Anterior Oblique Subsystem Integration

By Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, H/FS

The Anterior Oblique Subsystem (AOS) is comprised of:

  • External Obliques
  • Anterior Adductors

  • Function (Brief):

    The muscles that comprise the AOS are the global movers of the anterior trunk and the adductors. This subsystem plays a significant role in stabilizing the thoracic and lumbar spine, sacroiliac joint (SIJ), pubic symphysis and hip, as well as transferring force between lower and upper extremities. The AOS plays an active role in all pushing and rotational movement patterns (especially turning in), multi-segmental flexion, and eccentrically decelerating spinal extension and rotation, as well as hip extension, abduction and external rotation (knees bow in and excessive forward lean). The AOS is the functional antagonist of the Posterior Oblique Subsystems (POS).

    • Concentric Function: Pushing, rotation "inward", multi-segmental flexion
    • Isometric Function: Transfer force between lower and upper extremities, stabilization of the SIJ, pubic symphasis thoracic and lumbar spine and hips
    • Eccentric Function: Decelerate spine extension and rotation, as well as hip extension, abduction and external rotation

    Common Maladaptive Behavior

    • Over-active

    Signs of AOS Dysfunction

    Practical Application

    Research Corner:

    Abdominal Fascia (Anterior Layer):

    The rectus sheath envelopes the rectus abdominis anteriorly and posteriorly. From 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 (1). Below the level of the arcuate line the posterior sheath does not continue, and the fascia of the internal obliquesexternal obliques and transverse abdominis continue anterior to the rectus abdominis. The fusion of the layers of the abdominal fascia below the arcuate line, may serve as a fascial connection between the anterior abdominal fascia of the AOS, and the middle and posterior layers of abdominal fascia of the Intrinsic Stabilization Subsystem (ISS).

    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 vertically between the two rectus abdominis muscles, is a thickening created by the union of the transverse fibers of the fascial sheaths from either side (2). The transverse inscriptions that run horizontally through the rectus abdominis are also continuations of the oblique fascia (3). In addition, fascia from the sternal fibers of the pectoralis major and the fascia of the serratus anterior invests in the fascia of the external obliques (and sometimes rectus abdominis)(1, 4-7). These findings expand the original description of the AOS as described by Vleeming et al. (1) to include two powerful upper extremity muscles.

    Relative to function, any significant lateral, posterior

    , or rotational force imparted on the trunk will result in an increase in rectus abdominispyramidalisexternal obliquesinternal obliques, and transverse abdominis activity (recruitment of the AOS and ISS) (2), and may increase quadratus lumborum and psoas activity (7-9). This increase in muscle activity will also increase tension of the abdominal fascia, transverse inscriptions and linea alba. Studies show that force imparted by a trunk muscle will be transmitted between all layers of abdominal fascial network (10, 11). This may imply that muscle recruitment and/or fascial tension may signal an increase in the other. Studies on the amount any muscle can displace a layer of abdominal fascia are not available as they are for the thoracolumbar fascia (TLF) (10); however, Vleeming makes the following analogy (6) – The abdominal fascia features muscles encased in a fascial network, much like the TLF. The paired rectus abdominis muscles are encased in the fascia of investing muscles (transverse abdominisinternal 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.

    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 (5). 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 instrument assisted soft tissue mobilization (IASTM) on the abdominal region, but based on the idea 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.">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.

    Image of Transverse Abdominis and Rectus Abdominis Modified image from Gray's Anatomy - https://en.wikipedia.org/wiki/Transverse_abdominal_muscle

    Rectus Abdominis (and Pyramidalis)

    The rectus abdominis may enhance rigidity or aid in transferring force between left and right sides of the abdominal fascia; however, the relationship between the rectus abdominis and the abdominal fascia has not been well-researched. The proximity and continuity of the rectus abdominis tendon, and the tendon of the adductor longus may be the most significant link between the trunk muscles and adductor muscles that comprise the AOS.

    The rectus abdominis is a strong lumbar flexor, also contributing to posterior tilting of the pelvis, and the sacral counter-nutation linked to lumbar flexion (13-15).  This muscle may be active during axial rotation and lateral stabilization of the spine (16); however, it is doubtful that this recruitment contributes to rotation and/or side-bending force vectors. It is more likely this activity is a co-contraction with the lumbar erectors to aid in bracing (stabilization of) the lumbar spine (17). This bracing function should not be confused with the type of stabilization demonstrated by the Intrinsic stabilization Subsystem (ISS), which is anticipatory, bilateral, non-direction dependent, and noted even during low intensity tasks. Recruitment of the rectus abdominis is direction specific and related to larger loads (18).

    The activity of the rectus abdominis (as well as the external obliques) relative to low back pain and LPHCD is complex. Sway back postures may result in an increase or decrease in activity (19, 20), low back pain may result in decreased rectus abdominis activity during rotation (21), but increased reliance when fatigued (22), low back pain patients generally are weaker in trunk flexion than extension (23); however, they recruit the rectus abdominis more during stair climbing (24), and chronic low back pain patients typically cannot differentiate between transverse abdominis and rectus abdominis activation during the  abdominal drawing in maneuver (ADIM) (25). This pattern of simultaneously "more and less" may suggest that the rectus abdominis is compensating for inhibition of primary stabilizers (ISS); a concept referred to as synergistic dominance. Generally, over-active synergists demonstrate an 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.

    Note: The pyramidalis lies between the right and left rectus abdominis, within the anterior rectus sheath at the linea alba.  Although it is mentioned in this article, it is only mentioned in an attempt to be comprehensive. This muscle does not play a role in intervention selection or  practical application, as it only serves to increase tension in the linea alba, and is absent in 17 - 25% of individuals (26).

    Muscles that attach to the pubis including Fascial Attachment between Rectus Abdominis and Adductor Tendons Fascial Attachment between Rectus Abdominis and Adductor Tendons

    External Obliques

    The anterior layer of the abdominal fascia is a continuation of the external oblique fascia, which passes superficial to the rectus abdominis, and invests in, or is continuous with the fascia from the contralateral side at the linea alba (27). The external obliques are likely the prime movers for trunk rotation and lateral flexion (16, 28-30), and are active during flexion and forceful expiration (30-32). The recruitment of the external obliques varies 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 (16, 33). 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) (34), and in response to larger loads (bracing) (17). Further, the external obliques are also more active during a posterior pelvic tilt than during the abdominal drawing-in maneuver (ADIM) (35). In fact, their activity is not necessary to increase intra-abdominal pressure (36), which may be attributed to a lack of attachment to the thoracolumbar fascia (37). In short, the external oblique should likely be categorized as a global mover with the rectus abdominis and as a muscles the AOS, where as the internal obliques and transverse abdominis behave like stabilizers and other muscles of the Intrinsic stabilization Subsystem (ISS).

    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 the external obliques, relative to a decrease in internal obliques and transverse abdominis activity and in some cases rectus abdominis activity (22 - 25, 38). Like the rectus abdominis, the external obliques exhibit less activity in sway standing (19), may be more active (bilaterally) to stabilize the spine (bracing) during functional tasks in those with low back pain, and are more active during exercises requiring more stability (ex. bridges on ball) (19, 39, 40). This behavior implies that in those exhibiting dysfunction, the external obliques become synergistically dominant for an inhibited transverse abdominis and internal obliques;  behavior that is most often attributed to muscles that have adopted maladaptive behvior of long and over-active.  This behavior and categorization is the same as the rectus abdominis.

    http://clinicalgate.com/anatomy-and-mechanics-of-the-abdominal-muscles/ Layers of abdominal muscles and fascia. - http://clinicalgate.com/anatomy-and-mechanics-of-the-abdominal-muscles/

    Anterior Adductors

    The abdominal fascia runs with some continuity from abdomen, through pubic symphysis, into the tendons of the anterior adductors. The strongest fascial relationship likely exists between the tendons of the rectus abdominis and the tendons of the adductor longus muscles. The continuity between the rectus abdominis and the adductor longus can then be expanded upon by location to the tendons of the rest of the anterior adductors. The tendon of the pectineus abuts the lateral side of the rectus abdominis tendon, and the attachments of the gracilis and adductor brevis abut the tendon of the adductor longus inferiorly and laterally.

