By now you should all know the dual role the diaphragm plays in both postural stability and respiration. If not read on.
In browsing the Postural Restoration Institute's website, I stumbled across a link to this article by Boyle (Kyndall, not Mike), Olinick and Lewis. "The value of blowing up a balloon" was recently published in the North American Journal of Sports Physical Therapy primarily discusses the importance of achieving and maintaining an optimal zone of apposition (ZOA) of the diaphragm and provides an example of a simple (but not easy) exercise that can be performed by your patients whether they aim to improve respiration patterns or core integrity. But before I introduce the exercise, let me provide you with some background information.
As I mentioned above, a number of researchers have looked at the dual role played by the diaphragm in postural stability and respiration. These studies can be accessed here, here and here. Unfortunately, the maintenance of an optimal balance of stability and respiration of the diaphragm is not necessarily an easy one. One challenge, in particular, is the achievement and conservation of an ideal zone of apposition of the diaphragm. To put it simply, this zone of apposition can be thought of as the area of the diaphragm that encompasses the parachute-like portion of this muscle that Dr. Charlie Weingroff so frequently speaks about. The importance of this ZOA lies in the fact that it is directly controlled by the abdominals and contributes to diaphragmatic tension. In the presence of a suboptimal ZOA, several consequences may present themselves, namely:
As a result, faulty breathing patterns and inefficient core stability may lead to clinical conditions such as low back and pelvic dysfunction (I'd say pain but I'd rather not go there either). To illustrate the relationship between the diaphragm and the abdominals further, it has been shown that in the presence of increased stability demand, the diaphragm contracts concentrically while specific abdominal musculature contract eccentrically during inhalation. During expiration, the roles of these muscles are reversed. Most importantly, however, is the coordination of the two sets of muscle groups. As a result, it would likely be worthwhile for those of us privileged enough to work with the low back "dysfunction" population to adopt several strategies aimed at improving this dual and simultaneous role played by the diaphragm. But before I discuss the exercise by the authors of this paper, let me speak further about the diaphragm and ZOA that they describe in detail.
Some of you may have listened to Dr. Craig Liebenson's recent interview on Sports Rehab Expert. In his discussion with Joe Heiler, he frequently mentions the importance of the "exhalation position of the rib cage" and subsequently faulty "inhalation position" that many North American's display.
To put it simply, the exhalation position is the position of the rib cage that should be maintained with ventilation during normal activities of daily living. Just forcefully blow (cool not warm) air out of your mouth and you'll know what I mean. Well in the presence of this rib cage position, the dome of the diaphragm should move caudally during inhalation in order to create negative pressure in the thorax (to let air in). For those that possess a faulty breathing pattern, the inhalation position, the upper chest expands while the abdominals cave in. You may witness this in anyone who displays hypertonic scalenes and SCMs (i.e. those with high anxiety levels) or in individuals with respiratory diseases.
Lateral expansion of the rib cage is an ideal finding in those with normal breathing patterns and is largely the result of the ZOA. The ZOA creates this lateral expansion, or external rotation, since the pressure in the thoracic cage prevents the ribs from moving inward. The diaphragm's crura, which attaches asymmetrically on the upper aspect of the lumbar spine (L1-2 with the left hemidiaphragm and L1-3 with the right for those of you who are manual therapists), functions to assist with the caudal pull of this muscle. When this "parachute" is optimized, or dome-shaped, with the exhalation position rather than flat (with the inhalation position) then maximal postural and respiratory efficiency is achieved (efficiency = minimal accessory muscle activity, or E = MA squared). This leads to increased intra-abdominal pressure and subsequently, stability. Not an easy task owing to the fact that some level of relaxation of the musculature must occur with caudal movement of the diaphragm in order to facilitate organ displacement...but who says it's supposed to be easy?
So how do we achieve this dome-shaped parachute while simultaneously facilitating optimal abdominal co-contraction? The authors suggest a "90/90 Bridge with Ball and Balloon Technique". Since the exercise and its objectives are described in full in this open access paper, I will simply redirect you to pages 183-185 of their paper. I am curious, however, of the intentional posterior pelvic tilting and adductor facilitation advocated in their exercise. Personally, I would rather keep rib depression independent of spine motion as well as maximize abductor activity. These modifications will ensure a neutral spine and minimize contraction of an already prone to hypertonic adductor group. Those familiar with Dynamic Neuromuscular Stabilization will recognize the "dying bug"-type of position whereby bands are placed around the thighs to elicit gluteal activity. This is where I would go with the exercise.
Regardless, the value of the exercise lies in its use of the balloon during abdominal co-contraction since intra-abdominal pressure is required during the second consecutive breath (so long as inhalation is performed through the nasal airway) in order to prevent air form escaping from the balloon and into the mouth.
This is breathing and bracing.