Lumbo Pelvic Hip Complex Dysfunction (LPHCD):
Predictive Model of Lumbo Pelvic Hip Complex Dysfunction
By Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, H/FS
For an introduction to Postural Dysfunction and Movement Impairment please refer to:
By any other name:
Lumbo Pelvic Hip Complex Dysfunction (LPHCD) has been previously described as "lower crossed syndrome" or an "anterior pelvic tilt"(1, 3), is likely similar to, or includes the dysfunctions described as kyphotic lordotic-posture, sway back posture (4), and is correlated with many low back and lumbosacral dysfunctions (4, 6-9). Lumbosacral Dysfunction (LSD) will be addressed in a separate article, as a "variation" of the LPHCD model. To our knowledge, the first organization to refer to the integrated system of joints of the lumbar spine, sacrum, pelvis and hips as the "lumbopelvic-hip complex" was the National Academy of Sports Medicine (3), with the intent of better defining the term "core." We have chosen to use the same segment-descriptive label for this model. Again, labeling by segment allows the model to evolve with ever increasing detail and accuracy as new theories, research, techniques and outcome measures increase our knowledge of impairment. Further, the risk is reduced that the title itself will imply a certain set of altered motions, muscle activity, fascial dysfunctions, changes in sensation, perception, motor unit recruitment, limit the tissues included, or limit the movement related hypotheses used to construct the model.
LPHCD is limited to common impairments of the lumbar spine, sacroiliac joint, hip and knee. This definition is not intended to exclude the possibility that more distal structures may impact motion of the LPHC; it is simply a border for the purposes of analysis. These borders were influenced by:
- Practice - considering a minimum number of joints that should be assessed in those with complaints related to the LPHC.
- Education - considering the minimum number of joints that would be included in describing all of the muscles and fascial structures with attachments to the pelvis.
Summary of Model:
Recommended Assessments and Techniques
Common Osteokinematic Dysfunction:
|Commonly observed/studied impairments:|
Common Muscular Dysfunction
|Short/Over-active (Release and Lengthen)||Recommended Assessments:|
|Short/Under-active (Prime Mover Inhibition - Integrate)|
|Long/Under-active (Activate)||Recommended Assessments|
|Long/Over-active (Synergistically Dominant – Release Only)||Recommended Assessments:|
Recommended Techniques (Release Only)
|Restricted Mobility (Thickening, histochemical changes, decrease in tensile strength, addition of disordered collagen fibers)|
Additional manual techniques (videos coming soon):
Myofascial Synergies (Subsystems)
Over-active (Release and Avoid)
Common Arthrokinematic Dysfunction
Considering the Traditional Model of LPHCD; Janda's Lower-crossed Syndrome (LCS) (1):
The recognition of a pattern of muscle dysfunction related to common impairments is likely the most well known contribution Vladimir Janda made to practice. The description of lower crossed syndrome was the first pattern described by Janda, and closely resembles the model constructed in this article (see table above). The difference between the current BI model and the original Janda model is the amount of detail. This can be attributed in large part to a larger body of relevant research and advancements in research methods. Additional advancements are made via integration of muscular, articular, fascial and motor control models, and a concerted effort to innovate solutions for gaps in the current body of research/knowledge. Janda built a strong foundation; the BI continues to build on that foundation. The table below, was constructed using the wording used by Paige (1) in reference to Janda's work.
Lower-crossed Syndrome (LCS)
|Lordosis||Anterior trunk muscles|
|Anterior pelvic tilt|
In the table above, note the reference to altered osteokinematic motion (anterior pelvic tilt and increased lordosis) and a list of tight and weak muscles. These considerations are a huge step beyond consideration of local "musculoskelatal lesion" or "neuromuscular lesion" being the sole contributor to a patient's complaints.
There are few issues with the model above that should be considered:
- First, the model does not clearly define all the joints involved in Lower-crossed Syndrome (LCS), and it does not discuss the excessive or inadequate motions of each joint in terms of osteokinematic joint actions (flexion, extension, abduction, etc.). Unfortunately this results in ambiguity and a challenge when comparing this model to research studies. For example, an anterior pelvic tilt may imply a relatively "hip flexed" position during static standing, but the inclusion of hip flexion as a component of an anterior pelvic tilt is not agreed upon by all human movement professionals.
- Second, this model does not consider the maladaptive changes of all tissues that cross all joints included in LCS. For example, how is the tensor fasciae latae (TFL) affected by LCS? It has been noted that Janda assumed that "tightness" was the predominate dysfunction (weakness being secondary) (1), and several studies have noted over-activity of the TFL, but the inclusion of the TFL is not explicitly mentioned. This is just one example of the many excluded muscles that cross joints of the LPHC.
- Third, the LCS model does not account for all of the combinations of relative changes in muscle activity and length that are implied by research. Janda used the terms Tonic and Phasic, which loosely approximate the terms short/over-active and long/under-active, but research implies that dysfunction may also result in muscles that are short/under-active and long/over-active. Some of the terms used to describe these additional dysfunctional behaviors include "synergistic dominance," "prime mover inhibition," "compensation pattern," and "altered recruitment patterns."
- Fourth, this model misses analysis that would infer the use of techniques intended to address arthrokinematic dysfunction (mobilizations, manipulations, muscle energy techniques) and fascial dysfunction (pin and stretch, myofascial release, IASTM, etc). That is, the original model of LCS does not consider arthrokinematic or fascial dyskinesis. If the body is an adaptable, holistic system, than all tissue systems should be accounted for. Further, a comprehensive model would include all effective modalities as demonstrated by 3rd party research.
- Last, despite intent of the model to describe a pattern of common impairments related to pain, the LCS does not attempt to list or define related diagnoses and pathologies.
Summary of Issues with the "Traditional" Model:
- Joints included in the model are not clearly defined.
- Many of the muscles crossing joints of the LPHC are not considered.
- Categorization of muscles as either "tonic" and "phasic" is not sufficient for a comprehensive muscular model of impairment.
- Fascial and arthorkinematic dysfunctions are not included in the LCS model.
- No attempt is made to list the diagnoses and pathologies correlated with LCS.
Analysis by Research on Related Impairments, an Evidence-based Osteokinematic Analysis:
Lumbo Pelvic Hip Complex Dysfunction (LPHCD) model could be defined by related osteokinematic impairments that appear in the body of research, as well as the their synonyms. This includes:
- Knees Bow In (a.k.a. functional knee valgus, medial knee displacement, hip adduction, etc.)
- Knees bow out (a.k.a. functional varus, lateral knee displacement, hip abduction, etc.)
- Excessive Lordosis (a.k.a. anterior pelvic tilt, sway back, etc.)
- Arms fall (a.k.a loss of shoulder flexion)
Assessment of LPHCD using the Overhead Squat Assessment (OHSA)
Research on Osteokinematic Dysfunction:
- Excessive Lordosis (Anterior Pelvic Tilt) - Several studies have noted a relationship between pelvic angle, sacral slope and the lordotic curve (extension) in the lumbar spine (20 - 25, 550). That is, an anterior pelvic tilt is correlated with an increase in lordotic curve and sacral slope angle, especially in standing (20-25). The opposing motions are also linked; actively posteriorly tilting the pelvis will reduce sacral slope angle and the lordotic curve of the spine (23, 550). These studies reinforce the concept that the pelvis, sacroiliac joint (SIJ) and lumbar spine move as a functional unit, which in standing includes the hip joint. Although research could not be located correlating osteokinematic hip joint actions with changes in pelvic angle, observation suggests that that an anterior pelvic tilt will increase relative hip flexion and a posterior pelvic tilt will increase relative hip extension. The reasons for the link between these joints may be related to biomechanics (for example, the erector spinae contributes to both lumbar and sacral extension), reflex coordination of joint motion to maintain equilibrium around the body's center of mass (22), and/or a reflexive drive to maintain upright posture and eyes forward (28). Studies have demonstrated that both anterior and posterior pelvic tilts may be associated with low back pain (26 - 40). It is the assertion of the Brookbush Institute (BI) that these studies are representative of two related but separate compensation patterns resulting in a similar set of symptoms. The model discussed in this article will consider compensation related to an anterior pelvic tilt and excessive lordosis. The compensation pattern related to a posterior pelvic tilt and a decrease in the lumbar lordosis will be discussed in the Lumbosacral Dysfunction (LSD) model.
- Anterior Pelvic Tilt = Hip Flexion + Lumbar Extension + Increase in Sacral Slope Angle (Discussed in this article and associated with LPHCD)
- Posterior Pelvic Tilt = Hip Extension + Lumbar Flexion + Decrease in Sacral Slope Angle (Discussed in the article Lumbosacral Dysfunction (LSD))
- More Hip External Rotation than Hip Internal Rotation, limited Hip Flexion (with knee Extension) and limited Hip Extension – Comparing asymptomatic controls to low back pain patients, research has demonstrated a relative loss of hip internal rotation, more external rotation than internal rotation, and more asymmetry in ROM between right and left hips (43-48). Further, several studies have noted a limit in "hip flexion" when measured by straight leg raise or forward bending (43-44, 49, 50), and one study demonstrated a correlation between a loss of hip extension and low back pain (65). Additionally, these studies and others imply altered movement patterns that include a disassociation, or change in the relative contribution from hip and/or lumbar spine to accomplish functional tasks, such as sitting, standing and rotation (more spine motion during rotation and standing up) (40, 46, 49, 51-57, 58). Some of these studies, also demonstrated significant changes in balance, coordination and velocity of movement (53 - 56).
- Knees Bow In - The correlation between changes in hip ROM and commonly noted signs during an Overhead Squat Assessment (OHSA) (and lower extremity alignment) has not been researched specifically, but we do have clues. In a study by Cholewicki et al (58) it was demonstrated that delayed trunk muscle reactivity was a predictor of low back pain, and similar delayed trunk muscle reactivity was correlated with future knee injury by Zazulak et al. (59). A study by Leetum et al. may have provided the biomechanical link between low back pain and lower extremity injury by demonstrating that low back pain resulted in a significant decrease in hip abductor and external rotation strength (60). A decrease in hip abductor strength and external rotation strength are very common findings in studies related to functional knee valgus (Knees Bow In), knee injury and pain. A full review of this research is beyond the scope of this article; however, a thorough review is included in the article Lower Extremity Dysfunction (LED). Two studies by Padua et al. and Mauntel et al. may be of particular interest, as these studies include range of motion and EMG data on individuals who exhibit a functional valgus (Knees Bow In), demonstrating similar changes in EMG and hip ROM to the studies related to low back pain (62-63). Last, a prospective study by Nadler et al. demonstrated correlation; athletes who had experienced lower extremity injury had a higher prevalence of low back pain during the season (61).
- Knees Bow Out - The studies discussed in "Knees Bow In" would seem to indicate that low back pain would have a higher correlation with Knees Bow In; however, that does not seem congruent with a decrease in hip internal rotation and increase in hip external rotation. In fact, a correlation between decreased hip internal rotation and assessed functional varus (Knees Bow Out) during a squat was demonstrated in a study by Noda et al. (64). Practice, suggests that Knees Bow In or Knees Bow Out may be correlated with more hip external rotation than hip internal rotation, and that either may be related to symptoms of low back pain. The clinical solution to the problem of being presented with one of two possible compensations patterns is to follow an OHSA with goniometry and address altered hip ROM and muscle activity as assessed. Based on these finding the BI has elected to include both Knees Bow In or Knees Bow Out as signs contributing to LPHCD, along with the goniometric finding - hip external rotation > (more than) hip internal rotation.
- Arms Fall (loss of shoulder flexion, positive lat length test) - Although research has yet to investigate this relationship, the correlation between a loss of shoulder flexion and LPHCD has been noted clinically. It may be hypothesized that this is due to reflexive over-activity of the lumbar extensors, which include the latissimus dorsi, a powerful shoulder extensor.
- Research is not available correlating hip flexion/extension angle with pelvic tilt.
- More research is needed to correlate changes in hip range of motion to compensation during functional movement patterns and dynamic postural assessments (e.g. OHSA)
- Research has not directly investigated the correlation between Knees Bow In and Knees Bow Out and low back pain or an anterior pelvic tilt.
- Research is not available correlating low back pain or LPHCD with increased latissimus dorsi activity and a loss of shoulder flexion or positive lat length test.
Lower Extremity Dysfunction based on Research of Impairments
|Hip Internal Rotation||Hip External Rotation|
|Hip Flexion||Hip Extension|
|Lumbar Extension||Lumbar Flexion|
Summary of Issues with the "Evidence-based Osteokinematic Analysis":
The evidence-based osteokinematic analysis solves many of the issues that exist in the "traditional model." This includes a more accurate account of which joints should be included in the model and their excessive joint actions. Further, using this analysis allows for a better account of altered muscle lengths. It is notable that unlike other models, the osteokinematic model of LPHCD only suffers from one muscle appearing on both sides of the graph, the psoas. Based on this table it is tempting to end our construction of this model, list short muscles as over-active and long muscles as under-active and dismiss the categorization of the psoas as anomalous. However, in the next section many muscles will need to be re-categorized based on current EMG studies. The relationship between LPHCD and some diagnoses, pathologies and symptoms (e.g. low back pain) was identified in the above analysis; however, this analysis is far from comprehensive. Last, this model still ignores fascial, myofascial synergy and arthrokinematic contributions.
- Psoas appears both long and short sides of the table without a clear reason (muscles cannot be long and short at the same time).
- Analysis of altered muscle activity is incomplete.
- Fascial structures have been excluded from this analysis.
- Arthorkinematic dysfunction has been excluded from this analysis.
- A list of diagnoses and pathologies related to LPHCD is incomplete.
Analysis by Research on Individual Muscles (Evidence-based Muscular Approach):
To create a detailed model of practice that will help to refine exercise selection, further analysis is required to determine the relative changes in activity of all muscles included in the LPHCD model. In this "level of analysis" an attempt is made to aggregate all relevant research on all muscles crossing the lumbo pelvic hip complex.
Tensor Fasciae Latae (TFL) and Gluteus Minimus - First, attention should be brought to a study published in 1936 that was well ahead of it's time by Dr. Ober (creator of the "Ober's Test"), which discusses the relationship between the TFL/ITB and Low Back Pain/Sciatica (71). The TFL and gluteus minimus contribute to the same joint actions at the hip, including flexion, abduction, internal rotation and the ability to contribute to an anterior pelvic tilt. Further, these muscles seem to become synergistically dominant for an inhibited gluteus medius; that is, over-activity of the TFL and gluteus minimus may result from, or contribute to a decrease in gluteus medius activity. We may presume this is a commonly observed phenomenon, as a study was published by Selkowitz et al. in 2013 comparing various gluteus medius exercises with the intent of reducing TFL activity (316). Several studies have noted over-activity of the TFL and inhibition of the gluteus medius in those exhibiting a functional knee valgus (62, 63, 66 - 69). Support may also be found in a study by Sutter et al. demonstrating that abductor tendon tears (gluteus medius and gluteus minimus tendon) are correlated with TFL hypertrophy; which may imply prolonged synergistic dominance and dysfunction is a precursor to this type of injury (70). This relationship becomes more pertinent to the LPHCD model when we look at several studies demonstrating a reduction in gluteus medius activity with low back pain (61, 302). This may also partially explain the relationship between knee pathology and LPHC dysfunction noted earlier (58-61) - a reduction in gluteus medius activity will result in an increase in TFL activity, which may be correlated with low back pain or functional knee valgus, and may result in one pathology contributing to the other.
Unfortunately, no studies exist (to our knowledge) that investigate activity of the gluteus minimus. This is likely due to its location deep to the TFL, gluteus medius, and iliotibial band. Functionally, the muscle acts much like the TFL, contributing to hip flexion, abduction and internal rotation, and the muscle is innervated by the same nerve (superior gluteal nerve)(72). One notable difference is the investment of the gluteus minimus into the hip joint capsule, which may have implications relative to complaints of hip pain (73). BI recommends treating the TFL and gluteus minimus similarly relative to Lower Extremity Dysfunction (LED), LPHCD or Lumbosacral Dysfunction (LSD).
Anterior Adductors - Over-activity of the adductors has been correlated with functional knee valgus (62, 63, 67), hinting at this muscle groups common maladaptive behavior. In individuals with sacroiliac joint (SIJ) pain, adductor activity remained unchanged (along with the TFL, biceps femoris) while internal oblique, lumbar multifidus, and gluteus maximus activity decreased or fired later (74). This change in recruitment, could be viewed as a relative increase in synergistic activity of the adductors. Although it may not be a direct indicator of relative changes in length, the adductors (and adductor tendons) are commonly associated with tendonitis and groin pain (75-77), of these muscles the adductor longus seems to be the most often affected (78). As will be discussed later in "myofascial synergies," the adductor longus and rectus abdominis tendons exhibit fascial continuity and synergistic activity, implying a role in core function.
Rectus Femoris, Sartorius and Vastus Lateralis - The rectus femoris and sartorius are categorized as short/over-active due to their ability to contribute to hip flexion and an anterior pelvic tilt; however, to our knowledge, EMG studies do not exist comparing activity of the rectus femoris and sartorius in asymptomatic controls to those exhibiting dysfunction. The vastus lateralis is included due to its investment in the iliotibial band and research implying a relationship with the rectus femoris and TFL, both hip flexors. Like the sartorius no studies could be located correlating vastus lateralis activity with low back pain. We do have a few studies that may provide vague indicators of their common maladaptive behavior. The rectus femoris and sartorius play a similar role in gait, being most active during late stance to swing transition, and early swing phase during running (deceleration of hip extension/knee flexion, and initial impulse of hip flexion) (79 - 81). These studies highlight that hip flexion may be their primary role (eccentric deceleration of hip extension being the same). Further, the impact of over-activity of these muscles can be hypothesized as early push-off (limited extension); increasing reliance on lumbar extension to compensate for lost hip extension. Studies have shown that the quadriceps may be inhibited by knee joint effusion (82); however, based on this study by Spencer et al. the vastus medialis obliquus has been shown to be affected by much lower volumes of fluid (less swelling) than the vastus lateralis and rectus femoris - these two muscles seem to be affected similarly. Another study by Vaz et al., demonstrated similar recruitment patterns between the vastus lateralis and the rectus femoris during a fatiguing protocol (83). An odd clinical finding during the Ely's Test, Ober's test and the "back leg" of a lunge, is the ability of a short/over-active rectus femoris to contribute to, or deflect the thigh into abduction during extension. To our knowledge, the rectus femoris contributing to abduction is only mentioned in one text (Muscles Alive, 1985)(79). The sartorius is most often compared to the TFL, contributing to hip flexion and abduction of the hip, and although these muscles contribute to opposing directions of rotation at the hip and knee, these opposing actions do not seem to interfere with both muscle contributing similarly to various motions (84, 85). Although, direct evidence of maladaptive changes in length and activity of the rectus femoris and sartorius are not documented in the body of research, relationships between the sartorius and TFL, as well as the vastus lateralis and rectus femoris may suggest a synergistic relationship. It is the BIs recommendation that these muscles are considered a "flexion/abduction synergy" and treated similarly
Latissimus Dorsi - The latissimus dorsi has been implicated as a lumbar extensor via the thoracolumbar fascia; however, studies show that the potential contribution is relatively small (161 - 164). Strangely, the muscle behaves like a global mover of the spine, demonstrating a marked increase in activity during the initiation of squat and stoop lifts and asymmetrical activation during trunk rotation (126, 165). A correlation between a loss of shoulder flexion and LPHCD has been noted clinically, leading to the hypothesis that the latissimus dorsi is reflexively over-activity in conjunction with other global lumbar extensors (erector spinae). The BI recommends release and lengthening techniques for this muscle; however, further research is needed to correlate changes in latissimus dorsi activity with LPHCD.
Quadratus Lumborum - There is not much research on the quadratus lumborum (QL), likely due its location deep to other paraspinal muscles. Studies have demonstrated a moment arm too small to contribute to large amounts of force, and motion of the lumbar spine results in little change to QL length (111, 112). Lying lateral flexion and the side plank result in significant recruitment of the QL (114, 115); however, the muscle's size and short moment arm suggests its acting as a "stabilizer", and not a prime mover (9). An interesting finding by McGill et al. demonstrated an increase in EMG activity with increased load during bilateral carrying (9), and two studies have shown that the QL is still active during the "flexion-relaxation phenomenon" (113, 114). The bilateral carrying results in comprehensive forces, which may imply the increase in QL activity is similar to that of the TVA and internal obliques in response to compression of the lumbar spine. Further, activity during the flexion-relaxation phenomenon is another trait of intrinsic stabilizing muscles (ISS).
