I have always heard to stay away from a belt during squats because it "weakens" your core. However, I'm tall and have long limbs, so I lean forward when squatting. I recently started to put a belt really tight during heavier sets and I feel like it helps me stay upright. Furthermore, now my abs are crazy sore after squatting (3 X's a week) whereas before they would never get sore. Could it be that a belt may increase core activation?