Introduction

Behavior in Postural Dysfunction

Rectus Abdominis Trigger Points

There Is No Such Thing As Lower Abs

Attachment and Innervation

Relative Location

Palpation

Actions

Arthrokinematics

Fascial Integration

Fascial Integration of the Recuts Abdominis

Subsystems

Rectus Abdominis and Pyramidalis

AOTA

NASM

ACSM

NYPT

AUSactive

PTAGlobal

CIMSPA

TPTA

ISSA

YOGA

NCBTMB

AFAA

PACE

REPS

CanFitPro

ProCert

WITS

REPSI

AUSPHYSIO

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 rectus abdominis and pyramidalis <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> (a.k.a. the abdominal <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>, abdominis <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>, abs, rectus <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>, 6-pack muscles, or six-pack <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>). The rectus abdominis originates on the pubic symphysis and inserts on the costal cartilages of the fifth through seventh ribs and the xiphoid process of the sternum. The pyramidalis originates on the ramus of the pubis and inserts into the linea alba, but the pyramidalis is absent in about 20% of the population. The rectus abdominis is composed of a fairly even distribution 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; however, a larger proportion of type II fibers is more common. The rectus abdominis and pyramidalis cross the torso and pelvis, influencing motion of the pelvis, thoracic spine, lumbar spine, and ribs. The rectus abdominis is the primary lumbar flexor, will contribute to a <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> pelvic tilt, and potentially <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> flexion of the spine. This course also describes the role of the rectus abdominis <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> 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 rectus abdominis 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 (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 rectus abdominis and pyramidalis (e.g. lumbar flexion with the external obliques, internal obliques, and psoas), and rectus abdominis <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 rectus abdominis 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 Rectus Abdominis (see videos below):</h4>
<ul>
 <li>Activation: <a href="https://brookbushinstitute.com/videos/ball-crunch-and-progressions">Ball Crunch</a>&#xA0;</li>
 <li>Activation: <a href="https://brookbushinstitute.com/videos/kneeling-chop-pattern">Kneeling Static Chop</a></li>
 <li>Reactive Activation: <a href="https://brookbushinstitute.com/videos/core-transverse-abdominis-reactive-integration-crunch-catch">Crunch and Catch</a></li>
 <li>Integration: <a href="https://brookbushinstitute.com/videos/anterior-oblique-subsystem-integration-step-up-to-chest-press">Anterior Oblique Subsystem </a><a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">Integration</a> Step-Up to Chest Press</li>
</ul>
<img alt="Cadaver dissection of the rectus abdominis " title="The rectus abdominis muscle running from the ribcage to the pelvis" src="https://www.datocms-assets.com/25800/1638277038-screen-shot-2016-10-18-at-8-42-10-pm.png">

 Course Description: Rectus Abdominis and Pyramidalis

<h4>What&#x2019;s in a name?</h4>
<ul>
 <li>Rectus Abdominis
 <ul>
 <li>Rectus &#x2013; <a href="http://www.etymonline.com/index.php?term=rectify&amp;allowed_in_frame=0" target="_blank" rel="noopener">rectify (v.)</a> c.1400, from Old French rectifier, literally &#x201C;to make straight&#x201D; (14c.), from Late Latin rectificare &#x201C;make right,&#x201D; from Latin rectus &#x201C;straight&#x201D; (see <a href="http://www.etymonline.com/index.php?term=right&amp;allowed_in_frame=0" target="_blank" rel="noopener">right</a> (adj.1)) + root of facere &#x201C;to make&#x201D; (see <a href="http://www.etymonline.com/index.php?term=factitious&amp;allowed_in_frame=0" target="_blank" rel="noopener">factitious</a>). Related: Rectified; rectifying. (<a href="http://www.etymonline.com/index.php?term=rectify&amp;allowed_in_frame=0" target="_blank" rel="noopener">Etymology Online</a>)</li>
 <li>Abdominis &#x2013; <a href="http://www.etymonline.com/index.php?term=abdomen&amp;allowed_in_frame=0" target="_blank" rel="noopener">abdomen (n.)</a> 1540s, &#x201C;belly fat,&#x201D; from Latin abdomen &#x201C;belly,&#x201D; which is of unknown origin, perhaps from abdere &#x201C;conceal,&#x201D; with a sense of &#x201C;concealment of the <a id="viscera" data-tip="1278" target="_blank" href="/glossary-term/viscera" class="glossary">viscera</a>,&#x201D; or else &#x201C;what is concealed&#x201D; by proper dress. (<a href="http://www.etymonline.com/index.php?term=abdomen&amp;allowed_in_frame=0" target="_blank" rel="noopener">Etymology Online</a>)
 <ul>
 <li>&quot;the straight <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> that conceals the abdominal viscera&quot;</li>
 </ul>
 </li>
 </ul>
 </li>
 <li>Pyramidalis
 <ul>
 <li><a href="http://www.etymonline.com/index.php?term=pyramid&amp;allowed_in_frame=0" target="_blank" rel="noopener">pyramid (n.)</a> - 1550s (earlier in Latin <a id="posture" data-tip="1660" target="_blank" href="/glossary-term/posture" class="glossary">form</a> piramis, late 14c.), from French pyramide (Old French piramide &quot;obelisk, stela,&quot; 12c.), from Latin pyramides, plural of pyramis &quot;one of the pyramids of Egypt,&quot; from Greek pyramis (plural pyramides) &quot;a pyramid,&quot; apparently an alteration of Egyptian pimar &quot;pyramid.&quot; Financial sense is from 1911. Related: Pyramidal. (<a href="http://www.etymonline.com/index.php?term=pyramid&amp;allowed_in_frame=0" target="_blank" rel="noopener">Etymology Online</a>)</li>
 <li><a href="http://www.etymonline.com/index.php?term=-al&amp;allowed_in_frame=0" target="_blank" rel="noopener">-al (1)</a> suffix forming adjectives from nouns or other adjectives, &quot;of, like, related to, pertaining to,&quot; Middle English -al, -el, from French or directly from Latin -alis (see <a href="http://www.etymonline.com/index.php?term=-al&amp;allowed_in_frame=0" target="_blank" rel="noopener">-al</a> (2)). (<a href="http://www.etymonline.com/index.php?term=-al&amp;allowed_in_frame=0" target="_blank" rel="noopener">Etymology Online</a>)
 <ul>
 <li>A <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> shaped like a pyramid</li>
 </ul>
 </li>
 </ul>
 </li>
</ul>
<a href="https://www.datocms-assets.com/25800/1644871718-pyramidalis-cadaver.png"><img src="https://www.datocms-assets.com/25800/1644871718-pyramidalis-cadaver.png" width="294" height="383" title="Cadaver dissection of the pyramidalis and rectus abdominis muscles" alt="The rectus abdominis and pyramidalis muscle"></a>
Pyramidalis (being traced with surgical tool in image) - https://academic.amc.edu/martino/grossanatomy/site/medical/lab%20manual/gastrointestinal/Dissections/Anterior%20Abd%20Wall/Anterior%20Abd%20Wall%2034.html