To our knowledge no studies exist comparing the EMG activity of the QL in symptomatic low back pain patients to asymptomatic controls; however, two MRI studies have shown a decrease in QL cross-sectional area in those with chronic low back pain (97, 110). A study by Hua et al. demonstrated good reliability for locating myofascial trigger points when matched to tenderness upon palpation and replication to patient symptoms (116), and a case study by Graber reported targeted inhibtion/relaxation of the QL to resolved low back pain symptoms (551). Activity similar to other stabilizers, development of trigger points, and atrophy in those with low back pain is similar to the behavior noted in the multifidus. It is the recommendation of the BI that the QL and multifidus are addressed as short/over-active muscles, with release techniques, lengthening techniques when necessary, and ISS (stabilization) exercises.
Multifidus - There is a significant amount of research on the multifidus, including the relationship between the multifidus and low back pain. In fact, there is so much research on the multifidus it highlights a potential over-simplification inherent in the terms "under-active" and "over-active", and may aid in the development of more nuanced definitions. Regarding the LPHCD model and categorization of this muscle relative to activity and length, this muscle does not cleanly fall into one category. Similar to the Psoas this muscle may be short/over-active or short/under-active; however, it is BI's assertion that short/over-active is more likely. Starting with biomechanics: the lumbar multifidus forms five distinct bands that are innervated segmentally by the nerve root corresponding to the vertebrae they attach to (117). The primary forces they contribute to are extension and compression with have some potential to contribute to posterior shear; however, fiber arrangement suggests a larger role in frontal plane stabilization (118 - 121). In a resting position the multifidus are in a relatively shortened position, reaching optimal length/tension as the spine flexes (121). Although these muscles are often considered important to proprioception studies have demonstrated that these muscles have very low muscle spindle density (122, 123).
The multifidus seem to function primarily as stabilizers. Although these muscles contract ipsilaterally during weighted trunk rotation, they contract bilaterally during unweighted rotation (124). They also co-contract with spinal flexors during flexion and their activity increases with increases in load (125). Further, during asymmetric lifting tasks these muscles contract bilaterally (126). During isometric activities (holding a load in one hand) the multifidus contract first and fatigue faster when compared to the iliocostalis (127). Some distinction may need to be made between deep and superficial fibers. Several studies have shown that the multifidus are only active during active postures (upright sitting, walking, swinging both arms forward) (127 - 129). However, a study by Moseley et al. demonstrated the deep fibers behaved more like the transverse abdmonis and were active during static standing and during unilateral and bilateral arm swings in both directions (130). In summary, like other stabilizing muscles of the trunk, the multifidus contract bilaterally regardless of direction of motion, the deep fibers are active during low intensity tasks (static postures), activity increases during active postures and loading, and these muscles may fire before larger movers of the spine.
The case for categorizing the multifidus as under-active relative to low back pain and Lumbo Pelvic Hip Complex Dysfunction (LPHCD) starts with a group of studies showing atrophy, histochemical and connective tissue changes. Several studies have shown that cross-sectional area of these muscles decreases in those with chronic low back pain. The atrophy is often segment specific and is likely to occur unilaterally in those with sided pain (95 - 100, 131-136, 143). Although preferential atrophy of type II fibers has been observed in some studies, it is not clear whether this is correlated with low back pain or a byproduct of surgery and/or age related changes (136 - 140). Connective tissue changes are worthy of further investigation, as a study by Lehto et al, found fibrosis correlated with impaired ability to recover (141). Last, although not clinically relevant for human movement professionals, core-targetoid (moth eaten) changes to type I fibers may have relevance to diagnosis and prognosis if lab tests can be made easily implantable (142). It is important that we do not confuse atrophy with under-activity, relative to our categorization for use during exercise selection. Although it may be more difficult to hypothesize a process that results in atrophy from over-activity; research and clinical findings on activity relative to dysfunction must be considered in addition to findings of atrophy.
As mentioned above, the activity of the multifidus is complex. There are a couple of studies that imply dennervation is a cause of multifidus dysfunction (138, 144); however, this does not appear to be a consistant finding (137, 142). It seems more likely that dennervation is specific to surgical intervention and retrolisthesis (138, 144). In those individuals exhibiting chronic low back pain the multifidus are less active especially in lumbar extended positions (145, 146), are weaker and fatigue faster (147, 148), are more active during static standing and stabilization (149-151), peak higher during flexion, spontaneously discharge around hypermobile segments (146, 149, 151), and remain active for longer after a lift (152). Changes in motor behavior are also demonstrated by a "decoupling" of the bilateral contraction normally seen during lifting tasks (126, 153). Trigger point development may also be common (16, 154). To summarize, optimal function of the multifidus is replaced with continuous low force output, unilateral and asymmetrical recruitment in response to stress, spasm or high-activity with any high intensity task or task requiring significant stability, and increased activity for a longer period post recruitment. This change in behavior would seem to replace an appropriately low intensity stabilization function, with bracing and over-activity. Even the loss of force output, quicker time to fatigue and inactivity in extended positions can be explained by adaptive shortening and altered length/tension, resulting in less efficient force output and active insufficiency in extended positions.
Hypothesized compensation pattern of the Multifidus:
- Low activity at all times (not quite during static posture)
- Weaker and fatique faster
- Bilateral activation replaced by directions specfic unilateral activation
- Spasm/increased activity in response to load and instability
- Increased activity for longer post response to stress
- Trigger point development
Exercise has been shown to be effective for increasing multifidus cross sectional area, although it would seem that stabilization exercises are generally more effective than loaded extension (155, 156). Research by Hides et al. has shown that recovery of the multifidus is not automatic post low back pain; however, stabilization exercises are effective for both a short-term reduction of symptoms and reduction of low back pain recurrence long-term (157 - 159). Last, it may be prudent to not "wait for injury", as a study by Lee et al (1999) demonstrated that imbalance between spine flexors and extensors was a risk factor for low back injury in a 5-year prospective study (160). Based on the compensation pattern adopted, and the stabilization exercise being more effective than specific multifidus strengthening, the Brookbush Institute recommends treating these muscles as short/over-active (release and lengthening). However, careful attention during core integration exercise is also recommended; specifically using cuing to enhance bilateral activation of the multifidus during Instrinsic Stabilization Subsystem Integration.
A comprehensive analysis of core muscle function should not exclude any muscles crossing the lumbar spine. Deep to the multifidus are several small sets of muscles fibers known as the rotatores (from spinous process to transverse process spanning 1 or 2 segments), intertransversarii (running vertically between transverse processes), and interspinales (running vertically between spinous process). These fibers are multipennate (especially the rotatores) highly aerobic, with fibers organized in parallel, an arrangement that may be advantageous for “fine-tuning” of vertebral movements (552). However, McGill (9) noted that these deeper muscles are so small and have such small moment arms that is unlikely they contribute to motion.
There is evidence to suggest that the rotatores, intertransversarii, and interspinales serve a sensory function. Two studies demonstrate these muscles have a much higher muscle spindle concentration (4.5 to 7.3 times higher) than the multifidus or erector spinae (553 - 554). Another study by Waters and Morris demonstrated that these muscles are active in conjunction with the multifidus; however, the graphs depicting EMG activity in the published paper seem to illustrate the onset of deep muscle activity prior to the multifidus (555). Note: the difference in onset timing of the multifidus and deep rotators was not evaluated for statistical significance. Assuming the onset timing was significant, it is plausible that the deep rotators initially respond to stretch with an increase in activity, followed by a reflexive increase in activity of the larger multifidus. Supporting this hypothesis are two studies that show the supraspinous, interspinous and iliolumbar ligaments are abundantly innervated by Pacinian receptors and Ruffini endings (352, 361). The supraspinaous and interspinous ligaments are continuations of the fascial sheath of the interspinous and intertransversarii muscle fibers. Although additional studies show that these receptors may only be stimulated at end range as limit detectors, the finding reinforces the role of these fibers as primarily sensory (362-363).
The rotatores, intertransversarii, and interspinales are often omitted from analysis of core muscles, were not included in the original description of subsystems (which also excluded all the muscles of the ISS), and these muscles are scarcely mentioned in research and texts on the intrinsic stabilizers. The BI asserts these muscles may be viewed as a deeper set of segmental stabilizers/extensors serving a role as proprioceptors or sensory organs. More research should be designed to determine whether a feedback loop exists that results from an initial lengthening of these deep muscles and reflexive increases in tone of the multifidus, and perhaps a cascade that stimulates the ISS.
Erector Spinae - The erector spinae is the primary lumbar extensor, especially the iliocostalis thoracis which may produce 70 - 86% of total extensor torque (119, 163). These muscles are also important for frontal plane stabilization (120), can rotate the spine ipsilaterally (124), contribute to anterior shear of the lumbar vertebrae (more with increased lordosis) (163, 171), and may have an effect or be affected by the ribs and costovertebral joints (123). The iliocostalis has a higher muscle spindle density than the multifidus, demonstrating that muscle spindle density increases from the most medial to the most lateral fibers of the lumbar extensors (122, 123). Unlike the multifidus, asymmetrical activity of the iliocostalis is common when challenged by asymmetric loads (126, 129). For example, holding weight in the right hand increases left iliocostalis activity, but bilateral multifidus activity. This behavior is expected if the iliocostalis is considered a prime mover and the multifidus a stabilizer. The behavior of the erector spinae relative to dysfunction is complex, but implies "over-activity", mirroring the behavior of the multifidus. To review (excluding citations that did not include erector spinae activity), erector spinae relative to chronic low back pain exhibited less activity in lumbar extended positions (145), less torque and fatigued faster during isometric extension (147, 148, 167), was more active during static standing (149-151), peaked higher during flexion, spontaneously discharged around hypermobile segments (149, 151), and remained active for longer after a lift (152). Changes in motor behavior also demonstrated delayed activity during lifting tasks (126, 166). Trigger point development may also be common (16, 154). Additional findings include a study by Renkawitz et al. that showed an imbalance in EMG activity between right and left sides in those exhibiting low back pain (168), Nourbkhsh et al. found that extensor endurance had the highest correlation with low back pain when compared to 16 additional mechanical factors (other variables were also strongly correlated) (169), and Cooper et al. found erector spinae atrophy in those with chronic low back pain (170). Make note, that like the multifidus the erector spinae are over-active and prone to atrophy. Last, it may prudent to assess before injury, as a study by Lee et al (1999) demonstrated that imbalance between spine flexors and extensors was a risk factor for low back injury in a 5-year prospective study (160). The BI recommends treating the erector spinae similar to the multifidus, using release and lengthening techniques to address changes in length and activity and core integration techniques to address core muscle endurance and atrophy.
Iliacus - A study by Andersson et al. demonstrated that in most cases the psoas and iliacus are recruited together; however, some differences were noted. Relative to the psoas, the iliacus is more involved in stabilizing the pelvis when the contralateral lower extremity is in motion, and is less active during frontal plane stress on the lumbar spine (93). Based on the origin of the psoas and iliacus, this matches what we might expect to find (iliacus stabilizes pelvis, psoas stabilizes spine). An interesting study showed that the iliopsoas was "tighter" in those with a functional flat foot (101), implying a link between Lower Extremity Dysfunction (LED) and LPHCD. Clinically, the Brookbush Institute has noted during palpation and manual release that over-activity of the iliacus related to LPHCD is the more common maladaptive behavior, and that "under-activity" of this muscle is not common. This differs from the behavior of the psoas described below. It is not uncommon during palpation to note increased tissue density (sign of over-activity) in the iliacus and no change or a decrease in tissue density (under-activity) of the psoas, in conjunction with marked decrease in hip flexion strength. This is one of those rare instances where release and activation may be combined, although the intent is to release the iliacus and activate the psoas. Further evidence of iliacus over-activity may be found in the effectiveness of release of the iliopsoas tendon in condition termed painful "snapping hip syndrome" (101 - 109). This would seem to imply that a short/over-active iliopsoas can become pathological and lengthening can be effective. Author's note, it may be interesting to research the effectiveness of surgery when compared to release and lengthening (stretching). In summary, the iliacus should be considered separate from the psoas, categorized as short/over-active in those exhibiting signs of LPHCD, and addressed with manual release and lengthening techniques.
Psoas - The psoas is a hip flexor; however, it is likely not a primary hip flexor until the end of hip flexion range of motion (14, 88, 89). This muscle is most active during activities requiring maximal effort hip flexion, and only active up to 25% of maximum voluntary isometric contraction (MVIC) during activities like push-ups (89). Further, in a study by Anderson et al., the psoas was shown to be active during upright sitting and frontal plane stabilization of the lumbar spine when carrying a contralateral load, but quiet during static standing (93). The duel function of the psoas as a lumbar spine stabilizer and hip flexor is further highlighted by the duel nerve innervation from the femoral nerve and direct branches from the anterior rami of nerve roots L1 - L3 (90-92). More consideration should be given to the psoas belonging to a group of lumbar stabilizers and perhaps less to its function as a hip flexor.
The loss of hip extension, increased lordosis and anterior pelvic tilt commonly noted in those exhibiting signs of LPHCD would suggest this muscle is short, and if over-active could contribute to these impairments (20-25, 65). Further, this muscle may contribute to spinal compression, to a lesser degree anterior shear (mostly at L5, S1), and flexion of the lower lumbar spine (increased lordosis) (86, 87), all of which have been implicated as contributing factors (or irritants) to a herniated nucleus pulposus (HNP) and/or nerve root impingement. This muscles contribution to hip external rotation would also be worthy of exploration given the decrease in hip internal rotation associated with LPHCD (43 - 48); at this time no studies could be located. Several studies have shown atrophy of the psoas on the side of low back pain, and potentially segmentally specific atrophy corresponding to the level of HNP (94-98). There is some evidence that strength may be further affected by fatty infiltrate in the psoas post injury, but conflicting research exists (99-100). The activity, compensation, atrophy and morphologic change in response to low back pain of the psoas is very similar to findings for the multifidus and QL.
Clinically, the BI notes the presence of trigger points and increased tissue density in the iliacus more often than the psoas. Findings based on palpation may be less reliable, but are presented here to inspire a potential direction for research. It is the assertion of the BI that the psoas, QL and multifidus function and compensate similarly, and should be addressed similarly with release techniques (when necessary), lengthening techniques (when necessary), and ISS (stabilization) exercises.
Long/Over-active (Over-active Synergists)
The biceps femoris, adductor magnus and piriformis all have attachments to the sacrotuberous ligament. Their is a significant amount of research on the biceps femoris; however, research on the piriformis, and adductor magnus is lacking. Further, there is no research on activity of the deep rotators which are presumed to behave similar to the piriformis. Clinically, it has been observed that these muscles behave similarly, in a manner congruent with the behavior of the DLS, and addressing all of these muscles together seems to improve outcomes related to DLS and SIJ dysfunction.
Several studies have demonstrated increased biceps femoris activity relative to decreased gluteus maximus activity in those exhibiting knees bow in (functional valgus), an anterior pelvic tilt, lumbar spine instability, sacroiliac joint dysfunction and/or low back pain (63, 169, 173-176). These studies may be evidence of a relationship betweem the DLS and POS that results in POS inhibition and synergistic dominance of the DLS. Release and stretching may be effective ways to treat this change in activity. A study by Hasegawa et al. on the relative activity of knee musculature, demonstrated that stretching the biceps femoris resulted in a relative increase in vastus medialis obliquus (VMO) activity (176). This begs consideration of whether stretching resolved an over-activity of the biceps femoris that was reciprocally inhibiting its functional anatogonist (VMO), and whether similar changes in activity would be observed at the hip. Further, foam rolling the hamstrings has been shown to be an effective strategy for increasing extensibility (177). Note, based on the relative increase in length in static posture in those exhibiting an anterior pelvic tilt, the Brookbush Institute (BI) suggests that better long-term results may be noted with release techniques alone, despite stretching providing some short-term benefits.
Very few studies have investigated activity of the piriformis, and no studies exist investigating the deep rotators to our knowledge. This is likely due to their location deep to the thick gluteus maximus. It is hypothesized that the deep rotators and piriformis behave similarly. The piriformis has been shown to be more active during external rotation, abduction and extension of the femur, and increased tension will contribute to stabilization (compression) of the sacroiliac joint (SIJ) (178-181). Note, the piriformis is unique among DLS muscles due to its ability to compress the SIJ via muscular action, as well as increased tension in the sacrotuberous ligament. Based on function, over-activity and adaptive shortening of these muscles would contribute to the compensation patterns Knees Bow Out (Functional Varus), Asymmetrical Weight Shift to the opposite side, and SIJ stiffness. Clinically, palpation of the piriformis would imply this muscle is commonly over-active, even in cases of, LED and LPHCD resulting in Knees Bow In and a presumed increase in length. There is some research to support that piriformis (and perhaps deep rotator) trigger points are common, occurring in 25 - 50% of the population (16, 182). Release has proven clinically effective; however, do to a presumed increase in length in those exhibiting dysfunction, stretching is only recommended if release techniques do not return normal extensibility.
There is a void in the body of research regarding the adductor magnus and activity. Three older publications, suggest that despite the adductor group being active during the entirety of the gait cycle, the posterior or "ischiocondylar" head of the adductor magnus has spikes and troughs in activity similar to recruitment pattern that is similar to the hamstrings (16, 79, 183). That is, the posterior head of the adductor magnus is an extensor, an external rotator, and is active during mid stance, push-off and the late swing phase of gait. Anatomically, this muscle does share an origin with the biceps femoris on the sacrotuberous ligament and has neural innervation from the sciatic nerve via the tibial nerve (much like the hamstrings). Throughout the Brookbush Institute content, the term "adductor magnus" is used to reference the posterior head of the adductor magnus, and this muscle is addressed in the same manner as the biceps femoris. (as well as the piriformis and deep rotators) The anterior head of the adductor magnus is grouped with all other adductor muscles, referred to as the "anterior adductors", and all perform similar functions.
There is insufficient research on these muscles to build an evidence based model of maladaptive length and activity change that would match the level of detail and support of other muscles of the LPHC. However, the research that is available and various clinical findings suggest these muscle often act synergistically, perhaps as muscle of the Deep Longitudinal Synergy (DLS), and dysfunction results in a maladaptive increase in length and increase in activity. The BI most often recommends release techniques for these muscle. Note: these muscles play a larger role in Lumbosacral Dysfunction (LSD).
Rectus Abdominis - The rectus abdominis is enveloped by the fascial sheath that extends from the internal obliques and external obliques (236). This fascial relationship may serve an important function in transferring force between left and right sides of the anterior abdominal wall; however, how the rectus abdominis may contribute to this force transfer is not well defined. The function of the rectus abdominis and its recruitment relative to low back pain, resembles the activity of the external obliques - as opposed to the internal obliques which is recruited like the transverse abdominis. This muscle is a strong lumbar flexor, also contributing to posterior tilting of the pelvis, and the sacral counter-nutation linked to lumbar flexion (23, 237, 550). The rectus abdominis may be active during axial rotation and lateral stabilization of the spine (124); however, it is doubtful that this recruitment contributes to rotation and/or side-bending force vectors. It is more likely this activity is the result of co-contraction with the lumbar erectors to aid in bracing (stabilization of) the lumbar spine (125). This stabilizing function should not be confused with the type of stabilization noted in the anticipatory, bilateral, non-direction dependent, and even at low intensity recruitment of muscles of the Intrinsic stabilization Subsystem (ISS). Recruitment of the rectus abdominis is direction specific and related to larger loads (185). The rectus abdominis may contribute to very forceful exhalation; however, even during very forceful exhalation the activity of the rectus abdominis is always far less than the external obliques and internal obliques (238).
It should be noted that there is no need to divide the rectus abdominis into upper and lower portions relative to this model, orthopedic rehabilitation or sports performance. Despite being innervated segmentally, all studies show the rectus abdominis is recruited as a unit during motion and/or stabilization of the spine, hips and/or pelvis (240-247). Only one study found an activity that resulted in voluntary and separate recruitment of the upper and lower portions of the rectus abdominis - the activity was the stomach roll in belly dancing (239).
The activity of the rectus abdominis (as well as the external obliques) is complex relative to low back pain and LPHCD. Sway back postures may result in an increase or decrease in activity (128, 248), low back pain may result in decreased rectus abdominis activity during rotation (229), but increased reliance when fatigued (230), low back pain patients generally are weaker in trunk flexion than extension (58); however recruit the rectus abdominis more during stair climbing (250), and chronic low back pain patients cannot differentiate between transverse abdominis and rectus abdominis activation during the abdominal drawing in maneuver (ADIM) (249). This pattern suggests that the rectus abdominis is acting as an "over-active synergist" (long/over-active); a relationship that results in a puzzling increase in activity due to inhibition of other primary musculature, but less strength due to an increase in length and disruption of optimal length/tension relationship. The over-activity of this muscle should be addressed by increasing the activity of the primary stabilizers (ISS), and the increase in length should be addressed with integrated strengthening. Several studies suggest that unstable environments result in an increase in core muscle activity (251, 252). However, it is more interesting to note that exercises with the goal of improving pelvic position (posterior pelvic tilting out of an anterior tilt) also improved strength and function, and core exercise caused an immediate increase in activity during gait resulting in less trunk and hip motion and less pain in low back patients (255 - 257).
