - the proportion of negatives in a group that were assessed incorrectly (assessed as negative when the patient was actually positive)
<ul>
 	<li>Test Results: Although most tests/assessments result in either a positive or negative, the accuracy of a test is dependent on the number  of positives and negatives that are correct. Therefore, when the accuracy of a test is determined, their are 4 possible results, because a positive or negative result could be right (true) or wrong (false).</li>
</ul>

False Positive - the proportion of positives in a group that were assessed incorrectly (assessed as positive when the patient was actually negative)
<ul>
 	<li>Test Results: Although most tests/assessments result in either a positive or negative, the accuracy of a test is dependent on the number  of positives and negatives that are correct. Therefore, when the accuracy of a test is determined, their are 4 possible results, because a positive or negative result could be right (true) or wrong (false).</li>
</ul>

The function of fascia is to transmit force, provide support, and protect tissues. Fascia can effect motion by:
Transmitting force from one or more muscles (example: the thoracolumbar fascia)
Restricting motion in cases of adaptive shortening and/or adhesion to proximal structures (example: iliotibial band in cases of lower-leg dysfunction)
Elastic recoil after stretching can contribute to force production (example: plyometric exercise)

Note: There is evidence that fascia may house more receptors related to human movement than other tissues. In this way fascia may act as a motherboard for the nervous system

The fascial system does not contract or develop trigger points, and its capacity to adapt to stretching and or strengthening exercise is limited, especially when compared to the adaptive capacity of muscle tissue.

Fibromyalgia - A loosely defined diagnosis that is associated with a combination of widespread pain in combination with 2) tenderness at 11 or more of the 18 specific tender point sites. Consideration may also be given to the presence of psychosocial stressors and inflammatory disease in the patients history. Newer research suggests that fibromyalgia may be at least in part due to central sensitization of myofascial pain, often associated with trigger points (1 - 4).
<ol>
 	<li>Wolfe, F. (2018). Fibromyalgia Syndrome and Fibromyalgia Syndrome Criteria: Problems in Definition and Validity. Fibromyalgia Syndrome and Widespread Pain: From Construction to Relevant Recognition.</li>
 	<li>Wolfe, F., Smythe, H. A., Yunus, M. B., Bennett, R. M., Bombardier, C., Goldenberg, D. L., ... &amp; Fam, A. G. (1990). The American College of Rheumatology 1990 criteria for the classification of fibromyalgia. Arthritis &amp; Rheumatism: Official Journal of the American College of Rheumatology, 33(2), 160-172.</li>
 	<li>Alonso-Blanco, C., Fernandez-de-las-Penas, C., Morales-Cabezas, M., Zarco-Moreno, P., Ge, H. Y., &amp; Florez-García, M. (2011). Multiple active myofascial trigger points reproduce the overall spontaneous pain pattern in women with fibromyalgia and are related to widespread mechanical hypersensitivity. The Clinical journal of pain, 27(5), 405-413.</li>
 	<li>Staud, R., Nagel, S., Robinson, M. E., &amp; Price, D. D. (2009). Enhanced central pain processing of fibromyalgia patients is maintained by muscle afferent input: a randomized, double-blind, placebo-controlled study. PAIN®, 145(1-2), 96-104.</li>
</ol>
&nbsp;

Muscles that act to reduce or prevent movement at proximal joints to improve force transmission.
Example: The muscles of the core are important fixators; reducing motion of the spine/trunk to enhance force transmission between the extremities and environment.

An increase in joint stability via compressive forces resulting from muscular contraction and increased tension in fascial structures (1,2).
<ul>
 	<li>This term is most often used in reference to core intrinsic stabilizers, the thoracolumbar fascia and the sacroiliac joint; however, force closure and form closure have been mentioned in the literature referring to other joints.</li>
 	<li>Related term: Form closure</li>
</ul>
<ol>
 	<li>Andry Vleeming, Vert Mooney, Rob Stoeckart. Movement, Stability &amp; Lumbopelvic Pain: <a class="glossaryLink " title="Glossary: Integration" href="https://brentbrookbush.com/glossary/integration/" target="_blank" rel="noopener noreferrer" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Integration&lt;/div&gt;&lt;div class=glossaryItemBody&gt;Making a whole of parts.&lt;br /&gt;&lt;br /&gt;Example, The Brookbush Institute uses an integrative approach to explaining and addressing human movement.&lt;/div&gt;">Integration</a> of Research and Therapy. (c) 2007 Elsevier Limited</li>
 	<li id="gs_cit1" class="gs_citr" tabindex="0">Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., &amp; Snijders, C. J. (1995). The Posterior Layer of the Thoracolumbar Fascia| Its Function in Load Transfer From Spine to Legs. Spine, 20(7), 753-758.</li>
</ol>