Introduction to the Rectus Abdominis and Pyramidalis

<h4>Rectus Abdominis</h4>
<ul>
 <li>Origin: The tendons of each individual rectus abdominis attach to the pubic crest; however, fibers from the two tendons cross and interlace over the pubic symphysis (8, 11).</li>
 <li>Insertion: Costal cartilages of the fifth through seventh ribs and xiphoid process of the sternum (8, 11).</li>
 <li>Nerve: Segmentally innervated from the 7 - 11th intercostal nerves, arising from the <a id="ventral" data-tip="1553" target="_blank" href="/glossary-term/ventral" class="glossary">ventral</a> rami of the corresponding spinal nerves with a potential contribution from T5-T6 and/or T12 (8, 11).</li>
</ul>
<h4>Pyramidalis</h4>
<ul>
 <li>Origin: <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">Anterior</a> surface of the ramus of the pubis (11).</li>
 <li>Insertion: Linea alba halfway between the pubis and umbilicus (this <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> lies within the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> rectus sheath) (11).</li>
 <li>Nerve: Innervated by a branch of the 12th intercostal <a id="nerve-cell" data-tip="1361" target="_blank" href="/glossary-term/nerve-cell" class="glossary">nerve</a>, arising from the <a id="ventral" data-tip="1553" target="_blank" href="/glossary-term/ventral" class="glossary">ventral</a> rami of the corresponding spinal <a id="nerve-cell" data-tip="1361" target="_blank" href="/glossary-term/nerve-cell" class="glossary">nerve</a> (8)
 <ul>
 <li>This <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> is typically absent in 17 - 25% of the population (8).</li>
 </ul>
 </li>
</ul>
<a href="https://www.datocms-assets.com/25800/1644871947-rectus-sheath.png"><img src="https://www.datocms-assets.com/25800/1644871947-rectus-sheath.png" title="The rectus sheath showing the connection of the rectus abdominis, obliques, transverse abdominis and linea alba" alt="The rectus abdominis, obliques, and linea alba"></a>
Rectus Sheath - 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 399, Public Domain, https://commons.wikimedia.org/w/index.php?curid=561473

Attachments & Innervation: Rectus Abdominis and Pyramidalis

The rectus abdominis is fairly superficial, lying just beneath the skin, <a id="connective-tissue-cell" data-tip="1776" target="_blank" href="/glossary-term/connective-tissue-cell" class="glossary">adipose tissue</a>, and a fairly complex fascial sheath. The rectus sheath envelopes the rectus abdominis anteriorly and posteriorly. From the costal cartilage to the arcuate line (the level of the umbilicus), the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> sheath is comprised of a continuation of the <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external oblique</a> fascia while the <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> sheath is comprised of a continuation of the <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal oblique</a> and transverse abdominis fascia. Below the level of the arcuate line, the <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> sheath does not continue, and the fascia of the <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>, <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external obliques</a>, and transverse abdominis (<a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> abdominal muscles) continue anteriorly to the rectus abdominis. The pyramidalis actually lies within the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> rectus sheath, from the pubis to approximately half the distance to the umbilicus. The fascial sheaths converge at the linea alba, where they continue into identical fascial tissue on the opposite side. The linea alba, running down the midline of the abdomen, between the two rectus abdominis muscles, is itself a thickening created by the crossing of the fibers of the fascial sheaths (3). The rectus abdominis is separated into segments by transverse <a id="connective-tissue-cell" data-tip="1368" target="_blank" href="/glossary-term/connective-tissue-cell" class="glossary">connective tissue</a> inscriptions which fuse the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> rectus sheath, and are thought to reinforce the rectus abdominis, resisting distension and aiding in the muscle&apos;s ability to eccentrically decelerate extension, and transfer force between <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> abdominal muscles (17, 19). In an older study of 115 cadavers, it was noted that the number of transverse inscriptions is variable in humans, ranging from 1 - 4 (20). The <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> borders of the rectus abdominis are separated from the <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> abdominal muscles by a narrow border that may be palpated (the semilunar lines) where the layers fascia converge before separating again to create the rectus sheath.
<a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">Posterior</a> to the rectus abominis lies the peritoneum and <a id="viscera" data-tip="1278" target="_blank" href="/glossary-term/viscera" class="glossary">viscera</a>. Although this may seem fairly obvious, an understanding of the relative location and anatomy of that <a id="viscera" data-tip="1278" target="_blank" href="/glossary-term/viscera" class="glossary">viscera</a> is essential before pressure is applied to the rectus abdominis for therapeutic or exercise purposes.
The insertion of the rectus abdominis on the costal cartilage is a continuation of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> rectus sheath, is superficial to the ribs and external intercostals, and runs continuous with the pectoral fascia and some <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a>, deep fibers of the <a href="https://brookbushinstitute.com/courses/pectoralis-major" target="_blank" rel="noopener">pectoralis major</a>. The origin of the rectus abominis is a complex network emanating from two distinct tendons; fascial slips cross and invest in the pubic symphysis, just <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> to the tendon of the <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">adductor longus</a> and <a id="medial" data-tip="1568" target="_blank" href="/glossary-term/medial" class="glossary">medial</a> to the origin of the <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">pectineus</a>. Several texts have made inferences about the continuity between the rectus abdominis and adductor tendons and their ability to transmit force between the two <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> groups. This will be discussed further under &quot;Subsystems&quot; and &quot;Fascia Integration&quot; (3, 6, 17).
<a href="https://www.datocms-assets.com/25800/1644872056-transversus_abdominis.png"><img src="https://www.datocms-assets.com/25800/1644872056-transversus_abdominis.png" title="The transverse abdominis and rectus abdominis sheath " alt="The muscles of the core"></a>
Transverse Abdominis and Rectus Abdominis Sheath - By modified by Uwe Gille - Gray397.png, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2601348

Where are the Rectus Abdominis and Pyramidalis Located?

The palpations below have been placed in an order that makes locating each individual <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> a bit easier.
This <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> is visible in athletic, lean individuals. If a student with a visible rectus abdominis is willing to volunteer, using them as a <a id="model" data-tip="1469" target="_blank" href="/glossary-term/model" class="glossary">model</a> to teach this technique may be advised. In some lean individuals the rectus abdominis, transverse inscriptions, and semilunar lines are all visible upon contraction of the rectus abdominis.
<h4>Palpating the Rectus Abdominis:</h4>
<ol>
 <li>With your partner in a <a id="supine" data-tip="1562" target="_blank" href="/glossary-term/supine" class="glossary">supine</a> position, locate the xiphoid process (notch at the bottom of the sternum) and pubis (bony shelf, just above the genitals).</li>
 <li>Place your hands between these landmarks. Start by sinking your hands gently through the skin and <a id="connective-tissue-cell" data-tip="1776" target="_blank" href="/glossary-term/connective-tissue-cell" class="glossary">adipose tissue</a> to find the groove created by the linea alba running vertically at the midline between the two rectus abdominis muscles.</li>
 <li>Have your partner crunch (lift their upper back off the table) and you should feel the rectus abdominis contract around your fingers.</li>
 <li>Start exploring the vertical rectus abdominis fibers, and try to locate the transverse inscriptions.</li>
 <li>Trace the rectus abdominis inferiorly and try to identify the two thick tendons that invest into the pubis.</li>
 <li>Trace the <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> borders of the rectus abdominis and try to identify the semilunar lines.</li>
</ol>
<h4>Palpating the Pyramidalis</h4>
<ul>
 <li>It may be possible to feel a few fascicles of this <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> attached to the linea alba just <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> to the pubis. If they can be palpated they should feel distinct from the rectus abdominis, which is primarily tendon at this point. A small gap between the <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> fibers of the pyramidalis on the linea alba and the rectus abdominis tendon may be felt.</li>
</ul>
<a href="https://www.datocms-assets.com/25800/1644872145-sidney-wilson.jpeg"><img src="https://www.datocms-assets.com/25800/1644872145-sidney-wilson.jpeg" title="Sidney Wilson with visible rectus abdominis, linea alba, transverse inscriptions, and semilunar lines" alt="Bodybuilder with a 6-pack abdominal muscle"></a>
Sidney Wilson - www.SidneyWilson.com Rectus abdomonis, linea alba, transverse inscriptions and semilunar lines visible.

