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Tuesday, June 6, 2023

Alterations of Diaphragm Behavior in Individuals with Sacroiliac Joint Pain

Brent Brookbush

Brent Brookbush


Research Review: Alterations of Diaphragm Behavior in Individuals with Sacroiliac Joint Pain

By Jinny McGivern, PT, DPT, Certified Yoga Instructor

Edited by Brent Brookbush DPT, PT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: O’Sullivan, P. B., Beales, D. J., Beetham, J. A., Cripps, J., Graf, F., Lin, I. B., … & Avery, A. (2002). Altered motor control strategies in subjects with sacroiliac joint pain during the active straight-leg-raise test. Spine27(1), E1-E8. ABSTRACT

The above picture depicts the members of our core stabilizers who make up our "cylinder" of support. Image courtesy of https://osteopathysouthwest.wordpress.com/2013/09/21/sacroiliac-joint-dysfunction/

Why is this relevant?: The sacroiliac joint (SIJ) is the "bridge" or "keystone" between the spine and the lower extremity. It is subject to high levels of stress and load as we perform daily activities such as walking, climbing stairs, squatting and lifting. As O'Sullivan et al. reports in this research, 13-30% of non-specific low back pain may be related to SIJ dysfunction. Our deep core stabilizers, including the diaphragm and pelvic floor, play a role in stabilization of the SIJ (see Intrinsic Stabilization Subsystem (ISS) ). This research demonstrates how these muscles behave differently in individuals with and without SIJ pain during a task that requires a load transfer through the pelvis. These differences in behavior are essential to our understanding of optimal SIJ motion and intervention for neuromuscular and stability impairments that may be present in patients/clients with SIJ pain.

Study Summary

Study Design Cohort study
Level of Evidence 2b - Individual cohort study
Subject DemographicsThus study considered 2 groups of subjects: 13 individuals with SIJ pain (SIJP group) & 13 age, gender & BMI matched pain free controls (PFC group).
  • Age: Mean age SIJP 32.3 +/- 11.2, PFC 31.4 +/- 11.4
  • Gender:11 women, 2 men per group
  • Characteristics:
    • SIJP group: mean duration of symptoms 40.8 +/- 35.7 months; 5 subjects post partum; 13 subjects post trauma; 13 subjects with bladder dysfunction

  • Inclusion Criteria:
    • For SIJP group: pain over SIJ with no proximal referral; Active Straight Leg Raise (ASLR) Test (+); (+) in min 4/5 SIJ pain provocation tests from among distraction/compression test; thigh thrust test; pelvic torsion; sacral thrust; palpation of the long dorsal SI ligament.

  • Exclusion Criteria:
    • For both groups: History (hx) of neurologic dysfunction; facial pain (needed to use spirometry mask); hx of significant respiratory disorder; pregnancy or less than 6 months post partum; BMI < 31kg/m
    • For PFC group: Past medical history (PMH) resulting in inability to perform ASLR; hx of low back, pelvis, hip, knee or ankle pain within the last 6 months; hx of surgery  to the lumbar spine, pelvis, chest or abdomen within the last 12 months; any inflammatory disorders.

Outcome MeasuresOutcome measures were collected during 3 conditions: rest, ASLR, ASLR with manual compression. The following parameters were assessed:
  • Movement of the diaphragm via Ultrasound (probe at mid clavicular line just below costal margin) - mean of 3 breaths.
  • Movement of the pelvic floor (PF) via Ultrasound (probe at pubic symphysis - movement of inferior margin of the bladder measured as an indicator of PF movement).
  • Respiratory Rate via a Spirometer
  • Tidal Volume via a Spirometer
  • Respiration patterns via visual observation of spirometric tracings

Test-retest repeatability study was performed for 5 subjects to establish reliability of the outcome measures.


No significant difference in age, gender or anthropometric measurements between SIJP & PFC groups.