External Obliques - The external obliques are likely the prime movers for trunk rotation and lateral flexion (112, 124, 232, 233), and are active during flexion and forceful expiration (233, 234, 258). An interesting note, according to a study by Drysdale et al., the external obliques may be segmentally recruited depending on posture and position (261). The recruitment of the external obliques does vary significantly from the other muscles of the lateral abdominal wall. The external obliques contribute to contra-lateral rotation of the spine and do not demonstrate the "bilateral co-activation" often noted in the internal obliques and transverse abdominis during static or dynamic rotation of the trunk (124, 126). Although the external obliques may also contribute to stabilization, they do so in a direction dependent manner (ex. unilaterally active during eccentric deceleration of rotation) (260) and in response to larger loads (bracing) (125). The external obliques are also more active in posteriorly tilting the pelvis than during the abdominal drawing-in maneuver (ADIM) (261); in fact, there activity is not necessary to increase intra-abdominal pressure (262). These traits may be attributed to a lack of attachment to the thoracolumbar fascia (263). In short, the external obliques should likely be categorized with the rectus abdominis as prime movers and/or "global muscles" of the core, where as the internal obliques and transverse abdominis act as stabilizers and should be categorized as "intrinsic muscles."
As mentioned above, the behavior of the external obliques relative to LPHCD and low back pain resembles that of the rectus abdominis; however, the alterations in activity are easier to predict. Studies show that low back pain and fatigue increase reliance on external obliques, relative to a decrease in internal obliques and transverse abdominis activity and in some cases rectus abdominis activity (229, 230, 264). Like the rectus abdominis, the external obliques exhibit less activity in sway standing (128), may be more active (bilaterally) to stabilize the spine during functional tasks in those with low back pain (bracing), and are more active in exercise requiring more stability (ex. bridges on ball) (128, 265, 266). The BI categorizes the behavior of the external obliques as acting as "over-active synergists" (long/over-active), like the rectus abdominis; however, when comparing research on the two muscles it may be noted that the external obliques trend toward over-activity with more consistency. Again, like the rectus abdominis, the over-activity of this muscle should be addressed by increasing the activity of the primary stabilizers (ISS), and the increase in length should be addressed with integrated strengthening. Note: the BI addresses the rectus abdominis and the external obliques together with the same set of exercises and techniques.
Transverse Abdominis - The transverse abdominis (TVA) has been thoroughly researched due to the popularity of ground-breaking studies published by Hodges, Richardson and Hides in the late 1990's through early 2000's (184-186, 195-196, 201-208, 215). This work would lead to the publication of a textbook in 1999 -Therapeutic Exercise for Lumbo Pelvic Stabilization – A Motor Control Approach for the Treatment and Prevention of Low Back Pain, which had a dramatic impact on the treatment and prevention of low back pain, as well as our understanding of human movement. The function of the TVA is relatively well understood, and may serve as a model for understanding the behavior of a muscle whose primary role is stabilization and is prone to inhibition in those exhibiting dysfunction. The muscle contracts prior to planned activity, bilaterally, regardless of the direction of limb motion, and activity increases with changes in posture including increased center of gravity height, increased respiration and speed of locomotion (184-187, 213). The stabilizing function of the transverse abdominis appears to occur by two primary mechanisms. First, increased tension in the muscle results in increased tension of the thoracolumbar fascia (TLF) resulting in increased stiffness of the lumbar spine and force closure of the sacroiliac joint (188-194). Contraction of this muscle also results in a decrease in intra-abdominal volume and an increase in intra-abdominal pressure. Intra-abdominal pressure has been shown to increase rigidity of the spine, decompress the spine and resist flexion torque (195 - 197). Recent studies have attempted to rebuke the initial findings of the late 1990's, but only add nuance to our understanding of the behavior of the TVA. In studies by Morris et al., asymmetrical firing of the TVA was demonstrated with greater resistance and speed, and synergy was demonstrated between the TVA, obliques and lumbar multifidus muscles (198, 199); note these same findings were demonstrated by Hodges et al. more than a decade earlier (201, 202). Although this may seem to contradict the bilateral contraction noted above, it simply implies that the TVA contracts bilaterally and relatively equally at lower intensities, and as larger forces are generated by the limbs (either due to increased weight or velocity) activity of the TVA on the more stressed side increases to match. Because the Brookbush Institute recommends "Quadrupeds and Progressions" for TVA Activation, which includes both the purposeful recruitment of the synergy of muscles mentioned above (Intrinsic Stabilization Subsystem) and progression toward higher velocity movement patterns, BI's approach is supported by these findings. In another study by Masse-Alarie et al. (200), the bilateral activation mentioned earlier only occurred for certain patterns at higher speeds, again, this does not change recommendations, but may explain why some movement patterns or speeds are more problematic than others, especially relative to low back pain.
In 1996, Hodges et al. published a pivotal study that demonstrated the TVA fired prior to the initiation of arm swing in asymptomatic individuals, but fired after the initiation of arm swing in individuals with low back pain (203). Hodges et al. would follow-up this study with research demonstrating the same pattern also occurred during leg movement, various speeds of arm movement, and demonstrated the same recruitment pattern could be acutely created with injection induced low back pain (204-207). Further, they would show that low back pain results in not only decreased recruitment of intrinsic muscles (TVA, obliques and lumbar multifidus muscles), but increased reliance on "global muscles" (208). More recent research has demonstrated that altered recruitment patterns increased the likelihood of low back pain/injury in the following year, that unresolved altered recruitment patterns resulted in worse outcomes a year post physical therapy, changes in TVA recruitment patterns correlate strongly with a disability index, and that even adductor/groin injury/pain may result in altered TVA recruitment strategies (209 - 212). In one study, an increase in lumbar multifidus activity, but not TVA activity, was correlated with better clinical success (228). Although the findings relative to the lumbar multifidus are not surprising, the findings relative to the TVA are surprising. These findings differ from so many studies that the power of the study and sensitivity of the equipment should be considered, and the study repeated.
The practical application of TVA research is the inclusion of exercise that challenges or cues the "abdominal drawing in maneuver" (ADIM) (during Quadrupeds may be best).
- Abdominal Drawing-in Maneuver (ADIM) - A light contraction of the transverse abominis (and potentially the entire intrinsic stabilization subsystem) 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 transverse abdominis resulting in a "vacuum pose".
Low back pain has been shown to reduce the ability to perform the ADIM (214), and assessment of the ADIM has been shown to be a reliable assessment for decreased TVA function (215). ADIM preferentially recruits the TVA, to the exclusion of more superficial muscles (rectus abdominis and external obliques) (216), and cuing the ADIM increases TVA contraction during more functional tasks (217). Specific training of deep muscles results in immediate change to recruitment strategies, neutral spine has been demonstrated to result in greater TVA thickness, and somewhat strangely, adding ankle dorsiflexion to ADIM exercises increases TVA activity (218-221). Quadrupeds (TVA Activation) with cuing of the ADIM resulted in similar TVA activity in asymptomatic individuals and those with low back pain, which may suggest this exercise is ideal for normalizing recruitment patterns (222). Leg raises resulted in greater TVA activity; however, this exercise also sharply increased erector spinae activity (223), a muscle prone to over-activity. Although interventions should be specific to a low back pain patients assessed issuess, generally, stabilization exercise results in better outcomes than stretching, and a "segmental stabilization (TVA Activation)" approach results in better outcomes than global muscle training (224, 225). Correlations have been made between TVA thickness, lumbar stability and balance, which may have implications for injury prevention and sports performance (226). Using the ADIM during Pilates resulted in increased TVA thickness, but only during Pilates exercises (no carry-over) (227). This does not suggest that the ADIM should not be used by Pilates instructors, but rather that Pilates may not be an ideal exercise methodology for low back pain patients and those with goals other than Pilates performance (227). In summary, the Brookbush Institute categorizes this muscle as commonly under-active in those exhibiting LPHCD, recommends "Quadrupeds and Progressions" for TVA Activation, and ADIM should be cued during all functional activities in a clinical or performance setting.
Internal Obliques - The internal obliques can perform the same actions as the external obliques, but function and behave like the transverse abdominis relative to stabilization and altered recruitment in those exhibiting low back pain. Studies have demonstrated these muscle are active during rotation (112, 232), have the potential to contribute to side bending (233), and may contribute to flexion via transmission of force through the semilunar lines (234). However, the activity of these muscles increases with increased respiration and gait speed (similar to the transverse abdominis) (187), and are active bilaterally when lifting asymmetric loads (unlike the external obliques) (126). Studies have also demonstrated that the internal obliques are active when the spine is compressed, perhaps contributing to the "unloading" force generated when intra-abdominal pressure increases (89, 197). The internal obliques invest in the thoracolumbar fascia contributing to lateral force on the spinous process (primarily below L3), compression (force closure) of the sacroiliac joint (SIJ), and as mentioned above, increased intra-abdominal pressure via the abdominal tourniquet (188, 189, 192). Interestingly, despite behavior/activity that resembles "stabilizing" muscles that are generally smaller, the internal obliques are the thickest lateral wall muscle in adolescents when observed using ultrasound in supine (235).
It is common to see reference to "intrinsic stabilizers" and "global muscles" when discussing the function of trunk musculature (2, 8, 9, 14); this visual model aids in understanding the change in recruitment patterns noted in those with low back pain. Based on the research above, the internal obliques behave like the "intrinsic stabilizers" often implicated as under-active by research. In two studies by Ng et al., increased external obliques activity and decreased internal obliques activity was noted during static and dynamic axial rotation in those exhibiting symptoms of low back pain (229, 230). Further, decreased internal obliques activity has been noted in those with "sway back" posture, and those exhibiting SIJ pain (128, 174). Although not always mentioned, the internal obliques are commonly studied in conjunction with transverse abdominis. For example, Hodges et al. demonstrated that the internal obliques and the transverse abdominis fired before lower extremity activity in asymptomatic individuals, but both muscles demonstrated latent firing patterns in those with low back pain (185). Further, in the study by Chon et al., adding dorsiflexion to exercises using the abdominal drawing-in maneuver (ADIM) increased internal obliques as well as the TVA (221). In summary, the Brookbush Institute (BI) categorizes this muscle as commonly under-active in those exhibiting LPHCD, and considers this muscle part of the Intrinsic stabilization Subsystem (ISS), which the BI commonly addresses with "Quadrupeds and Progressions" and TVA Activation. Further, the ADIM should also be cued during all functional activities in a clinical, and/or performance settings.
Diaphragm – Hodges et al. (271) describes the relationship between breathing, diaphragm activity, and posture for a given exercise.
© 2017 Brent Brookbush">postural change as “time-locked” and potentially linked via reflex. Two studies by Hodges et al. demonstrated that stimulus of the diaphragm resulted in increased stiffness of the spine (196, 267), and various studies have noted a change in diaphragm activity during lifting, changes in position and posture for a given exercise.
© 2017 Brent Brookbush">posture, movement of the limbs, and changes in gait speed (268 - 272, 276, 279). A study by Hodges et al. (270), may give inference of how the diaphragm accomplishes respiration and stabilization concurrently. In this study repetitive upper body motion (arm swings) resulted in an increase in average diaphragm activity (EMG) (270). Further, a study by Kolar et al. demonstrated lower average activity and a higher relative position in those exhibiting low back pain (273). Based on these findings we may be able to assume that postural stability with respiration is accomplished by higher average activity and a lower relative position, decreasing intra-abdominal space and increasing intra-abdominal pressure. This pattern is disrupted in those exhibiting signs of pain and dysfunction.
Lower activity/higher relative position may be part of the compensatory pattern associated with low back pain. The studies by Kolar et al. and Hodges et al. (270, 273) mentioned above are supported with additional studies on diaphragm activity and impairment (274 – 278). Hodges et. al, demonstrated less diaphragmatic motion and activity in low back pain patients (278). Further, Vastatek et al. demonstrated that those with sacroiliac joint (SIJ) pain exhibited altered diaphragm activity during isometric lifting of the limbs; activity returned to normal when the SIJ was stabilized via manual
For example, during a squat the femoral head is compressed into the acetabulum by muscular forces, bodyweight and any additional external load.">compression of the pelvis (274). Several studies have noted increases in respiratory demand, and/or diaphragm fatigue result in a loss of lumbar stability (276-278). The studies by Jansen et al. demonstrate that low back patients are quicker to diaphragm fatigue, and that diaphragm fatigue resulted in a more rigid stabilization pattern during lifting (276, 277). Last, a study by McGill et al. demonstrated that
For example, during a squat the femoral head is compressed into the acetabulum by muscular forces, bodyweight and any additional external load.">compression and
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.">shear forces on the spine increase when ventilatory demand increases (279), which may imply that research is needed to determine the correlation between diaphragm activity and injury. Considering these studies together, the compensatory pattern adopted by the diaphragm in those exhibiting pain and dysfunction may be lower average activity, a higher relative position, with smaller excursion during respiration, which results in a more rigid (and likely weaker) stabilization strategy resulting in quicker fatigue, which in turn results in larger
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.">shear and
For example, during a squat the femoral head is compressed into the acetabulum by muscular forces, bodyweight and any additional external load.">compressive forces on the spine during motion and posture for a given exercise.
© 2017 Brent Brookbush">postural change. To date, no prospective studies are available to determine whether altered diaphragm activity and motion may increase the risk of injury; however, studies have demonstrated that altered core control and an increase risk of injury (58, 59).
Hypothesized compensation pattern of the diaphragm:
- Lower average activity
- Higher relative position
- Decrease in excrusion with respiration
- More rigid stabilization strategy (less change in response to changing stimulus)
- Quicker fatigue
- Larger shear and compressive forces on the lumbar spine
The study mentioned above by Vastatek et al. (274) implies that stabilization exercise may aid in both low back pain and diaphragm function. Further, a
Example: In the study by Makofsky et al. (1) investigating the effect of joint mobilizations on hip abductor torque, participants were randomly assigned to either:
">randomized control trial by Mehling et al. demonstrated that “controlled-breath therapy” was effective for the treatment of low back patients (280). Although core stabilization exercise are recommended by the Brookbush Institute (BI), “controlled-breathe therapy” admittedly deserves more attention. Based on the research and compensatory patter above, it may be worth testing breathing from a higher activity/lower position. Not just deep breathing in-and-out, but breathing in deeper and trying to maintain normal tidal volume from a “deeper place”. This could be added to tasks that challenges stability (e.g. standing chops).
The increase in activity with changes in posture, and the decrease in activity with increased length exhibited in those with signs of dysfunction is similar to the behavior of the TVA and internal obliques.
Intercostals - A study by Rimmer et al. seems to demonstrate that intercostal muscle activity is similar to activity of the diaphragm. That is to say, during rotation of the trunk intercostal muscle activity increased overall - this is in conjunction with the normal increase in external intercostal activity and decrease in internal intercostal activity noted during inspiration (287). Further consideration of the intercostals role in posture and motion may be inspired by their relatively high muscle spindle density (288). There is not enough research to determine maladaptive changes in length and activity relative to dysfunction; however, the potential role these muscles play in posture and proprioception should inspire further research. To date the Brookbush Institute does not recommend specific exercise or interventions for the intercostals; however, consideration is given to the ribs role in thoracic mobility in the Upper Body Dysfunction (UBD) model.
Pelvic Floor - Research concerning symptoms and pathology specific to pelvic floor dysfunction (stress urinary incontinence, female pelvic organ prolapse, pelvic floor pain, etc.) will not be covered in this section. This decision was made for 3 reasons: these topics deserve more consideration than should be covered in this article, these dysfunctions may be separate from a model of LPHCD, and to date little research has correlated specific pelvic floor pathology to LPHCD. The research discussed here is specific to pelvic floor function as it relates to LPHC function and dysfunction.
Several studies indicate that the pelvic floor muscles (PFM) behave like, and in conjunction with, the diaphragm and TVA. A study by Hodges et al. that mirrors their pivotal 1996 study on TVA activity (203), demonstrated the PFM is active prior to deltoid activation during arm swing, and activity is not direction specific (281). Sapsford et al. demonstrated that the voluntary activation of core muscles during various common exercises also recruited PFM (282). Madill and colleagues showed the reverse relationship - voluntary contractions of the PFM resulted in an initial increase in lower vaginal pressure, along with an increase in PFM, rectus abdominus, internal obliques, and TVA activity, with later increases in pressure (last 30% maximum pressure) being associated with primarily increases in rectus abdominus, internal obliques, and TVA activity (283).
One study was located that demonstrated individuals with chronic pelvic pain also had a higher incidence of signs that are commonly associated with Sarcroiliac Joint Dysfunction (LSD) (284). A relationship between the pelvic floor and the sacroiliac joint seems very plausible, if for no other reason than the potential of a change in PFM length/tension with sacral motion. A study examining whether PFM activity continues to mimic the diaphragm and TVA in those experiencing low back pain, should also be explored as a continuation of the work by Hodges et al. mentioned above (203) .
Relevant to exercise, a study Critchley demonstrated that cuing PFM contraction during the quadruped exercise increased TVA contraction strength (285). This may suggest that although the PFM fires with the TVA reflexively, the addition of a voluntary PFM contraction may stimulate further recruitment of the TVA. Pilates exercises have also shown evidence of being effective for increasing PFM muscle strength, demonstrating similar result when compared to a specific PFM program (286). Based on the function and behavior of the PFM the Brookbush Institute considers these muscles part of the Intrinsic Stabilization Subsystem (ISS) , behaving like the TVA and diaphragm. Based on the function of the PFM and the results of the study by Critchley and Culligan (285, 286) it is unlikely that specific exercise is necessary relative to LPHCD, but cuing a PFM contraction while doing ISS exercise may be beneficial.
Gluteus Maximus and Gluteus Medius - A reduction in gluteus maximus and gluteus medius activity has been correlated with pain and dysfunction of the low back, sacroiliac joint (SIJ), and all lower extremity joints, including the hip, knee and ankle (174 - 175, 180, 294 - 305). Even in the absence of pain, gluteus maximus and gluteus medius weakness has been noted in those with functional knee valgus, a loss of hip extension, an anterior pelvic tilt, and a lack of forward lean during running (62-63, 66, 173, 304 - 306). Gluteus maximus and gluteus medius weakness are such common findings in research concerning both LED and LPHCD, it may be hypothesized as the "bridge" which spreads dysfunction from one to another. Consider just a few of the studies cited in this article, Cooper et al. demonstrated the prevalence of gluteus medius weakness in those experiencing low back pain (302), Bolga et al. demonstrated gluteus medius weakness in those with patellofemoral pain (305), Cholewicki et al. demonstrated altered core muscle recruitment as a predictor of low back pain (58), Zazulak et al. demonstrated core recruitment deficits are correlated with future ACL injury (59), and another prospective study by Nadler et al. demonstrated correlation between lower extremity injury and a higher prevalence of low back pain during the season (61). Pertinent to rehabilitation and sports performance, greater gluteus medius and gluteus maximus strength has been correlated with better squatting, stair climbing, running and landing mechanics (305-310).
Several studies have shown that targeted exercise for these muscles can have a positive impact on lower extremity biomechanics and pain (308-311). In a study by Bell et al., a corrective intervention similar to that recommended in this article, improved movement quality (reduced functional knee valgus) (312), and based on two studies by Bolga et al. the intervention may not have to make measurable change in mechanics to reduce pain and dysfunction (306, 307). The notable weakness of this group of studies is the lack of research demonstrating that targeted intervention for the gluteus medius and gluteus maximus has a positive or negative effect on low back pain and LPHCD. This is not to say that the targeted intervention will not have an impact on low back pain, but that there is no research testing the hypothesis. Several studies have demonstrated altered gluteus medius and gluteus maximus recruitment patterns during extension, abduction and standing - including latent firing and reduced strength/endurance in those with chronic low back pain (298-300, 313 - 315). However, unlike research on the lower extremity, it appears no researcher has tested the efficacy of targeted exercise for the gluteus medius and gluteus maximus to correct the pattern in low back pain patients. It is important to note, that based on personal accounts and discussion with other professionals targeted intervention is common in clinical practice with great benefit to low back patients.
