The Stabilizing Role of the Diaphragm

Study Title: Stabilizing Function of the Diaphragm: Dynamic MRI and Synchronized Spirometric Assessment
Authors: P Kolar, J Sulc, M Kyncl et al.
Journal: Journal of Applied Physiology
Date: August 2010

Summary:

• For those of you who are familiar with DNS, PRI, NMT, FMS or any other system that places great emphasis on the importance of the diaphragm for postural stability of the locomotor system, here is a good article that identifies one mechanism behind this phenomenon. Pavel Kolar and friends utilized dynamic MRI to examine diaphragmatic excursion and positioning during tidal breathing and under load with isometric extremity movement. Along with spirometric evaluation, the objective of this study was also to examine the the dual respiratory and postural function of this important muscle. In studying thirty healthy subjects it was revealed that in comparison with tidal breathing, diaphragmatic excursion increases in the presence of both upper and extremity load. However, it should be noted that unlike many other muscles within the human body, the function of the diaphragm does not seem to function as one entire unit during stabilization. The investigators revealed that the highest level of excursion occurred at its apex and posterior fibers. Further, in comparison between upper and lower extremity loads, diaphragmatic tonicity and excursion was greater with lower extremity loads. Not surprising since it is not atypical for the lower extremity to warrant a greater load than that of the upper extremity. From these results, it was suggested that this muscle contributes to spinal stability via a hydraulic effect on the abdominal cavity thereby increasing intra abdominal pressure.

Kolar, P et al. (2010). Stabilizing function of the diaphragm: Dynamic MRI and synchronized spirometric assessment. Journal of Applied Physiology, 109; 1064-1071