you want to do reverse abdominal breathing i.e. fill the abdomen with air at the start of the lift. Then activate the the TVA to increase hoop tension in the core. You now have a non-collapsable cylinder that will protect your spine during heavy lifts.
When you lift heavy and momentarily hold your breath you initiate a lifting force that decompresses the lumbar vertebrae due to the attachments of the cura of the diaphragm to the lumbar spine.
Here's the detailed explanation from the CHEK institute:
The TVA, in concert with other inner unit muscles activates to increase stiffness of spinal joints and the sacroiliac joints.(6,7,15) Activation of the inner unit provides the necessary stiffness to give the arms and legs a working foundation from which to operate. Failure of the TVA to activate 30-110 ms prior to arm or leg movements respectively has been correlated with back pain and dysfunction.(6, 16) The inner unit is part of a system of stabilizer mechanisms, all of which are dependent on the integrated function of all inner unit muscles. To better appreciate how the inner unit creates stability in the body, let's look at each of the proposed mechanisms of stabilization: Thoracolumbar Fascia Gain, Intra-Abdominal Pressure and the Hydraulic Amplifier Effect.
Thoracolumbar Fascia Gain
Studying the anatomy of the TVA makes it clear that contraction of this muscle can only produce one action, drawing in the abdominal wall. This is evidenced by movement of the umbilicus toward the spine.
When activated, the transversus abdominis and posterior fibers of the obliquus internus draw the umbilicus inward toward the spine . This creates intra-abdominal pressure and hoop tension, which serve to stabilize the lumbar spine.
The synergistic action of the TVA and IO produce a characteristic hoop tension through the thoracolumbar fascia (TLF), which has been shown to create an extension force on the lumbar spine.(8,17) This is referred to as thoracolumbar fascia gain. TLF gain is thought to be an important element, buffering the transfer of force between the muscular and ligamentous systems during forward bending or rising from a forward bent position. The point at which the force transfer occurs is called the critical point, occurring at approximately 90% lumbar flexion.(17)
Thoracolumbar Fascia Gain Mechanism
Contraction of the transversus abdominis and obliquus internus generates lateral tension on the thoracolumbar fascia. The superficial lamina of the posterior layer of thoracolumbar fascia generates tension via its attachments at L2 and L3 , while the deep lamina generates tension upward through its attachments at L4 and L5 . These mutually opposing vectors tend to approximate or oppose separation of the L2 and L4 vertebra and the L3 and L5 vertebra, creating what is referred to as "thoracolumbar fascia gain". (8,17,21)
Intra-Abdominal Pressure
As the TVA is activated, drawing the abdominal wall inward, the viscera are pushed upward into the diaphragm and downward into the pelvic floor, creating intra-abdominal pressure (IAP). The pressure of viscera upon the diaphragm and pelvic floor is referred to by Wirhed, as the piston effect. (18) When the viscera rise secondary to TVA contraction a lift pressure is created under the diaphragm. As you are likely aware, when lifting a heavy object or exerting yourself to throw or move an object such as in work or sports, it is natural to hold the breath. Holding the breath under load is associated with increased tension in the diaphragm. The concomitant elevation of the viscera against a tightening or tightened diaphragm from holding our breath produces a lift force through the cura of the diaphragm, which attach at the L2 and L3 level. Wirhed believes this to be a major contributing factor of spinal stabilization and joint/disk protection by reducing compression of the lower lumbar discs by as much as 40%.(18)(F
Intra-abdominal Pressure Mechanism Applied
When lifting any heavy object, the load is transmitted downward through the spine to the legs (A). To stabilize the axial skeleton and minimize compressive loading of the lower lumbar segments, the transversus abdominis and posterior fibers of the obliquus internus should draw the umbilicus inward. The hoop tension created by activation of the deep abdominal wall pushes the viscera upward into the diaphragm and downward into the pelvic floor (B). Because of the innate tendency to hold one's breath while under load, there is increased tension in the diaphragm. Wirhed proposes this mechanism may decompress the L4 and L5 segments by as much as 40%. (18)
hope this helped?
S
