Core Subsystems

Posted: 19/11/2012 in English, Science and stuff

By Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS (web)

Deep Longitudinal Subsystem Integration

The Deep Longitudinal Subsystem (DLS) is comprised of:

  • Sacrotuberous Ligament
  • Biceps Femoris
  • Head of Fibula
  • Peroneus Longus
  • Tibialis Anterior

Function (Brief):

Stabilization of the SI joint and longitudinal arch of foot, eccentric deceleration of forward leg swing and heel strike, proprioceptive mechanism – especially in response to ground reaction forces.

Functional Arthrokinematics:

This subsystem plays a role in stabilization of the sacrum and optimal alignment of the sacroiliac joint.  The biceps femoris via fascial slips runs nearly continuous with the sacrotuberous ligament.  When the biceps femoris contracts this force is transmitted through the sacrotuberous ligament and aids in optimal stabilization of the  sacrum.  Commonly the biceps femoris (and the DLS) becomes synergistically dominant for an underactive glute complex leading to relative counter-nutation (tucking under) of the sacrum and anterior tilting of the ilium, contributing to SI joint dyskinesis.

Considering the knee – Although the biceps femoris may be thought of as a resistive force preventing an anterior glide of the femur and preventing ACL sprains, it can only act in this role if tonicity and length/tension are optimal.  However, this musculature is commonly overactive.  When overactive the muscle can contribute to knee dysfunction by creating an adduction and internal rotation moment of the femur.  It is probably easiest to visualize this action in closed-chain movement patterns (relative to a fixed tibia).  The biceps femoris is commonly thought of as a flexor and external rotator of the tibia on the knee.  However, external rotation of the tibia in relation to the femur is the same as femoral internal rotation.  The biceps femoris’ position on the lateral side of the knee also helps to contribute to an adduction moment of the knee; bringing the lateral aspect of the femur and the lateral aspect of the tibia closer together.  When the foot and tibia are fixed in a closed chain position an overactive biceps femoris (DLS) will actually cause the knee to “cave-in” by internally rotating the femur and “adducting” the knee. When visualizing this motion it may be helpful to imagine the short head of the biceps femoris as a “bow string” getting tighter and tighter, and the femur and tibia as the “bow” getting bent out of position.

Considering the ankle – This subsystem plays a significant role in maintaining the longitudinal arch of the foot and/or pronation and supination during gate in response to ground reaction forces.  Dysfunction of the DLS may result in over-pronation and excessive force placed on talometatarsal joints.  Further, inability to optimally dorsi-flex and/or early/over-pronation can result in an anterior glide of the talus.

Integrated Function:

Optimally, the Deep-Longitudinal Subsystem would eccentrically decelerate external load, stabilize the SI joint and longitudinal arch of the foot, and act as a proprioceptive mechanism for foot/ankle, knee, and LPHC position. For example, during gate the DLS would eccentrically decelerate forward leg swing, followed by stabilization of the SI joint, and act as a proprioceptive mechanism to relay information about ground reaction forces upon heel strike, ensuring optimal recruitment of prime movers during mid-stance and toe off.  Based on practice its function as a mechanism of proprioception takes priority.  The propensity of this subsystem to become overactive has a detrimental effect on performance and often leads to synergistic dominance of the biceps femoris and peroneals and dyskinesis of the ankle, knee, and SI joint dyskinesis.

Motor Behavior:

The Deep Longitudinal Subsystem (DLS) could be nicknamed the “Always Overactive Subsystem.”  This subsystem becomes reflexively hypertonic in response to SI joint and lumbar spine dyskinesis, and is commonly paired with under-activity of the Intrinsic Stabilization Subsystem and Posterior Oblique Subsystem, and over-activity of the Anterior Oblique Subsystem.

Generally speaking, this subsystem is not related to upper-body dysfunction; however,  when upper-body dysfunction results in dyskinesis of the SI joint this subsystem may become reflexively overactive.

In LPHC dysfunction the DLS is also overactive.  The DLS is compensating for an underactive posterior oblique subsystem (discussed under “Posterior Oblique Subsystem Integration), in essence the DLS is “synergistically dominant” for an inhibited POS.  Commonly, this causes or is exacerbated by lumbosacral dysfunction.