    A few publications support a relationship that includes the sacroiliac joint, pubic symphysis, anterior abdominal activity and adductor activity (1, 42-45). The most direct support in the research to date can be found in a study by Snijders et al..  This study demonstrated that crossing the legs decreased the activity of the internal obliques (45). 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. Another study worth mentioning investigated altered muscle activity in individuals exhibiting signs of sacroiliac joint pain. In this study, sacroiliac joint dysfunction was correlated with adductor activity that remained unchanged (along with TFLbiceps femoris), which is a relative increase when compared to internal obliquelumbar multifidus, and gluteus maximus activity that decreased or fired later (42). Although these studies are not direct evidence of a myofascial synergy that includes the abdominal fascia, the studies imply a relationship between the muscles and joints that comprise the AOS.

    Over-activity of the adductors has been correlated with functional knee valgus (46-48), hinting at this muscle groups common maladaptive behavior. As mentioned above, individuals with sacroiliac joint dysfunction demonstrated a relative increase in adductor activity during functional tasks (49). 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 (50-52), of these muscles the adductor longus seems to be the most often affected (53). Although more research is needed, current evidence suggests these muscles are commonly over-active, and observations in clinic would suggest that this muscle has a propensity to adaptively shorten and restrict mobility.

    Muscle Attachments on Anterior Pelvis, Femur and Lumbar Spine - Donald A. Neumann, “Kinesiology of the Musculoskeletal System: Foundations of Rehabilitation – 2nd Edition” © 2012 Mosby, Inc. Muscle Attachments on Anterior Pelvis, Femur and Lumbar Spine - Donald A. Neumann, “Kinesiology of the Musculoskeletal System: Foundations of Rehabilitation – 2nd Edition” © 2012 Mosby, Inc.

    Pectoralis Major

    The most superficial fibers of the sternal head of the pectoralis major invest in the fascia of the external obliques and sometimes the rectus abdominis (4, 54). This inspires consideration of the pectoralis major (and serratus anterior discussed below) as part of the AOS, and the AOS as the primary synergy responsible for generating force during some of the most powerful activities in sports (e.g. throwing a baseball, swing a golf club, chop patterns, lineman pushing, etc.).

    Research has demonstrated that the pectoralis major contributes to horizontal adduction and internal rotation, as well as extension and adduction from an arm elevated position (55-58). This includes activities, such as the tennis forehand and serve, the concentric phases of golf swing or baseball pitch, swimming and dumbbell pull-overs (59-64). Several studies have compared dumbbell pressbench press and chest flye variations. Incline press, flat and decline press result in varied recruitment of pectoralis major fibers, with lower fibers (sternal head) being recruited more during a decline press; the clavicular head seems to be recruited similarly at all angles (65-67). Flyes resulted in a shorter recruitment period than pressing movements (68). Unstable environments often result in similar recruitment of the pectoralis major with less external load; however, most studies do not demonstrate that the addition of instability to an exercise increases pectoralis major recruitment (other muscles are often recruited more) (69, 71 -74).

    The pectoralis major behaves like a prime mover; that is, it is recruited for the concentric phase of large powerful movements, following the recruitment of smaller stabilizers. In a study by David et al. it was demonstrated that the pectoralis major fired after recruitment of the rotator cuff muscles and the biceps brachii during internal and external rotation, and in a study by Saeterbakken et al. instability during a chest press did not increase pectoralis major activity, but did increase biceps brachii activity (75, 76). In a study by Wang et al. the pectoralis major was more active during concentric internal rotation than eccentric external rotation, and a study by Kronberg et al. demonstrated that the pectoralis major is not active and does not aid in shoulder stabilization during flexion (77, 78). An interesting study by Hirashima et al. demonstrated that overhead throwing followed a proximal to distal recruitment pattern; that is, although the rotator cuff and biceps brachii may fire prior to the pectoralis major, the pectoralis major fires prior to elbow extensors and wrist flexors (79). This study also demonstrated synergy between the external obliquesserratus anterior, and pectoralis major.

    The pectoralis major does appear to be one of the few muscles that adopts the maladaptive behavior of short/under-active in those exhibiting dysfunction, supporting the notion of "prime mover inhibition." In two studies that compared pectoralis major activity in those exhibiting signs shoulder dysfunction, the pectoralis major demonstrated less activity (64, 80). However, a study on patients with major rotator cuff tears demonstrated increased pectoralis major activity during flexion, and that activity returned to normal when pain decreased following subacromial injection (70). Although these may be viewed as contradictory findings, it may also imply a role reversal from concentric force producer to eccentric stabilizer. Further, this may be normal activity for an inhibited prime mover; more research is needed.  Relative to exercise, the pectoralis major may exhibit more activity than the serratus anterior during pushing motions in those exhibiting scapular winging; however, this activity may be reversed with band resisted abduction during serratus anterior exercise (81, 82).

    Serratus Anterior

    The superficial fascia of the serratus anterior runs continuous with the fascia of the external obliques, which is continuous with the anterior abdominal fascia (1). This fascial relationship may imply that this important stabilizer and mover of the scapula is part of the AOS, and that the AOS is a synergy responsible for generating power in many explosive upper and lower body sporting activities, e.g. throwing a baseball, swinging a golf club, pushing a defender, etc. (as mentioned under "Pectoralis Major"). An interesting study by Hirashima et al. demonstrated that overhead throwing followed a proximal to distal recruitment pattern that started with contralateral then ipsilateral external obliques, then serratus anterior, then pectoralis major followed by elbow extensors (79). Additional stabilizing muscles were also recruited, but the sequence demonstrated in this study may be the best example of loading and recruiting the AOS during a functional activity.

    The serratus anterior is a protractor, upward rotator and posterior tipper. Studies show that the serratus anterior is highly active in the trailing arm of forward swing and throughout back swing during golf (83, 84), works in synchronization with the pectoralis major during a windmill style softball pitch (85) and pushing motions that include protraction (86, 87), and works in syncrhonization with the upper trapezius during the tennis serve (88). These studies suggest that the serratus anterior acts like a prime mover, and in conjunction with other prime movers.  However, the serratus anterior is also highly active during all 3 tennis strokes (89), is active continually during all phases of the freestyle stroke during swimming (90, 91), and is active throughout all upper body PNF patterns (92). This continuous activity, regardless of direction of motion, suggests a role in scapular stabilization. These findings suggest that the serratus anterior likely functions as both prime mover and stabilizer of the scapula (along with the trapezius muscles).