Respiratory Function

  • No difference in tidal volume between groups (p = .816) or conditions (p = .0599).
  • Minute ventilation significantly different  between the SIJP & PFC groups (p = .028).
  • Minute ventilation significantly different between testing conditions (p = .011).
  • Minute ventilation increased in the group with SIJP during ASLR (p = .046).
  • Minute ventilation decreased to a level comparable to controls during ASLR with manual compression - i.e. no significant difference between groups.
  • No significant difference between lying supine & ASLR with compression (p = .80).
  • Repeatability ICC for the measurements taken in the 3 conditions: resting .91, ASLR .92, .74 ASLR with manual compression.

Respiration patterns

  • PFC group demonstrated similar spirometry tracings for all 3 conditions.
  • SIJP group demonstrated high variability when performing ASLR.
    • Overall the trend for this group was increased respiratory rate with episodes of breath holding.  2 individuals demonstrated decreased respiratory rate.
    • Tidal volume varied largely in SIJP group both between participants & from breath to breath within 1 subject.
    • During rest & ASLR with compression respiratory rate * tidal volume normalized.

Diaphragm Excursion

  • The magnitude of diaphragmatic excursion was not significantly different between the 2 groups (p = .335).
  • Significant differences existed between the 3 conditions (p < .001).
  • SIJ group demonstrated decreased diaphragmatic excursion during ASLR as compared to resting conditions (p<.001) and the PFC group. (On 7 SIJ participants diaphragm motion was 0 during ASLR).
  • SIJP group demonstrated a restoration of diaphragmatic excursion comparable to that of PFC group with the addition of manual compression to ASLR (p<.001).
  • There was a significant difference between resting conditions and ASLR with compression in the SIJP group (p = .005).  Diaphragmatic excursion was greater in the SIJP group during resting conditions than in the PFC.
  • Repeatability ICC values were .94 resting, .71 for ASLR, .89 for ASLR with compression.

Pelvic Floor Descent

  • There was no pelvic floor motion in either group during the resting condition.
  • There were significant differences between the 2 groups (p < .001) and between the ASLR & ASLR with compression conditions (p < .001).
  • The SIJ group demonstrated significantly greater descent of the PF during ASLR & ASLR with compression (p < .001).
  • Repeatability ICC values were .95 for ASLR, .85 for ASLR with compression.
ConclusionsThis research demonstrates that the behavior of the diaphragm is altered in individuals with SIJ pain during activities that require load transfer through the pelvis. This research  supports the inclusion of the diaphragm & pelvic floor as members of the core musculature that aid in providing stability to the lumbopelvic-hip complex.
Conclusions of the ResearchersThis research indicates that the movement of the diaphragm & pelvic floor, as well as minute ventilation, differs between individuals with SIJ pain & pain free controls during performance of an ASLR. This research demonstrates that these changes may be related to a lack of form and/or force closure of the SIJ because the application of manual compression to the SIJ eliminated the differences in the behavior of these muscles between groups.

Form closure of the SIJ is achieved via structural congruity of the bones. Force closure is achieved via dynamic muscular stabilization (concepts from the work of Vleeming). Image courtesy of http://www.methodistorthopedics.com/online-courses/online-courses/sacroiliac-joint-dysfunction.

Review & Commentary:

There are many features of this research that contribute to its strong methodology. The results on the makeup of each subject group indicate that good control matching procedures were implemented to minimize confounding variables between groups. Well defined inclusion criteria for the SIJP group provided a clear clinical picture of how the researchers delineated primary SIJ pain. It was appropriate that individuals with a history of lower extremity injury/pain be excluded from the PFC group because it is known that mechanics of the lower extremity have an impact at the SIJ. The test-retest repeatability study within the larger study allowed the reader to appreciate that the methods used to collect the data were reliable.

One limitation of this study was that the SIJP group consisted of a mix of individuals who were post pregnancy and those who were not. Pregnancy results in a series of unique changes to a women's body which may result in dysfunction that is different from mechanisms of trauma or repetitive stress. Future researchers should repeat this study with groups of individuals who are exclusively post-partum and those who have not had children. It would also be interesting to observe if differences in motor control existed between those with chronic SIJP versus those with a more acute injury/trauma. It would have been beneficial if EMG of the diaphragm and pelvic floor could also have been assessed. This would have allowed the findings of the movements of muscle to be correlated with muscle activity. The addition of EMG of the Transverse Abdominis (TVA) and/or Internal Oblique (IO) would have provided insight into how these muscles interacted with respect to timing of activity onset and intensity of firing during the ASLR & ASLR with compression conditions. Finally, future researchers should investigate the changes in behavior of these muscles during functional tasks in weight bearing positions such as standing, walking and squatting.

