In an article in Musculoskeletal Science and Practice, researchers looked to quantify the hydration changes with the McKenzie prone push-up and MRI.
The intervertebral disc supports most of the weight in the upright posture. It is the largest avascular tissue in the human body and is a common source of pain in the case of discogenic problems. A popular therapeutic technique to reduce disc herniation is the McKenzie prone push-up. This is thought to centralize the nucleus pulposus of the disc to allow an improvement in healing.
Using MRI, the authors attempted to measure the pixel density of T2 weighted images to estimate disc fluid content and displacement. As a base line, they had the 22 subjects lay down for 40 minutes before the study began. Then, they had the subjects conduct a series of prone push-ups to immediately follow-up with MRI imaging. They looked at the midsagittal slice of L4-5 and L5-S1.
In their conclusion they did not see any significant pixel re-orientation suggesting that the disc did not change with respect to hydration content. They did see significant anterior displacement at the L4-5 level, however.
Limitations to the Study
It is important to note that in the methods there were many limiting factors. For one, the researchers instructed the subjects to lay down for 40 minutes prior to the study. Previous work has shown that laying down for 10 minutes has an effect on disc height and respective hydraulics of the lumbar discs. Therefore, the subjects may have already had changes prior to the beginning of the prone push-ups. Another significant limitation to the study was that only the midsagittal section of the disc was measured and therefore changes outside of the field of view was not measured.
A congratulations to the authors for publishing this manuscript. However, much more research must be conducted to suggest that the prone push-up does not affect hydration and/or distribution of the intervertebral disc.