In lower-leg dysfunction the DLS is overactive.  Pronation, femoral adduction and internal rotation, and sacral counter-nutation may be viewed as both the concentric action of this subsystem and the “characterization” of a predictive model of lower-leg dysfunction.  The DLS may be the link between lower-leg dysfunction and the common occurrence of SI joint dyskenisis.

Exercise Selection:

If movement assessment leads us to believe that the Deep-Longitudinal Subsystem is over-active consider the following changes to your exercise programming.

Core:

No hamstring strengthening.

Flexibility:

Release:

  • Biceps Femoris
  • Peroneals
  • Piriformis (If SI joint Dyskinesis is suspected)

Stretch

  • Pigeon Toed Calve Stretch (Peroneals)
  • Active Biceps Femoris Stretch

Mobilization

  • Lying Active Trunk Rotation

Subsystem Integration/Whole Body Exercise Selection:

  • Integrate POS Subsystem

Resistance Training:

  • No Hamstring Curls
  • No Stiff-leg (locked-knee) Dead-lifts
  • No Kettle Bell Windmills

Anterior Oblique Subsystem Integration

The Anterior Oblique Subsystem (AOS) is comprised of:

  • External Obliques
  • Abdominal Fascia
  • Contralateral Anterior Adductors

Function (Brief):

Transfer force between lower and upper extremities, stabilization of the anterior kinetic chain, integrated pushing movements (legs w/ push), “turning in” of the kinetic chain, eccentric deceleration of total-body supination.

Functional Arthrokinematics:
The Anterior Oblique Subsystem (AOS) is an important stabilizer of the anterior kinetic chain.  This subsystem has little direct effect on joint arthrokinematics (when compared to the POS and the sacroiliac joint); however, it is indirectly involved in stabilization of the lumbar spine, pubic symphysis, and hip joint.

The AOS is responsible for eccentric deceleration of rotation and extension of the lumbar spine – a movement pattern that has been indicated in lumbar spine injury.  The AOS is also involved in preventing an anterior pelvic tilt, especially during “pushing motions” in a standing position.  An anterior pelvic tilt may be synonymous with lumbar spine extension and rotation, or may include dyskinesis between the ilium and sacrum resulting in SI joint dysfunction.

Asymmetrical dysfunction in the AOS may lead to dyskinesis of the lumbar and thoracic spine, SI joint, and pubic symphysis. This dysfunction may present as rotation and/or lateral flexion of the lumbar spine, a hip hike, anterior or posterior tilting of one or both sides of the pelvis, and dysfunction of the pubic symphysis.  Note that asymmetrical postural dysfunction like these has been correlated with injury.  At the very least, these dysfunctions will increase strain on the human movement system leading to pattern overload and the cumulative injury cycle.

Integrated Function:

These muscles play an important role in transferring force between lower and upper extremities and stabilizing the anterior kinetic chain.  The AOS is stressed most during pushing motions, and “turning-in” of the kinetic chain.  This musculature also functions as an eccentric decelerator of “total-body supination” (spinal extension and rotation, hip extension, abduction and external rotation).  The importance of decelerating total body supination can be seen during the “loading phase” of a throw or swing, or when an individual is hit from the front – for example, a football lineman being hit in the upper-body by an opponent.  Along with the optimal function of our ISS (Intrinsic Stabilization Subsystem) and POS (Posterior Oblique Subsystem) the AOS  ensures optimal stabilization, alignment and movement of the LPHC, and optimal arthrokinematics of our hip joint and lumbo-sacral joints.

Motor Behavior:

The AOS could be termed “the Jeckyl & Hyde”  of the core subsystems.  In upper-body dysfunction the AOS is over-active and in LPHC dysfunction the AOS is often underactive.

In upper-body dysfunction the AOS is overactive and is paired with under-activity of the POS.  This may be most obvious in those individuals who exhibit an excessive thoracic kyphosis (flexion of the thoracic and lumbar spine).  However, the factors contributing to the dominance of the AOS in upper-body dysfunction can be far more intricate and nuanced.  The increase in latissimus dorsi activity in upper-body dysfunction may lead to an alteration in the motor pattern used to stabilize the LPHC.  That is – synergistic dominance of the latissimus dorsi leads to inhibition of the ISS; either due to changes in arthrokinematics or the adoption of a compensatory pattern that results in a latent firing pattern of the ISS and eventual deconditioning.  In time, the lack of intrinsic stabilization creates a need for recruitment of the global musculature to stabilize the LPHC leading to over-activity of the AOS.  In this case it is likely best to avoid exercise that would increase AOS activity and strength.  Examples may include planks, crunches, chops, and standing push patterns.