Research has compared various gluteus medius and gluteus maximus exercises, and to what extent over-active synergists are recruited – including tensor fasciae latae, biceps femoris and erector spinae (316 - 325). These studies suggest that hip abduction along with hip extension results in a relative increase in gluteus medius and gluteus maximus activity and/or a reduction in tensor fasciae latae and biceps femoris activity. Additionally, clams and side-lying leg raise may be effective for targeting the gluteus medius and incorporate the superior fibers of the gluteus maximus (319). Three studies suggest cues may improve gluteus maximus activity during exercise - a study by Lewis et al. suggests cuing gluteus maximus contraction (squeeze the glutes) (313), a study by Oh et al. suggests cuing the abdominal drawing in maneuver (ADIM) (318), and a study on several Pilates exercises suggested cuing “posterior pelvic tilt”(321). Finally, a study by Berry et al. demonstrated more forward lean during resisted side-stepping may also increase gluteus maximus activation (322). The Brookbush Institute uses mild hip abduction, ADIM, posterior tilting and "squeezing the glutes" as cues during gluteus medius and gluteus maximus activation exercises, and forward bending during resisted side-stepping.
Semitendinosus and Semimembranosus (Semi's) - Unfortunately, there is very little research to suggest the common compensatory pattern adopted by the Semi's in those exhibiting signs of LPHCD. Most studies examining hamstring activity use biceps femoris EMG as an indicator of overall hamstring activity (169, 173 - 175). No studies could be located that directly compared biceps femoris and Semi's activity. Considering these muscles have opposing actions in the transverse plane, measuring one or the other is likely insufficient for determining behavior of the hamstrings as a group. Several studies (mentioned above) demonstrate a decrease in hamstring extensibility during forward bending and the active straight leg raise test in those exhibiting low back pain (43, 44, 49, 50); however, this reduction in hamstring extensibility cannot be attributed to an increase in muscle stiffness (289 - 292). This may be an indicator that changes in extensibility are due to changes in relative activity/tone, reinforcing a hypothesis that over-activity is the cause of extensibility loss. One study by Guimarães et al. used the Semi's as an indicator of hamstring activity while testing the hip extension recruitment pattern, demonstrating that the Semi's fired first, then the erector spinae and last the gluteus maximus (293). This recruitment pattern is similar to studies using the biceps femoris as an indicator of hamstring activity (173, 174). Although the loss of hamstring extensibility and similarity to the biceps femoris during extension patterns seems to indicate this muscle is long and over-active, these muscles are also tibial internal rotators. Tibial internal rotators were found to be long and under-active in the Lower Extremity Dsyfunction (LED) model. More research comparing the biceps femoris and Semi's is needed.
Summary of findings:
- The evidence-based muscular model of LPHCD benefits from more research than the other predictive models of dysfunction.
- Transverse abdominis, internal obliques, diaphragm, pelvic floor and potentially the Psoas behave similarly. Dysfunction leads to under-activity and perhaps an increase in length, despite the increase in length not contributing to a joint action.
- The gluteus maximus and gluteus medius are prone to under-activity and an increase in length in both Lower Extremity Dsyfunction (LED) and LPHCD. These muscles may be "the bridge" that propagates dysfunction from one to the other. Note: the semitendinosus and semimembranosus (semi’s) may behave similarly to the gluteus maximus and gluteus medius
- The tensor fascia latae, sartorius, vastus lateralis, and rectus femoris appear to behave similarly. Although sartorius and rectus femoris activity in those exhibiting dysfunction should be researched further, research does hint at similar changes in activity to the tensor fascia latae and vastus lateralis.
- The biceps femoris, piriformis, deep rotators of the hip, and adductor magnus are over-active despite being lengthened by hip extension, and the rectus abdominis and external obliques are also over-active despite being lengthened by lumbar extension. This behavior is categorized as long/over-active and is believed to imply these muscles are acting as "over-active" synergists.
In this graph "red muscles" are over-active, note that muscles no longer appear on both sides of the table.
Lumbo Pelvic Hip Complex Dysfunction based on Muscle Research
|Lumbar Stabilizer||Lumbar Stabilizer|
|Lumbar Extensors||Lumbar Flexors|
Summary of Issues with the "Evidence-based Muscular Analysis":
The research used to construct an "evidence-based muscular analysis," when used to refine the evidence-based osteokinematic analysis, offers a more refined account of changes in muscle activity and length. This offers several advantages when creating a corrective intervention; however, more research and further analysis is needed.
- As evidenced by the following two points, more consideration should be given to lower extremity muscles and LPHCD and the link between LPHCD and Lower Extremity Dsyfunction (LED).
- Several muscles are categorized with muscles of similar functions, because insufficient research exists to assess the muscle's behavior (gluteus minimus, rectus femoris, sartorius, gracilis, semitendinosus & semimembranosus, intercostals, adductor magnus).
- Further research is needed for a few muscles that compare activity and recruitment in asymptomatic individuals and individuals exhibiting LPHC symptoms (latissimus dorsi and anterior adductors).
The Introduction of Fascia into a Predictive Model of Movement Impairment
Introduction to the Muscular and Fascial System
Our understanding of fascia has benefited from an exponential increase in research over the past two decades. This includes more research on its traditional functions as a passive medium that supports, protects, and encapsulates tissues (323), and its capacity to store elastic energy for explosive activity (324, 325). This also includes exciting new research that implicates fascia as a medium of communication. Levangin hypothesized that this may occur via electrical, cellular and/or mechanical signals (326). Histological studies have shown this tissue to be densely innervated by free nerve endings, as well as by pacinian corpuscles and ruffini endings (323, 324). This inspires consideration of fascia as a sensory organ with a strong link to motion and neuromuscular reflex. Further, Stecco et al. has demonstrated that deep fascia is arranged in layers that may 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.">slide over one another (325). This finding is likely most responsible for inspiring various fascia specific interventions, and most often referred to when describing fascia’s role in “interrupting” optimal motion. Carvalhais et al. demonstrated that tension may be transmitted through fascial sheaths to investing musculature, and Vleeming et al. has demonstrated the ability of fascia to transmit the force of multiple muscles to aid in joint stabilization (191, 201, 208, 327, 337 - 346, 376).
Research also suggests the existence of myofibroblasts within fascia, which may give fascia the ability to "contract" (151, 328, 329). This ability is limited when compared to skeletal muscle, however, this "contraction" was found to be significant enough to alter mechanics (in the lumbar spine) (328). It should be noted that contraction in this study was very slow and was the result of response to antihistaminic substance, mepyramine with some tissues also responding to histaminic substance, oxytocin (similar to smooth muscle). These myofibroblasts do not respond to electric current, tension, epinephrine, acetylcholine or adenosine. Although these findings are difficult to apply to practice currently, they do inspire more
Fascia as a Passive Tissue (Traditional Functions):
Fascia as an Active Medium of Communication
- Innervated with free nerve endings, pacinian corpuscles and ruffuni endings
- Arranged in layers that 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 growing body of research has started to investigate the effect movement impairment has on fascial tissue, and what role fascial dysfunction may play in contributing to movement impairment. This statement by Schleip is a great example of this trend, “tonic muscles contain more perimysium and are therefore stiffer than phasic muscles” (151). The terms, tonic and phasic refer to a categorization of muscles based on their roles in maintaining posture for a given exercise.
© 2017 Brent Brookbush
Fascia does seem to follow a predictable set of responses to excessive stress. This includes thickening, histochemical changes, decrease in tensile strength (increased risk of rupture), the addition of disordered collagen fibers, and potentially a reduction of shear (motion) between layers (192, 358-359, 367, 380-383). These consistent changes may have important implications for how fascia should be addressed. In practice, fascial techniques have been biased toward increasing mobility using manual therapy, for example, myofascial release techniques, instrument assisted soft-tissue mobilization (IASTM) and pin-and-stretch techniques. However, research does not paint a clear picture of how these techniques address dysfunction, and findings to date suggests that a more complex and nuanced description will likely replace current hypotheses.
Hypothesized Response to Therapeutic Intervention
Strain Hardening - In two studies, it was shown that fascia stiffens when repetitively stretched or put under static tension, and this process was termed "strain hardening" (365, 366). This process seems to be achieved (or is heavily influenced) by an increase in tissue hydration that starts returning to normal levels about 1 hour after the strain is removed. Further, repetitive strain/rest periods results in adaptation, which included a higher base level of hydration even after a recovery period (366). Note, strain hardening is likely a different process than the increase in tension hypothesized from contraction of myofibroblasts (151, 328, 329), as strain hardening was achieved in previously frozen tissues (freezing often destroys cells) (366). Evidence of "strain hardening in response to repeated lengthening" does seem to contradict the increase in extensibility reported by manual therapists using fascia intended techniques.
Improve Shear Between Layers - In a study by Levangin et al. comparing shear strain (movement between fascial planes) of the thoracolumbar fascia (TLF), a chronic low back pain group showed approximately 20% less shear strain than asymptotic controls (367). Although the TLF tissues were not directly tested for chemical, cellular or structural changes between layers, it was hypothesized that mal-adaptive cross-bridging by collagen fibers between layers may be a response to damage and inflammation and limit normal fascial motion and extensibility. Note, the application of "shearing forces" to disrupt mal-adaptive cross-bridging has been proposed as a primary mechanism and benefit of many myofascial shear (myofascial release), IASTM, and pin-and-stretch techniques.
Altered Sympathetic Tone and Local Circulation - In trying to explain the palpable change noted by manual therapists (especially during slow, deep pressure), Schleip hypothesized an "integrated systems" model of connective tissue's response to pressure - "stimulation of intrafascial sympathetic afferents (e.g. via manual medicine therapy) may trigger modifications in global autonomic nervous system tone, as well as in local circulation and matrix hydration"(358, 359). This hypothesis includes not only the hydration processes mentioned in relation to strain hardening, but stimulation of fibroblasts discussed above via sympathetic reflex arcs stimulated by receptors embedded in fascia (358, 359, 374), and the alterations in tone may include a reduction in electroymygraph (EMG) activity of related muscles (373). This integrated systems explanation of tissue response to manual pressure is likely the most complete; however, Schleip may need to add the role strain hardening plays on the "palpable tissue response."
Increased Stability: Several studies have demonstrated the ability of fascia to transmit the force of multiple muscles to aid in joint stabilization (191, 201, 208, 327, 337 - 346, 376). This may have interesting implications relative to manual therapy - the mediation of fibroblast activity via sympathetic reflex arcs and strain hardening may increase fascial stiffness, improving force transmission from invested musculature, joint stability and arthorkinematic motion. However, further explanation would be needed to explain the "palpable" feelings of release and increased mobility. Further implications of fascias role in stabilization is hypothesized "myofascial synergies" that incorporate multiple muscles, transmitting force through a fascial sheaths, to aid in stabilization and motion. This has a profound impact on exercise that is discussed below under "Myofascial Synergies".
In summary, the role of fascia and it's response to intervention are complex. This includes strain hardening by repetitive or constant tension, decreased shear and the potential of cross-bridging between fascial layers, changes in both muscle tone and fibroblast mediated pre-tension via deep sustained pressure, and fascias role in transmitting the force of multiple muscles to stabilize a joint. These roles are used as the rationale for techniques that include static release techniques, IASTM techniques, pin-and-stretch, and stabilization/activation exercise. Below the fascial structures that have the largest impact on the lumbo-pelvic hip complex (LPHC) are discussed.
Fascia's Response to Fascia Directed Intervention:
- Strain hardening
- Improve Shear Between Layers
- Altered Sympathetic Tone and Local Circulation
- Enhanced Joint Stability
The thoracolumbar fascia (TLF) is likely the most well researched fascial structure. Much of the research cited on the potential of fascial tissue to contribute to movement, dysfunction and/or pain seems to be based on research performed on the TLF (6, 326-328, 335, 352, 354, 357-360, 366-367). The TLF can be described as a 3 layer system, with the posterior layer having a deep and superficial laminae (layers), and the anterior layer often being omitted from movement analysis because it is thought to be too thin to contribute to lumbar stability (192, 337). (The anterior layer may be continuous with the posterior abdominal fascia). The division of the TLF into 3 layers (or 4 if counting the two layers of the posterior layer separately), is often described as a 2 layer system in research, combining the two laminae of the posterior layer and omitting the anterior layer all together. The 3 layer system is used in this article.
Anatomy - The superficial laminae of the posterior layer is continuous with the latissimus dorsi, serratus posterior inferior, gluteus maximus, as well as part of the external obliques and lower trapezius (6, 192, 330 - 334). Medially, the majority of the superficial layer is bordered by the supraspinous ligament and spinous process cranial to L4, but fibers do cross to attach to the contralateral sacrum, PSIS and iliac crest (6). Some fibers of the TLF, arising from the gluteus maximus, also cross the mid-line attaching to the opposite sacrum, PSIS or lateral raphe (6, 192, 333). The deep laminae of the posterior layer runs continuous from the splenius capitis and cervicis, superficial rhomboids, envelops the erector spinae (acting as a retinaculum), and is continuous with the sacrotuberous ligament and potentially the biceps femoris (192, 334, 337). The middle layer of the TLF extends from the transverse processes, between the quadratus lumborum and erector spinae, and runs continuous with the aponeurosis of the transverse abdominis and internal obliques (192, 330-334). The deep laminae of the posterior layer and middle layer fuse to form the lateral raphe, which may be thought of as a thickening of the middle layer to reinforce the attachment of the abdominal tourniquet muscles (192, 337). As mentioned above, the anterior layer is generally given little attention; the thinnest of the 3 layers it likely does not contribute much to lumbar stability or force transmission between muscles (192, 337), but may be continuous with the posterior abdominal fascia, abutting the transverse fascia and perotineum.
- Posterior layer (Superficial laminae derived from the aponeurosis of the latissimus dorsi and serratus posterior inferior) investing muscles:
- Posterior layer (Deep laminae - retinacular sheath of the erectors) investing muscles:
- Middle layer (Combines with Deep Laminae of Posterior Layer at LIFT to form Lateral Raphe) investing muscles:
- Anterior layer (Thin) investing muscles (May be continuous with posterior layer of abdominal fascia):
By Anatomist90 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=17900177; Thoracolumbar fascia. Notice the lighter colored band of tissue. This is the fascia.
Stability - Several studies have implicated the TLF as instrumental to lumbar spine and sacroiliac joint (SIJ) stability (191, 201, 208, 337 - 346). Some of these studies imply the significance of the role of the TLF indirectly; that is, via the attachment of the transverse abdominis and internal obliques and their contribution to lumbar and SIJ stability (191, 201, 208, 338). Other studies have directly tested increased tension in the TLF and its impact on lumbar rigidity using cadavers (334, 339 - 340). A model proposed by Vleeming et al. further supports the importance of the TLF (and investing musculature) to SIJ stability, suggesting that the bumps, ridges and friction coefficient of the intra-articular surfaces of the SIJ (form closure) are insufficient to stabilize the joint without additional compression from muscles and connective tissue (force closure) (340, 341). Studies by Cisco et al., Vleeming et al. and Richardson et al. reinforced this assertion, demonstrating increased SIJ stability with muscle activity and form closure (191, 194, 342). Additional evidence for the importance of the TLF's role in stability of the LPHC is the review of muscle behavior discussed in this article, and how many of these muscles would not directly impact the lumbar spine, SIJ or pelvis if not for their investment in the TLF (including the sacrum and sacrotuberous ligament).
Contribution to motion - The TLF was originally thought to aid in lumbar extension, but further research refuted this hypothesis (343 - 347). However, several studies have noted that the TLF may aid in resisting lumbar flexion (aid in eccentric deceleration) by increasing in length while decreasing in width (192, 334, 347). "Traction studies" (studies in which force is applied to the TLF in a similar way to a particular set of muscle fibers would pull on the TLF), aids in understanding the ability of the TLF to communicate or transfer force. The amount of displacement of fascial tissue and the distance displacement of fascial tissue occurs away from the site of traction are indicators of the ability of fascia to communicate force from one muscle to another structure. Several studies have demonstrated displacement, especially when replicating the force from the latissimus dorsi, gluteus maximus (superficial posterior layer of TLF), transverse abdominis and internal obliques (middle layer of TLF) (162, 327, 335, 348).
Results from Vleeming et al. (348):
- Traction of trapezius muscle - ipsilateral displacement up to 2 cm
- Traction to the cranial muscle fibers of the latissimus dorsi - ipsilateral displacement up to 2–4 cm
- Traction to the caudal part of the latissimus dorsi - ipsilateral displacement 8 - 10 cm up to the midline
- Between L4–L5 and S1–S2 levels, the displacement spread to the contralateral side.
- Traction to the gluteus maximus ipsilateral and contralateral displacement up to 4 to 7 cm.
Additionally, studies have demonstrated similar recruitment between muscles linked by the TLF. Kim et al. demonstrated contralateral muscle activity of the latissimus dorsi and gluteus maximus during gait, which increased when speed increased or weights were held (348). Hodges et al. demonstrated a relationship between increased arm speed and recruitment of ipsilateral and contralateral trunk musculature (tourniquet/middle layer TLF) (201). Stevens et al. demonstrated the co-contraction of various muscles investing in the TLF during a "quadruped" exercise (349). Last, DeRiddler et al. demonstrated the recruitment of muscles investing in the deep posterior layer of the TLF during an extension exercise (350). An interesting study by Schuenke et al. demonstrates the complexity and necessity for intramuscular coordination of muscles investing in the TLF (356). In this study, inflation of the deep posterior layer by extensor muscles altered the moment arm and load angle of muscles investing in the superficial posterior layer and middle layer of the TLF (356). This could imply that the force, action and function of individual muscles could be altered when the order of muscle recruitment is altered (as seen in those with low back pain). Further, Huskins et al. proposed a model that demonstrated that the deep laminae (extensor retinaculum) could aid in increasing the force output of the erector spinae by up to about 30%, by restricting its radial expansion (364).
Sensory Innervation - Various studies and texts have implicated fascia, and the TLF specifically, as a sensory organ closely tied to neurmuscular reflex, motion, dysfunction and pain. The presence of corpuscular receptors in the posterior layer of the TLF is commonly described by the older studies - such as Golgi, Pacini and Ruffini endings which imply a role in proprioception (352-354). Interestingly, the most recent study (using modern methods) by Tesarz et al. failed to find such corpuscular endings, with the exception of possible Ruffini endings (354). If the TLF does plays a role in proprioception it would likely be indirect through forces imparted on the supraspinous, interspinous and iliolumbar ligaments, which are abundantly innervated by Pacinian receptors and Ruffini endings (352, 361). However, additional studies show that these receptors may only be stimulated at end range as limit detectors which implies they have less of a role in mid-range (362-363).
The study by Tesarz et al. did find that the TLF was especially dense in free nerve endings, presumably nociceptors, in the posterior layer (354). These findings are supported by several studies as research in this area has increased in recent years (355, 557 - 559). Although these findings do not support the notion of the TLF as a proprioceptive organ, they do support the hypothesis that micro-trauma and inflammation of the TLF may contribute to low back pain. There is additional evidence to suggest that an increase in sympathetic activity, and/or inflammation may "sensitize" the posterior layer of the TLF contributing to an increase in nociception (357-359). The role of the TLF in low back pain was originally discussed by Hirsh in 1963 (352), revisited as a potential mechanism for chronic low back pain by Punjabi in 2oo6 (356), and beautifully summarized in the quote below by Vleeming (192):
Quote from Vleeming et al. (192):
- To summarize, the sensory innervation of the TLF suggests (may imply) at least three different mechanisms for fascia-based low back pain sensation: (1) microinjuries and resulting irritation of nociceptive nerve endings in the TLF may lead directly to back pain; (2) tissue deformations due to injury, immobility or excessive loading could also impair proprioceptive signaling, which by itself could lead to an increase in pain sensitivity via an activity-dependent sensitization of wide dynamic range neurons; and finally (3) irritation in other tissues innervated by the same spinal segment could lead to increased sensitivity of the TLF, which would then respond with nociceptive signaling, even to gentle stimulation.
Fascial Mobility, SIJ Stability and Practice -
As mentioned above a study by Levangin et al. compares shear strain (movement between fascial planes) of the TLF in those with and without a history of low back pain (367). It was proposed that mal-adpative cross-bridging in response to tissue damage and inflammation may have reduced movement between layers. The Brookbush Institute does recommend IASTM techniques with the intent of disrupting these cross-bridges; however, careful consideration must be given to the irritability of the patient and the receptor density of the TLF.
Perhaps the most obvious application of TLF research is a focus on activation and strengthening of investing musculature with the goal of increased stability of the lumbar spine and SIJ. Mooney et al. showed the effectiveness of rotary exercises for the treatment of SIJ dysfunction (368), and many of the previously mentioned studies by Richardson et al., Hides et al, Hodges et. al. and Morris et al. have demonstrated the efficacy of transverse abdominis and internal oblique activation/strengthening for stabilization of the lumbar spine and SIJ, and treatment of low back pain (157-159, 194-196).