Palpating the Rectus Abdominis and Pyramidalis

<h4>Rectus Abdominis</h4>
<ul>
 <li>Spine: Primary flexor of the lumbar and thoracic spine, unilaterally (one side) the rectus abdominis may contribute to <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> flexion (8, 11).
 <ul>
 <li>Despite having a larger moment arm, the trunk flexors generally have a lower capacity to generate force and have less endurance than the lumbar extensors (21, 22). This is due in large part to the larger mass of the lumbar extensors and their more vertical fiber arrangement.</li>
 </ul>
 </li>
 <li>Pelvis: Will contribute to a <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> pelvic tilt.</li>
 <li>Intra-abdominal Pressure: This <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> is active during bracing and very forceful exhalation (for example, coughing), but is not active during &quot;drawing in&quot; or other less vigorous functional tasks (16).</li>
</ul>
<h4>Pyramidalis</h4>
<ul>
 <li>Linea Alba: Increases <a id="tension" data-tip="1229" target="_blank" href="/glossary-term/tension" class="glossary">tension</a> and rigidity of the linea alba.</li>
</ul>
<a href="https://www.datocms-assets.com/25800/1644872641-abdominal-fascia.png"><img src="https://www.datocms-assets.com/25800/1644872641-abdominal-fascia.png" title="The rectus abdominis, external obliques, internal obliques, transverse abdominis, and linea alba" alt="Abdominial fascia and abdominal muscles "></a>
Abdominal Fascia - 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 392, Public Domain, https://commons.wikimedia.org/w/index.php?curid=287550
<h3>Integrated Function:</h3>
<ul>
 <li>Stabilization: Stabilization of the lumbar spine, thorax, and pubic symphysis.
 <ul>
 <li>Isometrically this <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> &quot;fixes&quot; the torso and ribcage allowing other musculature that anchor on the rib cage and spine to produce force more efficiently.</li>
 </ul>
 </li>
 <li>Eccentrically Decelerates:
 <ul>
 <li>Eccentric deceleration of lumbar extension</li>
 <li>Eccentric deceleration of <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> tilting of the pelvis
 <ul>
 <li>These functions are of particular importance in preventing hyperextension and excessive reduction of the neural foramina.</li>
 </ul>
 </li>
 <li>The rectus abdominis is mildly active from stance phase to push-off during gait - likely to maintain a neutral pelvis during hip extension (eccentrically decelerating an <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> pelvic tilt). The rectus abdominis is also slightly active during the swing phase of gait, countering the force generated by the hip flexors (3)</li>
 </ul>
 </li>
 <li>Synergists:
 <ul>
 <li>Lumbar Flexion: The rectus abdominis is the primary flexor of the lumbar spine, acting synergistically with the <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external obliques</a>, <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>, and psoas on a fixed pelvis.</li>
 <li>Psoas (3)
 <ul>
 <li>The &quot;drawing-in&quot; action of the transverse abdominis may enhance the efficiency of the rectus abdominis by aligning fibers vertically (in the sagittal plane) between the pubis and ribcage, increasing force production by enhancing <a id="lengthtension-relationship" data-tip="1685" target="_blank" href="/glossary-term/lengthtension-relationship" class="glossary">length/tension</a> relationships. As opposed to, the rectus abdominis working in a lengthened position around a distended <a id="viscera" data-tip="1278" target="_blank" href="/glossary-term/viscera" class="glossary">viscera</a>.</li>
 <li>Psoas - <a id="synergists" data-tip="1854" target="_blank" href="/glossary-term/synergists" class="glossary">Synergist</a> or Antagonist: When the hip and pelvis are fixed, the psoas may contribute to lumbar flexion (3). However, the psoas originates on the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> aspect of the lumbar spine and is a strong hip flexor. When the pelvis and hip are not fixed and the pelvis may tilt freely, the psoas will create an <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> force on the lumbar spine during hip flexion, contributing to an <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> pelvic tilt and an increasing in the lumbar lordosis (extension). In short, when the pelvis is fixed the psoas is a <a id="synergists" data-tip="1854" target="_blank" href="/glossary-term/synergists" class="glossary">Synergist</a>, when the pelvis is not fixed it is an <a id="antagonists" data-tip="1705" target="_blank" href="/glossary-term/antagonists" class="glossary">antagonist</a>.</li>
 </ul>
 </li>
 </ul>
 </li>
</ul>
<a href="https://www.datocms-assets.com/25800/1644872691-rectus-abdominis-insertion.png"><img src="https://www.datocms-assets.com/25800/1644872691-rectus-abdominis-insertion.png" title="The rectus abdominis, internal obliques, and TVA insertion into the pubis" alt="Insertion of the rectus abdominis, internal obliques, and transverse abdominis"></a>
Complex insertion of the Rectus Abdominis, Internal Obliques and Transverse Abdominis - 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 398, Public Domain, https://commons.wikimedia.org/w/index.php?curid=561471

Rectus Abdominis and Pyramidalis Muscle Actions

<ul>
 <li>The Spine: The spine is comprised of <a id="gliding-joint" data-tip="1616" target="_blank" href="/glossary-term/gliding-joint" class="glossary">gliding joints</a> (facet joints) whose motion could be described as <a id="arthrokinematics" data-tip="1701" target="_blank" href="/glossary-term/arthrokinematics" class="glossary">arthrokinematic motion</a> (<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>) at each facet, that 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 joint is summated. For example, extension is nothing more than 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 all facets at several segments of the spine, and flexion 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 all facets at several segments of the spine. &#x201C;Closing&#x201D; and &#x201C;opening&#x201D; of facets are often described relative to manual therapy in which extension, <a id="ipsilateral" data-tip="1550" target="_blank" href="/glossary-term/ipsilateral" class="glossary">ipsilateral</a> flexion, and <a id="ipsilateral" data-tip="1550" target="_blank" href="/glossary-term/ipsilateral" class="glossary">ipsilateral</a> rotation result in maximal congruence of facet joint surfaces and flexion, <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> flexion and <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> rotation result in minimal congruence of joint surfaces.
 <ul>
 <li>The rectus abdominis, via a <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> to <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> force on the costal cartilage, produces <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> synonymous with lumbar and thoracic flexion, and <a id="compression" data-tip="1595" target="_blank" href="/glossary-term/compression" class="glossary">compression</a> of the vertebral column (23). 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 related to pathologies including <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> and posterior-lateral herniation of lumbar disks, degenerative joint and disk 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 (3). Paradoxically, the rectus abdominis may also eccentrically decelerate hyper-extension, reduce an excessive lordosis in the lumbar spine, and decrease <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> tilting of the pelvis which would reduce both <a id="compression" data-tip="1596" target="_blank" href="/glossary-term/compression" class="glossary">compressive forces</a> (particularly on <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> structures) 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> forces. This seemingly contradictory relationship likely implies the need for a strong rectus abdominis; with careful attention paid to relative length and <a id="extensibility-2" data-tip="1308" target="_blank" href="/glossary-term/extensibility-2" class="glossary">extensibility</a>. The pyramidalis would have little if any effect on the spine.</li>
 </ul>
 </li>
 <li>The Pubic Symphysis: The pubic symphysis is a cartilaginous joint that allows for little motion. <a id="arthrokinematics" data-tip="1701" target="_blank" href="/glossary-term/arthrokinematics" class="glossary">Arthrokinematic motion</a> occurs as a <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> or <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 pubis relative to the <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> side. This is often in conjunction with a &quot;pelvic torsion&quot;, that is one side of the pelvis anteriorly or posteriorly rotated relative to the other.
 <ul>
 <li>The rectus abdominis may act unilaterally to <a id="glide" data-tip="1598" target="_blank" href="/glossary-term/glide" class="glossary">glide</a> one side of the pubis superiorly. This motion may occur naturally, as when paired with sacroiliac motion, to allow for pelvic torsion during gait. In static <a id="posture" data-tip="1658" target="_blank" href="/glossary-term/posture" class="glossary">posture</a>, or in excess, malalignment of the pelvis (relative <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>) may be a sign of compensation that includes &quot;pelvic torsion&quot; and sacroiliac dysfunction. The pyramidalis would contribute, very slightly, to <a id="compression" data-tip="1595" target="_blank" href="/glossary-term/compression" class="glossary">compression</a> of the pubic symphysis.</li>
 </ul>
 </li>
</ul>
<img src="https://classconnection.s3.amazonaws.com/693/flashcards/839693/jpg/rectus_abdominis1318976334055.jpg" alt><img src="https://www.datocms-assets.com/25800/1644872873-rectus_abdominis.png" alt="Rectus abdominis covering the anterior portion of the torso" title="The superficial rectus abdominis muscle running vertically on the torso">
Note: The Rectus Abdominis converges into two distinct tendons inserting on either side of the pubic crest and pubic symphysis - http://classconnection.s3.amazonaws.com