The AOS is generally not involved in lower-leg dysfunction, however, some lower-leg dysfunction is paired with an excessive forward lean.  In this scenario the AOS is over-active.  Again, avoid exercise that could increase the strength and activity of this musculature.

In the most common LPHC dysfunction (Anterior Pelvic Tilt – APT) the AOS is under-active, and is paired with under-activity of the POS.  In this case the AOS is not capable of tilting the pelvis posteriorely or maintaining enough lumbar flexion to attain a neutral spine.  This is likely due to the powerful latissimus dorsi and psoas pulling the individual into lumbar extension, and synergistically dominant lumbar extensors inhibiting spinal flexors.  Utilizing a posterior pelvic tilt to reinforce optimal pelvic alignment and integrating the AOS (legs w/ push) is an effective means of improving this dysfunction.  Note: The use of an AOS integration exercise with an individual who has an APT will usually correct lumbo-pelvic hip alignment, but in some cases results in an excessive forward lean.  In this case it is appropriate to follow an AOS integration exercise with a POS integration exercise.

Exercise Selection: 

If movement assessment leads us to believe that the AOS is underactive (Anterior Pelvic Tilt) consider the following changes to your exercise programming.

Core:  It may be beneficial to add planks, crunches, and chop patterns to the core portion of the integrated warm-up.  Note: If the AOS is dominant omit crunches, planks, chops, and add bridges.

Subsystem Integration/Whole Body Exercise Selection: The exercises used to integrate the AOS can be summarized as “legs with push.”  Because of the inherent difficulty of these exercises it may be necessary use a static chop progression and standing chest press progression as prerequisites before starting the integrated exercise progression below.

Subsystem Integration/Whole Body Exercise Selection:

  • Standing Static Chop Pattern and Progressions
  • Standing Chest Press and Progressions
  • Legs w/ Push
  1. Step-Up to Chest Press
  2. Step-Up to Unilateral Chest Press
  3. Step-Up to Balance to Chest Press
  4. Step-Up to Balance to unilateral Chest Press
  5. Frontal Plane Step-Up to balance to Chest Press
  6. Frontal Plane Step-Up to balance to unilateral Chest Press
  7. Transverse Plane Step-Up to balance to Chest Press
  8. Transverse Plane Step-Up to balance to unilateral Chest Press
  9. Reverse Lunge to Chest Press
  10. Reverse Lunge to Contra-lateral Chest Press
  11. Transverse Plane Lunge to Contralateral Chest Press
  12. Reverse Lunge to Single Leg Balance to Chest Press
  13. Reverse Lunge to Single Leg Balance to Unilateral Chest Press
  14. Transverse Plane Lunge to Single Leg Balance to Contralateral Chest Press

Resistance Training:  There is no difference between the exercises selected forSubsystem Integration found on the “Integrated Warm-Up Template” and the Whole Body Movement used in the “Resistance Training Template.”  If someone presents with an under-active AOS it may be ideal to continue using “legs w/ push” movements during theWhole Body Movement.  If you choose to use the same exercise for both Subsystem Integration and Whole Body Movement, than the last exercise of your integrated warm-up is also the first exercise of your resistance training program; there is no need to repeat sets.  If someone has “cleaned-up” the majority of their dysfunction you can add other whole body movement patterns to their resistance training routine that may or may not relate to their movement dysfunction.

Progress chest and back movements to exercises without a stable back support.  For example, dumbbell press on a stability ball, or standing rows.  It may also be wise to limit overhead pressing for shoulder movements until better LPHC stabilization is attained.

We could say that once you have completed an integrated warm-up; your knowledge of subsystems and movement assessment will influence, but not dictate, your resistance training exercise selection.