In conclusion, mobility and/or activation techniques may result in positive changes. Current studies suggest that manual therapy and other myofascial modalities may increase TLF stiffness, while increasing shear (movement) between layers, effect tone of fibroblasts and investing musculature, while activation and strengthening of investing musculature may improve stability of the lumbar spine and SIJ. Care should be taken in addressing these tissues directly, as there is evidence to suggest that the TLF could be a source of nociceptive input for those suffering from chronic low back pain. The Brookbush Institute does recommend IASTM techniques and Posterior Oblique Subsystem Integration (POS) (discussed below) based on these findings.
Anatomy - The rectus sheath envelopes the rectus abdominis anteriorly and posteriorly. From the costal cartilage to the the arcuate line (the level of the umbilicus), the anterior sheath is comprised of a continuation of the external oblique fascia while the posterior sheath is comprised of a continuation of the internal oblique and transverse abdominis fascia. Note, some texts suggest the internal oblique fascia splits, contributing to both anterior and posterior rectus sheaths (6). Below the level of the arcuate line the posterior sheath does not continue, and the fascia of the internal obliques, external obliques and transverse abdominis continue anterior to the rectus abdominis. Posteriorly, deep to the fascia of the internal oblique and transverse abdominis, the transverse fascia (not to be confused with the fascia of the transverse abdominis) lines the abdominal muscles, quadratus lumborum, psoas, inferior surface of the diaphragm, and blends with the fascia of the iliacus; lying between the deep (investing) fascia and the perotineum (18). Based on texts and current research, it is difficult to determine if there is continuity between the deep fascia of the transverse abdominis, the anterior layer of the TLF and the inferior layer of fascia lining of the diaphragm, in addition to, or perhaps in conjunction with transverse fascia, although it seems likely. The pyramidalis actually lies within the anterior rectus sheath, from pubis to approximately half the distance to the umbilicus. The fascial layers of the abdomen converge at the linea alba, where they continue into identical fascial sheaths on the opposite side. The linea alba, running down between the two rectus abdominis muscles, is itself a thickening created by the crossing of transverse oriented fibers of the fascial sheaths (14). The transverse inscriptions that run through the rectus abdominis are also continuations of the oblique fascia (192). In addition, the pectoralis major invests in the abdominal fascia, and the serratus anterior invests in the external oblique fascia (6, 16, 370, 371), which invites ideas of an anterior myofascial synergy extending from shoulder to femur.
- Anterior layer (Combines with deep laminae of posterior layer of the TLF at LIFT to form the lateral raphe) investing muscles:
- Posterior layer (Does not exist below arcuate line and may be continuous with anterior layer of TLF) investing muscles:
Function - Any lateral, posterior, or rotational force imparted on the trunk will result in an increase in rectus abdominis, pyramidalis, external obliques, internal obliques, and transverse abdominis activity (14), and potentially an increase in quadratus lumborum and psoas activity (89, 93, 115). This increase in muscle activity will also result in an increase tension of the abdominal fascia, transverse inscriptions and linea alba, and any force imparted by one muscle will be transmitted between layers of abdominal fascial network (372, 373). The corset like effect of this myofascial synergy has been discussed by several researchers/authors, contributing to Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., & 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. ">force closure of the sacroiliac joints and pubic symphysis, an increase in intra-abdominal pressure, posterior shift of the abdominal viscera into the lumbar vertebrae, and enhanced force transmission from the lower to upper extremities (6, 14, 18, 192, 219, 264, 348). Vleeming makes the following analogy (6) - like the thoracolumbar fascia (TLF), the abdominal fascia features muscles encased in a fascial network. The paired rectus abdominis muscles are encased in the fascia of investing muscles (transverse abdominis, internal obliques and external obliques). Tension in these muscles increases tension in the abdominal fascia like the latissimus dorsi and gluteus maximus increases tension in the TLF.
The relationship between internal obliques and transverse abdominis with the abdominal fascia and the middle layer of the TLF completes the loop necessary to create a tourniquet or belt that may aid in lumbar spine and SIJ stability via increased compression and intra-abdominal pressure. The selection of exercises with the intent of targeting these muscles has been discussed above and will be discussed further under the heading Intrinsic Stabilization Subsystem (ISS). Further, the anterior layer of fascia along with the fascia of the rectus abdominis and external obliques may imply a synergy of muscles known as the Anterior Oblique Subsystem (AOS) which also has implications for exercise selection.
To our knowledge only one study could be located that may imply the efficacy of a technique directed at the abdominal fascia. In this study deep, slow pressure resulted in a decrease in muscle activity (370). Admittedly, this is not a common or comfortable technique to apply to the abdomen. If manual pressure is applied a tangential force is recommended to reduce discomfort. No studies could be located that investigated IASTM on the abdominal region, but based on the idea that shear between layers may be reduced as a result of dysfunction, careful application in practice may be warranted, especially where the layers converge at the semilunar lines and lateral raphe of the TLF.
Several of the muscles discussed above, invest in, and may increase tension in the sacrotuberous ligament. The biceps femoris and gluteus maximus seem particularly adept at increasing tension in this structure (191, 377); however, the piriformis, semitendinosus, semimembranosus, obturator internus and multifidus have also been implicated due to their attachments (378). The Brookbush Institute considers the adductor magnus part of this group due to the attachment of fibers from the ichiocondylar (posterior) head to the sacrotuberous ligament; however, there is a void in the literature regarding this muscle. Of importance to the development of the Lower Extremity Dysfunction (LED) and LPHCD ">models is the role these muscles have on stabilization and/or dysfunction of the sacroiliac joint (SIJ). Studies by Vleeming et al. have shown that contraction of the muscles mentioned can increase tension of the sacrotuberous ligament, and contribute to Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., & 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. ">force closure of the SIJ (191, 375-376). Further, increased tension of the sacrotuberous ligament via muscular contraction can resist nutation (376, 377), and potentially contribute to altered movement patterns and arthrokinematic 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.">dyskinesis of the SIJ, lumbar spine, pelvis and potentially the hip via muscles crossing from femur to sacrum.
As mentioned above, the piriformis, biceps femoris and adductor magnus are prone to over-activity. This over-activity may result in increased tension of the sacrotuberous ligament and limit sacral nutation during functional activities. Although further research is needed, a limit to sacral nutation would be congruent with various components of the LPHCD (as well as LED) model. It is the Brookbush Institute's recommendation that the sacrotuberous ligament is treated indirectly via release of the investing muscles and mobilization of the SIJ. Although deep pressure to the sacrotuberous ligament is likely possible, no benefit has been seen in practice, and no research to date has investigated efficacy. The sacrotuberous ligament and research cited above also play a role in exercise selection as part of the Deep Longitudinal Subsystem (DLS) discussed below.
Muscles investing in the sacrotuberous ligament:
- Gluteus maximus
- Obturator internus
- Biceps femoris
The iliotibial band is a thickening of the fascia lata of the leg, creating a complex network of investing structures. Based on studies by Faircough et al. and Stecco et al. the ITB invests in the following (379, 380):
- Iliac Spine
- Gluteus Maximus
- Tensor Fasciae Latae (TFL)
- Vastus Lateralis
- Biceps Femoris
- Patellar tendon
- Lateral collateral ligament (LCL)
- Lateral intermuscular septum with strong attachment to the lateral femoral condyle
- Lateral patellar retinaculum
- Fascial slips to Gerdy’s tubercle (just inferior to the lateral tibial plateau)
- Fibular head
- Anterior tibiofibular ligament
These research studies by Faircough et al. and Stecco et al. are what inspired consideration of the TFL, vastus lateralis and ITB as a synergy involved in resisting hip extension and adduction, and the vastus lateralis being treated in conjunction with the TFL in those exhibiting LPHCD. That is, although the vastus lateralis is not a hip flexor or abductor, it may contribute to LPHCD by increasing tension in the ITB. Further, the ITB creates a bridge for the propagation of dysfunction from LPHCD to the knee and Lower Extremity Dysfunction (LED). As mentioned above, the ITB also invests in the biceps femoris adding another powerful tibial external rotator to the synergy. Over-activity of this synergy may contribute to tibial external rotation noted in feet turn out, as well as knees bow in (combination of tibial external rotation and femoral internal rotation in a closed chain), and inadequate anteriorFor 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.">glide of the fibular head. Although a relationship between the TFL and biceps femoris can be deduced from their common action as external rotators of the tibia, the synergy establishes a rationale for why release of vastus lateralis (commonly and mistakenly referred to as “foam rolling the iliotibial band”) is often effective in alleviating knee pain. The relationship between the ITB and gluteus maximus is harder to explain. This muscle is prone to under-activity, and therefore, cannot be a contributor to dysfunction/diagnoses that are related to increased stress. The gluteus maximus should likely be viewed as a muscle that pulls the entire lower extremity/ITB synergy as a unit. That is, the gluteus maximus acts as an antagonist, providing an opposing force to the synergy as a whole. The gluteus maximus is also the bridge between the ITB with the TLF (6), linking two of the largest fascial systems in the body.
The ITB is often considered a source of dysfunction and pain. Several studies investigating knee pathology have noted the same histochemical changes seen in dysfunction of other fascial structures (379 - 383). Although a couple of case reports have been published on myofascial release and instrument assisted soft-tissue mobilization (IASTM) applied directly to the ITB, these publications did not demonstrate better outcomes or additional benefit when compared with release, stretching or activation of the muscles investing in the ITB (384-385). In practice, the Brookbush Institute has noted that interventions that address the ITB directly (myofascial release, pin-and-stretch, IASTM) tend to be very uncomfortable, and offer little benefit relative to objective outcomes. Addressing the investing musculature, and considering the ITB as the fascial component of a synergy that includes the TFL, vastus lateralis, and biceps femoris has proven an effective addition to an integrated approach to treatment, and superior to ITB directed techniques.
Summary of Findings:
- Fascial dysfunction results in a predictable set of changes to the tissue including thickening, histochemical changes (which may stimulate nociceptors and pain), decrease in tensile strength, the addition of disordered collagen fibers, and a reduction in shear.
- The TLF, abdominal fascia, ITB and sacrotuberous ligament are invested by multiple muscles, and may play an important role in the synergistic function of those muscles.
- The TLF, abdominal fascia, and iliotbial band are layered, and may be a site of restriction due an interruption of “sliding layers”.
- Research on techniques directed at these fascial structures is lacking; however, evidence does support treating investing musculature. (This is not to imply that fascial techniques do not work, only that they have not been well researched.)
Research leading to the development of
Under-active Posterior Oblique Subsystem (POS):
- Lower Trapezius
- Latissimus Dorsi
- Thoracolumbar Fascia (Superficial Posterior Layer)
- Contralateral Gluteus Maximus
- Gluteus Medius (via the gluteal fascia)
The muscles that comprise the POS are the largest in the body. This subsystem plays a significant role in transferring force between lower and upper extremities, is involved in all pulling and rotational movement patterns (especially turning out), multi-segmental extension, and eccentrically decelerates spinal flexion and rotation, as well as hip flexion, adduction and internal rotation (knees bow in and excessive forward lean).
Several studies have demonstrated the synergistic function of these muscles, force transfer between the latissimus dorsi and gluteus maximus via the thoracolumbar fascia, and the contribution of the POS to lumbar and sacroiliac joint stabilization (6, 191-192, 201, 208, 330 – 334, 337 – 346). These are larger muscles, and seemingly in congruence with the “law of parsimony,” appear to be recruited at higher intensities, but may not act as prime movers during low intensity tasks (such as walking) (387). At all intensities, the POS must work in conjunction with the Intrinsic Stabilization Subsystem (ISS) and Deep Longitudinal Subsystems (DLS) (specifically the erector spinae, biceps Femoris, and multifidus (350, 387).
As mentioned above, a reduction in gluteus maximus and gluteus medius activity has been correlated with pain and dysfunction of the low back, sacroiliac joint (SIJ), and all lower extremity joints, including the hip, knee and ankle (74, 180, 297, 302, 303, 310). Even in the absence of pain, gluteus maximus and gluteus medius weakness has been noted in those with functional knee valgus, a loss of hip extension, an anterior pelvic tilt, and a lack of forward lean during running (62, 63, 173, 303, 304, 310, 317). Most pertinent to practice, greater gluteus maximus strength has been correlated with better landing mechanics, running mechanics, and squat mechanics (66, 303, 304, 308, 309, 317).
In asymptomatic individuals, the latissimus dorsimuscle behaves like a global mover of the spine, demonstrating a marked increase in activity during the initiation of squat and stoop lifts and asymmetrical activation during trunk rotation (126, 165). A correlation between a loss of shoulder flexion and LPHCD has been noted clinically, which has lead to the
Based on research, the function of the POS, and the impairments noted (gluteus maximus and gluteus medius weakness) in the LPHCD ">model, it is our
Under-active Intrinsic Stabilization Subsystem (ISS):
- Posterior layer of abdominal fascia
- Anterior layer of thoracolumbar fascia
- Continuous with investing fascia of Diaphragm and Pelvic Floor
- Transverse Fascia?
The muscles that comprise the ISS are the same muscles that have been referred to as intrinsic stabilizers, proximal stabilizers, and segmental stabilizers of the lumbar spine (1-3, 6-9, 14). Their categorization as stabilizers is the result of research demonstrating an ability to increase tension in the thoracolumbar fascia (TLF), increase tension in the abdominal fascia, resist rotation and extension torques, increase stiffness of the lumbar spine, and contribute to force closure of the sacroiliac joint (188 - 194). Further, these muscle are responsible for increasing intra-abdominal pressure, which may also increase rigidity of the spine, as well as contribute to decompression forces and resist flexion torque (195 - 197, 267). By integrating fascial research and research on motor control with the concept of "subsystems", it is the Brookbush Institute's intent to develop a single model of core muscle behavior that may aid in exercise/intervention selection.
The activity of the transverse abdominis, internal obliques, diaphragm and pelvic floor are incredibly similar relative to function and dysfunction. These muscles show an increase in activity with increases in respiration, gait speed, increases in intra-abdominal pressure, compressive loads on the spine, increase in center of gravity and changes in posture, are are active bilaterally even with asymmetric loads, and fire prior to movement of the upper or lower extremities in asymptomatic individuals (89, 126, 128. 174, 184-189, 192, 197, 213, 268-272, 276, 279). Further, decreased activity (and/or latent firing) has been demonstrated in those exhibiting "sway back" posture, low back pain and SIJ pain, (128, 174, 266-267, 274-278, 284), resulting in altered recruitment patterns that more heavily rely on "global muscles" (AOS and DLS) (208).
Similarities in function and behavior also exist between the multifidus, psoas, and quadratus lumborum (QL). All 3 muscles seemingly play a larger role in frontal plane stabilization than sagittal plane stabilization or motion, as evidence by EMG studies (93, 114, 115, 118-121). For example, unilateral carries may result in larger increases in activity than activities that resist traditionally assigned joint actions. Further, all 3 muscles are prone to atrophy in those exhibiting low back pain; often atrophy is sided and specific to the affected segment (94-100, 110, 131-136, 143). Unlike the transverse abdominis, internal obliques, diaphragm and pelvic floor - the multifidus, psoas, and QL seem to be more prone to over-activity and may respond well to release techniques (16, 146, 149-151, 154, 551).
The link between these muscles may be several layers of continuous fascia. Deep to the fascia of the internal oblique and transverse abdominis, the transverse fascia (not to be confused with the fascia of the transverse abdominis) lines the abdominal muscles, quadratus lumborum, psoas, inferior surface of the diaphragm, and blends with the fascia of the iliacus. This layer is between the deep (investing) fascia and the perotineum (18). The fascia of the internal obliques and transverse abdominis completes a loop, investing in the posterior layer of abdominal fascia, and the middle layer of the TLF (192, 330 - 334, 337). The middle layer of the TLF also would be continuous with the laminae enveloping the multifidus. The published research that is missing is the layer between the transverse fascia and the "middle layer" fascia. That is, does the internal layer of transverse abdominis fascia run continuous with the anterior layer of the TLF (which envelopes the psoas and QL) and with the fascia of the pelvic floor or diaphragm. The continuity of this fascial linings seems likely but more research is needed.
All of the muscles of the ISS are prone to either under-activity or atrophy, resulting in the categorization of the ISS as under-active as a system. Studies support the use of the abdominal drawing-in maneuver (ADIM), Quadrupeds, stabilization type exercise, perhaps with the addition of dorsiflexion, pelvic floor activation and controlled breathing for addressing ISS under-activity (214 - 216, 218-222, 224-225, 280, 285-286). The Brookbush Institute includes these cues in the progression recommended for TVA Activation. However, it would be more accurate to title these exercises, as well as all exercises targeting the transverse abdominis, "ISS" activation.
Consider how bilateral contraction of the TVA would increase tension on the thoracolumbar fascia, pulling laterally on both sides simultaneously increasing rigidity. Further, consider how an increase in pressure anterior to the lumbar vertebrae would resist and anterior translation and shear. - http://www.bandhayoga.com/online-courses/online-courses/shaktitest/images/Blog/b38_thoraco-lumbar_section.jpg
Over-active Anterior Oblique Subsystem (AOS)
- External Obliques
- Rectus Abdominis and Pyramidalis
- Abdominal Fascia (Anterior Layer)/Linea Alba
- Contralateral Anterior Adductors
The muscles that comprise the AOS are also large, but have less mass than the the muscles of the POS. This subsystem plays a significant role in transferring force between lower and upper extremities, is involved in all pushing and rotational movement patterns (especially turning in), multi-segmental flexion, and eccentrically decelerates spinal extension and rotation, as well as hip extension, abduction and external rotation. Although a bit over-simplified, it may be worth considering this to be the anti-rotation/anti-extension subsystem, and a primary mechanism of defense against acute lumbar injuries. When this subsystem is over-active it may also contribute to hip flexion, adduction and internal rotation (knees bow in and excessive forward lean).
A few publications indicate that their may be a relationship between the sacroiliac joint, pubic symphysis, anterior abdominal activity and adductor activity (6, 174, 388-390). Discussing this relationship with the addition of abdominal muscle motor control studies can be complicated, but if considered from the perspective of how the adductors are involved and how facial continuity may play a role, the relationship can be presented with more clarity. In a study by Snijders et al., it was found that crossing the legs decreased the activity of the internal obliques (390). It is hypothesized that crossing the legs altered adductor activity and force imparted on the pubis, resulting in a reduction in activity by the internal obliques to equalize force on the pubis. In another study on individuals with sacroiliac joint pain, adductor activity remained unchanged (along with TFL, biceps femoris) while internal oblique, lumbar multifidus, and gluteus maximus activity decreased or fired later (174). This could be viewed as a relative increase in adductor activity (along with TFL and biceps femoris) when SIJ kinematics are affected. Linking the abdominal musculature to SIJ kinematics, several studies have demonstrated that anterior abdominal muscle activity increases tension on the thoracolumbar fascia (TLF) resulting in increased stiffness of the lumbar spine and force closure of the sacroiliac joint (188-194). Although, these studies do not directly support the relationship between the anterior abdominal muscles and the adductors, it may be evidence of the importance of fascia role in transmitting the force of multiple muscles to stabilize joints, and an intricate relationship between the SIJ, pelvis and abdominal muscles. Relative to the "abdominal fascia", any increase (or decrease) in abdominal muscle activity will also result in a change in tension of the abdominal fascia, transverse inscriptions and linea alba, and any force imparted by one muscle will be transmitted between layers of abdominal fascial network (372, 373). The strongest continuity between the abominal fascia and adductors may exist between the rectus abdominis and adductor longus tendons (see image below).
Note: Relationship of the serratus anterior and pectoralis major muscles will be considered in the predictive ">model of Upper Body Dysfunction (UBD), as these muscles has no other relationship to the LPHC.
As mentioned above, over-activity of the adductors has been correlated with knees bow in (62-63, 66), and it may be presumed based on function (and research on dysfunction and over-activity of the external obliques and rectus abdominis) that an over-active AOS may contribute to an excessive forward lean. Based on this, our
Fascial Attachment between Rectus Abdominis and Adductor Tendons
Over-active Deep Longitudinal Subsystem (DLS)
- Erector Spinae
- Posterior Layer of the thoracolumbar fascia (deep laminae)
- Sacrotuberous Ligament
- Biceps Femoris
- Head of Fibula
- Fibularis Longus (aka Peroneals)
It is likely easiest to consider the function of the DLS relavite to gait. Optimally, the DLS would eccentrically decelerate hip flexion, knee extension and supination during late phase swing, stabilize the sacroiliac joint (SIJ) and arch of the foot during heel strike, and aid in propulsion during early stance and push-off phases. Further, this myofascial synergy may act as a proprioceptive mechanism to relay information about ground reaction forces upon heel strike, ensure adequate but not excessive pronation, and as a product of the proprioceptive information relayed to the CNS – result in optimal recruitment of prime movers during mid-stance and push-off.