The relative contribution of joint shape and structure to the stability of a joint (1,2).
<ul>
 	<li>This term is most often used in reference to the "rough" articulating surfaces of the sacroiliac joint and the wedge shape of the sacrum; however, force closure and form closure have been mentioned in the literature referring to other joints.</li>
 	<li>Related term: Force closure</li>
</ul>
<ol>
 	<li>Andry Vleeming, Vert Mooney, Rob Stoeckart. Movement, Stability &amp; Lumbopelvic Pain: <a class="glossaryLink " title="Glossary: Integration" href="https://brentbrookbush.com/glossary/integration/" target="_blank" rel="noopener noreferrer" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Integration&lt;/div&gt;&lt;div class=glossaryItemBody&gt;Making a whole of parts.&lt;br /&gt;&lt;br /&gt;Example, The Brookbush Institute uses an integrative approach to explaining and addressing human movement.&lt;/div&gt;">Integration</a> of Research and Therapy. (c) 2007 Elsevier Limited</li>
 	<li id="gs_cit1" class="gs_citr" tabindex="0">Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., &amp; Snijders, C. J. (1995). The Posterior Layer of the Thoracolumbar Fascia| Its Function in Load Transfer From Spine to Legs. Spine, 20(7), 753-758.</li>
</ol>

An arthrokinematic motion - linear motion across a joint surface parallel to the plane of the adjacent joint surface, just as your posterior moves relative to a "slide" in a park.

For example, the glide of facet joint in the spine during spinal flexion and extension, or the posterior glide of the humeral head that must accompany anterior roll to maintain congruence with glenoid fossa during shoulder horizontal adduction.

A plane joint (also called an arthrodial joint, gliding joint or plane articulation) is a synovial joint which allows only gliding movement in the plane of the articular surfaces. The opposed surfaces of the bones are flat or almost flat, with movement generally limited by tight capsules and ligaments. Plane joints are numerous, are most often small, and allow very little motion.  Examples include the carpal joints of the wrist, the tarsal joints of the ankle, and the facet joints of the spine.

"...refers to the measurement of angles, in particular the measurement of angles created at human joints by the bones of the body (1).

&nbsp;
<ol>
 	<li>Cynthia C. Norkin, D. Joyce White. Measurement of Joint Motion: A Guide to Goniometry 3rd Edition. Copyright (C) 2003 by F.A. Davis Company</li>
</ol>

Ground reaction force (GRF) - The force exerted by the ground on the body in contact with it.

For example, when a runner's foot strikes the ground with a force equal to the mass of the individual times their acceleration due to gravity, momentum and muscular exertion, the ground exerts an equal and opposite force on the runner's foot.
<ul>
 	<li>GRF is often measured in research studies using force plates as a means of quantitatively measuring the force generated by an individual.</li>
</ul>

H-Band - Refers to the central zone of a sarcomere that looks lighter under a microscope.  This area of the sarcomere is a lighter portion of the A-band where there is no overlap between the thinner filaments (actin), and the thicker filaments (myosin).
<ul>
 	<li>Example, when a muscle contracts, actin and myosin cross-bridging occurs in the region of the A-band until the H-band is reached where no overlap occurs.</li>
</ul>
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

A hinge joint (also called a ginglymus) is a synovial joint in which the articular surfaces fit one another in a way that only permits motion in one plane. Examples include the elbow, the knee (unless considered a condyloid joint) and the interphalangeal joints.

