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Deep longitudinal subsystem (DLS). The role and function of the fibularis (peroneal) muscles, erector spinae, sacrotuberous ligament, and biceps femoris in the stability, strength, and power produced between the lower and upper body. Summary of the function, arthrokinematics, integration between individual subsystems, behavior in postural dysfunction, exercise selection for the DLS, and examples of subsystem exercises and progressions.

This course describes the deep longitudinal subsystem (DLS). The deep longitudinal subsystem may also be referred to as the deep longitudinal sling, deep longitudinal system, deep posterior subsystem, deep posterior sling, deep posterior myofascial synergy, and is similar to the concepts of body slings, muscle synergies, myofascial lines, myofascial trains, anatomy trains, superficial back line, spiral line, and the serape effect. This course covers a detailed analysis of the posterior oblique subsystem (sling) including anatomy, research, integration techniques and a sample routine.

The Deep Longitudinal Subsystem (DLS) is comprised of:

Thoracolumbar Fascia (Deep Posterior layer)

Obturator internus (and deep hip external rotators)

The concepts and techniques described in this course may be particularly beneficial for neuromuscular re-education, coordination, motor pattern integration, whole-body strength, functional strength, and sports performance. Sports medicine professionals (personal trainers, fitness instructors, physical therapists, massage therapists, chiropractors, occupational therapists, athletic trainers, etc.) should consider adding these exercises to their repertoire to improve the outcomes of their integrated exercise programs, sports performance programs, and therapeutic (rehabilitation) interventions.

For additional self-administered joint mobilization techniques check out:

Course Description: Deep Longitudinal Subsystem

Deep Longitudinal Subsystem Study Guide

Study Guide: Deep Longitudinal Subsystem 

Introduction

Quick Study Guide: Deep Longitudinal Subsystem (DLS)

The DLS is comprised of muscles with a propensity to act synergistically; rarely do these muscles act as prime movers. This subsystem plays an important role in the motion of the 

, sacroiliac joints, and spine, and may aid in proprioception by altering recruitment strategies based on the load and stretch imparted on the system during heel strike. The DLS is active during gait, forward bending (more so when knees are near full extension), and lumbar extension, and eccentrically decelerates spine flexion,

 inversion. Over-activity of the DLS is often accompanied by relative inhibition of the

Picture of the muscles in the deep longitudinal subsystem

Assists with propulsion from heel strike to push-off during gait, assists with lifting from a forward bent position, and is the prime mover of lumbar hyper-extension.

Contributes to stabilization of the tibiofibular joints, hip joints, sacroiliac joints, and all segments of the spine.

 Decelerates leg swing and impact during heel strike, eccentrically decelerates forward bending, and eccentrically decelerates ankle inversion.

Dr. Brent Brookbush demonstrating feet turn out during the overhead squat assessment

Signs of DLS Dysfunction 

Sample Routine

The communicating fascial structures of the DLS are the deep laminae of the posterior layer (DL) of the thoracolumbar fascia (TLF), the sacrotuberous ligament, and the fascial continuity between the biceps femoris and fibularis muscles at the fibular head.

Deep Laminae of the Posterior Layer (DL) of the Thoracolumbar Fascia (TLF):

Layers of the thoracolumbar fascia with supporting muscles including the latissimus dorsi, erector spinae, psoas, and iliacus

Sacrotuberous Ligament

The location of the sacrotuberous ligament on the pelvis

Erector Spinae

Biceps Femoris, Piriformis, Deep Rotators, and Adductor Magnus

Image of the piriformis muscle (but also note the bicep femoris and posterior fibers of adductor magnus)

Fibularis (Peroneal) Muscles

Rhomboids

The location and attachment of the rhomboid muscles on the scapula and thoracic spine

Splenius Capitis and Splenius Cervicis (Splenii)