Lateral Subsystem (LS)

The Lateral Subsystem (LS) is comprised:

  • Gluteus Medius
  • Adductors
  • Contralateral Quadratus Lumborum

Function (Brief):

Frontal plane stabilization of the LPHC, transfer of force between lower and upper extremities, active role in all integrated (whole body) frontal plane and single-leg movement patterns

Functional Arthrokinematics:

This subsystem plays a key role in the optimal alignment of the hip joint and lumbar spine.  Dysfunction of this subsystem often leads to synergistic dominance of the QL, and will inevitably lead to lumbar spine dyskinesis.  The propensity of the QL to become over-active seems to be reinforced by a relationship that results in reflexive hypertonicity of the QL when the SI joint becomes “fixed” or shifted.  In this way the deep longitudinal subsystem may also become dysfunctional as a victim of dysfunction in the posterior oblique subsystem and/or deep longitudinal subsystem.

Considering the hip, dysfunction of the lateral subsystem usually results in under-activity of the gluteus medius and over-activity of the adductors.  This may result in a hip-drop (positive Trendelenburg’s sign), hip hike, knees bow in (anterior adductor dominance), or knees bow out (posterior adductor magnus dominance) during movement.  In time this leads to adaptive shortening of the posterior and inferior capsule, a superior and anterior shift of the femoral head, and hip dyskinesis.  The most common pathologies include hip-impingement syndrome, groin strains, and over a lifetime – osteoarthritis.

Integrated Function

Although we may be tempted to consider kinetic chain (total body) side-bending and lateral movement the primary function of the lateral subsystem; it serves a more important role in human movement.  Side-bending and lateral movement simply do not make-up a large enough portion of our daily activity to be considered a primary concern for most individuals.  However, the Lateral Subsystems functions as the primary subsystem for frontal plane stabilization of the LPHC.  All single-leg activity through the sagittal plane and the transverse plane will create a need for frontal plane stability of the LPHC.  When the lateral subsystem (LS) is dysfunctional we may notice hip drop (positive Trendelenburg’s sign), a hip hike, the knees bowing outward, or caving inward during static and dynamic postures.  It’s role as a stabilizer to maintain optimal alignment and posture ensures optimal length tension relationships, neuromuscular efficiency, and proper arthrokinematics.  The integrated function of this subsystem could be summarized as – “keeping the spine straight, the pelvis level, and the femur aligned.”

 Motor Behavior

The lateral subsystem could be nicknamed “The Victim System.”  The LS often becomes dysfunctional as a result of dysfunction in other core subsystems and dyskinesis of  the lumbar spine, sacroiliac joint or hip.  It is often paired with Posterior Oblique Subsystem under-activity and over-activity of the Deep Longitudinal Subsystem.

In Upper Body Dysfunction the LS rarely plays a role; however, there are a couple scenarios in which this subsystem may be affected.  In some cases of upper body dysfunction, the under-activity of the Intrinsic Stabilization Subsystem leads to over-activity of our global trunk musculature.  This would include the latissimus dorsi, the Anterior Oblique Subsystem and the LS .  The adductors being part of both the LS and the anterior oblique subsystem, along with the “tonic quadratus lumborum” (propensity to become over-active) make this an issue for individuals with a long history of upper-body dysfunction.

The second scenario of LS involvement in upper-body dysfunction involves upper-body asymmetry.  If one side of the upper body is more affected than the other, leading to latissimus dorsi tightness on one side, SI joint dysfunction, and right to left asymmetry of the lumbosacral complex (ex. hip hike) the lateral subsystem will also develop  asymmetrical dysfunction from left to right.

In LPHC dysfunction the lateral subsystem may become underactive as under-activity of the Posterior Oblique Subsystem and over-activity of the Deep Longitudinal Subsystem leads to dyskinesis of the lumbosacral complex.

In lower-leg dysfunction the lateral subsystem is commonly under-active.  This is due in large part to the relative external rotation of the tibia and internal rotation of the femur leading to frontal plane instability in the lower-body.  It should be noted that relationship between subsystems described in the paragraph above is commonly noted in lower-leg dysfunction as well.  Subsystem Integration during lower-leg dysfunction is the most common use for exercises that stress this subsystem.

Exercise Selection:

If movement assessment leads us to believe that the LS is underactive consider the following changes to your exercise programming.