Holism (holistic) (biological holism) - (from Greek holos "all, whole, entire") is the idea that systems and their properties should be viewed as wholes, not just as a collection of parts.
<ul>
 	<li>Summarized by Aristotle in his "Metaphysics": "The whole is more than the sum of its parts". However, the term "holism" was introduced into language by the South African statesman Jan Smuts as recently as 1926. (Smuts J. C. 1987 [1926]. Holism and evolution. Cape Town: N &amp; S Press.)</li>
</ul>
Example: The Brookbush Institute promotes a holistic approach to human movement science, in which the muscular, fascial, articular and neural systems are not viewed as separable and all proximal segments are considered.

Hormone: Chemical messengers produced by the endocrine system, transported via tissue fluids such as blood, to stimulate cells to "act."
<ul>
 	<li>Example: Growth hormone is secreted by the pituitary gland in the brain; stimulating growth, cell reproduction and cell regeneration in certain types of cells</li>
</ul>
The English physician E. H. Starling discovered in collaboration with the physiologist W. M. Bayliss secretin, the first hormone, in 1902. (1).
<ol>
 	<li>Henriksen, J. H., &amp; de Muckadell, O. S. (2000). Secretin, its discovery, and the introduction of the hormone concept. Scandinavian journal of clinical and laboratory investigation, 60(6), 463-472.</li>
</ol>

A range of motion achieved by the patient/client that is more than normal.
<ul>
 	<li>Note: Both hyper-mobility and hypo-mobility may adversely affect motion and may lead to deleterious effects on joints and soft tissue over time. There is no evidence to suggest that more or less flexibility than normal is beneficial.</li>
</ul>
Example: If an individual can place their forehead on their knees they are likely hypermobile at one, if not several joints

Example 2: 110° of shoulder external rotation would be considered hyper-mobile.

Hyperplasia is an increase in organic tissue size due to an adaptive increase in the number of cells per organ.
<ul>
 	<li>Although muscle hyperplasia has been noted in some animals, human muscle tissue does not seem to have this adaptive ability.</li>
</ul>

A condition of excessive tone of the skeletal muscles; increased resistance of muscle to passive stretching.  May be related to increased neural drive, synergistic dominance, trigger points, reflexive over-activity, and/or muscle length.
Example:  Individuals who exhibit ankle eversion and abduction during an overhead squat assessment likely have hypertonic fibularis (peroneal) muscles.

Muscular hypertrophy is an increase in muscle mass/size due to increase in the volume and cross-sectional area (CSA) of individual muscle cells. The increase in cross-sectional area can be attributed to an an increase in contractile proteins and structural elements (myofibrillar hypertophy), as well as an increase in glycogen storage and elements related to metabolism (sarcoplasmic hypertophy). Hypertrophy is an adaptation of both cardiac and skeletal muscle fibers in response to progressive increases in workload.
<ul>
 	<li>Note: Hypertrophy is not hyperplasia. Hyperplasia is an increase in muscle size due to an adaptive increase in the number of muscle fibers/cells per muscle. This type of adaptation does not occur in human muscle tissue.</li>
</ul>

A range of motion achieved by a patient/client that is less than normal.
<ul>
 	<li>Note: Both hyper-mobility and hypo-mobility may adversely affect motion and may lead to deleterious effects on joints and soft tissue over time. There is no evidence to suggest that more or less flexibility than normal is beneficial.</li>
</ul>
Example: If the end range of shoulder external rotation is reached and measured as 75° during goniometric assessment, the client/patient is exhibiting hypomobility of the glenohumeral joint (shoulder).

Hypothesis - a proposed explanation for a phenomenon; "scientific hypotheses" are generally constructed in a way that is testable or falsifiable.
<ul>
 	<li>Example: The hypothesis, "excessive knee valgus may be correlated with future knee pain and injury," has been the subject of several studies published over the last decade.</li>
</ul>

Diminished tone of skeletal muscles; diminished resistance of muscles to passive stretching.   May be related to inhibition, reciprocal inhibition, arthrokinematics inhibition and/or  increased resting length of muscle.
Example:  If your knees cave (hip adduction) during a squat or leg-press it is likely that your gluteus medius is hypotonic.