My Fascial Hypothesis: Large fascial sheaths not only play a role in the transmission of mechanical force but may also play a role in dictating the function of muscular synergies. This is likely caused by reducing or increasing <a id="tone" data-tip="1639" target="_blank" href="/glossary-term/tone" class="glossary">tone</a> of invested musculature via reflex arcs formed between mechanoreceptors embedded in the <a id="connective-tissue-cell" data-tip="1368" target="_blank" href="/glossary-term/connective-tissue-cell" class="glossary">connective tissue</a> and the attached musculature. In this way, my view of fascia differs slightly from noted expert on the subject Tom Myers. I think of these large fascial sheaths (specifically the thoracolumbar fascia, iliotibial band, and abdominal fascial sheath) as nature&apos;s &quot;motherboard.&quot; A place for mechanical information to be communicated to the <a id="nervous-system" data-tip="1690" target="_blank" href="/glossary-term/nervous-system" class="glossary">nervous system</a> for more efficient recruitment of the <a id="muscular-system" data-tip="1691" target="_blank" href="/glossary-term/muscular-system" class="glossary">muscular system</a>. Despite having a slightly different philosophy it does not change the fact that fascia plays an important communicative role in the human body and we have Tom Myers to thank for his work.
<a href="https://www.datocms-assets.com/25800/1644872934-fascia-web-in-body.jpeg"><img src="https://www.datocms-assets.com/25800/1644872934-fascia-web-in-body.jpeg" title="Image of the fascial system of the body connecting muscles" alt="The fascial web connecting two muscle fascicles"></a>

