There's no denying the improved performance when we add a weight belt into the mix. Doing so allows for greater intra-abdominal pressure and stability. Use one once you approach the 90% of 1RM threshold.
How to Use a Lifting Belt
If you watch how most people use the belt, you'll often see an overemphasis on pushing the belly into the belt. This can be problematic in that it causes an exaggerated arch in the lumbar spine which can compromise stability. The better approach is to incorporate 3D, or 360 degrees of expansion, where you push air all the way around to the front, side, and back of the belt.