Core: Use the side plank progression as part of your routine.  Limit side-bending, as the QL tends to become overactive.

Subsystem Integration/Whole Body Exercise Selection: The exercises used to integrate the LS can be summarized as “Single Leg w/ Shoulder Series – Frontal Plane Preferred”

LS Integration Progression

  1. Side-Step to Balance to Curl
  2. Side-Step to Balance to Scaption
  3. Side-Step to Balance to Curl & Press
  4. Side-Step to Balance to Contralateral Curl
  5. Side-Step to Balance to Contralateral Scaption
  6. Side-Step to Balance to Contralateral Curl & Press
  7. Step-Up to Balance to Curl
  8. Step-Up to Balance to Scaption
  9. Step-Up to Balance to Curl & Press
  10. Step-Up to Balance to Contralateral Curl
  11. Step-Up to Balance to Contralateral Scaption
  12. Step-Up to Balance to Contralateral Curl & Press
  13. Frontal Plane Step-Up to Balance to Curl
  14. Fontal Plane Step-Up to Balance to Scaption
  15. Frontal Plane Step-Up to Balance to Curl & Press
  16. Frontal Plane Step-Up to Balance to Contralateral Curl
  17. Fontal Plane Step-Up to Balance to Contralateral Scaption
  18. Frontal Plane Step-Up to Balance to Contralateral Curl & Press
  19. Single Leg Dead-lift Touchdown to Balance to Curl
  20. Single Leg Dead-lift Touchdown to Balance to Scaption
  21. Single Leg Dead-lift Touchdown to Balance to Curl & Press
  22. Single Leg Dead-lift Touchdown to Balance to Contralateral Curl
  23. Single Leg Dead-lift Touchdown to Balance to Contralateral Scaption
  24. Single Leg Dead-lift Touchdown to Balance to Contralateral Curl & Press
  25. Reverse Lunge to Balance to Curl
  26. Reverse Lunge to Balance to Scaption
  27. Reverse Lunge to Balance to Curl & Press
  28. Reverse Lunge to Balance to Contralateral Curl
  29. Reverse Lunge to Balance to Contralateral Scaption
  30. Reverse Lunge to Balance to Contralateral Curl & Press
  31. Frontal Plane Reverse Lunge to Balance to Curl
  32. Fontal Plane Reverse Lunge to Balance to Scaption
  33. Frontal Plane Reverse Lunge to Balance to Curl & Press
  34. Frontal Plane Reverse Lunge to Balance to Contralateral Curl
  35. Fontal Plane Reverse Lunge to Balance to Contralateral Scaption
  36. Frontal Plane Reverse Lunge to Balance to Contralateral Curl & Press

Resistance Training:  There is no difference between the exercises selected forSubsystem Integration found on the “Integrated Warm-Up Template” and the Whole Body Movement used in the “Resistance Training Template.”  If someone presents with an under-active LS it may be ideal to continue with “Single Leg w/ Shoulder Series – Frontal Plane Preferred”  movements for the Whole Body Movement.  It may also be beneficial to integrate as much unilateral and single leg activity as the individual’s ability will allow.

If you choose to use the same exercise both Subsystem Integration and Whole Body Movement, than the last exercise of your integrated warm-up is also the first exercise of your resistance training program; there is no need to repeat sets.

If someone has “cleaned-up” the majority of their dysfunction you can add other whole body movement patterns to their resistance training routine that may or may not relate to their movement dysfunction.  We could say that once you have completed an integrated warm-up; your knowledge of subsystems and movement assessment will influence, but not dictate, your resistance training exercise selection.

Posterior Oblique Subsystem (POS)

The Posterior Oblique Subsystem (POS) is comprised of:

  • Latissimus Dorsi
  • Thoracolumbar Fascia
  • Contralateral Gluteus Maximus

Function (Brief):

Stabilization of the posterior kinetic chain, transfer force between lower and upper extremities, integrated (whole body) pulling movements, “turning out” of the kinetic chain, eccentric deceleration of total-body pronation.