The cervical muscles including the splenius, trapezius, and levator scapulae

Summary of Research Findings

A runner with a potential of having an overactive deep longitudinal subsystem

Research Corner

More on Function

The Deep Longitudinal Subsystem (DLS) eccentrically decelerates leg swing during gait, and may act as a proprioceptive mechanism to rate heel strike force, and reflexively aid in the recruitment of propulsion muscles. During the swing phase of gait (hip flexion/knee extension), tension and activity increase in the lower extremity muscles of the DLS, peaking during heel strike and the initiation of propulsion (97 - 101). Research has also demonstrated that the stretch-shortening cycle (muscle spindle excitation) and afferentation (sural nerve, bottom of foot) at the end of the swing phase alters recruitment of the 

 (102-103). Due to a "law of parsimony" hierarchy in the body, lower-level activities often rely on smaller synergists for motion, and larger prime movers are not recruited unless motion is resisted by an external force. In this way, the muscle spindle excitation and additional afferentation from structures of the DLS during heel strike may be the difference between relying only on the DLS, or additionally recruiting larger muscles from the 

 during tasks like walking uphill or stair-climbing (101 - 104).

Sacroiliac Joint (SIJ) Stability during Functional Tasks

As mentioned above, increased activity of the DLS muscles increases tension in the sacrotuberous ligament, which may resist nutation, contribute to 

, and increase stiffness of the sacroiliac joint (SIJ) (16, 17, 19, 20, 105). This may have important implications relative to SIJ stabilization for gait and other high-intensity activities. For example, as the innominate posteriorly rotates on the sacrum (nutation) during the swing phase of gate, tension develops in the lower extremity DLS muscles increasing tension in the sacrotuberous ligament. The tension may aid in eccentrically decelerating nutation and is highest around heel strike (97 - 101) when increased rigidity of the SIJ and pelvis would be most beneficial for transferring force from hip muscles to the lower extremity for the initiation of propulsion. This same mechanism would be beneficial for higher intensity tasks such as stair-climbing, sprinting,

 when stability of the pelvis and SIJ may be essential for optimal performance and reducing the risk of

 Lumbo Pelvic Hip Complex Dysfunction (LPHCD)

As mentioned above, many of the muscles of the DLS are synergists, acting to assist larger prime-movers. This is especially true of the extension mechanism that is essential for gait and lifting. Several studies have demonstrated a correlation between dysfunction, a reduction in relative 

 activity (106 - 112). Visually, this may present as an increase in the lumbar lordosis during gait, and/or a reliance on lumbar flexion and extension (as opposed to 

 flexion and extension) during bent-over lifting. Although it may be important to have an alternative movement pattern or set of motor units to maintain function during fatigued or dysfunctional states, research and practice imply that that dominance of one system results in a decrease in the activity of the other. That is, targeting the muscles of the DLS with strengthening techniques is likely to increase reliance on the DLS, and reduce reliance on the larger more powerful muscles of the

Clinically it has been noted that lifting nearer to full 

, resisted adduction during squatting, stepping, and gait increases reliance on 

, and targeted interventions for any muscle of the DLS prior to functional tasks will increase the targeted muscles activity. To increase reliance on the

, research suggests the following cues may be beneficial (113 - 117):

Cue the abdominal drawing-in maneuver (ADIM)

Cue posterior tilting (to neutral, do not lift with a posterior pelvic tilt)

Band resisted hip abduction during bridging, squatting, deadlifting, etc.

The DLS is prone to over-activity, specifically becoming synergistically dominant for an inhibited

. Perhaps more than any other subsystem, all of the muscles in this subsystem exhibit the same compensatory behavior (over-activity), many of them also exhibiting a relative increase in length during postural assessments. In the Brookbush Institute's predictive models of

, Sacroiliac Joint Dysfunction (SIJD), and

 this sub-system is categorized as long/over-active (playing no significant role in 

. The most common scenario may be described as inhibition of the

 Intrinsic Stabilization Subsystem (ISS) 

followed by dominance and over-activity of the

, leading to altered reciprocal inhibition and under-activity of the

, and compensatory synergistic dominance and over-activity of the DLS. Evidence of DLS dominance during an

. Dominance of the DLS (and under-activity of the

) is generally most dramatic in those individuals exhibiting

Overhead squat assessment with modification

Practical Application

Signs of Deep Longitudinal Dysfunction

Best-use and Progressions 

Compensation and Models of Postural Dysfunction:

Biceps Femoris (Self-Administered) Static Release

Biceps Femoris (Self-administered) Dynamic Release Technique

Biceps Femoris Vibration Release

Biceps Femoris Manual Static Release

Videos

Willard, F.H., Vleeming, A., Schuenke, M.D., Danneels, L., Schleip, R. The thoracolumbar fascia: anatomy, function and clinical considerations. Journal of Anatomy, 2012. 221, 507-536.