    The serratus anterior has a propensity toward under-activity in those exhibiting dysfunction.  Several studies demonstrate that anterior shoulder pain and/or impingement is correlated with a decrease in serratus anterior activity, including altered timing and decoupling from syncrhonization with the lower trapezius (64, 93-95). A similar decrease is noted in those diagnosed with anterior shoulder instability (96, 97). Both cervical dysfunction and forward head posture also decrease serratus anterior activity (98 - 102), and even lateral epicondylitis has been correlated with scapular dyskinesis (103). This propensity toward under-activity may be a precursor to shoulder dysfunction, as two studies demonstrate that a fatiguing shoulder raise protocol results in scapular dyskinesis and altered activity (103, 104). Could it be that reinforcement of this "fatigue/compensatory pattern" during repetitive daily tasks, causes a shift toward this pattern over time? The under-activity of the serratus anterior is also coupled with an increase in length.  Several studies have noted that shoulder dysfunction results in excessive downward rotation, anterior tipping and internal rotation of the scapula, that is, during functional tasks that rely on elevation of the arm, those exhibiting dysfunction exhibit inadequate upward rotation, posterior tipping and maintenance of the scapula against the ribcage (104 - 109).

    A variety of interventions affecting the serratus anterior have been researched. Pressing motions, including pressing with "a plus" (protraction), and pressing that requires more or less stability have been well-researched. The largest issue with pressing motions is that many variations of pushing also increase upper trapezius and pectoralis minor activity which may reinforce compensatory patterns discussed above. Wall push-ups, push-ups with a plus, and feet-up push-ups significantly increase upper trapezius activity and punch-ups increase pectoralis minor activity (110 - 113). Unstable pushing motions may be effective for a variety goals; however, it is unlikely that stability progressions will result in a relative increase serratus anterior activity. Bench press actually had a better ratio of serratus anterior to upper trapezius activity than stable and unstable push-ups variations (114). Two studies comparing push-ups to push-ups on a stability ball showed no increase in EMG activity (115, 116), and bench press was shown to increase serratus anterior activity better than either variation (114). Additionally, those exhibiting scapular dyskinesis had less serratus anterior activity and more upper trapezius and pectoralis major activity during pushing, even when a stability ball was added to push-ups (81, 119). The hypothesis that stability training would preferentially recruit the serratus anterior is likely flawed because it does not consider how other muscles may participate in stabilization of the shoulder girdle; however, this does not diminish the use of stability training. Studies have demonstrated that instability increases the activity of other musculature including the anterior deltoidpectoralis majortrapezius and core musculature (69, 71, 114, 116). The increase in activity of multiple muscles may aid in enhancing inter-muscular coordination, and integration of the AOS, once relative activity has been addressed with release and activation techniques.  Interesting note, although unstable environments do not consistently increase serratus anterior EMG, oscillations/vibration training does (117, 118). More systematic experimentation and research is needed to develop easy ways to implement vibration training.

    An alternative technique to pressing is scaption (elevation/abduction in the scapular plane). Several studies comparing various "rehabilitation exercises" and motions of the arm showed scaption to create the highest serratus anterior EMG activity (120-128). Further, unlike pressing motions that also increase activity of commonly over-active muscles (upper trapezius and pectoralis minor), scaption pairs the serratus anterior with the commonly under-active lower trapezius (120-126). Scaption should likely be performed through the largest available range (without compensation or pain), as exercise that results in the most upward rotation resulted in the largest increase in serratus anterior activity (128). Additional variations including prone scaption, scaption in quadruped position and wall slides may also be beneficial, but consideration should be given to patient ability and recruitment of additional musculature (123-124).

    As mentioned above, those exhibiting scapular dyskinesis had less serratus anterior activity and more upper trapezius and pectoralis major activity during pushing type exercise (81, 119). Further, a study by Lucas et al. demonstrated that addressing latent trigger points in muscles of the scapula, aided in normalizing muscle recruitment patterns, including increased serratus anterior activity (129). This may imply that release techniques for typically over-active muscles, and targeted intervention for the serratus anterior should precede multi-joint movement patterns.

    Summary of Research Findings

    Primary stabilizer of anterior kinetic chain during high intensity activity:

    Research implies a relationship that includes the sacroiliac joint, pubic symphysis, anterior abdominal activity and adductor activity (1, 42-45). The most direct support of this relationship is a study by Snijders et al. demonstrating that crossing the legs decreases activity of the internal obliques (45). Another study by Hungerford et al. demonstrated sacroiliac joint dysfunction resulted in a relative increase in adductorTFLbiceps femoris activity compared to internal obliquelumbar multifidus, and gluteus maximus activity that decreased or fired later (42). Although this research does not directly investigate the role of the AOS in stabilization of the pelvis and lumbar spine, it implies a relationship between the structures involved that may be explained by its role as a stabilizer.

    It may be hypothesized that the AOS is the counter to the Posterior Oblique Subsystem (POS). That is, the AOS aids in bracing and control of the pubic symphysis, pelvis and the lumbar spine from the front, and the POS aids in bracing and control of the SIJ, pelvis and lumbar spine from the back. Note, the term "bracing" is used rather than stabilization, as the AOS and POS are recruited during higher intensity activities to "brace" the lumber spine. "Drawing in" and Intrinsic Stabilization Subsystem (ISS) recruitment should be sufficient for low level activities, and should be synergistic with the AOS and POS during higher intensity activities. This is as analgous to the "size principle" of motor unit recruitment. When load is greater than the capacity of the ISS, the AOS and POS are generally recruited in a direction specific manner to resist additional load. Several studies have demonstrated that the rectus abdominis and external obliques are recruited more in those with low back pain (guarding and ISS impairment), and during higher intensity activity (17, 19, 22, 24, 25, 34, 39, 40).

    Primary eccentric decelerator during high intensity activity:

    The AOS may play an important "protective" role, as this subsystem can decelerate rotation and extension of the lumbar and thoracic spine. Further, the AOS is involved in eccentric deceleration of an anterior pelvic tilt, especially during standing and pushing motions (133-135). Lumbar extension, rotation and an anterior pelvic tilt, have been hypothesized to lead to facet joint and posterior disk compression, and have been correlated with low back pain (130-132).

    The ability to contribute to eccentric deceleration of shoulder elevation and external rotation, scapular retraction, spine rotation and extension, and hip extension make the AOS the subsystem "loaded" during the "loading phase" of a throw or swing. This may be the best example of loading a myofascial synergy for recoil and optimal power production.

    Throwing, serving and pushing with power:

    The study by Hirashima et al. (mentioned above) demonstrated proximal to distal recruitment of the AOS during overhead throwing; that is, contralateral then ipsilateral external obliques, followed by serratus anterior, then shoulder stabilizers, and finally pectoralis major and elbow extensors (79). Further, the joint actions described during this motion are a return from the eccentric function of the AOS described above. The majority of this pattern may also seen during pushing a defender, a tennis serve, a volleyball spike, and the butterfly stroke in swimming. The concentric function of this subsystem may imply it is one of the most important to sports performance.

    Compensations and models of postural dysfunction:

    The AOS could be viewed as a system prone to synergistic dominance. In the Brookbush Institute's predictive models of Upper Body Dysfunction (UBD), Lumbo Pelvic Hip Complex Dysfunction (LPHCD), Sacroiliac Joint Dysfunction (SIJD), and Lower Extremity dysfunction (LED) this sub-system is over-active and long. Commonly, the over-activity is paired with under-activity of the Posterior Oblique Subsystem (POS) and may be compensatory for under-activity of the Intrinsic Stabilization Subsystem (ISS). Evidence of AOS dominance may result in knees bow-inexcessive forward lean or arms fall during an Overhead Squat Assessment, and/or an excessive kyphosis, spinal flexion, or an excessive forward lean during an Overhead Squat Assessment with Modification.  Dominance of the AOS (and under-activity of the POS) is generally most dramatic in those individuals exhibiting UBD and LED.