The synergistic relationship, or at least similar recruitment pattern noted between the erector spinae and biceps femoris has been well documented during the push-off phase of gait. It may be important to note that this synergy also plays a role in other extension type exercises, for example quadruped with opposite arm/leg raise and reverse-hypers (350, 391). Pertinent to LPHCD, several studies show a trend toward earlier onset and increased activity of erector spinae and biceps femoris in those with low back pain (392-393). As mentioned earlier, the increased activity of erector spinae and biceps femoris is often paired with a reduction in gluteus maximus activity (POS activity) (173-175). Leinonen et al, demonstrated this relationship precisely, showing earlier and increased activity of the erector spinae and biceps femoris and a reduction in gluteus maximus activity during gait in those with low back pain (392). If the synergy does arise from fascial integration, it is likely through the complex network of fascia and ligaments of the lumbosacral region. Specifically, Vleeming et al. showed that the erector spinae and biceps femoris contribute to Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., & 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. ">force closure of the SIJ via the thoracolumbar fascia and sacrotuberous ligaments (190), and van Wingerden et al. demonstrated that “Tension in the long dorsal sacroiliac ligament increased during loading of the ipsilateral sacrotuberous ligament and erector spinaemuscle (191).”
As mentioned earlier, several studies by Vleeming et al. have shown that contraction of the biceps femoris can increase tension of the sacrotuberous ligament, contribute to Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., & 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. ">force closure of the SIJ, and this increased tension may resist nutation (181, 191, 375, 377). One of the primary functions of this myofascial synergy may be to stabilize the SIJ during heel strike to ensure a stable “platform” from which the gluteus maximus may generate force. It is our
Note: The piriformis, semitendinosus, semimembranosus, obturator internus and multifidus may also been implicated in this synergy due to their attachments and ability to increase tension in the sacrotuberous ligament (378).
The last connection to be made in this synergy is between the biceps femoris and the fibularis muscles. The most obvious connections are anatomical connections, as both the biceps femoris and the fibularis muscles insert on the fibular head. Further the iliotibial band (ITB) invests in the fibular head, invest in the biceps femoris via the lateral intermuscular septum, and continues into and over the fibularis muscles with a more expansive attachment into the anterior tibiofibular ligament (often continuous with the biceps femoris tendon) and crural fascia (379, 380, 394). Note, consideration of the iliotibial band may implicate a relationship between the DLS and a myofascial synergy noted earlier that include the ITB, TFL and vastus lateralis. Although, no further research examining muscle activity between the biceps femoris and the fibularis muscles could be located, an arthrokinematic relationship may also exist. Over-activity of the biceps femoris (along with muscles investing in the ITB) would result in excessive posteriorFor 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.">glide of the proximaltibiofibular joint. The tendons of the fibularis muscles pass behind the lateral malleolus in a groove, and may be able to 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.">glide the distaltibiofibular jointanteriorly. It has been hypothesized that the tibiofibular joints (distal and proximal) move in opposition to one another due to the fiber arrangement of the interosseous membrane. That is, posteriorFor 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.">glide of one will result in anteriorFor 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.">glide of the other. As both biceps femoris and the fibularis muscles are prone to over-activity, motion of the proximal and distal tibiofibular joints may add a biomechanical link to this synergistic relationship.
Based on this research, the function of the DLS, and the impairments noted in the LPHCD ">model, it is our
Summary of Myofascial Synergy Findings:
- Research specific to myofascial synergy adds to our understanding of how groups of muscles (synergies) may be recruited, and how the force they generate may be summated to aid in stabilization of a joint and/or multi-joint motion.
- The categorization implied in the evidence-based muscular and fascial models above can be applied to myofascial synergies.
- The POS has a propensity toward under-activity.
- The addition of an ISS unites motor control and myofascial synergy research, for a more comprehensive model of core behavior. Note: the ISS is typically under-active in those exhibiting dysfunction.
- The AOS, although important for stabilizing the pelvic girdle, has propensity toward over-activity. In instances of an assessed anterior pelvic tilt, some activation may be necessary initially.
- The DLS has a propensity to become over-active and synergistically dominant for an inhibited/under-active POS.
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 Posterior Oblique Subsystem (POS) integration exercise.
Summary of the Subsystem involvement in LPHCD:
|LPHCD||DLS||ISS --> POS||AOS –> POS|
An Evidence-based Arthrokinematic Model:
As mentioned earlier, if various approaches are effective for different reasons (as implied by their varied intents), than an integrated approach may have the potential to improve outcomes by addition of these benefits. Based on this premise, a weakness of the previous analyses (Traditional, Osteokinematic, Muscular, Fascial and Myofascial Synergies) is a failure to consider the effectiveness of well established joint-based approaches. For example, osteopathic medicine, chiropractics, Cyriax/Maitland, Mulligan, Paris, etc.. Although measuring small amounts of arthrokinematic motion poses a considerable challenge for researchers, the body of research is growing. Further, several studies have noted a change in muscular activity as a result of joint mobilizations (401, 413, 414), implying some interdependence between the muscular and articular systems. In this “level of analysis” an attempt is made to aggregate all relevant research on altered arthrokinematics associated with impairments of the lower extremity (LED).
Knee: Inadequate anterior glide of the tibia on the femur (the lateral compartment may be more restricted)
- It is hypothesized that arthrokinematic dysfunction of the tibiofemoral joint results from inadequate anterior glide of the tibia on the femur during terminal extension. This hypothesis is congruent with the over-activity of the biceps femoris noted in the "Evidence-based Muscular Analysis". Further, it may be hypothesized that the lateral compartment may be more restricted as evidenced by the over-activity of all external rotators of the tibia (TFL, vastus lateralis, biceps femoris via the ITB) and the common occurrence of functional valgus (knees Bow In) (femoral internal rotation, tibial external rotation) noted in the "evidence-based osteokinematic model." Unfortunately, direct evidence of these altered arthrokinematics is not available. One study showed that rotation played a larger roll than glide in terminal knee extension during weight bearing activities (395), which may partially explain the clinical observation of passive accessory stiffness of the knee being less common than stiffness in other joints of the lower extremity (ankle, tibiofibular joints, hip). That is, osteokinematic motion plays a larger role than arthrokinematic restriction. An exception to this observation, would be the stiffness noted post knee surgery. Indirect evidence of the direction of arthrokinematic dysfunction exists, as the majority of studies on knee joint mobilization use either posterior to anterior tibia on femur mobilizations, or anterior to posterior femur on tibia mobilizations. Knee mobilizations have proven very effective for reducing pain (396, 398-399, 404-405), increasing range of motion (ROM) in those exhibiting limitation (228,230,232), improving function (although not in all cases, additional strengthening may be necessary) (396, 400, 403), quality of motion (397), and may result in an immediate increase in quadriceps strength and activity (401).
- Although excessive lateral glide of the patella is an often cited dysfunction, in recent years it has been widely accepted that this is due to forces related to a functional valgus (knees bow in). These forces may include altered quadriceps angle (Q-angle), tibial external rotation, femoral internal rotation, increased tension on the lateral retinaculum via the iliotibial band (ITB), and potentially a decrease in VMO activity. A way to visualize the relationship is to imagine knees bow in underneath a patellae that stays in place, ending up on the lateral side of the femoral condyles. A wonderful review of this relationship can be found in a paper published in 2003 by Christopher M. Powers, PhD (406). Not surprisingly, no recent studies could be located that investigated the use of patellofemoral mobilizations alone, although some evidence exists that patellofemoral mobilizations may be effective when used in conjunction with other therapeutic modalities (407, 408). It is the stance of the Brookbush Institute that correcting Lower Extremity Dysfunction (LED) or LPHCD is a better treatment option for patellofemoral pain, and that mobilization of the patellofemoral joint is rarely necessary or effective, and should only be considered an adjunct therapeutic modality.
Hip: Inadequate posterior and inferior glide of the femur in the acetabulum
- There is a surprisingly scarce amount of research on hip arthrokinematics and the effects of hip mobilization. Research has called for a better understanding of arthrokinematics and femur-labrum contact, asserting that bone-on-bone models are insufficient (410). Another study on osteoarthritic patients demonstrated that pain during the FABER and FADIR tests could be explained by fibrotic shortening of the inferior capsule, resulting in an increase in capsule stretching, stretching of the investing sensory nerves, muscle spasm, and a reduction in arthrokinematic motion increasing compressive forces (411). Although this is a great study, it can only lead to more hypotheses to be tested. Research has demonstrated that the the femur may glide anterior and posterior in the acetabulum (409, 410). Inferior, anterior and posterior mobilizations of the hip have shown promising results for improving range of motion, muscle strength and reducing pain (410-412). Superior to inferior Grade IV mobilizations increased range of motion and gluteus medius strength, and Grade IV posterior to anterior mobilizations increased gluteus maximus strength (413-414). In the study by Loubert et al, it was shown that end range anterior to posterior mobilizations were necessary to improve hip flexion ROM, and that mobilizations performed in a more neutral hip position resulted in little if any change (412). Examining the methods used in the 3 studies on mobilizations cited in this section, all mobilizations were performed in or near end range (412-414). Based on the current research the Brookbush Institute (BI) recommends end range, Grade III and IV hip mobilizations, done prior to activation techniques. Further, BI hypothesizes that the femur has a propensity to excessively glide anterior and superior in the capsule. This is based on the increase in activity noted in posterior hip muscles (piriformis, deep rotators) and femoral internal rotators (tensor fasciae latae (TFL), gluteus minimus) and a hypothesized fibrotic shortening of the inferior and posterior capsules. The direction of mobilization most often performed by the Brookbush Institute is lateral distractions at end range hip flexion and internal rotation.
Lumbar Spine: Combination of Hyperemobile and Hypomobile Segments
- Arthrokinematic dysfunction in the lumbar spine cannot be described by direction (i.e. inferior glide, closed, extended, etc.) with currently published research; however, there is some evidence to describe patterns of stiffness and altered translation (timing) of vertebrae during flexion and extension. These patterns are complicated by the alterations being noted while in motion, primarily in mid-range, rendering studies using end-range radiographs less reliable, and studies using lumbar range of motion as an outcome measure less significant (415 - 431). A study by Teyhen et al. may provide the best data relative to motion of the lumbar spine in those exhibiting dysfunction (432). Using digital fluoroscopy, the study attempted to identify a sub-group of individuals suffering from low back pain (LBP) who would benefit from a stability exercise program (hyper-mobile participants). The findings suggest a mixture of excessive motion at L3 and L5/S1 segments and lag from L4, L5 segments during the first 15° of flexion and during 65° - 75° of extension, with little difference in imaging noted between groups at end range (Note: study was limited to L3 - S1 segments). (432). The motion described here supports a hypothesis about the "neutral zone" and altered motion originally published by Panjabi in 1992 (neutral zone = the zone in which connective tissue does not provide support)(433, 434), and adds detail to studies describing step wise motion of vertebral segments with inter-segmental lag in those exhibiting dysfunction (420, 421, 435). The contribution of lag to dysfunction may also explain why some studies show a stronger correlation between LBP and a reduction in movement velocity than LBP and a loss of ROM (57).
- The relationship between lag and stiffness is not clear due to the effects of muscular activity, but a relationship likely exists. In two studies, PA mobilization reduced bending stiffness (436-437); in one of these studies it was demonstrated that stiffness returned to near the levels of asymptomatic individuals with a significant decrease in pain (437). Although direct reference is not mentioned in the body of research, PA mobilizations with the intent of reducing stiffness seem to correspond well with PA mobilizations decreasing inter-segmental lag and hypomobility (420, 421, 432 - 435). Further, PA mobilizations have been shown to be effective for reducing pain, increasing range of motion and increasing function in those with LBP (438 - 446). Note, studies have shown mobilizations do not decrease stiffness, alter lumbar intervertebral motion or increase ROM in asymptomatic individuals (447 - 449). Further, some of the reduction in stiffness post PA mobilization may be a result of increased water diffusion in the inter-vertebral disk (456-457).
- PA mobilizations result in extension of lumbar segments (except L5/S1 which flexes) (450 - 454). It may be important to note the subtle variations in the direction of force applied during a PA (i.e. more cranial or caudal) may affect the stiffness noted by the therapist; however, this may be more important in research settings (452-452). It should also be noted that force applied to one segment affects adjacent segments (450-451).
- Studies have also demonstrated that hyper-mobility may be more associated with LBP symptoms (455. 458). Rather than consider this evidence in contradiction to research on PA mobilizations and stiffness, the research on aberrant motion in mid-range may indicate both hypo-mobile segments resulting in lag, and hyper-mobile segments that move early and excessively, exist in the same individual. It may also be possible that those segments that lag are hyper-mobile, but restrained by altered muscle activity. Several studies have noted altered muscle activity immediately following lumbar mobilizations (459 - 468). Note: returning to the "Evidence-based Myofascial Model" will highlight the relationships between altered muscle activity and low back pain.
- There are those who have proposed that the impact mobilizations/manipulations have on a patient's perceived pain and function is purely neural, and several studies have noted significant neural phenomenon including increased cutaneous pain tolerance (469), altered motorneuron excitability (as measured by H-reflex) (470, 471), change in pain and skin cunductance without objective changes in movement (motion not tested under fluoroscopy) (472, 473), and improved joint position sense (474). However, based on the effectiveness of mobilizations, the mechanical changes noted in stiffness and aberrant motion under dynamic flourascopy, and several studies that successfully demonstrated changes in ROM, it seems far more likely that mobilizations result in neural, mechanical, and muscular changes.
- In summary, dysfunction of the lumbar spine may be described as aberrant motion in mid-range. This aberrant motion may be due to a combination of segments that move early and excessively (hyper-mobile) and those that lag behind (hypo-mobile). The research trends toward "inter-segmental lag"; that is, hyper-mobility of the L5/S1 and upper lumbar segments, with stiffness noted in L2 - L4 segments (420, 421, 432, 435, 478) (note: individual differences likely occur, for example, hyper-mobility at L3/L4 or stiffness as high as T12). Mobilizations may be effective for decreasing joint stiffness (hypomobility), as well as reducing pain, increasing function, altering motor neuron excitability, and improving muscle activity. Further, it is recommended that mobilizations are followed by activation/stabilization exercise to address hypo-mobile segments. The effectiveness of stabilization exercise for LBP is discussed in the "Evidence-based Muscular Model" above, especially in the section titled "Transverse Abdominis". It is recommended by the Brookbush Institute, and supported by several studies that a combination of mobilizations and specific stabilization exercise are likely the best approach to addressing lumbar spine dysfunction (475-477).
Lumbar Spine Mobilization
Sacroiliac Joint (SIJ) - Asymmetric Stiffness/Laxity
- Much like the lumbar spine, the arthrokinematic dysfunction of the sacroiliac joints (SIJ) cannot be described by direction or position with currently published research. (i.e. excessive inferior glide, compression, nutation, subluxation, etc.). However, there is some evidence to imply asymmetrical changes in joint stiffness/laxity. Although, controversy existed regarding whether motion occurred at the SIJ, more recent research using roentgen stereophotogrammetric motion analysis (RSA) show small but significant motions. Garras et al. demonstrated that single leg stance resulted in pubic motion of 1.4 mm of motion in men, 1.6 mm in nulliparous (never given birth) women, and 3.1 mm in multiparous women (480); note, the pubic symphysis cannot move without concurrent motion of the SIJ. In several studies, Sturesson et al. investigated the mean SIJ mobility around the sagittal axis in patients with pelvic girdle pain. Average mobility was about 40% less for men than women, and mobility either increased or remained unchanged with age (up to 50 years old, the oldest participants in the study) for both "supine to sitting" and "standing to prone with hyperextension"(480-484). Note, Vleeming et al. demonstrated sacroiliac joint rotation of up to 4° in embalmed cadavers of elderly individuals (369). Motion studies also demonstrate upright standing may result in close-packed position for the SIJ, nutation increases in load-bearing situations (e.g. standing and sitting), and more nutation is present during prone versus supine lying (481, 483-484).
- Additional controversy existed on whether the sacroiliac joint could be a source pain (nociception), especially in those with chronic, non-specific low back pain. Again, over the last several decades confirmation of SIJ involvement has been confirmed with more advanced techniques, namely fluoroscopy guided injections (488 - 493). New referral pain maps, theories of etiology and potential mechanisms of pain and injury (anterior capsule strain/tears, ligament stress) have been proposed (485-487, 491, 494-495).
- Although both hypomobility and hypermobility (instability) have been proposed as the cause of SIJ dysfunction and related pain; two studies on pregnant woman may have resulted in a better hypothesis. Vleeming's summary of findings, "The conclusion of these latter studies (496-497) is that a relationship exists between pelvic asymmetric laxity and the severity of complaints (498)". This quote may serve as a model of arthorkinematic dysfunction that explains some of the contradictions in research, including why either SIJ mobilizations/manipulations, or specific stabilization exercises are effective, but not always effective. It seems logical that if asymmetry is the primary issue than assessment of which side is relatively hyper/hypomobile, and specifically targeting the appropriate side with the appropriate technique, is more important than the effectiveness of either technique alone. Studies on low back pain with concurrent SIJ pain/dysfunction (none of which included pregnant woman) may further support this model of asymmetry, noting a correlation between low back pain and asymmetries in hip ROM, foot pronation, and trunk and hip neuromuscular imbalances (499 - 505). A few of these studies should be highlighted - The study by Cibulka et al. compared low back pain to low back pain with SIJ dysfunction. The patients with low back pain had significantly greater hip external rotation than hip internal rotation bilaterally, whereas those with evidence of sacroiliac joint dysfunction showed the same trend unilaterally - specifically on the side of posterior innonimate (500). The study by Nadler et al. is worth noting, as it demonstrates that the presence of asymmetry correlated with increased occurrence of future episodes of low back pain (502). Last, the study by Renkawitz et al. provides implications for practice, demonstrating that the resolution of imbalances also resolved symptoms (503).
- In addition to hypermobility and hypomobility, SIJ dysfunction and SIJ manipulation have a significant effect on muscle activity. This is not surprising as several studies have demonstrated joint manipulations resulting in local muscle activity changes (401, 413, 414). Further, a model proposed by Vleeming et al. suggests that the bumps, ridges and friction coefficient of the intra-articular surfaces of the SIJ (form closure) are insufficient to stabilize the joint without additional compression from muscles and connective tissue (force closure) (340, 341). Studies by Cisco et al., Vleeming et al. and Richardson et al. reinforced this assertion, demonstrating that trunk muscle activity provides additional stability via form closure (191, 194, 342). Changes in trunk muscle activity have also been noted in response to changes in standing postures and SIJ motion/stability (484, 506, 508, 509). Several studies have noted the adoption of compensatory patterns of muscle activity by those exhibiting symptoms of SIJ dysfunction. This includes delayed onsets of the IO, lumbar multifidus (LM), and gluteus maximus (GMax), decreased diaphragm excursion and lower decent of the pelvic floor (275, 526), and increased activity of bicep femoris (BF) (74, 507). Adding implications for practice, laxity values of the SIJ decrease after application of a pelvic belt in patients with pelvic girdle pain (511 - 514), and Hu et al. demonstrated that pelvic belts decrease trunk muscle activity during an active straight leg raise (510).
- Again, like the lumbar spine, it is likely that mobilizations and manipulations of the SIJ result in a combination of neural, mechanical and muscular changes. In a study by Marshal et al., SIJ manipulation improved activation timing of the transverse abdominis (TVA) in those exhibiting SIJ dysfunction and altered TVA activity (515). Fox demonstrated that SIJ manipulation and hamstring stretching may be more effective than hamstring stretching alone (516), and Cibulka demonstrated that SIJ manipulations may have an immediate effect on hamstring peak torque in those with hamstring strains (521). Likely due to altered biomechanics, muscular activity and neuromuscular control, Méndez-Sánchez et al. demonstrated an immediate change in plantar pressure distribution after bilateral SIJ manipulations, and Son et al. showed SIJ mobilization decreased pain and improved balance (517, 525). Three studies have shown a decrease in quadriceps inhibition post SIJ manipulation, which may have interesting implications for those with patellofemoral pain (518-520). In congruence with research on manipulation of other regions of the spine (470-471), SIJ manipulations decreases H-reflex ipsilaterally (522 - 524, 542). Last, several studies have demonstrated the effectiveness of SIJ mobilizations relative to pain and function (527 - 529). An interesting note that may highlight the inter-dependence of the LPHC, the study by Kamali et al. demonstrated that SIJ manipulation in combination with lumbar manipulation was more effective than SIJ manipulations alone. Last, and most important to the hypothesis of asymmetry, two studies have demonstrated that mobilizations aid in reducing asymmetries in stiffness and weight distribution (530, 531). In summary, these studies imply that the effect of SIJ mobilizations/ manipulations is due to a complex set of changes in muscular activity, neuromuscular control and balance, altered H-reflex, SIJ stiffness and asymmetry that may result in reduced pain and improvements in function.