Barker, P. J., & Briggs, C. A. (2007). Anatomy and biomechanics of the lumbar fasciae: implications for lumbopelvic control and clinical practice. In

 Movement, Stability & Lumbopelvic Pain (Second Edition)

Gracovetsky, S. (1990). Musculoskeletal function of the spine.

 Multiple Muscle Systems: Biomechanics and Movement Organization

Fan, C., Fede, C., Gaudreault, N., Porzionato, A., Macchi, V., De Caro, R., & Stecco, C. (2018). Anatomical and functional relationships between the external abdominal oblique muscle and the posterior layer of the thoracolumbar fascia.

Schuenke, M. D., Vleeming, A., Van Hoof, T., & Willard, F. H. (2012). A description of the lumbar interfascial triangle and its relation with the lateral raphe: anatomical constituents of load transfer through the lateral margin of the thoracolumbar fascia.

Vleeming, A., Volkers, A. C. W., Snijders, C. J., & Stoeckart, R. (1990). Relation Between Form and Function in the Sacroiliac Joint: Part II: Biomechanical Aspects.

Kim, T., Yoo, W., An, D., Oh, J., Shin, S. (2013). The effects of different gait speeds and lower arm weight on the activities of the latissimus dorsi, gluteus medius, and gluteus maximus.

Stevens, V.K., Vleeming, A., Bouche, KG., Mahieu, N.N., Vanderstraeten, G.G., Danneels, L.A. Electromyograhpic activity of trunk and hip muscles during stabilization exercises in four-point kneeling in healthy volunteers. European Spine Journal, 2007. 16: 711-718.

Hukins, D. W. L., Aspden, R. M., & Hickey, D. S. (1990). Thorecolumlbar fascia can increase the efficiency of the erector spinae muscles.

Langevin, H., Fox, R., Koptiuch, C., Badger, G., Greenan-Nauman, A., Bouffard, N., Konofagou, E., Lee, W., Triano, J., Henry, S. (2011) Reduced thoracolumbar fascia shear strain in human low back pain. BMC Musculoskeletal Disorders. 12: 203.

De Coninck, K., Hambly, K., Dickinson, J. W., & Passfield, L. (2017). Measuring the morphological characteristics of ultrasound images of thoracolumbar fascia: an inter-rater reliability study.

Wong, K. K., Chai, H. M., Chen, Y. J., Wang, C. L., Shau, Y. W., & Wang, S. F. (2017). Mechanical deformation of posterior thoracolumbar fascia after myofascial release in healthy men: A study of dynamic ultrasound imaging.

Griefahn, A., Oehlmann, J., Zalpour, C., & von Piekartz, H. (2017). Do exercises with the Foam Roller have a short-term impact on the thoracolumbar fascia?–A randomized controlled trial.

 Journal of bodywork and movement therapies

Blain, M., Dinova, D., Bellin, M. F., Rocher, L., Gagey, O., Soubeyrand, M., & Creze, M. (2018). Influence of posterior thoracolumbar fascia stretching on lumbar back muscle stiffness: a supersonic shear wave elastography approach.

Vleeming, A., van Wingerden, J.P., Buyruk, H.M., Raissadat, K. Stabilization of the sacroiliac joint in vivo: verification of muscular contribution to force closure of the pelvis. European Spine Journal, 2004. 13: 199-205

Wingerden, J. V., Vleeming, A., Snijders, C. J., & Stoeckart, R. (1993). A functional-anatomical approach to the spine-pelvis mechanism: interaction between the biceps femoris muscle and the sacrotuberous ligament.

Woodley, S. J., Kennedy, E., & Mercer, S. R. (2005). Anatomy in practice: the sacrotuberous ligament.