    Dr. Brookbush instructs Melissa Ruiz on how to regress a stability ball push-up. Stability Ball Push-up

    Practical Application

    Based on available research on individual muscles, the Brookbush Institute's (BI's) predictive models of postural dysfunction, and observations in practice, this subsystem is categorized as "long/over-active".  As subsystems are synergies, dynamic multi-segmental postural assessment is recommended for determining compensatory activity, strengthening/activation of individual muscles within the system is avoided, but integrated exercise may be appropriate. The BI uses the research and theory of subsystems as a means of refining core and integrated exercise selection. Note, the BI's Corrective-Template addresses individual structures prior to addressing subsystems to reduce relative flexibility, synergistic dominance and compensatory patterns.

    Assessment: 

    Signs of AOS over-activity is based on the research, concentric function and motor behavior described above, and signs are considered relative to the BI's preferred dynamic postural assessment, the Overhead Squat Assessment (OHSA). Specifically, the AOS contributes concentrically to multi-segmental flexion, as well as  hip flexion, adduction and internal rotation implying excessive forward lean and knees bow in are signs of over-activity. Because of the role the AOS plays in core stability and motion an excessive lordosis (anterior pelvic tilt) is a sign of dysfunction; however, this is a sign of increased length that may be addressed with integrated strengthening exercise. The inclusion of the commonly under-active pectoralis major and serratus anterior implies that AOS dysfunction may also contribute to the signs shoulders elevate and arms fall. The role of the AOS in Upper Body Dysfunction (UBD) is complex, leading to a peculiar sign during the Overhead Squat Assessment with Modification. When the hands are placed on the hips (arms down), the lack of support from a lengthened POS exaggerates AOS dominance, leading to an excessive kyphosis, spinal flexion, or an excessive forward lean during  re-assessment. Although the exaggerated forward lean looks like Lumbo Pelvic Hip Complex Dysfunction (LPHCD), practice would suggest it is a sign of UBD. In summary, the signs knees bow in, excessive forward lean, excessive lordosisshoulders elevatearms fall and Forward Lean during an Overhead Squat Assessment with Modification may imply AOS over-activity.

    Core Exercise:

    As mentioned above, the external obliques and rectus abdominis have a propensity to become over-active, but are long in those exhibiting signs of LPHCD. The attributes long/over-active are often a sign of synergistic dominance; it is recommended that muscles in this category are addressed by reducing postural dysfunction to optimize length/tension. Research supports this recommendation - in several studies, bridges and exercises that focused on posterior tilting immediately improved trunk flexor strength and improved recruitment patterns during gait (139-143). Due to the categorization of long/over-active and these research findings the BI recommends avoiding specific strengthening exercises for the external obliques and rectus abdominis while dysfunction persists. Instead, focus on bridges, and chop progressions which may aid in improve posture, optimize length/tension and improve synergy between the AOS and POS

    Integrated Exercise:

    The BI suggests ending sessions with multi-joint exercise/activities (integrated exercise) to reinforce new motor patterns. The BI refines "integrated exercise" selection with research and theory on subsystems. As mentioned above, over-activity of the adductors has been correlated with knees bow in (62-63, 66). Further it may be implied by function and research that the external obliques and rectus abdominis are over-active in those exhibiting dysfunction (19, 22, 24, 25, 38 - 40), contributing to an excessive forward lean. Based on this research the BI categorizes the AOS as over-active. The Brookbush Institute addresses this issue with “release and avoid.” That is, the muscle and fascial structures that can be released are addressed, and exercises that place emphasis on the AOS are avoided until movement quality improves (example, avoid plankscrunches, leg raises, etc.).

    Alternatively, in an anterior pelvic tilt the external obliques and rectus abdominis are long, which creates a puzzling combination of both short and long muscles in the AOS and over-activity through-out. In this case the Brookbush Institute has found chop patterns (integrating anterior abdominal muscles and glute complex activity), and AOS integration

     followed immediately by POS integration very helpful.  Generally the result of this progression is from an anterior pelvic tilt to an excessive forward lean, followed by improvement of the excessive forward lean with POS integration.

    Instrument Assisted Soft Tissue Mobilization (IASTM) of the Abdominal Fascia:

    Fascia's response to specific intervention is complex. Responses may include strain hardening with repetitive or constant tension, enhanced shear and a reduction in cross-bridging between fascial layers, changes in both muscle tone and fibroblast mediated pre-tension (with sustained pressure), and/or altered transmission of force of multiple muscles acting to stabilize a joint (136-138). As mentioned above, one study implied deep, slow pressure to the abdominal region resulted in a decrease in muscle activity (5). This may be an example of a manual technique altering fibroblast mediated pre-tension, but more research is needed to support or refute this claim. 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. Careful re-assessment is recommended (as recommended with all techniques) to determine the efficacy on an individual basis.

    Subsystems Summary

    SubsystemCommon BehaviorCoreIntegration 
    Intrinsic Stabilization Subsystem (ISS)Under-activeTransverse Abdominis (TVA) ActivationN/A
    Anterior Oblique Subsystem (AOS)Over-active

    Chop Progression

    Avoid: planks, crunches, resisted hip flexion

    Legs with Push
    Posterior Oblique Subsystem (POS)Under-activeChop Progression and Bridge ProgressionLegs with Pull
    Deep Longitudinal Subsystem (DLS)Over-activeAvoid: leg curls, lumbar extensionsAvoid: straight-leg deadlifts, kettle bell windmills, Nordic curls

    Signs of AOS Over-activity

    Practical Application

    AOS Integration "Legs with Push" Progression

    1. Step-Up to Chest Press
    2. Step-Up to Unilateral Chest Press
    3. Step-Up to Balance to Chest Press
    4. Step-Up to Balance to unilateral Chest Press
    5. Frontal Plane Step-Up to balance to Chest Press
    6. Frontal Plane Step-Up to balance to unilateral Chest Press
    7. Transverse Plane Step-Up to balance to Chest Press
    8. Transverse Plane Step-Up to balance to unilateral Chest Press
    9. Reverse Lunge to Chest Press
    10. Reverse Lunge to Contra-lateral Chest Press
    11. Transverse Plane Lunge to Contralateral Chest Press
    12. Reverse Lunge to Single Leg Balance to Chest Press
    13. Reverse Lunge to Single Leg Balance to Unilateral Chest Press
    14. Transverse Plane Lunge to Single Leg Balance to Contralateral Chest Press

    Static Chop:

    Up Chop Pattern:

    Dynamic Chop Pattern:

    Anterior Oblique Subsystem Integration (Step Up to Chest Press):

    Anterior Oblique Subsystem Integration Progression (Dynamic Lunge to Press):

    Anterior Oblique Subsystem Power (Med Ball Smash):

    Anterior Oblique Subsystem Power (Sled Push):

    Bibliography

    1. Andry Vleeming, Vert Mooney, Rob Stoeckart. Movement, Stability & Lumbopelvic Pain: Integration of Research and Therapy. (c) 2007 Elsevier Limited
    2. Donald A. Neumann, “Kinesiology of the Musculoskeletal System: Foundations of Rehabilitation – 2nd Edition” © 2012 Mosby, Inc.
    3. Willard, F.H., Vleeming, A., Schuenke, M.D., Danneels, L., Schleip, R. The thoracolumbar fascia: anatomy, function and clinical considerations. Journal of Anatomy, 2012. 221, 507-536.
    4. 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
    5. Sanchez ER, Sanchez R, Moliver C. (2014). Anatomic relationship of pectoralis major and minor muscles: a cadaveric study. Aesthet. Surg. J. 34(2): 258-263.
    6. Porterfield, J. A., & Derosa, C. (1998). Mechanical low back pain: perspectives in functional anatomy.
    7. 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.
    8. Andersson, E., Oddsson, L., Grundström, H., & Thorstensson, A. (1995). The role of the psoas and iliacus muscles for stability and movement of the lumbar spine, pelvis and hip. Scandinavian journal of medicine & science in sports, 5(1), 10-16.
    9. 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.
    10. Brown, S. H., & McGill, S. M. (2009). Transmission of muscularly generated force and stiffness between layers of the rat abdominal wall. Spine34(2), E70-E75.
    11. Folkow, B., Gelin, L. E., Lindell, S. E., Stenberg, K., & Thorén, O. (1962). Cardiovascular reactions during abdominal surgery. Annals of Surgery156(6), 905.
    12. 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.