<ul>
 <li>The Rectus Sheath: The rectus sheath envelopes the rectus abdominis anteriorly and posteriorly. From the costal cartilage to the arcuate line (the level of the umbilicus), the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> sheath is comprised of a continuation of the <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external oblique</a> fascia while the <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> sheath is comprised of a continuation of the <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal oblique</a> and transverse abdominis fascia. Note, some texts suggest the <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal oblique</a> fascia splits, contributing to both <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> and <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> rectus sheaths (17). Below the level of the arcuate line, the <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> sheath does not continue, and the fascia of the <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>, <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external obliques</a>, and transverse abdominis (<a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> abdominal muscles) continue anteriorly to the rectus abdominis. Posteriorly, this same fascial sheath envelopes the quadratus lumborum and psoas, and superiorly this fascia lines the <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> surface of the diaphragm (18<a href="https://brookbushinstitute.com/article/psoas" target="_blank" rel="noopener">)</a>. The pyramidalis actually lies within the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> rectus sheath, from pubis to approximately half the distance to the umbilicus. The fascial sheaths converge at the linea alba, where they continue into identical fascial tissue on the opposite side. The linea alba, running down the midline of the abdomen, between the two rectus abdominis muscles, is itself a thickening created by the crossing of transverse oriented fibers of the fascial sheaths (3). Any <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a>, <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a>, or rotational force imparted on the trunk will result in an increase in rectus abdominis, <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external</a> and <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal oblique</a>, and transverse abdominis activity (3), and potentially an increase in quadratus lumborum and psoas. The transverse inscriptions through the rectus abdominis occur at the level of the oblique fascia and may reinforce and help to transfer force between sides (17). The corset-like effect of this myofascial synergy has been discussed by several researchers/authors, contributing to <a id="force-closure" data-tip="1448" target="_blank" href="/glossary-term/force-closure" class="glossary">force closure</a> of the sacroiliac joints and pubic symphysis, an increase in intra-abdominal pressure, <a id="posterior" data-tip="1565" target="_blank" href="/glossary-term/posterior" class="glossary">posterior</a> shift of the abdominal <a id="viscera" data-tip="1278" target="_blank" href="/glossary-term/viscera" class="glossary">viscera</a> into the lumbar vertebrae, enhanced force transmission from the lower to upper extremities and protections of the abdominal <a id="viscera" data-tip="1278" target="_blank" href="/glossary-term/viscera" class="glossary">viscera</a> (2, 3, 6, 13, 17, 18). In essence, the coordinated activation of all of the muscles investing in the rectus sheath (along with those investing in the thoracolumbar fascia) is required for stabilization of the lumbar vertebrae (and sacroiliac joint and pubic symphysis respectively), which do not benefit from the bony <a id="base-of-support" data-tip="1197" target="_blank" href="/glossary-term/base-of-support" class="glossary">support</a> the thoracic spine receives from the ribs. Changes in the recruitment pattern of these muscles would result in extremities trying to exert force on the external environment from an <a id="stability" data-tip="1194" target="_blank" href="/glossary-term/stability" class="glossary">unstable</a> <a id="base-of-support" data-tip="1196" target="_blank" href="/glossary-term/base-of-support" class="glossary">base</a>, or central column.</li>
 <li>Pectoralis Major and Serratus Anterior: At the lower part of the thoracic region the deep pectoral fascia is well-developed, and is continuous with the fibrous sheaths of the rectus abdominis and <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external obliques</a> (17). Further, the rectus sheath continues (or is comprised of) as the fascia of the <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external obliques</a>, which is continuous with the fascia of the interdigitating <a href="https://brookbushinstitute.com/courses/serratus-anterior" target="_blank" rel="noopener">serratus anterior</a> at the ribs. This implies a link between the rectus abdominis and the shoulder girdle, which may not only have implications for throwing sports (e.g. baseball, football, etc.), but imply relationships between shoulder girdle dysfunction and movement impairment/motor control issues emanating from the core musculature.</li>
 <li>Rectus Abdominis and Adductor Tendons: The abdominal fascia runs with some continuity from the abdomen, through the pubic symphysis, into the tendons of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">adductors</a> and superficial fascia of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> thigh, however, the strongest fascial relationship exists between the tendon of the rectus abdominis and the tendon of the <a href="https://brookbushinstitute.com/course/adductors" target="_blank" rel="noopener">adductor longus</a>. The continuity between the rectus abdominis and the <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">adductor longus</a> can then be expanded upon by the location of the adductor tendons relative to the rectus abdominis tendon and tendon of the adductor longus to the rest of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> adductors. The tendon of the <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">pectineus</a> abuts the <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> side of the rectus abdominis tendon, and the attachments of the <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">gracilis and</a> <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">adductor brevis</a> abut the tendon of the adductor longus inferiorly and laterally. This relationship not only implies a <a id="balance" data-tip="1190" target="_blank" href="/glossary-term/balance" class="glossary">balance</a> between the muscles of the rectus sheath and the adductors relative to the position of the pubic symphysis but a mechanism of transferring force from the lower extremities to the core.</li>
 <li>Anterior Fascial System: When the fascial connections above are considered in their entirety, an <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">Anterior</a> <a id="fascial-system" data-tip="1689" target="_blank" href="/glossary-term/fascial-system" class="glossary">fascial system</a> is implied that expands upon the <a href="https://brookbushinstitute.com/courses/core-subsystems/anterior-oblique-subsystem-aos/" target="_blank" rel="noopener">Anterior Oblique Subsystem (AOS)</a> discussed earlier. Note: this myofascial system may be expanded further upon closer <a id="assessment" data-tip="1481" target="_blank" href="/glossary-term/assessment" class="glossary">evaluation</a> of the <a href="https://brookbushinstitute.com/courses/serratus-anterior" target="_blank" rel="noopener">serratus anterior</a> and pectoral fascias, and the fascia lata.
 <ul>
 <li><a href="https://brookbushinstitute.com/courses/pectoralis-major" target="_blank" rel="noopener">Pectoralis Major</a></li>
 <li><a href="https://brookbushinstitute.com/courses/serratus-anterior" target="_blank" rel="noopener">Serratus Anterior</a></li>
 <li>Anterior Core (rectus abdominis, <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>, <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external obliques</a>, and transverse abdominis)</li>
 <li>Anterior Adductors (<a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">adductor longus, pectineus, adductor brevis, and gracilis</a>)</li>
 </ul>
 </li>
 <li>The function of this synergy can be observed during some of the most powerful activities in sport (e.g. throwing a baseball, swinging a bat, an axe chop, the &#x201C;Heisman Maneuver&#x201D;, lineman pushing, etc). Although some of the muscles of this &quot;expanded&quot; synergy do not demonstrate the same levels of activity relative to functional movement patterns, the expansion of the <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a> to include these muscles seems to be better <a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a> of previous work and theory including the &#x201C;Serape Effect&#x201D; and &#x201C;Spiral Line or Functional Front Line&#x201D; discussed by Tom Myers and others (6). Two of the muscles, <a href="https://brookbushinstitute.com/courses/serratus-anterior" target="_blank" rel="noopener">serratus anterior</a> and transverse abdominis, exhibit the opposite changes in activity relative to <a id="posture" data-tip="1659" target="_blank" href="/glossary-term/posture" class="glossary">postural</a> dysfunction; which may be evidence of superficial and deep systems, or an <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> and compensatory motor recruitment strategy. Clinically, I have found the consideration of the network above to be more useful as the pectoral, <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> axillary fascia and deltopectoral fascia are often a source of restriction in those with limited shoulder elevation (flexion, scaption, or abduction), and those same individuals often exhibit signs of an over-active <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a>. It is not hard to imagine a relationship between adaptive shortening and over-activity of any one of the muscles listed above and the resulting restriction throughout this fascial network.</li>
</ul>
<a href="https://www.datocms-assets.com/25800/1644873051-forward-head-posture-fix-discount.jpeg"><img src="https://www.datocms-assets.com/25800/1644873051-forward-head-posture-fix-discount.jpeg" title="Hyperkyphosis and forward head position of the torso and head" alt="Forward head position "></a>