Vleeming, A., Stoeckart, R., & Snijders, C. J. (1989). The sacrotuberous ligament: a conceptual approach to its dynamic role in stabilizing the sacroiliac joint.

Vleeming, A., Van Wingerden, J. P., Snijders, C. J., Stoeckart, R., & Stijnen, T. (1989). Load application to the sacrotuberous ligament; influences on sacroiliac joint mechanics.

Bogduk, N., Macintosh, J. E., & Pearcy, M. J. (1992). A universal model of the lumbar back muscles in the upright position.

Granata, K. P., & Marras, W. S. (1995). Coactivity on Dynamic Spinal Loads.

Crisco Iii, J. J., & Panjabi, M. M. (1991). The intersegmental and multisegmental muscles of the lumbar spine: a biomechanical model comparing lateral stabilizing potential.

Andersson, E. A., Grundström, H., & Thorstensson, A. (2002). Diverging intramuscular activity patterns in back and abdominal muscles during trunk rotation.

McGill, S. M., Hughson, R. L., & Parks, K. (2000). Changes in lumbar lordosis modify the role of the extensor muscles. Clinical Biomechanics, 15(10), 777-780.

Boyd-Clark, L. C., Briggs, C. A., & Galea, M. P. (2002). Muscle spindle distribution, morphology, and density in longus colli and multifidus muscles of the cervical spine.

Amonoo-Kuofi, H. S. (1983). The density of muscle spindles in the medial , intermediate and lateral columns of human intrinsic postvertebral muscles.

Danneels, L. A., Vanderstraeten, G. G., Cambier, D. C., Witvrouw, E. E., Stevens, V. K., & De Cuyper, H. J. (2001). A functional subdivision of hip, abdominal, and back muscles during asymmetric lifting.

Dofferhof, A. S., & Vink, P. (1985). The stabilising function of the mm. iliocostales and the mm. multifidi during walking.

Cassisi, J. E., Robinson, M. E., O’conner, P., & MacMillan, M. (1993). Trunk strength and lumbar paraspinal muscle activity during isometric exercise in chronic low-back pain patients and controls.

Nicolaisen, T., & Jørgensen, K. (1985). Trunk strength, back muscle endurance and low-back trouble.

 Scandinavian Journal of Rehabilitation Medicine

Jorgensen, K., & Nicolaisen, T. O. M. (1987). Trunk extensor endurance: determination and relation to low-back trouble.

Paquet, N., Malouin, F., & Richards, C. L. (1994). Hip-spine movement interaction and muscle activation patterns during sagittal trunk movements in low back pain patients. Spine, 19(5), 596-603.

Sihvonen, T., Partanen, J., Hänninen, O., & Soimakallio, S. (1991). Electric behavior of low back muscles during lumbar pelvic rhythm in low back pain patients and healthy controls.

 Archives of physical medicine and rehabilitation

Kuriyama, N., & Ito, H. (2005). Electromyographic functional analysis of the lumbar spinal muscles with low back pain.

Nouwen, A., Van Akkerveeken, P. F., & Versloot, J. M. (1987). Patterns of muscular activity during movement in patients with chronic low-back pain.

Soderberg, G. L., & Barr, J. O. (1983). Muscular function in chronic low-back dysfunction.

Radebold, A., Cholewicki, J., Panjabi, M. M., & Patel, T. C. (2000). Muscle response pattern to sudden trunk loading in healthy individuals and in patients with chronic low back pain.

David G. Simons, Janet Travell, Lois S. Simons,

 Travell & Simmons’ Myofascial Pain and Dysfunction, The Trigger Point Manual, Volume 1. Upper Half of Body: Second Edition

Janda, V. (1986). Muscle weakness and inhibition (pseudoparesis) in back pain syndromes.

 Modern manual therapy of the vertebral column

Renkawitz, T., Boluki, D., & Grifka, J. (2006). The association of low back pain, neuromuscular imbalance, and trunk extension strength in athletes.

Biceps Femoris, Adductors, Piriformis and Deep Rotators

Nourbakhsh, M. R., & Arab, A. M. (2002). Relationship between mechanical factors and incidence of low back pain.