I-Band - Refers to the part of the muscle cell that looks lighter under a microscope.  This area of the cell is lighter due to parallel arrangement of thinner filaments (actin), and no overlap with the thicker filaments (myosin).
<ul>
 	<li>As a muscle contracts, the I-bands will decrease in width and move closer to one another.</li>
</ul>
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

Independent variable - in research, this is the variable or phenomenon being manipulated in the study.
<ul>
 	<li>Example, in the study by Ghanbari et al. (1), the independent variable is "knee joint mobilization", the dependent variable is "quadriceps muscle strength."</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/effect-knee-joint-mobilization-quadriceps-muscle-strength/" target="_blank" rel="noopener noreferrer">Ghanbari A. and Kamalgharibi S. (2013). Effect of knee joint mobilization on quadriceps muscle strength. International Journal of Health and Rehabilitation Sciences. 2(4): 186-191</a></li>
</ol>

An anatomical direction; toward the bottom (below)

Example, the mouth is inferior to the eyes

A reduction in neural drive, muscular activity, and or force output due to altered neuromuscular reflex.  Alterations in neuromuscular reflex may occur due to increases in muscle length (hypothesis: increased excitation threshold), altered reciprocal inhibition in response to increased antagonist tone, and or alterations in joint motion (arthrokinematics inhibition).

Making a whole of parts.

Example, The Brookbush Institute uses an integrative approach to explaining and addressing human movement.

Intermuscular Coordination - Optimal timing and motor unit recruitment of agonists, antagonists, synergists, neutralizers, stabilizers and fixators.

Example: Role of Muscles during Hip Extension
<ul>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Prime Mover" href="https://brentbrookbush.com/glossary/prime-mover/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Prime Mover&lt;/div&gt;The muscle most responsible for a joint action under load -&lt;br /&gt;&lt;br /&gt;That is, the muscle that can produce the most force for a given joint action. Often this term is used synonymously with the term agonist. The prime mover as defined above, may or may not be the most active muscle for a joint action during activities of daily living.&lt;br /&gt;&lt;br /&gt;Example: the gluteus maximus is the most powerful hip extensor and therefore the prime mover; however, the hamstrings are likely the most active hip extensors during low level activities like walking or standing.">Prime Mover</a>:  <a href="https://player.vimeo.com/external/82855344.hd.mp4?s=54c3e7d98fb9d4e0af8d282c85ba9b3e">Gluteus maximus</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Synergists" href="https://brentbrookbush.com/glossary/synergists/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Synergists&lt;/div&gt;Muscles that assist the prime mover in performing a joint action.&lt;br /&gt;&lt;br /&gt;That is, all muscles that can perform a joint action that are not the prime mover, are termed synergists.&lt;br /&gt;Example: The rectus abdominis is the prime mover of spinal flexion. All other muscles that can perform spinal flexion are synergists including – external obliques, internal obliques and psoas.">Synergists</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/biceps-femoris/">Biceps femoris (long head)</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/semitendinosus-and-semimembranosus/">semitendinosus, semimembranosus</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/adductors/">posterior head of adductor magnus</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Antagonist" href="https://brentbrookbush.com/glossary/antagonists/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Antagonist&lt;/div&gt;Muscles that oppose the prime mover and synergists for a given joint action.&lt;br /&gt;&lt;br /&gt;That is, all the muscles that can perform the opposing joint action.&lt;br /&gt;&lt;br /&gt;Example: The triceps and anconeus are antagonists during elbow flexion.">Antagonists</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/psoas/">Psoas</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/iliacus/">iliacus</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/tensor-fascia-latae-tfl/">tensor fascia latae</a> (TFL),<a href="https://brentbrookbush.com/articles/muscular-anatomy/rectus-femoris/"> rectus femoris</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/adductors/">anterior adductors (especially pectineus)</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/sartorius/">sartorius</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Neutralizer" href="https://brentbrookbush.com/glossary/neutralizers/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Neutralizer&lt;/div&gt;Muscles that oppose unwanted joint motions created by the prime mover and/or synergists, and/or muscles that prevent unwanted ancillary motion.&lt;br /&gt;Example: The teres minor and infraspinatus neutralize the internal rotation force created by the pectoralis major during horizontal adduction of the shoulder.">Neutralizers</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/gluteus-minimus/">Gluteus minimus</a> and <a href="https://brentbrookbush.com/articles/muscular-anatomy/gluteus-medius/">anterior fibers of gluteus medius</a> neutralize external rotation force of <a href="https://brentbrookbush.com/articles/muscular-anatomy/gluteus-maximus/">gluteus maximus</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Stabilizer" href="https://brentbrookbush.com/glossary/stabilizers/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Stabilizer&lt;/div&gt;Muscles whose primary role is to improve arthrokinematics by maintaining optimal alignment of joint surfaces.&lt;br /&gt;&lt;br /&gt;Most often these muscles are the most intrinsic muscles of a joint, have a larger percentage of Type I muscle fibers and are rich in proprioceptors.&lt;br /&gt;Example: The muscles of the rotator cuff act as stabilizers for most shoulder motions.">Stabilizers</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/deep-rotators-of-the-hip/">Deep rotators of hip</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Fixator" href="https://brentbrookbush.com/glossary/fixators/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Fixator&lt;/div&gt;Muscles that act to reduce or prevent movement at proximal joints to improve force transmission.&lt;br /&gt;Example: The muscles of the core are important fixators; reducing motion of the spine/trunk to enhance force transmission between the extremities and environment.">Fixators</a>: <a href="https://brentbrookbush.com/articles/core-subsystems/intrinsic-stabilization-subsystem/">Intrinsic stabilization subsystem</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/rectus-abdominis/">rectus abdominis</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/internal-obliques/">internal</a> and <a href="https://brentbrookbush.com/articles/muscular-anatomy/external-obliques/">external obliques</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/quadratus-lumborum/">quadratus lumborum</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/erector-spinae/">erector spinae</a></li>
</ul>
&nbsp;