- Research generally finds specific stabilization exercise effective for treatment of SIJ pain and dysfunction, but studies do exist that contradict these findings. When considered from the perspective of "asymmetric stiffness" and the importance of assessment, the research findings may be understood. More studies find specific stabilization exercise effective for reducing pain and dysfunction (368, 552-557), than those that do not (538, 539). As mentioned in the study by Monticome et al., the difference may be due to the increased effectiveness of stabilization exercise when individuals with SIJ pain and dysfunction were also assessed as "hypermobile" (535). Further, as mentioned by Mooney et al (368) it may be important that the exercise returns muscle recruitment to normal, i.e. correcting asymmetries and compensation patterns. Last, several studies have demonstrated that exercise in conjunction with other techniques (manipulation, acupuncture, "standard physical therapy") is more effective than specific stabilization exercise alone (525, 536, 537) - this may allude to the need to address both stiffness and stabilization, albeit very indirectly. The two studies that were located that showed specific stabilization exercises ineffective were related to pregnancy (pregnant or peripartum period), and the studies did not include any assessment of instability or asymmetry (540, 541). In both studies pelvic stabilization belts were more effective than exercise, which may imply that the exercises used were not specific to assessment findings (or lack of assessment), and/or that these women had such instability that exercise was no longer effective and medical intervention is recommended (e.g. injections). Note. these studies contradict the results noted by Kluge et al. and Stuge et al. (532 - 534).
- It should be noted that lack of assessment for instability or stiffness in a research study is more than a methodological or research quality concern. There are significant issues with the reliability of SIJ motion assessments. Although pain provocation test clusters have shown reliability (543 - 546), movement assessment other than roentgen stereophotogrammetric analysis (528) are likely unreliable, even when computed tomography is used (547-549). This may be due in part to mobilizations resulting in no assessed change in arthrokinematic joint position (528, 544); reinforcing the hypothesis that dysfunction is related to stiffness/laxity not subluxation or position change. Further research is needed to determine a cluster of assessments that have high specificity and sensitivity for determining the stiff or hypermobile side, and/or innominate position. The BI recommends the movement testing cluster of Gillet's (Stork) Test, relative height of inferior angle of anterior superior iliac spine (ASIS), and relative height of inferior angle of posterior superior iliac spine (PSIS). Although this assessment cluster may not be currently supported by research, the results have proven to be consistent in clinic for determining the stiff side and innominate position. The BI continues to create more detailed directions and simplified protocols, both of which should improve reliability. Further, because the painful side can be either the hypermobile or hypomobile, it is the BIs assertion that this assessment cluster is likely far more accurate than "an educated guess based on subjective exam" when used to determine intervention.
- In summary, SIJ motion is small but significant to function, and dysfunction of the SIJ (hypermobile or hypomobile) may be a source of pain. It is likely that pain is not a result of joint position, but a result of asymmetric changes in laxity/stiffness. These asymmetric changes may also result in changes to muscle activity and recruitment, altered motion of proximal joints, and changes in balance/stability. Assessment is recommended to determine stiff (hypomobile) and unstable (hypermobile) sides, it is BIs assertion (as well as the assertion of Cibulka et al.(500)) that the stiff side most often correlates with the side of the relatively posterior tilted innominate. Manipulation/mobilization is recommended to treat the stiff side, and specific stability exercise (gluteus maximus activation and TVA activation) is recommended for the unstable side. Proximal joints should be assessed and treated appropriately.
Sacroiliac Joint Mobilization:
Symptoms, injuries and diagnoses associated with Lumbo Pelvic Hip Complex Dysfunction (LPHCD):
The Lumbo Pelvic Hip Complex Dysfunction (LPHCD) model is constructed based on research demonstrating the maladaptive alterations of tissues and motion associated with common impairments of the human movement system. If we create a list of these impairments, this adds to the definition of the LPHCD model, as the model itself could be defined as the expected maladaptive changes to arise from those impairments.
- Low Back Pain (24, 26-27, 30-31, 33-35, 37, 39-58, 65, 71, 95, 97-100, 110, 116, 131-132, 134, 144, 147-160, 166-170, 172, 203-206, 208-210, 212, 214, 218-219, 221-222, 224-225, 228, 229-231, 249-250, 256, 264, 276-277, 280, 290-293, 298-302, 314-315, 339-353, 357, 360, 388, 392-393, 418, 421, 422, 437, 438, 440-441, 445-446, 455-456, 458, 460, 465-466, 475-477, 485-487, 494, 499, 500-505)
- Disk Herniation (133, 136-143, 444)
- Spondylolisthesis (29, 32, 428)
- Instability/Hypermobility (146, 175, 426, 429-435, 462, 478)
- Sacroiliac Joint Pain (36, 38, 74, 174, 194, 275, 368-369, 389, 488-493, 500, 507, 515, 525-527, 529-530, 535, 544-546, 549)
- Sciatica (94, 96, 135)
- Peripartum Pelvic Pain (496-497, 511, 513-514, 532-534, 537-542)
- Knee Pain and Medial Knee Displacement (59-64, 66-70, 82, 303, 305-308, 310-312, 381-385, 396-408, 518-520)
- Hamstring Strain (521)
- Hip Pathology (180, 410-411)
- Snapping Iliopsoas Tendon (102-109)
- Adductor and Groin (77, 78, 211)
- Piriformis Trigger-point (182)
- Chronic Pelvic Pain (284)
I hope you have enjoyed this article. I believe it is the first attempt at integrating a postural dysfunction/movement impairment model with osteokinematic, muscular, fascial, myofascial synergy, motor control and arthrokinematic based approaches. Further, I have attempted to be as thorough in my review of relevant research as possible in pursuit of a comprehensive evidence-based model. If you take a moment to review the bibliography you will also notice it is is sub-divided into categories for easy review on any topic addressed in this article. It is my sincere hope that readers will have suggestions for additions to the bibliography, or alternate interpretations of the research cited as we continue to pursue optimal practice. Although this article represents a giant leap from my previous analysis, there is still a tremendous amount of work to be done.
- Phillip Page,Clare Frank, Robert Lander, Assessment and Treatment of Muscle Imbalance: The Janda Approach © 2010 Benchmark Physical Therapy, Inc., Clare C. Frank, and Robert Lardner
- Shirley A Sahrmann, Diagnoses and Treatment of Movement Impairment Syndromes, © 2002 Mosby Inc
- Dr. Mike Clark & Scott Lucette, “NASM Essentials of Corrective Exercise Training” © 2011 Lippincott Williams & Wilkins
- Florence Peterson Kendall, Elizabeth Kendall McCreary, Patricia Geise Provance, Mary McIntyre Rodgers, William Anthony Romani, Muscles: Testing and Function with Posture and Pain: Fifth Edition © 2005 Lippincott Williams & Wilkins
- Karel Lewit. Manipulative Therapy: Musuloskeletal Medicine © 2007 Elsevier
- Andry Vleeming, Vert Mooney, Rob Stoeckart. Movement, Stability & Lumbopelvic Pain: Integration of Research and Therapy. (c) 2007 Elsevier Limited
- Craig Liebenson, Rehabilitation of the Spine: A Practitioner’s Manual, (c) 2007 Lippincott Williams & Wilkins
- Stuart McGill, Low Back Disorders: Second Ediction © 2007 Stuart M. McGill
- 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
- Keith, A. (1923). Hunterian Lectures on Man's Posture: Its Evolution and Disorders: Given at the Royal College of Surgeons of England. British medical journal, 1(3251), 669.
- Ober, F. R. (1936). The role of the iliotibial band and fascia lata as a factor in the causation of low-back disabilities and sciatica. JBJS, 18(1), 105-110.
- Sackett, D. L., Rosenberg, W. M., Gray, J. M., Haynes, R. B., & Richardson, W. S. (1996). Evidence based medicine: what it is and what it isn't. Bmj, 312(7023), 71-72.
- Clark, M. A. (2001). Integrated training for the new millennium. Thousand Oaks, CA: National Academy of Sports Medicine.
- Donald A. Neumann, “Kinesiology of the Musculoskeletal System: Foundations of Rehabilitation – 2nd Edition” © 2012 Mosby, Inc.
- Leon Chaitow, Muscle Energy Techniques: Third Edition, © Pearson Professional Limited 2007
- 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,© 1999 Williams and Wilkens
- Cynthia C. Norkin, D. Joyce White, Measurement of Joint Motion: A Guide to Goniometry - Third Edition. © 2003 by F.A. Davis Company
- Schleip, R., Findley, T. W., Chaitow, L., & Huijing, P. Fascia: The Tensional Network of the Human Body: The science and clinical applications in manual and movement therapy, 1e. Churchill Livingstone, 1.
- Janda V. Muscle weakness and inhibition (pseudoparesis) in back pain syndromes. In: Grieve GP, editor. Modern manual therapy of the vertebral column. New York: Churchill-Livingston; 1986. p. 197-201.
- Correlations between angles and pathology
- Legaye, J., & Duval-Beaupere, G. (2005). Sagittal plane alignment of the spine and gravity: a radiological and clinical evaluation. Acta Orthop Belg, 71(2), 213-20.
- Legaye, J., Duval-Beaupere, G., Hecquet, J., & Marty, C. (1998). Pelvic incidence: a fundamental pelvic parameter for three-dimensional regulation of spinal sagittal curves. European Spine Journal, 7(2), 99-103.
- Vaz, G., Roussouly, P., Berthonnaud, E., & Dimnet, J. (2002). Sagittal morphology and equilibrium of pelvis and spine. European spine journal, 11(1), 80-87.
- Levine, D., & Whittle, M. W. (1996). The effects of pelvic movement on lumbar lordosis in the standing position. Journal of Orthopaedic & Sports Physical Therapy, 24(3), 130-135.
- During, J., Goudfrooij, H., Keessen, W., Beeker, T. W., & Crowe, A. (1985). Toward Standards for Posture: Postural Characteristics of the Lower Back System in Normal and Pathologic Conditions. Spine, 10(1), 83-87.
Roussouly, P., Gollogly, S., Berthonnaud, E., & Dimnet, J. (2005). Classification of the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the standing position. Spine, 30(3), 346-353.
- Evcik, D., & Yücel, A. (2003). Lumbar lordosis in acute and chronic low back pain patients. Rheumatology international, 23(4), 163-165.
Christie, H. J., Kumar, S., & Warren, S. A. (1995). Postural aberrations in low back pain. Archives of physical medicine and rehabilitation, 76(3), 218-224.
Cromwell, R. L., Newton, R. A., & Carlton, L. G. (2001). Horizontal plane head stabilization during locomotor tasks. Journal of motor behavior, 33(1), 49-58.
Spondylolysis, spondylolisthesis and spondylitis result in different lumbar angle
Hanson, D. S., Bridwell, K. H., Rhee, J. M., & Lenke, L. G. (2002). Correlation of pelvic incidence with low-and high-grade isthmic spondylolisthesis. Spine, 27(18), 2026-2029.
Jackson, R. P., & McManus, A. C. (1994). Radiographic Analysis of Sagittal Plane Alignment and Balance in Standing Volunteers and Patients with Low Back Pain Matched for Age, Sex, and Size: A Prospective Controlled Clinical Study. Spine, 19(14), 1611-1618.
Harrison, D. D., Cailliet, R., Janik, T. J., Troyanovich, S. J., Harrison, D. E., & Holland, C. (1998). Elliptical modeling of the sagittal lumbar lordosis and segmental rotation angles as a method to discriminate between normal and low back pain subjects. Clinical Spine Surgery, 11(5), 430-439.
- Marty C, Boisaubert B, Descamps H, Montigny JP, Hecquet J, Legaye J, Duval-Beaupère G.The sagittal anatomy of the sacrum among young adults, infants and spondylolisthesis patients.Eur Spine J2002 ; 11 : 119-125.
- Norton, B. J., Sahrmann, S. A., & Van Dillen, L. R. (2004). Differences in measurements of lumbar curvature related to gender and low back pain. Journal of Orthopaedic & Sports Physical Therapy, 34(9), 524-534.
- Schultz, A., Andersson, G., Ortengren, R., Haderspeck, K., & Nachemson, A. (1982). Loads on the lumbar spine. Validation of a biomechanical analysis by measurements of intradiscal pressures and myoelectric signals. JBJS, 64(5), 713-720.
- Lumbosacral Pain, Asymmetry and loss of Lumbar Lordosis
- Cibulka, M. T. (1999). Low back pain and its relation to the hip and foot. Journal of Orthopaedic & Sports Physical Therapy, 29(10), 595-601.
- Cibulka, M. T., Sinacore, D. R., Cromer, G. S., & Delitto, A. (1998). Unilateral hip rotation range of motion asymmetry in patients with sacroiliac joint regional pain. Spine, 23(9), 1009-1015.
- Harrison, D. D., Cailliet, R., Janik, T. J., Troyanovich, S. J., Harrison, D. E., & Holland, C. (1998). Elliptical modeling of the sagittal lumbar lordosis and segmental rotation angles as a method to discriminate between normal and low back pain subjects. Clinical Spine Surgery, 11(5), 430-439.
- Maigne, J. Y., Aivaliklis, A., & Pfefer, F. (1996). Results of sacroiliac joint double block and value of sacroiliac pain provocation tests in 54 patients with low back pain. Spine, 21(16), 1889-1892.
- Murray, E., Birley, E., Twycross-Lewis, R., & Morrissey, D. (2009). The relationship between hip rotation range of movement and low back pain prevalence in amateur golfers: an observational study. Physical Therapy in Sport, 10(4), 131-135.
- Porter, J. L., & Wilkinson, A. (1997). Lumbar-hip flexion motion: a comparative study between asymptomatic and chronic low back pain in 18-to 36-year-old men. Spine, 22(13), 1508-1513.
- No Relationship (between pain and lordosis)
- Nourbakhsh, M. R., Moussavi, S. J., & Salavati, M. (2001). Effects of lifestyle and work-related physical activity on the degree of lumbar lordosis and chronic low back pain in a Middle East population. Clinical Spine Surgery, 14 (4), 283-292.
- Youdas, J. W., Garrett, T. R., Egan, K. S., & Therneau, T. M. (2000). Lumbar lordosis and pelvic inclination in adults with chronic low back pain. Physical therapy, 80(3), 261-275.
- Hip Range of Motion and Low Back Pain
- Chesworth, B. M., Padfield, B. J., Helewa, A., & Stitt, L. W. (1994). A comparison of hip mobility in patients with low back pain and matched healthy subjects. Physiotherapy Canada, 46(4), 267-274.
- Jones, M. A., Stratton, G., Reilly, T., & Unnithan, V. B. (2005). Biological risk indicators for recurrent non-specific low back pain in adolescents. British journal of sports medicine, 39(3), 137-140
- and 35
- More external range of motion than internal range of motion
- Ellison, JB., Rose, S., Sahrmann, S. (1990). Patterns of Hip Rotation Range of Motion: A Comparison Between Healthy Subjects and Patients with Low Back Pain. Phys Ther 1990. 70: 537-541
- Esola, M. A., McClure, P. W., Fitzgerald, G. K., & Siegler, S. (1996). Analysis of lumbar spine and hip motion during forward bending in subjects with and without a history of low back pain. Spine, 21(1), 71-78.
- Van Dillen, L. R., Bloom, N. J., Gombatto, S. P., & Susco, T. M. (2008). Hip rotation range of motion in people with and without low back pain who participate in rotation-related sports. Physical Therapy in Sport, 9(2), 72-81.
- Vad, V. B., Bhat, A. L., Basrai, D., Gebeh, A., Aspergren, D. D., & Andrews, J. R. (2004). Low back pain in professional golfers. The American journal of sports medicine, 32(2), 494-497.
- Loss of hip flexion/hamstring extensibility
- van Dieën, J. H., Cholewicki, J., & Radebold, A. (2003). Trunk muscle recruitment patterns in patients with low back pain enhance the stability of the lumbar spine. Spine, 28(8), 834-841.
- Citation 39 - 41 demonstrate similar findings to this category
- Rebain, R., Baxter, G. D., & McDonough, S. (2002). A systematic review of the passive straight leg raising test as a diagnostic aid for low back pain (1989 to 2000). Spine, 27(17), E388-E395.
- Altered motion (changes in coordination between hip and spine during sitting, standing and turning)
- Shum, G. L., Crosbie, J., & Lee, R. Y. (2005). Effect of low back pain on the kinematics and joint coordination of the lumbar spine and hip during sit-to-stand and stand-to-sit. Spine, 30(17), 1998-2004.
- Wong, T. K., & Lee, R. Y. (2004). Effects of low back pain on the relationship between the movements of the lumbar spine and hip. Human movement science, 23(1), 21-34.
- Lee, R. Y., & Wong, T. K. (2002). Relationship between the movements of the lumbar spine and hip. Human movement science, 21(4), 481-494.
- Shum, G. L., Crosbie, J., & Lee, R. Y. (2007). Movement coordination of the lumbar spine and hip during a picking up activity in low back pain subjects. European spine journal, 16(6), 749-758.
- Mok, N. W., Brauer, S. G., & Hodges, P. W. (2004). Hip strategy for balance control in quiet standing is reduced in people with low back pain. Spine, 29(6), E107-E112.
- Nelson, J. M., Walmsley, R. P., & Stevenson, J. M. (1995). Relative lumbar and pelvic motion during loaded spinal flexion/extension. Spine, 20(2), 199-204.
- Marras, W. S., & Wongsam, P. E. (1986). Flexibility and velocity of the normal and impaired lumbar spine. Archives of Physical Medicine and Rehabilitation, 67(4), 213-217.
- Tie between low back pain and knee valgus
- 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
- Zazulak, B. T., Hewett, T. E., Reeves, N. P., Goldberg, B., and Cholewicki, J. (2007). Deficits in neuromuscular control of the trunk predict knee injury risk. The American journal of sports medicine, 35(7), 1123-1130
- Leetun, D. T., Ireland, M. L., Willson, J. D., Ballantyne, B. T., & Davis, I. M. (2004). Core stability measures as risk factors for lower extremity injury in athletes. Medicine & Science in Sports &
- Nadler, S. F., Wu, K. D., Galski, T., & Feinberg, J. H. (1998). Low back pain in college athletes: a prospective study correlating lower extremity overuse or acquired ligamentous laxity with low back pain. Spine, 23(7), 828-833.
- Similar muscular and range of motion deficits
- Padua, D. A., Bell, D. R., & Clark, M. A. (2012). Neuromuscular characteristics of individuals displaying excessive medial knee displacement. Journal of athletic training, 47(5), 525.
- 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, 27(7), 1813-1823
- Knees Bow Out
- Noda, T., & Verscheure, S. (2009). Individual
- Cynthia C. Norkin, D. Joyce White. Measurement of Joint Motion: A Guide to Goniometry 3rd Edition. Copyright (C) 2003 by F.A. Davis Company
- Hip Extension
Mellin, G. (1988). Correlations of hip mobility with degree of back pain and lumbar spinal mobility in chronic low-back pain patients. Spine, 13(6), 668-670.
- Tensor Fascia Latae
Assessments used by human movement professionals can be divided into three broad categories:
- "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.
- 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.
- Highlight Contraindications - Tests, assessments and evaluations used to stratify risk or preclude a professional from addressing certain tissues, motions or using a particular technique.
- 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.
- 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.
- Most movement assessments fall into this category. For example, a positive Ely's Test may indicate a need to release and/or lengthen the rectus femoris.
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!"
Ober, F. R. (1936). The role of the iliotibial band and fascia lata as a factor in the causation of low-back disabilities and sciatica. JBJS, 18(1), 105-110.
Beck, M., Sledge, J. B., Gautier, E., Dora, C. F., & Ganz, R. (2000). The anatomy and function of the gluteus minimus muscle. Bone & Joint Journal, 82(3), 358-363.
Walters, J., Solomons, M., & Davies, J. (2001). Gluteus minimus: observations on its insertion. Journal of anatomy, 198(2), 239-242.