 Journal of Orthopaedic & Sports Physical Therapy

Cooper, R. G., Forbes, W. S. C., & Jayson, M. I. V. (1992). Radiographic demonstration of paraspinal muscle wasting in patients with chronic low back pain. Rheumatology, 31(6), 389-394.

Lee, J. H., Hoshino, Y., Nakamura, K., Kariya, Y., Saita, K., & Ito, K. (1999). Trunk Muscle Weakness as a Risk Factor for Low Back Pain: A 5‐Year Prospective Study .

Mauntel, T., Begalle, R., Cram, T., Frank, B., Hirth, C., Blackburn, T., & Padua, D. (2013). The effects of lower extremity muscle activation and passive range of motion on single leg squat performance.

 Journal Of Strength And Conditioning Research / National Strength & Conditioning Association

Tateuchi, H., Taniguchi, M., Mori, N., Ichihashi, N. Balance of hip and trunk muscle activity is associated with increased anterior pelvic tilt during prone hip extension (2013)

 Journal of Electromyography and Kinesiology

Hungerford, B., Gilleard, W., Hodges, P. (2003) Evidence of altered lumbopelvic muscle recruitment in the presence of sacroiliac joint pain. Spine 28(14), 1593-1600

Jung, H., Kang, S., Park, J., Cynn, H., & Jeon, H., (2015). EMG activity and force during prone hip extension in individuals with lumbar segmental instability.

Hasegawa, K. T., Hori, S., Tsujita, J., & Dawson, M. L. (2001). Effects of Stretching Exercises on Vastus Medialis and Vastus Lateralis. Medicine & Science in Sports & Exercise, 33(5), S10.

Sullivan, K.M., Silvey, D.B.J., Button, D.C., Behm, D.G. (2013). Roller-massager application to the hamstrings increases sit-and-reach range of motion within five to ten seconds without performance impairments.

 International Journal of Sports Physical Therapy

Giphart, J. E., Stull, J. D., LaPrade, R. F., Wahoff, M. S., & Philippon, M. J. (2012). Recruitment and activity of the pectineus and piriformis muscles during hip rehabilitation exercises: an electromyography study.

Snijders, C. J., Hermans, P. F., & Kleinrensink, G. J. (2006). Functional aspects of cross-legged sitting with special attention to piriformis muscles and sacroiliac joints.

Grimaldi, A., Richardson, C., Stanton, W., Durbridge, G., Donnelly, W., & Hides, J. (2009). The association between degenerative hip joint pathology and size of the gluteus medius, gluteus minimus and piriformis muscles.

Baker, B. A. (1986). The muscle trigger: evidence of overload injury.

Basmajian, J. V., & De Luca, C. J. (1985).

 Muscles alive: their functions revealed by electromyography

Green, D. L., & Morris, J. M. (1970). Role of adductor longus and adductor magnus in postural movements and in ambulation.

 American Journal of Physical Medicine & Rehabilitation

Klein, P., Mattys, S., & Rooze, M. (1996). Moment arm length variations of selected muscles acting on talocrural and subtalar joints during movement: An in vitro study.

Basmajian JV, Stecko G. The role of muscles in arch support of the foot. J Bone Joint Surg 1963;45A: 1184-90

Kim, K. M., Ingersoll, C. D., & Hertel, J. (2012). Altered postural modulation of Hoffmann reflex in the soleus and fibularis longus associated with chronic ankle instability.

 Journal of Electromyography and Kinesiology 

Pietrosimone, B. G., & Gribble, P. A. (2012). Chronic ankle instability and corticomotor excitability of the fibularis longus muscle.

Palmieri-Smith, R. M., Ty Hopkins, J., & Brown, T. N. (2009). Peroneal activation deficits in persons with functional ankle instability.

 The American journal of sports medicine 

Konradsen, L., & Ravn, J. B. (1991). Prolonged peroneal reaction time in ankle instability.

 International journal of sports medicine 

Nawoczenski, D. A., Owen, M. G., Ecker, M. L., Altman, B., & Epler, M. (1985). Objective evaluation of peroneal response to sudden inversion stress.

