On occasion or other we have discussed the importance of breathing during training. Here's how a simple breathing technique can help lift heavier loads in a much stronger overall setup. The intra-abdominal pressure (PIA) has been extensively analyzed and has been shown to Reduces potentially damaging compressive forces on spinal discs during heavy lifting.
Science has also suggested that increases lumbar stability by assisting with the formation of a "rigid cylinder" through the abdominal muscles and/or by stabilizing forces through fascial connections to the vertebral segments. Given these recent studies, it seems that a consensus is forming that the functional role of the PIA may be primarily help with stability.
Breathing and the lifting belt have a fundamental role
As we progress with our lifting experience, it becomes increasingly important to pay more attention to detail so that we can continue to progress as smoothly as possible. While breathing may be something that many people tend to take into account, it definitely plays an important role in performing heavy-load exercises correctly.
When we inhale, we push air into our lungs, pulling down on the contracting diaphragm and creating pressure on the abdominal cavity, obliques, and lower back muscles. You just need to inhale enough oxygen for your belly to "bulge out", to the point where you can still contract your abs and support your core.
If you breathe too much, you will most likely extend your back and decrease your ability to contract your abdominal muscles, ending up relying on your lumbar extensors. When using a lifting belt (tight enough that you can push your belly against the belt), you are providing your abdomen with an external force that pushes against you. And that's the point of using it.
You don't wear a belt to look cool, nor for it to passively apply force, it actually serves a purpose: by having a limited amount of breathing room due to the belt pushing against you, adding proper breathing technique it will increase intra-abdominal pressure even more, with consequent lumbar stability and increased safety as a result.