      • Rectus Abdominis

    13. 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.
    14. Kim, H. J., Chung, S., Kim, S., Shin, H., Lee, J., Kim, S., & Song, M. Y. (2006). Influences of trunk muscles on lumbar lordosis and sacral angle. European Spine Journal, 15(4), 409-414.
    15. Snijders, C. J., Hermans, P. F., Niesing, R., Spoor, C. W., & Stoeckart, R. (2004). The influence of slouching and lumbar support on iliolumbar ligaments, intervertebral discs and sacroiliac joints. Clinical Biomechanics19(4), 323-329.
    16. Andersson, E. A., Grundström, H., & Thorstensson, A. (2002). Diverging intramuscular activity patterns in back and abdominal muscles during trunk rotation. Spine, 27(6), E152-E160.
    17. Cholewicki, J., Panjabi, M. M., & Khachatryan, A. (1997). Stabilizing function of trunk flexor‐extensor muscles around a neutral spine posture. Spine, 22(19), 2207-2212.
    18. Hodges, P. W., & Richardson, C. A. (1997). Contraction of the abdominal muscles associated with movement of the lower limb. Physical therapy, 77(2), 132-142.
    19. 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.
    20. Fujitani, R., Jiromaru, T., Kida, N., & Nomura, T. (2017). Effect of standing postural deviations on trunk and hip muscle activity. Journal of physical therapy science, 29(7), 1212-1215.
    21. Ng, J. K. F., Richardson, C. A., Parnianpour, M., & Kippers, V. (2002). EMG activity of trunk muscles and torque output during isometric axial rotation exertion: a comparison between back pain patients and matched controls. Journal of Orthopaedic Research, 20(1), 112-121.
    22. Ng, J. K. F., Richardson, C. A., Parnianpour, M., & Kippers, V. (2002). Fatigue-related changes in torque output and electromyographic parameters of trunk muscles during isometric axial rotation exertion: an investigation in patients with back pain and in healthy subjects. Spine, 27(6), 637-646
    23. 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
    24. Larsen, L. H., Hirata, R. P., & Graven-Nielsen, T. (2016). Effects of unilateral and bilateral experimental low-back pain on trunk muscle activity during stair walking in healthy and recurrent low-back pain patients. In 16th World Congress on Pain.
    25. O'Sullivan, P., Twomey, L., Allison, G., Sinclair, J., Miller, K., & Knox, J. (1997). Altered patterns of abdominal muscle activation in patients with chronic low back pain. Australian journal of physiotherapy, 43(2), 91-98.
    26. 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

      • External Obliques

    27. Rizk, N. N. (1980). A new description of the anterior abdominal wall in man and mammals. Journal of anatomy, 131(Pt 3), 373.
    28. McGill, S. M. (1991). Kinetic potential of the lumbar trunk musculature about three orthogonal orthopaedic axes in extreme postures. Spine, 16(7), 809-815.
    29. McGill, S. M. (1991). Electromyographic activity of the abdominal and low back musculature during the generation of isometric and dynamic axial trunk torque: implications for lumbar mechanics. Journal of Orthopaedic Research, 9(1), 91-103.
    30. 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.

    31. McGill, S. M. (1996). A revised anatomical model of the abdominal musculature for torso flexion efforts. Journal of biomechanics, 29(7), 973-977.
    32. De Troyer, A., & Estenne, M. (1988). Functional anatomy of the respiratory muscles. Clinics in chest medicine, 9(2), 175-193.
    33. Danneels, L. A., Vanderstraeten, G. G., Cambier, D. C., Witvrouw, E. E., Stevens, V. K., & De Cuyper, H. J. (2001). A functional subdivision of hip, abdominal, and back muscles during asymmetric lifting. Spine, 26(6), E114-E121.
    34. Hodges, P., Cresswell, A., & Thorstensson, A. (1999). Preparatory trunk motion accompanies rapid upper limb movement. Experimental Brain Research, 124(1), 69-79.
    35. Drysdale, C. L., Earl, J. E., & Hertel, J. (2004). Surface electromyographic activity of the abdominal muscles during pelvic-tilt and abdominal-hollowing exercises. Journal of athletic training, 39(1), 32.
    36. Cresswell, A. G., & Thorstensson, A. (1989). The role of the abdominal musculature in the elevation of the intra-abdominal pressure during specified tasks. Ergonomics, 32(10), 1237-1246.
    37. Bogduk, N., & Macintosh, J. E. (1984). The applied anatomy of the thoracolumbar fascia. Spine, 9(2), 164-170.
    38. Richardson C, Jull G, Hodges P, Hides J. Therapeutic Exercise for Spinal Segmental Stabilization in Low Back Pain: Scientific Basis and Clinical Approach. Edinburgh: Churchill Livingstone: 1999.
    39. Granata, K. P., Slota, G. P., & Wilson, S. E. (2004). Influence of fatigue in neuromuscular control of spinal stability. Human factors, 46(1), 81-91.
    40. Lehman, G. J., Hoda, W., & Oliver, S. (2005). Trunk muscle activity during bridging exercises on and off a swissball. Chiropractic & osteopathy, 13(1), 14.
    41. Adductors
    42. Hungerford, B., Gilleard, W., Hodges, P. (2003) Evidence of altered lumbopelvic muscle recruitment in the presence of sacroiliac joint pain. Spine 28(14), 1593-1600
    43. Pool-Goudzwaard, A. L., Vleeming, A., Stoeckart, R., Snijders, C. J., & Mens, J. M. A. (1998). Insufficient lumbopelvic stability: a clinical, anatomical and biomechanical approach to ‘a-specific’ low back pain. Manual Therapy3(1), 12-20.
    44. 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 biomechanics8(6), 285-294.

    45. 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. Spine20(18), 1989-1993.

    46. 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.
    47. 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
    48. Bell, D. R., Vesci, B. J., DiStefano, L. J., Guskiewicz, K. M., Hirth, C. J., & Padua, D. A. (2012). Muscle activity and flexibility in individuals with medial knee displacement during the overhead squat. Athletic Training and Sports Health Care, 4(3), 117-125.
    49. Hungerford, B., Gilleard, W., Hodges, P. (2003) Evidence of altered lumbopelvic muscle recruitment in the presence of sacroiliac joint pain. Spine 28(14), 1593-1600
    50. Hägglund M, Waldén M, Ekstrand J. Risk factors for lower extremity muscle injury in professional soccer: the UEFA Injury Study. The American Journal Of Sports Medicine . February 2013;41(2):327-335. Available from: MEDLINE Complete, Ipswich, MA. Accessed May 4, 2016.
    51. Ekstrand J, Hägglund M, Waldén M. Epidemiology of muscle injuries in professional football (soccer). The American Journal Of Sports Medicine . June 2011;39(6):1226-1232. Available from: MEDLINE Complete, Ipswich, MA. Accessed May 4, 2016.
    52. Naal F, Dalla Riva F, Wuerz T, Dubs B, Leunig M. Sonographic prevalence of groin hernias and adductor tendinopathy in patients with femoroacetabular impingement. The American Journal Of Sports Medicine . September 2015;43(9):2146-2151. Available from: MEDLINE Complete, Ipswich, MA. Accessed May 4, 2016.
    53. 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.

