In my opinion the two biggest mistakes/misconceptions with bracing is that the bigger the breath the better and that the belt does the work for you. A bigger breath usually just means less intent for how the breath is used, and most likely results in a nice big chest breath and shoulder shrug. The second issue tends to be even worse, as a belt does not contract your abdominals. If all you are doing is breathing into your belt, you are just expanding your stomach, not bracing. I like the analogy that we are filling up a balloon. When you fill up a balloon it is not done by one big breath, it is done my multiple small breaths. So what I like to do is 3 small breaths. Each small breath expands the lungs and diaphragm further, and after each breath is taken you contract down with your core. It is almost like the abdominals are being use to try to crush the “balloon” being blown up inside of you. Now what does the belt’s purpose in all of this? An external cue to breathe into and for core contraction. We need 360 degree expansion into the belt, so that belt acts as a cue for the intent of each breath, as well as and external stimulus for muscle contraction. Think about if someone pushes their fist into your stomach. The natural reaction is to brace. That is what the belt is doing.
So putting this all together, here is the step by step bracing pattern/setup I use. After the walkout, contract their abs and lock down the ribcage. From there, take a small breath into the diaphragm to slowly fill that “balloon”. After that breath, lock down again with the abs. Then again, take another small breath to fill the ballon even further, then tighten the abs again. Then lastly, take a medium size breath to finish, which combined with the other two breaths in reality is a large breath, lock down the abs one final time, and squat. Sounds like a lot, but all of that should take less than 5 seconds. Its quick and small breaths. Not a relaxed meditation breath. Give this a try and let me know how it goes!