I found a paper that has interesting insights on the height benefits of spinal traction and the duration that it lasts for.
Changes in stature during and after spinal traction in young male subjects
“Spinal traction is a relatively popular procedure for increasing the intervertebral space by applying separating forces. The parameters of time and magnitude of the traction forces may influence the outcomes from this procedure and need to be investigated. The duration of the benefits derived from traction is unknown and needs to be determined so that physiotherapists can provide better and more effective treatments. OBJECTIVE: This study analyzed the relationship between load magnitude and time during spinal traction in relation to stature variations. Traction effect duration was also analyzed. METHOD: Fifteen healthy male subjects (23.1 ± 5.77 years; 1.80 ± 0.17 m and 87.0 ± 9.6 kg) were assessed under three traction conditions (0, 30 and 60% of body weight, BW) of 42 minutes. Stature variation was used to determine intervertebral disc height variation. Stature was assessed every 7 minutes during traction of 42 minutes and every 5 minutes for 45 minutes after traction ceased. RESULTS: 0 and 30% BW traction produced similar gains (6.09 ± 1.89 mm, 5.70 ± 1.88 mm, respectively; p>0.05), while these were smaller (p<0.05) than at 60% BW (7.01 ± 1.98 mm){since 60% BW traction produced more benefits than 30% it begs the question of whether even more percent of bodyweight would have greater benefit and when the stopping point would. The additional 1mm increase due 60% BW traction is pretty significant}. Significant differences (p<0.05) between 60% BW and the other conditions occurred only after the 21st minute. Stature loss after traction showed that the traction effects were transient and lasted for approximately one hour{it is conceivable to do a traction style exercise every hour but not for 42 minutes}. This suggests that traction loads of 30% BW are insufficient to produce stature gains similar to those observed with 60% BW. CONCLUSION: Traction showed a short-duration transient effect. For this effect to be maintained, it must be repeated at one-hour intervals. Its use is questioned because of its transient nature.”
“The objective of traction is to produce a separating force over the intervertebral discs to counteract the shrinkage caused by compressive loading and restore its mechanical functioning, thereby relieving symptoms. “
HEre’s an image of the traction:
“The stature profile after traction indicated that all the participants lost stature, irrespective of their previous gains (p<0.05). On average, the participants shrank by 3.01 ± 1.09 mm (0% of body weight), 3.35 ± 1.35 mm (30% of body weight) and 4.56 ± 1.51 mm (60% of body weight).”<-the greater the height gain, the more shrinkage there was. “It was noticed that, during the period after the procedure, the participants lost 49.0%, 58.7% and 65.0% of the gains obtained during traction (for 0, 30 and 60%, respectively)”
“As traction was applied only over the lumbar area, whole body length measurements must be interpreted with caution. It is possible that other spinal regions that were not interfered with during the traction protocol may have experienced a certain degree of height variation due to the lying down and standing positions”
“greater stature gains are expected under clinical conditions in which traction is applied continuously (i.e. with no breaks for measurements).”
” The condition of 60% of body weight showed a profile similar to the other two experimental conditions, but only until the 21st minute.”<-it would interesting to do more testing on this to see if even higher loads had greater benefit.
“gains in stature were still being observed at the end of the protocol”
“up to 70 mm in space flights”<-if this is the theoretical cap and they only gain 7 mm in the study then there is much more theoretical benefit to gain.
” During the first instants of traction, the disc height gains could have occurred by a slow fluid influx. Negative hydrostatic pressure increases with traction load, which causes greater fluid absorption by the nucleus pulposus. Because the fluid cannot migrate very rapidly to the center of the intervertebral disc, tension is applied to the fibers of the annulus fibrosus, causing them to deform towards the center of the disc. Therefore, the first gains in intervertebral disc height may be much more related to pressure variations than elastic deformation of the annulus fibrosus and ligaments. After some fluid has been absorbed, the elastic elements of the intervertebral disc are deformed more intensively. “
70 mm is a lot of potential height gain from spinal traction. That is 7 cm or almost 3 inches. If we could find a way to keep and maintain that height. That would be pretty significant height gain!