Have you tried wearing a belt? The belt helps me with over extension while pressing.
I am a chronic over-extender at the lumbar spine. I can arch my back at will and I used to be an "ARCH HARD" squatter in the past. Does anyone have any good tips about finding neutral spine?
I've tried clamping hard down on the abs, but I still do it in the squat all the time. I always end up with a 3-4 pain in the lumbar region for a few hours after I get done lifting.
Have you tried wearing a belt? The belt helps me with over extension while pressing.
+1 on the belt. It's essential if you're easily able to overextend. You might also just try arching a little less hard, and focusing even harder on your abs. Slight flexion is far preferable to overextension.
You should also submit a form check. Sometimes pain results from things you don't think of initially.