Fascial Integration of the Rectus Abdominis

<h4>Should the rectus abdominis be considered part of the <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">Anterior Oblique Subsystem (AOS)</a>?</h4>
<ul>
 <li>Although the <a href="https://brookbushinstitute.com/courses/core-subsystems/anterior-oblique-subsystem-aos/" target="_blank" rel="noopener">AOS</a> is traditionally depicted as the <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external oblique</a>, abdominal fascia, and <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> <a href="https://brookbushinstitute.com/course/adductors" target="_blank" rel="noopener">adductors</a>; as these subsystems are summaries of research on myofascial synergies and force transmission, it is worth noting that the strongest fascial relationships exist between the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> trunk muscles via the rectus sheath and the rectus abdominis and tendons of the adductors. The rectus abdominis is enveloped by the rectus sheath, which is a structure comprised of the continuation of the <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external oblique</a>, <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>, and transverse abdominis fascia. These structures aid in the transmission of force between the <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external oblique</a>, <a href="https://brookbushinstitute.com/courses/internal-obliques" target="_blank" rel="noopener">internal obliques</a>, transverse abdominis, and rectus abdominis, as well as transmitting force between right and left sides (3).</li>
</ul>
<a href="https://www.datocms-assets.com/25800/1644873096-anterior-oblique-subsystem.png"><img src="https://www.datocms-assets.com/25800/1644873096-anterior-oblique-subsystem.png" title="The external obliques and anterior adductors in the anterior oblique subsystem" alt="Anterior oblique subsystem (AOS)"></a>
A traditional depiction of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">Anterior</a> Oblique Subsystem (AOS) as the external oblique and adductors.
<ul>
 <li>The abdominal fascia may transmit changes in length and activity between the <a href="https://brookbushinstitute.com/courses/rectus-abdominis" target="_blank" rel="noopener">rectus abdominus</a>, <a href="https://brookbushinstitute.com/courses/external-obliques" target="_blank" rel="noopener">external obliques,</a> and <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">adductors</a> (17). The abdominal fascia runs with some continuity from the abdomen, through the pubic symphysis, into the tendons of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> <a href="https://brookbushinstitute.com/course/adductors" target="_blank" rel="noopener">adductors</a> and superficial fascia of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> thigh, however, the strongest fascial relationship exists between the tendon of the rectus abdominis and the tendon of the <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">adductor longus</a>. The continuity between the rectus abdominis and the <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">adductor longus</a> can then be expanded upon by the location of the adductor longus tendon to the abutting tendons of the <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">pectineus, gracilis, and adductor brevis</a>. In summary, fascially the rectus abdominis cannot be rationally excluded from any of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> core muscles, and the continuity between the adductors and <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> trunk muscles is at least partly dependent on the continuity between the adductor longus and rectus abdominis tendons.</li>
</ul>
<a href="https://www.datocms-assets.com/25800/1644873141-attachments-on-pubis.jpeg"><img src="https://www.datocms-assets.com/25800/1644873141-attachments-on-pubis.jpeg" title="Muscle attachments on the anterior pelvis, femur, and lumbar spine" alt="Attachment of the core muscles on the pelvis"></a>
<a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">Muscle</a> Attachments on <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">Anterior</a> Pelvis, Femur and Lumbar Spine - Donald A. Neumann, &#x201C;Kinesiology of the Musculoskeletal System: Foundations of Rehabilitation &#x2013; 2nd Edition&#x201D; &#xA9; 2012 Mosby, Inc.
<ul>
 <li>Functionally, the rectus abdominis is active during all functions of the <a href="https://brookbushinstitute.com/courses/core-subsystems/anterior-oblique-subsystem-aos/" target="_blank" rel="noopener">AOS</a> - forward bending, turning-in of the <a id="kinetic-chain-2" data-tip="1544" target="_blank" href="/glossary-term/kinetic-chain-2" class="glossary">kinetic chain</a>, total body pronation, eccentric deceleration of hyper-extension, and turning-out of the <a id="kinetic-chain-2" data-tip="1544" target="_blank" href="/glossary-term/kinetic-chain-2" class="glossary">kinetic chain</a>, as well as, the transfer of force between lower and upper extremities.</li>
 <li>Relative to <a id="posture" data-tip="1659" target="_blank" href="/glossary-term/posture" class="glossary">postural</a> dysfunction, the <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> activity and relative length of the rectus abdominis, when viewed relative to movement impairment/postural dysfunction, matches the activity of the <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a>. I have nicknamed the <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">AOS</a> the &quot;Jekyll &amp; Hyde&quot; system, because unlike other subsystems it may be under-active or over-active depending on the <a id="compensation-pattern" data-tip="1696" target="_blank" href="/glossary-term/compensation-pattern" class="glossary">compensation pattern</a> adopted. In <a href="https://brookbushinstitute.com/courses/lumbo-pelvic-hip-complex-dysfunction-lphcd" target="_blank" rel="noopener">Lumbo Pelvic Hip Complex Dysfunction</a> (LPHCD) the AOS is often under-active, in <a href="https://brookbushinstitute.com/courses/lower-leg-dysfunction" target="_blank" rel="noopener">Lower Leg Dysfunction (LLD)</a> and <a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">Upper Body Dysfunction UBD</a> this subsystem is often over-active. In Sacroiliac Joint Dysfunction (SIJD), the AOS is often over-active on the side of dysfunction and under-active on the <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> side. Most often the over-activity of the AOS is paired with the under-activity of the <a href="https://brookbushinstitute.com/courses/posterior-oblique-subsystem-pos" target="_blank" rel="noopener">Posterior Oblique Subsystem (POS)</a>. The rectus abdominis matches the activity of the <a href="https://brookbushinstitute.com/courses/core-subsystems/anterior-oblique-subsystem-aos/" target="_blank" rel="noopener">AOS</a> relative to these <a id="movement-impairment" data-tip="1579" target="_blank" href="/glossary-term/movement-impairment" class="glossary">dysfunctions</a> in all scenarios.
 <ul>
 <li>Based on the evidence above, it would seem that the exclusion of the rectus abdominis is an oversight. Although its exclusion from the <a href="https://brookbushinstitute.com/courses/core-subsystems/anterior-oblique-subsystem-aos/" target="_blank" rel="noopener">AOS</a> may be presented as a simpler <a id="model" data-tip="1469" target="_blank" href="/glossary-term/model" class="glossary">model</a> used for teaching purposes, or to reinforce the oblique lines of force and synergy between <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> limbs, it is incomplete. Based on the ideas above the <a href="https://brookbushinstitute.com/courses/core-subsystems/anterior-oblique-subsystem-aos/" target="_blank" rel="noopener">AOS</a> is likely comprised of all of the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> trunk muscles (including the rectus abdominis) and the <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">anterior adductors</a> (omitting the <a href="https://brookbushinstitute.com/courses/adductors" target="_blank" rel="noopener">adductor magnus</a>). As discussed below in &quot;fascial integration&quot;, the <a href="https://brookbushinstitute.com/courses/core-subsystems/anterior-oblique-subsystem-aos/" target="_blank" rel="noopener">AOS</a> may need to be expanded further to include the <a href="https://brookbushinstitute.com/courses/pectoralis-major" target="_blank" rel="noopener">pectoralis major</a> and <a href="https://brookbushinstitute.com/courses/deltoids" target="_blank" rel="noopener">deltoids</a>. Exercise selection for the rectus abdominis should be considered relative to the activity and function of the <a href="https://brookbushinstitute.com/courses/core-subsystems/anterior-oblique-subsystem-aos/" target="_blank" rel="noopener">AOS</a>, during core exercise, and subsystem <a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a> techniques for fitness, rehab, and performance enhancement programs.</li>
 </ul>
 </li>
</ul>
<a href="https://www.datocms-assets.com/25800/1644873196-diagram.jpeg"><img src="https://www.datocms-assets.com/25800/1644873196-diagram.jpeg" width="445" height="375" title="Relationship between the adductor muscles, rectus abdominis, and external obliques" alt="Connection of the external obliques, rectus abdominis, and anterior adductors"></a>
Relationship between adductor longus and rectus abdominis tendons - http://www.proscan.com/online-courses/online-courses/_filelib/ImageGallery/Case%20of%20the%20Month/2010/February/Diagram.jpg