Example from: <a href="https://brentbrookbush.com/articles/anatomy-articles/introduction-to-functional-anatomy/kinesiology-of-the-hip/" target="_blank" rel="noopener">Introduction to Functional Anatomy: Kinesiology of the Hip</a>

Intramuscular coordination refers to the coordinated recruitment of motor units within a single muscle. This concept is used to explain increases in maximal strength and power; however, the coordinated and sequential recruitment of motor units is also essential to strength endurance and smooth coordinated motion.  Related terminology may include; motor unit recruitment, preferential recruitment, rate coding, sequence, etc..

Example: It is hypothesized that the "shaking" noted during a novice exercisers attempt at an activity like the <a href="https://brentbrookbush.com/vimeo_videos/ball-crunch-and-progressions/" target="_blank">stability ball crunch</a> may be due to relatively poor intramuscular coordination. Rather than smooth, sequential firing of rectus abdominis motor units, groups of motor units turn on and off in an uncoordinated manner.

Pertaining to the same side

Example, the quadratus lumborum performs ipsilateral flexion; lateral flexion toward the same side as the muscle.

An isoform, or variant, is a member of a set of similar proteins, that originate from the same gene, or gene family.
<ul>
 	<li>Example, the variations in myosin heavy chain proteins (MHC I, MHC IIA, MHC IIB/X) that contribute to the characteristic differences between muscle fiber types.</li>
</ul>

“The Prime Assumption”
Everything crossing a joint will influence joint motion during every joint action.

A concept that has expanded over the past several decades to describe the integration of 4 body systems (muscle, joints, fascia and nerves), as well as, the coordinated function of various body segments (e.g. hip, knee and ankle) to produce motion. Kinetic referring to motion, and chain being an analogy for the interdependent link between systems.

Example, the posterior kinetic chain, refers to the integrated function of nerves, muscles, fascia and joints on the posterior side of the body.

The concept of the kinetic chain was originally adapted from the work of a mechanical engineer named Franz Reuleaux (Kinematics of Machinery (1875)) by Dr. Arthur Steindler in 1955 (Steindler A: Kinesiology of the Human Body. Springfield, IL, Charles C. Thomas Co.. 1955).

Latent Trigger Point - A myofascial trigger point that is not painful at rest, only painful when palpated, and may or may not exhibit a characteristic referral pain pattern when palpated.  Latent trigger points do result in an acute point of sensitivity, in a taut band of muscle, and may restrict range of motion (1).

