Can exercises designed to strengthen the intervertebral discs make you taller?

Many grow taller sites state that you can increase your height by increasing the size of your intervertebral discs.  For example, by hanging or by the cobra yoga stretch.  The question is:  Does the science support this? Of course, even if the science doesn't support it that may mean that effective exercises for increasing intervertebral disc size have not been tested yet.  However, it is unlikely that the intervertebral disc can stretch.  The chondrocytes within can proliferate and secrete more extracellular matrix and thereby expand.  But, I don't think stretching would accomplish that.


Effect of running exercise on proteoglycans and collagen content in the intervertebral disc of young dogs.  

"Collagen and proteoglycans in the intervertebral disc (LI-II) of young beagle dogs (age 55 weeks) were analyzed following a 15 weeks' daily 20 km running training on a treadmill with 15 degree uphill inclination. In nucleus pulposus no statistically significant alterations were found in the content of proteoglycans or collagen. In annulus fibrosus the total tissue wet weight and total amount of collagen (hydroxyproline) increased by 34-36% in the runners as compared to age-matched, untrained controls. Since the total amount of proteoglycans did not increase, the annulus fibrosus became relatively depleted of proteoglycans, as indicated by the 27% reduction in uronic acid concentration, expressed either per wet weight or hydroxyproline. The average molecular size of the remaining nonaggregating proteoglycans was larger, and there was also a trend towards increased proportion of proteoglycans aggregating with hyaluronan. Most of the chondroitin sulfate side chains were 6-sulfated (65-66%). Running did not alter the sulfation or length of the chondroitin sulfate chains. The decreased proteoglycan/collagen ratio in annulus fibrosus may result in altered mechanical properties of the tissue and reflects its adaptation to enhanced motion and stress."

The molecular size of the proteoglycans increased(indicating an increase in proteoglycan hypertrophy).  Total tissue weight and tissue wet weight increased indicating an increase in the secretion of extracellular matrix.  The number of proteoglycans did not increase.  This may be something interesting to study in the future the proliferation and differentiation of proteoglycans.

Now we need to study intervertebral disc anatomy to see if an increase in the total amount of collagen and the size of the proteogyclans would increase disc height.  Here's a picture from spine universe:

 

"The annulus fibrosus is a strong radial tire–like structure made up of lamellae; concentric sheets of collagen fibers connected to the vertebral end plates. The sheets are orientated at various angles. The annulus fibrosus encloses the nucleus pulposus.

Although both the annulus fibrosus and nucleus pulposus are composed of water, collagen, and proteoglycans (PGs), the amount of fluid (water and PGs) is greatest in the nucleus pulposus. PG molecules are important because they attract and retain water. The nucleus pulposus contains a hydrated gel–like matter that resists compression. The amount of water in the nucleus varies throughout the day depending on activity." 

In the dog exercise study,  the amount of collagen and proteoglycans increased in the annulus fibrosus but they did not increase in the nucleus pulposus.  And, it is the nucleus pulposus that resists compression therefore exercise(including stretching) probably cannot be used to help resist the compression forces that occur during day to day activity.   It was found that LIPUS was stimulatory on the nucleus pulposus and therefore LIPUS may increase disc height.

However, can an increase in the amount of collagen and the size of the proteoglycan molecules in the annulus fibrosus still be used to increase disc height? 

An increase in the size of proteoglycan molecules should not increase disc height as proteoglycans are proteins and do not contribute to the structure of the disc. 

Now, Marfan's Syndrome is a connective tissue disorder(collagen is a connective tissue) that increases height(Vincent Schievalli was 6'5" but remember correlation not equal to causation so Vincent Schievalli's height may have been a coincidence).  However, the exact manner in which Marfan's Syndrome can increase height is unknown. 

Is a collagen scaffold for a tissue engineered nucleus replacement capable of restoring disc height and stability in an animal model? 

"The idea of a tissue engineered nucleus implant is to seed cells in a three-dimensional collagen matrix. This matrix may serve as a scaffold for a tissue engineered nucleus implant. The aim of this study was to investigate whether implantation of the collagen matrix into a spinal segment after nucleotomy is able to restore disc height and flexibility. The implant basically consists of condensed collagen type-I matrix. For clinical use, this matrix will be used for reinforcing and supporting the culturing of nucleus cells. In experiments, matrixes were concentrated with barium sulfate for X-ray purposes and cell seeding was disclaimed in order to evaluate the biomechanical performance of the collagen material. Six bovine lumbar functional spinal units, aging between 5 and 6 months, were used for the biomechanical in-vitro test. In each specimen, an oblique incision was performed, the nucleus was removed and replaced by a collagen-type-I matrix. Specimens were mounted in a custom-built spine tester, and subsequently exposed to pure moments of 7.5 Nm to move within the three anatomical planes. Each tested stage (intact, nucleotomy and implanted) was evaluated for range of motion, neutral zone and change in disc height. Removal of the nucleus significantly reduced disc height by 0.84 mm in respect to the intact stage and caused an instability in the segment. Through the implantation of the tissue engineered nucleus it was possible to restore this height and stability loss, and even to increase slightly the disc height of 0.07 mm compared with the intact stage. There was no statistical difference between the stability provided by the implant and intact stage. Results of movements in lateral bending and axial rotation showed the same trend compared to flexion/extension. However, implant extrusions have been observed in three of six cases during the flexibility assessment. The results of this study directly reflect the efficacy of vital nucleus replacement to restore disc height and to provide stability to intervertebral discs. However, from a biomechanical point of view, the challenge is to employ an appropriate annulus fibrosus sealing method, which is capable to keep the nucleus implant in place over a long-time period. Securing the nucleus implant inside the disc is one of the most important biomechanical prerequisites if such a tissue engineered implant shall have a chance for clinical application." 

So collagen was able to increase height(thus maybe explaining the tall stature that individuals with Marfan's Syndrome tend to exhibit), however, this was collagen in the nucleus pulposus not the annulus fibrosus.  So the answer as to whether exercises can increase height via the intervertebral discs?  Maybe but the fact that the nucleus pulposus does not seem to be stimulated by exercise(LIPUS may have a stimulatory effect though) is a very limiting factor(removal of the nucleus decreased height very significantly by 0.84 mm).  So any height gained by the annulus fibrosus may not be able to be maintained by the nucleus pulposus however exercise may increase laying down height via intervertebral disc size which takes the nucleus pulposus' function to resist compression out of the equation. 

Elastin plays a role in the height of intervertebral discs too but only when the discs are loaded from the side and would therefore have no impact on overall body height. 

Typical height increase stretches are not likely to increase intervertebral disc height which can make you taller by 0.07mm a pop.  However, LIPUS may be able to if applied on the discs.