The rectus abdominis has been noted as long and under-active and/or short and over-active depending on the dysfunction, by several texts and clinicians (1. 2, 3, 6, 7, 13, 17). Further, as a <a id="prime-mover" data-tip="1662" target="_blank" href="/glossary-term/prime-mover" class="glossary">prime mover</a> of lumbar flexion, this <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> is often targeted during resistance training and core conditioning routines. The rectus abdominis is one of the few muscles that may adopt an increase or decrease in relative length and activity. The only way to ensure effective exercise/technique selection is movement <a id="assessment" data-tip="1478" target="_blank" href="/glossary-term/assessment" class="glossary">assessment</a>. Over-activity and adaptive shortening does create a practical issue, as <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> of the rectus abdominis is difficult and self-administered techniques are unlikely to be effective or recommended based on potential disruption of the abdominal <a id="viscera" data-tip="1278" target="_blank" href="/glossary-term/viscera" class="glossary">viscera</a>. Stretching the rectus abdominis may be problematic for those with lumbar spine pain. Generally, recommendations for addressing rectus abdominis activity and length, include whether or not rectus abdominis and <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem/" target="_blank" rel="noopener">anterior oblique subsystem (AOS)</a> <a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a> exercises should be performed.
In <a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">Upper Body Dysfunction (UBD)</a> the rectus abdominis does not play a direct role in <a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">UBD</a>; however, is often short/over-active. This can be explained mechanically, via the rectus abdominis&apos; ability to contribute to a thoracic kyphosis and the correlation between an increased thoracic kyphosis and shoulder pain (24). It can also be explained relative to motor control, in which changes in <a id="lengthtension-relationship" data-tip="1685" target="_blank" href="/glossary-term/lengthtension-relationship" class="glossary">length/tension</a> relationships and altered spine/pelvis position, resulting in inhibition of the <a href="https://brookbushinstitute.com/courses/intrinsic-stabilization-subsystem" target="_blank" rel="noopener">Intrinsic Stabilization Subsystem (ISS)</a> and <a id="synergistic-dominance" data-tip="1643" target="_blank" href="/glossary-term/synergistic-dominance" class="glossary">synergistic dominance</a> of the rectus abdominis and <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem/" target="_blank" rel="noopener">anterior oblique subsystem (AOS)</a> (13, 17). The latter can be demonstrated using an <a href="https://brookbushinstitute.com/course/solutions-table-overhead-squat-assessment" target="_blank" rel="noopener">overhead squat assessment</a>, in those exhibiting <a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">UBD</a>. If the individual being assessed exhibits the sign &quot;<a href="https://brookbushinstitute.com/video/overhead-squat-assessment-10-arms-fall" target="_blank" rel="noopener">Arms Fall</a>&quot; with the spine neutral or exhibits an &quot;<a href="https://brookbushinstitute.com/video/overhead-squat-assessment-9-anterior-pelvic-tilt-excessive-lordosis" target="_blank" rel="noopener">Excessive Lordosis (APT)</a>&quot;, it is often the case that the over-activity of the rectus abdominis is balanced by, or over-powered by the over-activity of the latissimus dorsi which have been lengthened by the arm position. However, if the <a href="https://brookbushinstitute.com/courses/sign-clusters-compensation-patterns-overhead-squat-assessment" target="_blank" rel="noopener">overhead squat is performed &quot;with modification&quot;</a>, and the hands are down, the individual will often collapse forward into <a href="https://brookbushinstitute.com/video/overhead-squat-assessment-13-sign-clusters-upper-body-dysfunction" target="_blank" rel="noopener">lumbar flexion or an excessive forward lean</a>. In those exhibiting <a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">UBD</a>, it may be recommended to reduce or eliminate spinal flexion and <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem/" target="_blank" rel="noopener">AOS</a> <a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a> exercise until the dysfunction is corrected.
In <a href="https://brookbushinstitute.com/courses/lumbo-pelvic-hip-complex-dysfunction-lphcd" target="_blank" rel="noopener">Lumbo Pelvic Hip Complex Dysfunction (LPHCD)</a> the rectus abdominis is often long and under-active contributing to an <a href="https://brookbushinstitute.com/video/overhead-squat-assessment-9-anterior-pelvic-tilt-excessive-lordosis" target="_blank" rel="noopener">anterior pelvic tilt</a> (1, 2, 6, 7). Although crunches alone are not likely to be effective, they are not contra-indicated for this population. Addressing short/over-active structures with <a href="https://brookbushinstitute.com/articles?category=mobility" target="_blank" rel="noopener">mobility techniques</a> prior to activation, <a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a>, and conditioning, and addressing the under-activity of all <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> trunk muscles (<a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem-aos" target="_blank" rel="noopener">Anterior Oblique Subsystem (AOS)</a>) is a far more effective solution.
In Sacroiliac Joint Dysfunction (SIJD) the rectus abdominis is often lengthened on one side relative to the other (longer on the side of the anteriorly rotated innominate). <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">Release</a> techniques for the relatively short side may prove to be beneficial, and it is not practical to try to isolate and activate the longer side. Addressing the length of this <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> by addressing stiffness in the sacroiliac joint, lumbar spine, and pubic symphysis and correcting the relative tilt of each innominate is a more effective strategy. It is not uncommon, for correction of SIJD to result in the client/patient adopting a dysfunctional, but symmetrical <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> pelvic tilt. This is an improvement and would be treated as <a href="https://brookbushinstitute.com/courses/lumbo-pelvic-hip-complex-dysfunction-lphcd" target="_blank" rel="noopener">LPHCD</a>.
In <a href="https://brookbushinstitute.com/courses/lower-leg-dysfunction" target="_blank" rel="noopener">Lower Leg Dysfunction (LLD)</a> the rectus abdominis does not play a direct role; however, may be affected by changes in pelvic position. In a similar scenario to that described in <a href="https://brookbushinstitute.com/courses/upper-body-dysfunction-ubd" target="_blank" rel="noopener">UBD</a>, changes in <a id="lengthtension-relationship" data-tip="1685" target="_blank" href="/glossary-term/lengthtension-relationship" class="glossary">length/tension</a> relationships and altered spine/pelvis position, resulting in inhibition of the <a href="https://brookbushinstitute.com/courses/intrinsic-stabilization-subsystem" target="_blank" rel="noopener">Intrinsic Stabilization Subsystem (ISS)</a> and <a id="synergistic-dominance" data-tip="1643" target="_blank" href="/glossary-term/synergistic-dominance" class="glossary">synergistic dominance</a> of the rectus abdominis and <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem/" target="_blank" rel="noopener">anterior oblique subsystem (AOS)</a> (13, 17). This can be demonstrated using an <a href="https://brookbushinstitute.com/course/solutions-table-overhead-squat-assessment" target="_blank" rel="noopener">overhead squat assessment</a>, in those exhibiting LLD. If the individual being assessed exhibits the sign &quot;<a href="https://brookbushinstitute.com/video/overhead-squat-assessment-8-excessive-forward-lean" target="_blank" rel="noopener">Excessive Forward Lean</a>&quot;, it is often the case that the lean is due to a lack of dorsiflexion and attempt to maintain the center-of-mass over the <a id="base-of-support" data-tip="1195" target="_blank" href="/glossary-term/base-of-support" class="glossary">base of support</a> - with no change in rectus abdominis or <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem/" target="_blank" rel="noopener">AOS</a> activity. However, if the <a href="https://brookbushinstitute.com/courses/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> is performed &quot;with modification&quot;, and a block is put under the heels, and the <a href="https://brookbushinstitute.com/video/overhead-squat-assessment-8-excessive-forward-lean" target="_blank" rel="noopener">Excessive Forward Lean</a> is still present then over-activity of the rectus abdominis or <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem/" target="_blank" rel="noopener">AOS</a> may be assumed. In those exhibiting this set of signs, it may be recommended to reduce or eliminate spinal flexion and <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem/" target="_blank" rel="noopener">AOS</a> <a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a> exercise until the dysfunction is corrected.
In short, the rectus abdominis is likely given too much attention, particularly in strength training program with the intent of isolating this <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>. The rectus abdominis has been noted as long and under-active and/or short and over-active depending on the dysfunction, although over-activity tends to be more common. <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">Release</a> of the rectus abdominis is difficult, and self-administered techniques are unlikely to be effective (or recommended based on the potential disruption of the abdominal <a id="viscera" data-tip="1278" target="_blank" href="/glossary-term/viscera" class="glossary">viscera</a>). Stretching the rectus abdominis may be problematic for those with lumbar spine pain. Generally, recommendations for addressing rectus abdominis activity and length, include whether or not rectus abdominis and <a href="https://brookbushinstitute.com/courses/anterior-oblique-subsystem/" target="_blank" rel="noopener">anterior oblique subsystem (AOS)</a> <a id="integration" data-tip="1472" target="_blank" href="/glossary-term/integration" class="glossary">integration</a> exercises should be performed. If <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger points</a> are to be an issue it is best to refer out to a manual therapist with experience treating abdominal musculature.
<h4>Clinical Implications:</h4>
<ul>
 <li>Rectus abdominis tendonitis</li>
 <li>Sports Hernia</li>
 <li>Diastasis Recti - Exercise may reduce the chance of this occurring ante- and post-natal by 35%, and reduce width in those affected (32)</li>
 <li>Low back pain</li>
 <li>Thoracic pain</li>
 <li>Groin pain</li>
 <li>Sacroiliac dysfunction</li>
 <li>Pubic symphysis dyskinesis</li>
</ul>
<h3>Signs of Altered Length/Tension and Tone:</h3>
<ul>
 <li>Overhead Squat:
 <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> Short/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> Short/Over-active on side of dysfunction</li>
 <li><a href="https://brookbushinstitute.com/video/overhead-squat-assessment-13-sign-clusters-upper-body-dysfunction" target="_blank" rel="noopener">Lumbar Flexion during Modification:</a> Short/Over-active</li>
 </ul>
 </li>
</ul>