Functional Arthrokinematics:

This subsystem is an important stabilizer of the posterior kinetic chain.  The fiber arrangement of this subsystem implies a special role in sacroiliac arthrokinematics, and lumbo-sacral function.  The fibers of each side run perpendicular to the SI joint; crossing from the gluteus maximus and associated fascia through the nearly continuous thoracolumbar fascia, across the lumbar spine, to the latissimus dorsi and associated fascia on the opposite side. During the forward leg and opposite arm swing of normal gait, this system is pulled taut via eccentric contraction of the POS.  Concurrently, the opposite side POS pulls the thoracolumbar fascia taut during the concentric contraction necessary for push off.  This phenomenon ensures stability during movement, especially cross body movement patterns.  Its role in stabilization of the SI joint and lumbo-sacral joint complex, combined with the discussion of motor behavior below, may give a clue as to why pain and dysfunction are so common in this “structurally” stable joint.

Integrated Function:

The muscles involved in this subsystem are the largest in the body.  These muscles play important roles in transferring force between lower and upper extremities, and are involved in all pulling and rotational movement patterns.  However, this musculature also has an incredibly important eccentric function as a decelerator of “total body pronation” (spinal flexion and rotation, hip flexion, adduction and internal rotation).  Every time we land from a jump, get pushed in the pack, step off a curb, or bend over to pick something-up – it is this subsystem, along with the optimal function of our ISS (Intrinsic Stabilization Subsystem) that ensures optimal stability of our LPHC, and arthrokinematics of our SI joint and lumbo-sacral joints.

Motor Behavior:

The POS could be termed “the almost always under-active subsystem”  in both upper-body dysfunction, and lower-leg dysfunction this system is underactive.  It is also under-active in many individuals with an anterior pelvic tilt.  Commonly, the under-activity of the POS is paired with dominance of the AOS (anterior oblique subsystem). This may be illustrated by an excessive kyphosis, spinal flexion, or an excessive forward lead during an overhead squat assessment.  Dominance of the AOS and under-activity of the POS is generally most dramatic in those individuals exhibiting upper-body dysfunction.

In lower-leg dysfunction the under-activity of the POS is paired with under-activity of the lateral subsystem, stemming in large part from an inhibited glute complex. This may be combined with AOS dominance resulting in an excessive forward lean during an overhead squat.

In those individuals who exhibit an anterior pelvic tilt there is under-activity of both the POS and the AOS.  I have had the most success using AOS integration exercises with an APT, however, it is not uncommon for AOS integration to correct lumbo-pelvic hip alignment, only to result in an excessive forward lean. In this case it is appropriate to follow an AOS integration exercise with a POS integration exercise.

It would seem, the only individuals who exhibit over-activity in the POS are those who exhibit a posterior pelvic tilt and  those who exhibit an inadequate forward lead.  Although these dysfunction are relatively rare, it may be seen in individuals with a history of low back pain, injury, or surgery.

Exercise Selection:

If movement assessment leads us to believe that the POS is underactive consider the following changes to your exercise programming.

Core: Use the bridge progression as part of your routine to strengthen the gluteus maximus. If the AOS is also dominant it may be beneficial to limit or omit crunches, planks and chops.

Subsystem Integration/Whole Body Exercise Selection: The exercises used to integrate the POS can be summarized as “legs with pull.”

POS Integration Progression

  1. Ball Wall Squat
  2. Squat to Row
  3. Squat to Unilateral Row
  4. Squat Unstable to Row
  5. Squat Unstable to Unilateral Row
  6. Static Lunge to Row
  7. Static Lunge to Unilateral Row
  8. Static Lunge Unstable (Front Foot) to Bilateral Row
  9. Static Lunge Unstable (Front Foot) to Unilateral Row
  10. Reverse Lunge to Row
  11. Reverse Lunge to Unilateral Row
  12. Reverse Lunge Unstable (Front Foot) to Bilateral Row
  13. Reverse Lunge Unstable (Front Foot) to Unilateral Row
  14. Single Leg Squat to Bilateral Cable Pull Down
  15. Single Leg Squat to Alternating Cable Pull Down
  16. Single Leg Squat Unstable to Bilateral Cable Pull Down
  17. Single Leg Squat Unstable to Alternating Cable Pull Down

Resistance Training:  There is no difference between the exercises selected forSubsystem Integration found on the “Integrated Warm-Up Template” and the Whole Body Movement used in the “Resistance Training Template.”  If someone presents with an under-active POS it may be ideal to continue with “legs w/ pull” movements for the Whole Body Movement, select back exercises without a chest support, and due to the potential for AOS dominance choose chest movements with a back support (ex. Dumbbell press on a stability ball).