Note: Based on the clinical experience, the Brookbush Institute suggests that latent trigger points (sometimes refereed to as Tender Points) are more common than active trigger points. Further, they are likely addressed more often than trigger points; being the intended target of many soft-tissue mobility techniques.
<ol>
 	<li>David G. Simons, Janet Travell, Lois S. Simons, Travell &amp; Simmons’ Myofascial Pain and Dysfunction, The Trigger Point Manual, Volume 1. Upper Half of Body: Second Edition,© 1999 Williams and Wilkens</li>
</ol>

An anatomical direction; further from the midline

Example, the anterior deltoid is lateral to the pectoralis major

Length/Tension Relationship - The amount of force generated by a muscle is dependent on sarcomere length.
<ul>
 	<li>The ability of sarcomere to maximally produce force occurs when sarcomere length results in optimal overlap between actin and myosin. Stretching a sarcomere decreases overlap between actin and myosin filaments and reduces force production (1-3). When length is less than optimal, actin from opposite ends overlap and interfere with cross-bridging, and myosin filament are compressed as they contact the the Z-disk also reducing force (4)</li>
</ul>
<ol>
 	<li>Gordon, A. M., Huxley, A. F., &amp; Julian, F. J. (1966). The variation in isometric tension with sarcomere length in vertebrate muscle fibres. The Journal of physiology, 184(1), 170-192.</li>
 	<li>Edman, K. A. P. (1966). The relation between sarcomere length and active tension in isolated semitendinosus fibres of the frog. The Journal of Physiology, 183(2), 407-417.</li>
 	<li>Lieber, R. L., Loren, G. J., &amp; Friden, J. (1994). In vivo measurement of human wrist extensor muscle sarcomere length changes. Journal of neurophysiology, 71(3), 874-881.</li>
 	<li>Lieber, R. L. (2002). Skeletal muscle structure, function, and plasticity. Lippincott Williams &amp; Wilkins.</li>
</ol>
&nbsp;

Levels of Evidence - Relative to evidence-based practice, levels of evidence are an attempt to describe the strength of the results measured in a clinical trial or research study.  Note: levels of evidence do not supersede the critical evaluation of an experienced professional, and should be viewed as guidelines - a meta-analysis may be poorly constructed (Level IA), and a comparative study (Level III) may employ new technologies and a strong methodology.


The Levels of Evidence used by the Brookbush Institute, as described by Shekelle et al.(1):
<ul>
 	<li class="p1">IA - Evidence from meta-analysis of randomized controlled trials</li>
 	<li class="p1">IB - Evidence from at least one randomized controlled trial</li>
 	<li class="p1">IIA - Evidence from at least one controlled study without randomization</li>
 	<li class="p1">IIB - Evidence from at least one other type of quasi-experimental study</li>
 	<li class="p1">III - Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies</li>
 	<li class="p1">IV - Evidence from expert committee reports or opinions or clinical experience of respected authorities, or both</li>
</ul>
<ol>
 	<li>Shekelle, P. G., Woolf, S. H., Eccles, M., &amp; Grimshaw, J. (1999). Developing clinical guidelines. Western Journal of Medicine, 170(6), 348.</li>
</ol>

Likelihood Ratios - Likilihood ratios are used for assessing the value of performing a diagnostic test. They use sensitivity and specificity to determine whether a test result usefully changes the practitioner's chance (probability) of reaching the correct assessment. Calculation of likelihood ratios is based on Baye's theorem.
<ul>
 	<li>Positive Likelihood Ratio (LR+) - The ratio of a positive test result in people with the pathology to a positive test result in people without the pathology.</li>
 	<li>Negative Likelihood Ratio (LR-) - The ratio of a negative test result in people with the pathology to a negative test result in people without the pathology.</li>
</ul>

Longitudinal Study - a research design that involves observing the same variables, several times over a period of time.
<ul>
 	<li>Example, the study by Hewett et al. (1) is a type of longitudinal study called a "cohort study." This study investigated whether excessive knee valgus during landing was a predictor of knee injury risk in adolescent females over the course of a season.</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/knee/research-review-increased-valgus-during-landing-predicts-acl-injury-in-adolescent-female-athletes/" target="_blank" rel="noopener noreferrer">Hewett, T. E., Myer, G. D., Ford, K. R., Heidt, R. S., Colosimo, A. J., McLean, S. G., &amp; Succop, P. (2005). Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes A prospective study. The American journal of sports medicine, 33(4), 492-501</a></li>
</ol>

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