Robinson, P., Barron, D. A., Parsons, W., Grainger, A. J., Schilders, E. M. G., & O’Connor, P. J. (2004). Adductor-related groin pain in athletes: correlation of MR imaging with clinical findings. Skeletal radiology, 33(8), 451-457.
- Rectus Femoris, Vastus Lateralis and Sartorius
Nene, A., Byrne, C., & Hermens, H. (2004). Is rectus femoris really a part of quadriceps?: Assessment of rectus femoris function during gait in able-bodied adults. Gait & posture, 20(1), 1-13.
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Bogduk, N. P. M. H. G., Pearcy, M., & Hadfield, G. (1992). Anatomy and biomechanics of psoas major. Clinical Biomechanics, 7(2), 109-119.
Santaguida, P. L., & McGill, S. M. (1995). The psoas major muscle: a three-dimensional geometric study. Journal of biomechanics, 28(3), 339343-341345.
Juker, D., McGill, S., & Kropf, P. (1998). Quantitative intramuscular myoelectric activity of lumbar portions of psoas and the abdominal wall during cycling. Journal of Applied Biomechanics, 14(4), 428-438.
Juker, D., McGILL, S., Kropf, P., & Steffen, T. (1998). Quantitative intramuscular myoelectric activity of lumbar portions of psoas and the abdominal wall during a wide variety of tasks. Medicine and science in sports and exercise, 30(2), 301-310.
Cunningham, D. J., & Romanes, G. J. (1986). Manual Of Practical Anatomy, Vol. 2: Thorax and Abdomen. OUP.
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Barker, K. L., Shamley, D. R., & Jackson, D. (2004). Changes in the cross-sectional area of multifidus and psoas in patients with unilateral back pain: the relationship to pain and disability. Spine, 29(22), E515-E519.
Kim, W. H., Lee, S. H., & Lee, D. Y. (2011). Changes in the cross-sectional area of multifidus and psoas in unilateral sciatica caused by lumbar disc herniation. Journal of Korean Neurosurgical Society, 50(3), 201-204.
Kamaz, M., Kiresi, D., Oguz, H., Emlik, D., & Levendoglu, F. (2007). CT measurement of trunk muscle areas in patients with chronic low back pain. Diagnostic and interventional radiology, 13(3), 144.
Parkkola, R., Rytökoski, U., & Kormano, M. (1993). Magnetic resonance imaging of the discs and trunk muscles in patients with chronic low back pain and healthy control subjects. Spine, 18(7), 830-836.
D'hooge, R., Cagnie, B., Crombez, G., Vanderstraeten, G., Dolphens, M., & Danneels, L. (2012). Increased intramuscular fatty infiltration without differences in lumbar muscle cross-sectional area during remission of unilateral recurrent low back pain. Manual therapy, 17(6), 584-588.
Danneels, L. A., Vanderstraeten, G. G., Cambier, D. C., Witvrouw, E. E., De Cuyper, H. J., & Danneels, L. (2000). CT imaging of trunk muscles in chronic low back pain patients and healthy control subjects. European Spine Journal, 9(4), 266-272.
- Citation 93 (Anderson et al.)
Jacobson, T., & Allen, W. C. (1990). Surgical correction of the snapping iliopsoas tendon. The American journal of sports medicine, 18(5), 470-474.
Ilizaliturri, V. M., Villalobos, F. E., Chaidez, P. A., Valero, F. S., & Aguilera, J. M. (2005). Internal snapping hip syndrome: treatment by endoscopic release of the iliopsoas tendon. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 21(11), 1375-1380.
Cardinal, E., Buckwalter, K. A., Capello, W. N., & Duval, N. (1996). US of the snapping iliopsoas tendon. Radiology, 198(2), 521-522.
Janzen, D. L., Partridge, E., Logan, P. M., Connell, D. G., & Duncan, C. P. (1996). The snapping hip: clinical and imaging findings in transient subluxation of the iliopsoas tendon. Canadian Association of Radiologists journal= Journal l'Association canadienne des radiologistes, 47(3), 202-208.
Taylor, G. R., & Clarke, N. M. (1995). Surgical release of the'snapping iliopsoas tendon'. Bone & Joint Journal, 77(6), 881-883.
Byrd, J. W. T. (2005). Evaluation and management of the snapping iliopsoas tendon. Techniques in Orthopaedics, 20(1), 45-51.
Deslandes, M., Guillin, R., Cardinal, É., Hobden, R., & Bureau, N. J. (2008). The snapping iliopsoas tendon: new mechanisms using dynamic sonography. American Journal of Roentgenology, 190(3), 576-581.
Dobbs, M. B., Gordon, J. E., Luhmann, S. J., Szymanski, D. A., & Schoenecker, P. L. (2002). Surgical correction of the snapping iliopsoas tendon in adolescents. JBJS, 84(3), 420-424.
- Quadratus Lumborum
- Citation 97
Phillips, S., Mercer, S., & Bogduk, N. (2008). Anatomy and biomechanics of quadratus lumborum. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 222(2), 151-159.
McGill, S. M. (1991). Kinetic potential of the lumbar trunk musculature about three orthogonal orthopaedic axes in extreme postures. Spine, 16(7), 809-815.
Callaghan, J. P., & Dunk, N. M. (2002). Examination of the flexion relaxation phenomenon in erector spinae muscles during short duration slumped sitting. Clinical Biomechanics, 17(5), 353-360.
Andersson, E. A., Oddsson, L. I. E., Grundström, H., Nilsson, J., & Thorstensson, A. (1996). EMG activities of the quadratus lumborum and erector spinae muscles during flexion-relaxation and other motor tasks. Clinical Biomechanics, 11(7), 392-400.
McGill, S., Juker, D., & Kropf, P. (1996). Quantitative intramuscular myoelectric activity of quadratus lumborum during a wide variety of tasks. Clinical Biomechanics, 11(3), 170-172.
Macintosh, J. E., Valencia, F., Bogduk, N., & Munro, R. R. (1986). The morphology of the human lumbar multifidus. Clinical biomechanics, 1(4), 196-204.
Macintosh, J. E., & Bogduk, N. (1986). The biomechanics of the lumbar multifidus. Clinical biomechanics, 1(4), 205-213.
Bogduk, N., Macintosh, J. E., & Pearcy, M. J. (1992). A universal model of the lumbar back muscles in the upright position. Spine, 17(8), 897-913.
O’sullivan, P. B., Grahamslaw, K. M., Kendell, M., Lapenskie, S. C., Möller, N. E., & Richards, K. V. (2002). The effect of different standing and sitting postures on trunk muscle activity in a pain-free population. Spine, 27(11), 1238-1244.
Dofferhof, A. S., & Vink, P. (1985). The stabilising function of the mm. iliocostales and the mm. multifidi during walking. Journal of anatomy, 140(Pt 2), 329.
Yoshihara, K., Shirai, Y., Nakayama, Y., & Uesaka, S. (2001). Histochemical changes in the multifidus muscle in patients with lumbar intervertebral disc herniation. Spine, 26(6), 622-626.
Hides, J. A., Stokes, M. J., Saide, M. J. G. A., Jull, G. A., & Cooper, D. H. (1994). Evidence of lumbar multifidus muscle wasting ipsilateral to symptoms in patients with acute/subacute low back pain. Spine, 19(2), 165-172.
Zhao, W. P., Kawaguchi, Y., Matsui, H., Kanamori, M., & Kimura, T. (2000). Histochemistry and morphology of the multifidus muscle in lumbar disc herniation: comparative study between diseased and normal sides. Spine, 25(17), 2191-2199.
Bajek, S., Bobinac, D., Bajek, G., Vranic, T. S., Lah, B., & Dragojevic, D. M. (2000). Muscle fiber type distribution in multifidus muscle in cases of lumbar disc herniation. Acta Medica Okayama, 54(6), 235-242.
Rantanen, J., Hurme, M., Falck, B., Alaranta, H., Nykvist, F., Lehto, M., ... & Kalimo, H. (1993). The lumbar multifidus muscle five years after surgery for a lumbar intervertebral disc herniation. Spine, 18(5), 568-574.
Ford, D., Bagnall, K. M., McFadden, K. D., Greenhill, B., & Raso, J. (1983). Analysis of vertebral muscle obtained during surgery for correction of a lumbar disc disorder. Cells Tissues Organs, 116(2), 152-157.
Fidler, M. W., Jowett, R. L., & Troup, J. D. G. (1975). Myosin ATPase activity in multifidus muscle from cases of lumbar spinal derangement. Bone & Joint Journal, 57(2), 220-227.
Lehto, M., Hurme, M., Alaranta, H., Einola, S., Falck, B., JÄrvinen, M., ... & PaljÄrvi, L. (1989). Connective Tissue Changes of the Multifidus Muscle in Patients with Lumbar Disc Herniation An Immunohistologic Study of Collagen Types I and III and Fibronectin. Spine, 14(3), 302-309.
Mattila, M., Hurme, M., Alaranta, H., PaljÄrvi, L., Kalimo, H., Falck, B., ... & JÄrvinen, M. (1986). The Multifidus Muscle in Patients with Lumbar Disc Herniation: A Histochemical and Morphometric Analysis of Intraoperative Biopsies. Spine, 11(7), 732-738.
Yoshihara, K., Nakayama, Y., Fujii, N., Aoki, T., & Ito, H. (2003). Atrophy of the multifidus muscle in patients with lumbar disk herniation: histochemical and electromyographic study. Orthopedics, 26(5), 493.
Nicolaisen, T., & Jørgensen, K. (1985). Trunk strength, back muscle endurance and low-back trouble. Scandinavian Journal of Rehabilitation Medicine, 17(3), 121-127.
Jorgensen, K., & Nicolaisen, T. O. M. (1987). Trunk extensor endurance: determination and relation to low-back trouble. Ergonomics, 30(2), 259-267.
Grabiner, M. D., Koh, T. J., & El Ghazawi, A. (1992). Decoupling of bilateral paraspinal excitation in subjects with low back pain. Spine, 17(10), 1219-1223.
Decoupled bilateral excitation
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. Spine, 24(1), 54-57.
- Latissimus Dorsi
- Daneels et al. citation 126
Bogduk, N., Johnson, G., & Spalding, D. (1998). The morphology and biomechanics of latissimus dorsi. Clinical Biomechanics, 13(6), 377-385.
Barker, P. J., Briggs, C. A., & Bogeski, G. (2004). Tensile transmission across the lumbar fasciae in unembalmed cadavers: effects of tension to various muscular attachments. Spine, 29(2), 129-138.
McGill, S. M., & Norman, R. W. (1988). Potential of lumbodorsal fascia forces to generate back extension moments during squat lifts. Journal of biomedical engineering, 10(4), 312-318.
- Erector Spinae
- Citations 119-120, 122-124, 126-129, 139, 145, 147, 152, 159-160, 163, 165
- Biceps Femoris
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. The American journal of sports medicine, 40(7), 1654-1663.
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. Clinical biomechanics, 21(2), 116-121.
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. Manual therapy, 14(6), 605-610.
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. Clinical Biomechanics, 4(4), 204-209.
Baker, B. A. (1986). The muscle trigger: evidence of overload injury. J Neurol Orthop Med Surg, 7(5), 35-44.
- Adductor Magnus
- and 79
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, 49(4), 223-240.
- Transverse Abdominis
Vleeming, A., Schuenke, M.D., Danneels,Willard, F.H. The functional coupling of the deep abdominal and paraspinal muscles: the effects of simulated paraspinal muscle contraction on force transfer to the middle and posterior layer of the thoracolumbar fascia. Journal of Anatomy, 2014. 225, 447-462
">force closure of the pelvis. European Spine Journal, 13(3), 199-205.
Hodges, P. W., Cresswell, A. G., Daggfeldt, K., & Thorstensson, A. (2001). In vivo measurement of the effect of intra-abdominal pressure on the human spine. Journal of biomechanics, 34(3), 347-353.
Hodges, P. W., Eriksson, A. M., Shirley, D., & Gandevia, S. C. (2005). Intra-abdominal pressure increases stiffness of the lumbar spine. Journal of biomechanics, 38(9), 1873-1880.
Stokes, I. A., Gardner-Morse, M. G., & Henry, S. M. (2010). Intra-abdominal pressure and abdominal wall muscular function: spinal unloading mechanism. Clinical Biomechanics, 25(9), 859-866.
Hodges, P. W., & Richardson, C. A. (1998). Delayed postural contraction of transversus abdominis in low back pain associated with movement of the lower limb. Clinical Spine Surgery, 11(1), 46-56.
Hodges, P. W., & Richardson, C. A. (1999). Altered trunk muscle recruitment in people with low back pain with upper limb movement at different speeds. Archives of physical medicine and rehabilitation, 80(9), 1005-1012.
Hodges, P. W. (2001). Changes in motor planning of feedforward postural responses of the trunk muscles in low back pain. Experimental brain research, 141(2).
Hodges, P. W., & Moseley, G. L. (2003). Pain and motor control of the lumbopelvic region: effect and possible mechanisms. Journal of Electromyography and Kinesiology, 13(4), 361-370.
Unsgaard-Tøndel, M., Nilsen, T. I. L., Magnussen, J., & Vasseljen, O. (2012). Is activation of transversus abdominis and obliquus internus abdominis associated with long-term changes in chronic low back pain? A prospective study with 1-year follow-up. Br J Sports Med, 46(10), 729-734.
Marshall, P., & Murphy, B. (2010). Delayed abdominal muscle onsets and self-report measures of pain and disability in chronic low back pain. Journal of Electromyography and Kinesiology, 20(5), 833-839.
Jansen, J., Weir, A., Dénis, R., Mens, J., Backx, F., & Stam, H. (2010). Resting thickness of transversus abdominis is decreased in athletes with longstanding adduction-related groin pain. Manual therapy, 15(2), 200-205.
Crommert, M. E., Ekblom, M. M., & Thorstensson, A. (2011). Activation of transversus abdominis varies with postural demand in standing. Gait & posture, 33(3), 473-477.
Hides, J. A., Boughen, C. L., Stanton, W. R., Strudwick, M. W., & Wilson, S. J. (2010). A magnetic resonance imaging investigation of the transversus abdominis muscle during drawing-in of the abdominal wall in elite Australian Football League players with and without low back pain. journal of orthopaedic & sports physical therapy, 40(1), 4-10.
França, F. R., Burke, T. N., Caffaro, R. R., Ramos, L. A., & Marques, A. P. (2012). Effects of muscular stretching and segmental stabilization on functional disability and pain in patients with chronic low back pain: a randomized, controlled trial. Journal of manipulative and physiological therapeutics, 35(4), 279-285.
França, F. R., Burke, T. N., Hanada, E. S., & Marques, A. P. (2010). Segmental stabilization and muscular strengthening in chronic low back pain: a comparative study. Clinics, 65(10), 1013-1017.
- Internal Obliques
- Including citations 89, 112, 128, 174, 185, 187 - 189, 192, 197, 205, 221
McGill, S. M. (1992). A myoelectrically based dynamic three-dimensional model to predict loads on lumbar spine tissues during lateral bending. Journal of biomechanics, 25(4), 395-414.
McGill, S. M. (1996). A revised anatomical model of the abdominal musculature for torso flexion efforts. Journal of biomechanics, 29(7), 973-977.
- Rectus Abdominis
Grenier, S. G., Vera-Garcia, F. J., & McGill, S. M. (2000). Abdominal response during curl-ups on both stable and labile surfaces. Phys. Ther, 86, 564-569.
No difference between upper and lower portions of the abdominals.
- External Obliques
- Including citations 112, 124-126, 128, 229 - 230, 232 - 234
- 187 and 196 from above
Hodges, P. W., Gurfinkel, V. S., Brumagne, S., Smith, T. C., & Cordo, P. C. (2002). Coexistence of stability and mobility in postural control: evidence from postural compensation for respiration. Experimental Brain Research, 144(3), 293-302.
Janssens, L., Brumagne, S., Polspoel, K., Troosters, T., & McConnell, A. (2010). The effect of inspiratory muscles fatigue on postural control in people with and without recurrent low back pain. Spine, 35(10), 1088-1094.
Janssens, L., Brumagne, S., McConnell, A. K., Hermans, G., Troosters, T., & Gayan-Ramirez, G. (2013). Greater diaphragm fatigability in individuals with recurrent low back pain. Respiratory physiology & neurobiology, 188(2), 119-123.
Hodges, P. W., Heijnen, I., & Gandevia, S. C. (2001). Postural activity of the diaphragm is reduced in humans when respiratory demand increases. The Journal of physiology, 537(3), 999-1008.
- Pelvic Foor
Tu, F. F., Holt, J., Gonzales, J., & Fitzgerald, C. M. (2008). Physical therapy evaluation of patients with chronic pelvic pain: a controlled study. American journal of obstetrics and gynecology, 198(3), 272-e1.
Duron, B. (1973). Postural and ventilatory functions of intercostal muscles. Acta Neurobiol. Exp, 33(355-380), 149a.
Guimarães, C. Q., Sakamoto, A. C., Laurentino, G. E., & Teixeira-Salmela, L. F. (2010). Electromyographic activity during active prone hip extension did not discriminate individuals with and without low back pain. Brazilian Journal of Physical Therapy, 14(4), 351-357.
- Gluteus Medius and Gluteus Maximus
- Including citations 58-59, 61 - 63, 132, 134 - 135, 173 - 175 and 180
Nelson-Wong, E., & Callaghan, J. P. (2010). Changes in muscle activation patterns and subjective low back pain ratings during prolonged standing in response to an exercise intervention. Journal of Electromyography and Kinesiology, 20(6), 1125-1133.
Marshall, P. W., Patel, H., & Callaghan, J. P. (2011). Gluteus medius strength, endurance, and co-activation in the development of low back pain during prolonged standing. Human movement science, 30(1), 63-73.
- Thoracolumbar Fascia
- As well as 6, 191, 192
Barker, P. J., & Briggs, C. A. (1999). Attachments of the posterior layer of lumbar fascia. Spine, 24(17), 1757.
- TLF and Stability
- TLF Contribution to Motion
Gracovetsky, S., Farfan, H. F., & Lamy, C. (1981). The mechanism of the lumbar spine. Spine, 6(3), 249-262.
- TLF and Receptors
Stilwell, D. L. (1957). Regional variations in the innervation of deep fasciae and aponeuroses. The Anatomical Record, 127(4), 635-653.
Schleip, R. (2003). Fascial plasticity–a new neurobiological explanation: Part 1. Journal of Bodywork and movement therapies, 7(1), 11-19.
Schleip, R. (2003). Fascial plasticity–a new neurobiological explanation Part 2. Journal of Bodywork and movement therapies, 7(2), 104-116.
Gibson, W., Arendt-Nielsen, L., Taguchi, T., Mizumura, K., & Graven-Nielsen, T. (2009). Increased pain from muscle fascia following eccentric exercise: animal and human findings. Experimental brain research, 194(2), 299.
Ianuzzi, A., Pickar, J. G., & Khalsa, P. S. (2011). Relationships between joint motion and facet joint capsule strain during cat and human lumbar spinal motions. Journal of manipulative and physiological therapeutics, 34(7), 420-431.
Proske, U., & Gandevia, S. C. (2009). The kinaesthetic senses. The Journal of physiology, 587(17), 4139-4146.
Hukins, D. W. L., Aspden, R. M., & Hickey, D. S. (1990). Thorecolumlbar fascia can increase the efficiency of the erector spinae muscles. Clinical Biomechanics, 5(1), 30-34.
- TLF, Myofibroblasts and Stretch Hardening
- Abdominal Fascia
- As well as 6, 14, 16, 18, 89, 93, 115, 219, 264
- Sacrotuberous Ligament
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. European Spine Journal, 2(3), 140-144.
- Iliotibial Band
- Myofascial Synergy
Logan, G. A., & McKinney, W. C. (1977). Anatomic kinesiology.
Snijders, C. J., Vleeming, A., & Stoeckart, R. (1993). Transfer of lumbosacral load to iliac bones and legs: Part 1: Biomechanics of self-bracing of the sacroiliac joints and its significance for treatment and exercise. Clinical biomechanics, 8(6), 285-294.
Snijders, C. J., Slagter, A. H., van Strik, R., Vleeming, A., Stoeckart, R., & Stam, H. J. (1995). Why Leg Crossing?: The Influence of Common posture for a given exercise.
© 2017 Brent Brookbush">Postures on Abdominal Muscle Activity. Spine, 20(18), 1989-1993.
- Patellofemoral Joint
- Lumbar Spine
- Sacroiliac Joint
- Additional Research
- Rotatores, Interspinalis and Intertransversarii
(C) 2018 Brent Brookbush
Comments, questions, and critiques are welcome and encouraged.