      • Pectoralis Major

    54. Sanchez ER, Sanchez R, Moliver C. (2014). Anatomic relationship of pectoralis major and minor muscles: a cadaveric study. Aesthet. Surg. J. 34(2): 258-263.
    55. Harms-Ringdahl, K. (1986). On assessment of shoulder exercise and load-elicited pain in the cervical spine. Biomechanical analysis of load--EMG--methodological studies of pain provoked by extreme position. Scandinavian journal of rehabilitation medicine. Supplement, 14, 1-40.
    56. Ekholm, J., Arborelius, U. P., Hillered, L., & Ortqvist, A. (1978). Shoulder muscle EMG and resisting moment during diagonal exercise movements resisted by weight-and-pulley-circuit. Scandinavian journal of rehabilitation medicine, 10(4), 179-185.
    57. Marchetti, P. H., & Uchida, M. C. (2011). Effects of the pullover exercise on the pectoralis major and latissimus dorsi muscles as evaluated by EMG. Journal of applied biomechanics, 27(4), 380-384.
    58. Pearl, M. L., Perry, J., Torburn, L. M. S. P. T., & Gordon, L. H. (1992). An electromyographic analysis of the shoulder during cones and planes of arm motion. Clinical orthopaedics and related research, (284), 116-127.
    59. Pink, M., Jobe, F. W., & Perry, J. (1990). Electromyographic analysis of the shoulder during the golf swing. The American journal of sports medicine, 18(2), 137-140.
    60. Jobe, F. W., Moynes, D. R., & Antonelli, D. J. (1986). Rotator cuff function during a golf swing. The American journal of sports medicine, 14(5), 388-392.
    61. Gowan, I. D., Jobe, F. W., Tibone, J. E., Perry, J., & Moynes, D. R. (1987). A comparative electromyographic analysis of the shoulder during pitching: professional versus amateur pitchers. The American journal of sports medicine, 15(6), 586-590.
    62. Ryu, R. K., McCormick, J., Jobe, F. W., Moynes, D. R., & Antonelli, D. J. (1988). An electromyographic analysis of shoulder function in tennis players. The American journal of sports medicine, 16(5), 481-485.
    63. Rokito, A. S., Jobe, F. W., Pink, M. M., Perry, J., & Brault, J. (1998). Electromyographic analysis of shoulder function during the volleyball serve and spike. Journal of Shoulder and Elbow Surgery, 7(3), 256-263.
    64. Scovazzo, M.L., Browne, A., Pink, M., Jobe, F.W., and Kerrigan, J.  (1991).  The painful shoulder during freestyle swimming: An electromyographic cinematographic analysis of twelve muscles. The American Journal of Sports Medicine.  577-582.
    65. Paton, M. E., & Brown, J. M. M. (1994). An electromyographic analysis of functional differentiation in human pectoralis major muscle. Journal of Electromyography and Kinesiology, 4(3), 161-169.
    66. Glass, S. C., & Armstrong, T. (1997). Electromyographical Activity of the Pectoralis Muscle During Incline and Decline Bench Presses. The Journal of Strength & Conditioning Research, 11(3), 163-167.
    67. Harms-Ringdahl, K. (1986). On assessment of shoulder exercise and load-elicited pain in the cervical spine. Biomechanical analysis of load--EMG--methodological studies of pain provoked by extreme position. Scandinavian journal of rehabilitation medicine. Supplement, 14, 1-40.
    68. Welsch, E. A., Bird, M., & Mayhew, J. L. (2005). Electromyographic activity of the pectoralis major and anterior deltoid muscles during three upper-body lifts. Journal of Strength and Conditioning Research, 19(2), 449.
    69. Lehman, G. J., MacMillan, B., MacIntyre, I., Chivers, M., & Fluter, M. (2006). Shoulder muscle EMG activity during push up variations on and off a Swiss ball. Dynamic Medicine, 5(1), 7.
    70. Steenbrink, F., De Groot, J. H., Veeger, H. E. J., Meskers, C. G. M., van de Sande, M. A. J., & Rozing, P. M. (2006). Pathological muscle activation patterns in patients with massive rotator cuff tears, with and without subacromial anaesthetics. Manual therapy, 11(3), 231-237.
    71. Santana, J. C., Vera-Garcia, F. J., & McGill, S. M. (2007). A kinetic and electromyographic comparison of the standing cable press and bench press. Journal of Strength and Conditioning Research, 21(4), 1271.
    72. Schick, E. E., Coburn, J. W., Brown, L. E., Judelson, D. A., Khamoui, A. V., Tran, T. T., & Uribe, B. P. (2010). A comparison of muscle activation between a Smith machine and free weight bench press. The Journal of Strength & Conditioning Research, 24(3), 779-784.
    73. McCaw, S. T., & Friday, J. J. (1994). A comparison of muscle activity between a free weight and machine bench press. J Strength Cond Res, 8(4), 259-64.
    74. Uribe, B. P., Coburn, J. W., Brown, L. E., Judelson, D. A., Khamoui, A. V., & Nguyen, D. (2010). Muscle activation when performing the chest press and shoulder press on a stable bench vs. a Swiss ball. The Journal of Strength & Conditioning Research, 24(4), 1028-1033.
    75. David, G., Magarey, M. E., Jones, M. A., Dvir, Z., Türker, K. S., & Sharpe, M. (2000). EMG and strength correlates of selected shoulder muscles during rotations of the glenohumeral joint. Clinical Biomechanics, 15(2), 95-102.
    76. Saeterbakken, A. H., van den Tillaar, R., & Fimland, M. S. (2011). A comparison of muscle activity and 1-RM strength of three chest-press exercises with different stability requirements. Journal of sports sciences, 29(5), 533-538.
    77. Wang HK, Cochorane T. 2001.  Mobility impairment, muscle imbalance, muscle weakness, scapular asymmetry and shoulder injury in elite volleyball athletes.  J Sport Med Phys Fitness 41(3): 403-10
    78. Kronberg, M., NÉmeth, G., & Broström, L. A. (1990). Muscle activity and coordination in the normal shoulder. An electromyographic study. Clinical orthopaedics and related research, (257), 76-85.
    79. Hirashima, M., Kadota, H., Sakurai, S., Kudo, K., & Ohtsuki, T. (2002). Sequential muscle activity and its functional role in the upper extremity and trunk during overarm throwing. Journal of sports sciences, 20(4), 301-310.
    80. Glousman R, Jobe F, Tibone J, Moynes D, Antonelli D, Perry J. Dynamic Electromyographic analysis of the throwing shoulder with glenohumeral instability. J Bone jugular). (Etymology Online)">Joint Surg 70A(2):220-226, 1988.
    81. Park, K. M., Cynn, H. S., Kwon, O. Y., Yi, C. H., Yoon, T. L., & Lee, J. H. (2014). Comparison of pectoralis major and serratus anterior muscle activities during different push-up plus exercises in subjects with and without scapular winging. The Journal of Strength & Conditioning Research, 28(9), 2546-2551.
    82. Park, K. M., Cynn, H. S., Yi, C. H., & Kwon, O. Y. (2013). Effect of isometric horizontal abduction on pectoralis major and serratus anterior EMG activity during three exercises in subjects with scapular winging. Journal of Electromyography and Kinesiology, 23(2), 462-468.

