Research Review: The Diaphragm, The Core and Chronic Ankle Instability
By Jinny McGivern PT, DPT, CFMT, Certified Yoga Instructor
Edited by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS
Original Citation: Terada, M., Kosik, K. B., McCann, R. S., & Gribble, P. A. (2016). Diaphragm Contractility in Individuals with Chronic Ankle Instability. Medicine and science in sports and exercise. ABSTRACT
Why is this relevant?: Traditionally, rehabilitation for an ankle sprain has consisted of stretching and strengthening exercises for the foot/ankle complex, as well as balance activities. Despite this fairly comprehensive approach to ankle rehabilitation, the ankle remains an area of the body that is very vulnerable to re-injury (1). Researchers are investigating the effect of distal injuries on proximal segments of the body. The research study reviewed in this article compares the function of the diaphragm (the least discussed muscle of the "deep core" or Intrinsic Stabilization Subsystem (ISS)) in individuals with and without chronic ankle instability.
Chronic Ankle Instability - https://ramblingautismmom.wordpress.com/tag/wandering/
Study Summary
| Study Design | Single Blinded Case Control Design |
| Level of Evidence | III - Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies |
| Subject Demographics | Volunteers were recruited from a local college campus and divided into a control group (CONG) with 28 participants and chronic ankle instability group (CAIG) with 27 participants.
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| Outcome Measures | Participant Characteristics:
Diaphragm Contractility:
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| Results |
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| Conclusions | This research demonstrates that altered neuromuscular strategies are observable proximal to the lower leg in individuals with chronic ankle instability. The altered left hemi-diaphragm function observed in individuals with chronic ankle instability may indicate impairments in more proximal stabilizing systems, such as the ISS. |
| Conclusions of the Researchers | The left hemi diaphragm demonstrated a smaller degree of contractility in individuals identified to have chronic ankle instability when compared to uninjured controls. It is possible that this difference in diaphragm function observed between the groups may indicate altered strategies of neuromuscular function from the Central Nervous System. |
Intrinsic Stabilization Subsystem
Review & Commentary:
The authors of this study used a strong methodology, with very clearly defined parameters. A questionnaire (Godin Leisure-Time Exercise Questionnaire) was used to define "physically active" within the population observed. The researchers indicated that their chronic ankle instability group (CAIG) had a history of lateral ankle sprains, thus removing potentially confounding variables associated with other types of ankle sprains. A thorough exclusion criteria screened all systems of the body which may have altered diaphragm function, thus the primary difference between the groups was related to chronic ankle instability. A combination of symptom based reporting and functional outcome measures provided a clear picture of both the subjective experience and the functional limitations associated with chronic ankle instability. The researcher measuring diaphragm thickness was blinded to the group assignment.
This research study also had limitations. No physical objective assessments were performed as part of the data collection on the subjects (i.e. range of motion or accessory joint motion for the foot/ankle). These measurements would have provided some insight into whether instability was related to local ligamentous instability, impairments in range of motion or muscle strength, or if the perceived instability was related more to proprioception. Further, the authors noted they did not perform an assessment of breathing, for example the use of spirometry. The subjects were assessed in supine, therefore it is not possible to determine if the differences noted in diaphragm function would be present in upright postures. More research is needed to observe diaphragm behavior in upright, functional postures. It may have been interesting to assess other muscles of the intrinsic stabilization subsystem (ISS), such as the multifidus , transverse abdominis (TVA) or the pelvic floor. These muscles could have been assessed at the same time to determine how diaphragm dysfunction related to behavior of the group, and chronic ankle instability. Finally, the authors acknowledge that it is not possible to determine whether the alterations in diaphragm contractility preceded or followed the respective ankle sprain injuries based on this research design.
An additional finding of the authors was that the difference in contractility between the CAIG and CONG was observed to be more significant for the left hemi diaphragm as compared to the right. The researchers hypothesize that this could contribute to asymmetrical patterns and result in an inability of the right and left diaphragms to work together, both for respiration and for core stability.
Why is this study important?
This research demonstrates the affect distal dysfunction may have on proximal structures, providing further evidence of regional interdependence. Specifically, it may be necessary to address diaphragm function and trunk stability in individuals with a history of ankle sprains, or potentially, as a means to reduce the risk of ankle sprains. Further, this study may provide evidence that ankle sprains may result in future orthopedic issues that can stem from an inhibited ISS and poor trunk control (such as low back pain).
How does it affect practice?
This research has implications for practice on multiple levels. It supports the inclusion of trunk stabilization activities for individuals recovering from an ankle sprain. There is more discussion below on specific exercises recommendations. Second, it may be important to stress breathing during exercise and rehab activities so the diaphragm is challenged to function simultaneously for respiration and core stabilization. Last, this study serves as a reminder to be thorough in our subjective assessment - Whether working with acutely injured, chronic injury, or uninjured populations, it is beneficial to understand how prior injures may contribute to a person developing compensations, and future injury. For example, a history of ankle sprain five years ago, enters your office/gym/clinic and is currently complaining of low back pain. Is the diaphragm involved?
How does it relate to Brookbush Institute Content?
This research supports the Brookbush Institute's predictive models of postural dysfunction , specifically how Lumbo Pelvic Hip Complex Dysfunction and Lower Leg Dysfunction may be related to one another via the tendency of the ISS to become inhibited in both. Further, it supports the inclusion of "Core Activation" as part of the "Integrated Warm-up Templates" and "Rehabilitation Templates" used for all conditions and populations (athletes, fitness clients and patients) by the Brookbush Institute. Other research reviews done previously, support that the ISS should fire prior to movement of the extremities or activation of global trunk musculature (2-4), which suggests that the findings of this study should not be surprising The videos below show several variations on how to activate and integrate the ISS (which you do immediately following "isolated activation" at the start of your activation circuit). A key point to remember in neuromuscular re-education of these muscles is that the diaphragm, TVA , multifidus and pelvic floor are designed to fire together. Unless there is significant structural dysfunction, getting one member to activate helps to increase the activity of the rest.
Transverse Abdominis TVA Isolated Activation
TVA and Gluteus Maximus Activation and Progressions
Hardest Quadruped Progression Ever Challenge
Quadruped Crawl
References:
- Swenson, D. M., Yard, E. E., Fields, S. K., & Comstock, R. D. (2009). Patterns of recurrent injuries among US high school athletes, 2005–2008.The American journal of sports medicine, 37(8), 1586-1593.
- Hodges, P. W., Butler, J. E., McKenzie, D. K., & Gandevia, S. C. (1997). Contraction of the human diaphragm during rapid postural adjustments. The Journal of physiology, 505(Pt 2), 539-548
- Kolar, P., Sulc, J., Kyncl, M., Sanda, J., Neuwirth, J., Bokarius, A. V., Kriz, J. & Kobesova, A. (2010). Stabilizing function of the diaphragm: dynamic MRI and synchronized spirometric assessment. Journal of Applied Physiology, 109(4), 1064-1071.
- 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. Spine, 27(1), E1-E8.
© 2016 Brent Brookbush
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