 Journal of Orthopaedic & Sports Physical Therapy 

Stecco, A., Macchi, V., Masiero, S., Porzionato, A., Tiengo, C., Stecco, C., … & De Caro, R. (2009). Pectoral and femoral fasciae: common aspects and regional specializations.

Sato, T., & Hashimoto, M. (1984). Morphological analysis of the fascial lamination of the trunk.

 The Bulletin of Tokyo Medical and Dental University

Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., & Snijders, C. J. (1995). The posterior layer of the thoracolumbar fascia.

Barker, P. J., & Briggs, C. A. (1999). Attachments of the posterior layer of lumbar fascia.

Smith, J., Padgett, D. J., Kaufman, K. R., Harrington, S. P., An, K. N., & Irby, S. E. (2004). Rhomboid muscle electromyography activity during 3 different manual muscle tests1.

Palmerud, G., Sporrong, H., Herberts, P., & Kadefors, R. (1998). Consequences of trapezius relaxation on the distribution of shoulder muscle forces: an electromyographic study.

Kao, J. T., Pink, M., Jobe, F. W., & Perry, J. (1995). Electromyographic analysis of the scapular muscles during a golf swing.

Pink, M., Perry, J., Browne, A., Scovazzo, M. L., & Kerrigan, J. (1991). The normal shoulder during freestyle swimming: an electromyographic and cinematographic analysis of twelve muscles.

Moseley JR, J. B., Jobe, F. W., Pink, M., Perry, J., & Tibone, J. (1992). EMG analysis of the scapular muscles during a shoulder rehabilitation program.

Lehman, G. J., Buchan, D. D., Lundy, A., Myers, N., & Nalborczyk, A. (2004). Variations in muscle activation levels during traditional latissimus dorsi weight training exercises: An experimental study.

Lee, S., Gong, W., Park, M., Lee, M., & Shim, J. (2011). A Study of Shoulder Stabilizer Muscle Exercise using the Contraction of the Finger Flexor Muscle.

Brindle, T. J., Nyland, J. A., Nitz, A. J., & Shapiro, R. (2007). Scapulothoracic latent muscle reaction timing comparison between trained overhead throwers and untrained control subjects.

 Scandinavian journal of medicine & science in sports

McMahon, P. J., Jobe, F. W., Pink, M. M., Brault, J. R., & Perry, J. (1996). Comparative electromyographic analysis of shoulder muscles during planar motions: anterior glenohumeral instability versus normal.

Yoo, W. G. (2013). Changes in pressure pain threshold of the upper trapezius, levator scapular and rhomboid muscles during continuous computer work.

An, H. J., Choi, W. S., Choi, J. H., Kim, N. J., & Min, K. O. (2015). Effects of muscle activity and number of resistance exercise repetitions on perceived exertion in tonic and phasic muscle of young Korean adults.

Benhamou, M. M., Revel, M., & Vallee, C. (1990). Surface electrodes are not appropriate to record selective myoelectric activity of splenius capitis muscle in humans.

Takebe, K., Vitti, M., & Basmajian, J. V. (1974). The functions of semispinalis capitis and splenius capitis muscles: an electromyographic study.

Conley, M. S., Meyer, R. A., Bloomberg, J. J., Feeback, D. L., & Dudley, G. A. (1995). Noninvasive analysis of human neck muscle function.

Vasavada, A. N., Li, S., & Delp, S. L. (1998). Influence of muscle morphometry and moment arms on the moment-generating capacity of human neck muscles.

Kumar, S., Narayan, Y., & Amell, T. (2003). Power spectra of sternocleidomastoids, splenius capitis, and upper trapezius in oblique exertions.

Blouin, J. S., Siegmund, G. P., Carpenter, M. G., & Inglis, J. T. (2007). Neural control of superficial and deep neck muscles in humans.

Falla, D., Farina, D., Dahl, M. K., & Graven-Nielsen, T. (2007). Muscle pain induces task-dependent changes in cervical agonist/antagonist activity.

Deep Longitudinal Subsystem (DLS)