      • Serratus Anterior

    83. Kao, J. T., Pink, M., Jobe, F. W., & Perry, J. (1995). Electromyographic analysis of the scapular muscles during a golf swing. The American journal of sports medicine23(1), 19-23.
    84. McHardy, A., & Pollard, H. (2005). Muscle activity during the golf swing. British journal of sports medicine39(11), 799-804.
    85. Maffet, M. W., Jobe, F. W., Pink, M. M., Brault, J., & Mathiyakom, W. (1997). Shoulder muscle firing patterns during the windmill softball pitch. The American journal of sports medicine25(3), 369-374.
    86. Seo, S. H., Jeon, I. H., Cho, Y. H., Lee, H. G., Hwang, Y. T., & Jang, J. H. (2013). Surface EMG during the push-up plus exercise on a stable support or Swiss ball: scapular stabilizer muscle exercise. Journal of physical therapy science25(7), 833-837.
    87. Park, Se-yeon, and Won-gyu Yoo. “Differential activation of parts of the serratus anterior
    88. muscle during push-up variations on stable and unstable bases of support.” Journal of Electromyography and Kinesiology

    21.5 (2011): 861-867.

  • Kibler, W. B., Chandler, T. J., Shapiro, R., & Conuel, M. (2007). Muscle activation in coupled scapulohumeral motions in the high performance tennis serve. British journal of sports medicine41(11), 745-749.
  • Ryu, R. K., McCormick, J., Jobe, F. W., Moynes, D. R., & Antonelli, D. J. (1988). An electromyographic analysis of shoulder function in tennis players. The American journal of sports medicine16(5), 481-485.
  • Pink, M., Perry, J., Browne, A., Scovazzo, M. L., & Kerrigan, J. (1991). The normal shoulder during freestyle swimming: an electromyographic and cinematographic analysis of twelve muscles. The American Journal of Sports Medicine19(6), 569-576.
  • Nuber, G. W., Jobe, F. W., Perry, J., Moynes, D. R., & Antonelli, D. (1986). Fine wire electromyography analysis of muscles of the shoulder during swimming. The american journal of sports medicine14(1), 7-11.
  • Witt, D., Talbott, N., & Kotowski, S. (2011). Electromyographic activity of scapular muscles during diagonal patterns using elastic resistance and free weights. International journal of sports physical therapy6(4), 322.
  • Diederichsen, L. P., Nørregaard, J., Dyhre-Poulsen, P., Winther, A., Tufekovic, G., Bandholm, T., ... & Krogsgaard, M. (2009). The activity pattern of shoulder muscles in subjects with and without subacromial impingement. Journal of Electromyography and kinesiology19(5), 789-799.
  • de Morais Faria, C. D. C., Teixeira-Salmela, L. F., de Paula Goulart, F. R., & de Souza Moraes, G. F. (2008). Scapular muscular activity with shoulder impingement syndrome during lowering of the arms. Clinical Journal of Sport Medicine18(2), 130-136.
  • Wadsworth, D. J. S., & Bullock-Saxton, J. E. (1997). Recruitment patterns of the scapular rotator muscles in freestyle swimmers with subacromial impingement. International journal of sports medicine, 18(08), 618-624.
  • McMahon, P. J., Jobe, F. W., Pink, M. M., Brault, J. R., & Perry, J. (1996). Comparative electromyographic analysis of shoulder muscles during planar motions: anterior glenohumeral instability versus normal. Journal of shoulder and elbow surgery, 5(2), 118-123.
  • Phadke, V., Camargo, P. R., & Ludewig, P. M. (2009). Scapular and rotator cuff muscle activity during arm elevation: a review of normal function and alterations with shoulder impingement. Brazilian Journal of Physical Therapy13(1), 1-9.
  • Thigpen CA, Padua DA, Michener LA, Guskiewicz K, Giuliani C, Keener JD, Stergiou N. (2010). Head and shoulder posture affect scapular mechanics and muscle activity in overhead tasks. Journal of Electromyography and Kinesiology. 20: 701-709.
  • Kwon JW, Son SM, Lee NK. (2015). Changes in upper-extremity muscle activities due to head position in subjects with a forward head posture and rounded shoulders. J Phys Ther Sci. 27: 1739-1742
  • Helgadottir, H., Kristjansson, E., Einarsson, E., Karduna, A., & Jonsson, H. (2011). Altered activity of the serratus anterior during unilateral arm elevation in patients with cervical disorders. Journal of electromyography and kinesiology,21(6), 947-953.
  • Weon, J. H., Oh, J. S., Cynn, H. S., Kim, Y. W., Kwon, O. Y., & Yi, C. H. (2010). Influence of forward head posture on scapular upward rotators during isometric shoulder flexion. Journal of Bodywork and movement therapies, 14(4), 367-374.
  • Ludewig, P. M., & Cook, T. M. (1996). The effect of head position on scapular orientation and muscle activity during shoulder elevation. Journal of Occupational Rehabilitation6(3), 147-158.
  • Cools, A. M., Witvrouw, E. E., Declercq, G. A., Vanderstraeten, G. G., & Cambier, D. C. (2004). Evaluation of isokinetic force production and associated muscle activity in the scapular rotators during a protraction-retraction movement in overhead athletes with impingement symptoms. British journal of sports medicine, 38(1), 64-68.
  • McQuade, K. J., Dawson, J., & Smidt, G. L. (1998). Scapulothoracic muscle fatigue associated with alterations in scapulohumeral rhythm kinematics during maximum resistive shoulder elevation. Journal of Orthopaedic & Sports Physical Therapy, 28(2), 74-80.
  • Borstad, J. D., Szucs, K., & Navalgund, A. (2009). Scapula kinematic alterations following a modified push-up plus task. Human movement science28(6), 738-751.
  • Cools, A. M., Witvrouw, E. E., Declercq, G. A., Vanderstraeten, G. G., & Cambier, D. C. (2004). Evaluation of isokinetic force production and associated muscle activity in the scapular rotators during a protraction-retraction movement in overhead athletes with impingement symptoms. British journal of sports medicine, 38(1), 64-68.
  • Lawrence, R. L., Braman, J. P., Laprade, R. F., & Ludewig, P. M. (2014). Comparison of 3-dimensional shoulder complex kinematics in individuals with and without shoulder pain, part 1: sternoclavicular, acromioclavicular, and scapulothoracic joints. journal of orthopaedic & sports physical therapy, 44(9), 636-A8.
  • Lin, J. J., Hanten, W. P., Olson, S. L., Roddey, T. S., Soto-quijano, D. A., Lim, H. K., & Sherwood, A. M. (2005). Functional activity characteristics of individuals with shoulder dysfunctions. Journal of Electromyography and Kinesiology15(6), 576-586.
  • Ludewig, P. M., & Cook, T. M. (2000). Alterations in shoulder kinematics and associated muscle activity in people with symptoms of shoulder impingement. Physical therapy, 80(3), 276-291.
  • Ludewig, P. M., Hoff, M. S., Osowski, E. E., Meschke, S. A., & Rundquist, P. J. (2004). Relative balance of serratus anterior and upper trapezius muscle activity during push-up exercises. The American journal of sports medicine32(2), 484-493.
  • Lear, L. J., & Gross, M. T. (1998). An electromyographical analysis of the scapular stabilizing synergists during a push-up progression. Journal of Orthopaedic & Sports Physical Therapy28(3), 146-157
  • Ludewig, P. M., Hoff, M. S., Osowski, E. E., Meschke, S. A., & Rundquist, P. J. (2004). Relative balance of serratus anterior and upper trapezius muscle activity during push-up exercises. The American journal of sports medicine32(2), 484-493.
  • Castelein, B., Cagnie, B., Parlevliet, T., & Cools, A. (2016). Serratus anterior or pectoralis minor: Which muscle has the upper hand during protraction exercises?. Manual therapy22, 158-164.
  • Martins, J., Tucci, H. T., Andrade, R., Araújo, R. C., Bevilaqua-Grossi, D., & Oliveira, A. S. (2008). Electromyographic amplitude ratio of serratus anterior and upper trapezius muscles during modified push-ups and bench press exercises. The Journal of Strength & Conditioning Research, 22(2), 477-484.
  • Lehman, G. J., Gilas, D., & Patel, U. (2008). An unstable support surface does not increase scapulothoracic stabilizing muscle activity during push up and push up plus exercises. Manual therapy13(6), 500-506.
  • de Oliveira, A. S., de Morais Carvalho, M., & de Brum, D. P. C. (2008). Activation of the shoulder and arm muscles during axial load exercises on a stable base of support and on a medicine ball. Journal of Electromyography and Kinesiology18(3), 472-479.
  • Kim, S. H., Kwon, O. Y., Kim, S. J., Park, K. N., Choung, S. D., & Weon, J. H. (2014). Serratus anterior muscle activation during knee push-up plus exercise performed on static stable, static unstable, and oscillating unstable surfaces in healthy subjects. Physical Therapy in Sport15(1), 20-25.
  • Kim, E. R., Oh, J. S., & Yoo, W. G. (2014). Effect of vibration frequency on serratus anterior muscle activity during performance of the push-up plus with a redcord sling. Journal of physical therapy science26(8), 1275-1276.
  • Pirauá, A. L. T., Pitangui, A. C. R., Silva, J. P., dos Passos, M. H. P., de Oliveira, V. M. A., Batista, L. D. S. P., & de Araújo, R. C. (2014). Electromyographic analysis of the serratus anterior and trapezius muscles during push-ups on stable and unstable bases in subjects with scapular dyskinesis. Journal of Electromyography and Kinesiology24(5), 675-681.
  • Ekstrom, R. A., Donatelli, R. A., & Soderberg, G. L. (2003). Surface electromyographic analysis of exercises for the trapezius and serratus anterior muscles. Journal of Orthopaedic & Sports Physical Therapy, 33(5), 247-258.
  • Moseley JR, J. B., Jobe, F. W., Pink, M., Perry, J., & Tibone, J. (1992). EMG analysis of the scapular muscles during a shoulder rehabilitation program. The American journal of sports medicine, 20(2), 128-134.
  • Büll, M. L., & Vitti, M. (1990). Electromyographic study of the trapezius (pars superior) and serratus anterior (pars inferior) in free movements of the arm. Anatomischer Anzeiger171(2), 125-133.
  • Tsuruike, M., & Ellenbecker, T. S. (2015). Serratus anterior and lower trapezius muscle activities during multi-joint isotonic scapular exercises and isometric contractions. Journal of athletic training50(2), 199-210.
  • Hardwick DH, Beebe JA, McDonnell MK, Lang CE. (2006). A comparison of serratus anterior muscle activation during a wall slide exercise and other traditional exercises. Journal of Orthopaedic & Sports Physical Therapy. 36(12) 903-910
  • Ha, Sung-min., Kown, Oh-yum., Cynn, Heon-seock., Lee, Won-hwee., Park, Kyue-nam., Kim, Si-hyun., & Jun, Do-young. (2012) Comparison of electromyographic activity of the lower trapezius and serratus anterior muscle in different arm-lifting scapular posterior tilt exercises. Physical Therapy in Sport, 13, 227-232.
  • Ha, S. M., Kwon, O. Y., Cynn, H. S., Lee, W. H., Park, K. N., Kim, S. H., & Jung, D. Y. (2012). Comparison of electromyographic activity of the lower trapezius and serratus anterior muscle in different arm-lifting scapular posterior tilt exercises. Physical Therapy in Sport, 13(4), 227-232.
  • Cools, A. M., Dewitte, V., Lanszweert, F., Notebaert, D., Roets, A., Soetens, B., ... & Witvrouw, E. E. (2007). Rehabilitation of scapular muscle balance: which exercises to prescribe?. The American journal of sports medicine35(10), 1744-1751
  • Decker, M. J., Hintermeister, R. A., Faber, K. J., & Hawkins, R. J. (1999). Serratus anterior 
  • muscle activity during selected rehabilitation exercises. The American journal of sports medicine, 27(6), 784-791.