If you choose to use the same exercise both Subsystem Integration and Whole Body Movement, than the last exercise of your integrated warm-up is also the first exerscise of your resistance training program; there is no need to repeat sets.

If someone has “cleaned-up” the majority of their dysfunction you can add other whole body movement patterns to their resistance training routine that may or may not relate to their movement dysfunction.  We could say that once you have completed an integrated warm-up; your knowledge of subsystems and movement assessment will influence, but not dictate, your resistance training exercise selection.

Intrinsic Stabilization Subsystem (ISS)

The Intrinsic Stabilization Subsystem (ISS) is comprised of:

Transverse abdominis

  • Diaphragm
  • Pelvic floor
  • Intrinsic muscles of the spine (multifidi, rotatores, semispinalis, intertransversarii, and interspinales)

Function (Brief):

This system increases intra-abdominal pressure and is responsible for segmental stabilization of the lumbar spine.

Functional Arthrokinematics:                      

Due to the lordotic curve and shape of the lumbar vertebrae in a normal healthy spine – compression and extension forces will include a vector that results in anterior translation (anterior shear force) of the lumbar vertebrae.  The lumbar extensors, latissimus dorsi, quadratus lumborum, and Iliopsoas are important movers and stabilizers of the core, but as extensors, compressors, and the psoas creating an anterior shear force – these muscles contribute to this tendency.  When functioning optimally the ISS increases pressure in the peritoneum (similar to squeezing a balloon) creating a posterior force against the anterior surface of the lumbar spine. In addition to this increased intra-abdominal pressure, the TVA contributes to rigidity of the thoracolumbar fascia and provides lateral stability, while the intrinsic muscles of the spine relay proprioceptive information back to the CNS and maintain micro-alignment of the lumbar vertebrae and disks.  If the ISS is not functionally optimally to mitigate the anterior translatory  force, than the forces created during movement may result in anterior subluxation, excessive force to passive structures, pain, dysfunction, and injury (sprains, strains, bulging disks, herniated disks, capsular damage, nerve impingement, arthritic changes, etc.).

Integrated Function:

The optimal function of this subsystem results in a stable lumbar spine and an LPHC capable of efficiently transferring force between lower and upper extremities.  It is important to note that this system, by itself, is not responsible for any movement.  The activation of the ISS will result in the drawing-in maneuver (belly button to spine) and increased stability of the LPHC, but no visible joint action.  Optimal recruitment of this subsystem is essential to the performance of all other core sub-systems.

Behavior:

Most postural dysfunctions lead to under-activity and/or inhibition of the ISS. This includes all 3 major postural dysfunctions (Upper-body, LPHC, and Lower-Leg).  The typically overactive synergists of the ISS are the latissimus dorsi and psoas.  Often inhibition of the ISS is concurrent with dominance of the AOS and global musculature of the lumbar spine.  This is most commonly noted in an individuals who exhibit upper-body dysfunction.  Addressing this issue will be discussed further in “Anterior Oblique Subsystem Integration”.

Exercise Selection:

Unlike other subsystems we will discuss, the “behavior” of this subsystem does not limit the optimal selection of core exercise, it does not influence the selection of exercise for subsystem integration or total-body exercise, and our understanding of the ISS will not help us write a more balanced program.  This subsystem is actually the musculature activated when we challenge the TVA –  discussed in Isolated Activation, under “TVA Activation.”  TVA activation could also be done as the first exercise of “Core Support” without negatively impacting the order of exercise.

Special Note:

The inability of a client to maintain activation of the ISS (drawing-in) during any exercise is a commonly used indicator that an exercise should be regressed.  Cueing the drawing-in maneuver during all exercises is an effective way of maintaining ISS strength once the majority of postural dysfunction has been “cleaned up”, and a client successfully completes a TVA activation progression.

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Comments
  1. epicathlete says:

    Do you know where one can find videos to the core subsystem exercise progressions?
    Thanks.

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