Postural Dysfunction and the Rectus Abdominis and Pyramidalis

<ul>
 <li>Pain is a terrible predictor of dysfunction, but it is a clue &#x2013; the structure or area perceived as painful is being affected by the dysfunction. Further, palpation and location of <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger points</a> may provide evidence that these muscles have adopted a less than <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> length, and <a id="tone" data-tip="1639" target="_blank" href="/glossary-term/tone" class="glossary">tone</a> has been adversely affected, even when the patient/client complaint is not directly related to the rectus abdominis complex.
 <ul>
 <li>Trigger points in the rectus abdominis can cause visceral-like symptoms and can be easily masked by visceral dysfunction (8). It is easy to mistake one for the other; 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.
 <ul>
 <li>Upper rectus abdominis <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger points</a> are generally found just below the level of the xiphoid process and refer pain horizontally around the torso to the mid-back.</li>
 <li>Lower rectus abdominis <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger points</a>, near the pubis and musculotendinous junction, may refer pain horizontally in <a id="a-band" data-tip="1347" target="_blank" href="/glossary-term/a-band" class="glossary">a band</a> that wraps around to cover the lower back and sacrum.</li>
 <li>Periumbilical (around the belly button) rectus abdominis <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger points</a> produce a variety of symptoms, similar to visceral pain and dysfunction. This may include nausea, vomiting, intestinal and rectal colic, pain in the genitals, and potentially dysmenorrhea (8).</li>
 </ul>
 </li>
 </ul>
 .
 </li>
</ul>
<a href="https://www.datocms-assets.com/25800/1644873486-rectus-abdominus-mcburneys-point.jpeg"><img src="https://www.datocms-assets.com/25800/1644873486-rectus-abdominus-mcburneys-point.jpeg" title="Common trigger points and referral pain patterns of the rectus abdominis" alt="Rectus abdominis trigger points"></a>
Rectus Abdominis Trigger Points David G. Simons, Janet Travell, Lois S. Simons, Travell &amp; Simmons&#x2019; Myofascial Pain and Dysfunction, The <a id="trigger-point" data-tip="1632" target="_blank" href="/glossary-term/trigger-point" class="glossary">Trigger Point</a> Manual, Volume 1. Upper Half of Body: Second Edition, Pg. 944&#xA9; 1999 Williams and Wilkens
The pyramidalis may refer pain along the linea alba between the pubis and umbilicus (8).
<a href="https://www.datocms-assets.com/25800/1644873603-rectus-abdominis-and-pyrmidalis-trigger-points.jpeg"><img src="https://www.datocms-assets.com/25800/1644873603-rectus-abdominis-and-pyrmidalis-trigger-points.jpeg" title="Common trigger points and referral pain patterns of the pyramidalis" alt="Pyramidalis trigger points"></a>
Pyramidalis <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger points</a> and <a id="referred-trigger-point-pain" data-tip="1709" target="_blank" href="/glossary-term/referred-trigger-point-pain" class="glossary">referral pain</a> pattern, and a rectus abdominis <a id="trigger-point" data-tip="1632" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger point</a> purported to result in dysmenorrhea - David G. Simons, Janet Travell, Lois S. Simons, Travell &amp; Simmons&#x2019; Myofascial Pain and Dysfunction, The <a id="trigger-point" data-tip="1632" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger point</a> Manual, Volume 1. Upper Half of Body: Second Edition,&#xA9; 1999 Williams and Wilkens

Rectus Abdominis Trigger Points and Referral Pain Patterns

Despite being segmentally innervated, all <a id="relevance" data-tip="1505" target="_blank" href="/glossary-term/relevance" class="glossary">relevant</a> studies demonstrate that the rectus abdominis is recruited as a single <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> during motion and stabilization of the spine, hips, and pelvis (25 - 33). One study demonstrated, that only one activity resulted in separate recruitment of the upper and lower portions of the rectus abdominis. The activity was the stomach <a id="roll" data-tip="1602" target="_blank" href="/glossary-term/roll" class="glossary">roll</a> in belly dancing (34). Note that the lumbar spine and pelvis do not move during a stomach <a id="roll" data-tip="1602" target="_blank" href="/glossary-term/roll" class="glossary">roll</a>.&#xA0;
There is a physics issue with the concept of targeting the lower rectus abdominis. If the <a id="inferior" data-tip="1569" target="_blank" href="/glossary-term/inferior" class="glossary">inferior</a> portion rectus abdominis contracts and the upper rectus abdominis does not contract at the same intensity, the lower fibers would stretch/lengthen the upper fibers, and the whole <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> would not change length. This would result in no motion occurring at the pelvis or ribcage.
What would happen if the upper and lower portions of the rectus abdominis contracted at different intensities? This is obvious for practitioners working with spinal cord patients. There is a <a id="assessment" data-tip="1482" target="_blank" href="/glossary-term/assessment" class="glossary">test</a> in which an examiner asks a patient with a thoracic spinal cord injury to &quot;crunch&quot; or raise their head against resistance. In this exam, called the &quot;Beevor&apos;s Sign&quot;, the umbilicus will be drawn toward the upper rectus abdominis fibers still innervated by the nerves above the spinal cord lesion. This results in a visual example of the upper section of the rectus abdominis contracting, stretching the non-contracting lower portion of the rectus abdominis, resulting in movement of the umbilicus (belly button), but no motion of the rib cage or pelvis. Clinically, this may provide insight into the level of thoracic spinal cord lesions.

There is No Such Thing as a Lower Rectus Abdominis

Exercises and Techniques for the Rectus Abdominis and Pyramidalis

Ball Crunch

Plank

Plank Progressions

Standing Static Chop

Dynamic Chop Pattern

Crunch and Catch

Reactive Activation for the Core (Modified Mountain Climber)

Step Up to Chest Press

Dynamic Lunge to Press

Push/Pull Core

Core Power

<ol>
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 <li>Tom Myers, Anatomy Trains: Second Edition. &copy; Elsevier Limited 2009</li>
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 <li>Cynthia C. Norkin, Pamela K. Levangie, Joint Structure and Function: A Comprehensive Analysis: Fifth Edition &copy; 2011 F.A. Davis Company</li>
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 <li>Eric Sternlicht and Stuart Rugg. Electromyographic Analysis of Abdominal Muscle Activity Using Portable Abdominal Exercise Devices and a Traditional Crunch. J. Strength Cond. Res. 17(3), 463-468. Copyright 2003 National Strength and Conditioning Association.</li>
 <li>William C. Whiting, Stuart Rugg, Andre Coleman, and William J. Vincent. Muscle Activity during Sit-ups Using Abdominal Exercise Devices. J. Strength Cond. Res. 13(4), 339-345. Copyright 1999 National Strength and Conditioning Association</li>
 <li>Lehman, G. J., &amp; McGill, S. M. (2001). Quantification of the differences in electromyographic activity magnitude between the upper and lower portions of the rectus abdominis muscle during selected trunk exercises. Physical Therapy, 81(5), 1096-1101.</li>
 <li>Marchetti, P. H., Kohn, A. F., &amp; Duarte, M. (2011). Selective activation of the rectus abdominis muscle during low-intensity and fatiguing tasks. Journal of sports science &amp; medicine, 10(2), 322.</li>
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</ol>

Bibliography

<html><head></head><body>© 2016 Brent Brookbush
Questions, comments, and criticisms are welcome and encouraged.</body></html>

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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