  • Lucas, K. R., Polus, B. I., & Rich, P. A. (2004). Latent myofascial trigger points: their effects on muscle activation and movement efficiency. Journal of Bodywork and Movement Therapies, 8(3), 160-166.

    • Additional Research on Function

  • 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.
  • 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.
  • Kang, T., Lee, J., Seo, J., & Han, D. (2017). The effect of bridge exercise method on the strength of rectus abdominis muscle and the muscle activity of paraspinal muscles while doing treadmill walking with high heels. Journal of physical therapy science, 29(4), 707-712
  • Yoo, W. G. (2014). Effect of the individual strengthening exercises for posterior pelvic tilt muscles on back pain, pelvic angle, and lumbar ROM of a LBP patient with excessive lordosis: a case study. Journal of physical therapy science, 26(2), 319-320.
  • Chang, M., Slater, L. V., Corbett, R. O., Hart, J. M., & Hertel, J. (2017). Muscle activation patterns of the lumbo-pelvic-hip complex during walking gait before and after exercise. Gait & posture, 52, 15-21.
  • Brookbush, B. Lumbo Pelvic Hip Complex Dysfunction. https://brentbrookbush.com/articles/postural-dysfunction-movement-impairment/lumbo-pelvic-hip-complex-dysfunction-lphcd/
  • Schleip, R. (2003). Fascial plasticity–a new neurobiological explanation: Part 1. Journal of Bodywork and movement therapies7(1), 11-19.

  • Schleip, R. (2003). Fascial plasticity–a new neurobiological explanation Part 2. Journal of Bodywork and movement therapies7(2), 104-116.

  • Calatayud, J., Casaña, J., Martín, F., Jakobsen, M. D., Colado, J. C., & Andersen, L. L. (2017). Progression of Core Stability Exercises Based on the Extent of Muscle Activity. American Journal of Physical Medicine & Rehabilitation96(10), 694-699

  • Marshall, P. W., & Murphy, B. A. (2005). Core stability exercises on and off a Swiss ball. Archives of physical medicine and rehabilitation86(2), 242-249.

  • Kang, T., Lee, J., Seo, J., & Han, D. (2017). The effect of bridge exercise method on the strength of rectus abdominis muscle and the muscle activity of paraspinal muscles while doing treadmill walking with high heels. Journal of physical therapy science29(4), 707-712.

  • Yoo, W. G. (2014). Effect of the individual strengthening exercises for posterior pelvic tilt muscles on back pain, pelvic angle, and lumbar ROM of a LBP patient with excessive lordosis: a case study. Journal of physical therapy science, 26(2), 319-320.

  • Chang, M., Slater, L. V., Corbett, R. O., Hart, J. M., & Hertel, J. (2017). Muscle activation patterns of the lumbo-pelvic-hip complex during walking gait before and after exercise. Gait & posture for a given exercise.

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