Our deep core stabilizers are often described as being arranged as a closed cylinder with the diaphragm and pelvic floor as the the top and bottom of the cylinder (see Intrinsic Stabilization Subsystem (ISS) ). TVA , IO and multifidi form the side walls of the cylinder. With respect to core stabilization function, it is thought that the diaphragm and pelvic floor maintain pressure at the top and bottom of the cylinder so that as TVA contracts and increases pressure on the sides of the tube, intra abdominal pressure thereby trunk rigidity is successfully increased. This research reports that in those with SIJ pain, the diaphragm moves less inferiorly (and in some not at all). The pelvic floor dropped down during the ASLR. It is reasonable to hypothesize that this absence of a solid top & bottom of our "support cylinder" results in a relatively unsuccessful increase in trunk rigidity and lack of stability which may play a role in continuing the cycle of pain in individuals with SIJ dysfunction.

Why is this study important?

This study is important because it provides a comparison of core muscle function between individuals with and without SIJ pain. This allows better understanding of the components of dysfunction in individuals with pain to allow us to design interventions and assessments to aid in improving movement impairment.

How does it affect practice?

In a previously posted research review (Kolar et al. ), it was demonstrated that in pain free individuals the diaphragm typically descends to a more inferior level when there is muscle activity in the lower extremity over rest conditions. This may aid in achieving an optimal increase in intra-abdominal pressure and stability. This research reports that in individuals with SIJ pain, the diaphragm does not descend as it should during an activity involving movement of the lower extremity. A very simple practical application of this information is to encourage your clients to BREATHE smoothly and evenly during exercise and functional activities. This research indicates that both respiratory rate and tidal volume varied from breath to breath as individuals with SIJP performed an ASLR. While encouraging breathing is not likely to "fix" significant dysfunction causing SIJ pain, it is a key element to restore as your patient or client progresses through exercise and manual therapy interventions to ensure optimal functioning of all sides of the "canister" (ISS ) of the core. If you suspect significant pelvic floor dysfunction (possible in the presence of ongoing bladder dysfunction, pelvic pain, ongoing SIJ pain that hasn't responded to stabilization or manual therapy interventions) in a patient or client with SIJ pain, you may want to refer them to a physical therapist that specializes in rehabilitation of the pelvic floor. (Possibly connecting to other red flags???)

How does it relate to Brookbush Institute Content?

This research supports the Lumbo Pelvic Hip and Sacroiliac Joint Motion predictive models of postural dysfunction as described by the Brookbush Institute. In both of these dysfunctions the Intrinsic Stabilization Subsystem (ISS) , which includes the diaphragm and pelvic floor, is viewed as under-active, which is consistent with the behavior of these muscles observed by the researchers above. Within the model of Sacroiliac Joint Motion Dysfunction , the Brookbush institute goes on to detail how other muscles of the lower extremity and trunk factor into SIJ dysfunction and potentially pain in this region. Other muscles that are typically observed to be under-active in this dysfunction include the Gluteus Maximus and Gluteus Medius . Below is a series of videos for isolated activation techniques for TVA (how the Brookbush Institute activates the ISS ), Gluteus Maximus, Gluteus Medius, and a gluteus maximus/TVA combo activation exercise. These are followed by reactive integration techniques for each. These activities require the given muscle group to respond in a time dependent fashion this adding an additional challenge. These activities should be performed after release, stretch and mobilization techniques as recommended in the Sacroiliac Joint Dysfunction Corrective Exercise and Sample Routine article .

Transverse Abdominis TVA Isolated Activation

Hardest Quadruped Progression Ever

Gluteus Maximus Isolated Activation

Gluteus Medius Isolated Activation

Gluteus Maximus with TVA Activation

Sidestepping Gluteus Medius Reactive Integration

Gluteus Maximus Reactive Integration

Core Reactive Integration Crunch & Catch

© 2014 Brent Brookbush

Questions, comments, and criticisms are welcomed and encouraged -