The Pittsburgh Steelers built their dynasty and won six Super Bowl rings along the way, thanks in large part to their punishing defenses. While physicality and toughness have always been the name of the game, some players stand out even among the most aggressive, and at the top of the list is James Harrison.Harrison made a name for himself in the NFL by bringing his intensely physical game to Pittsburgh. That's why many would be surprised to learn that one of the most dominant defenders in history supports new head coach Mike McCarthy ending live tackling at Steelers training camp. Speaking on his podcast, Deebo and Joe alongside co-host Joe Haden, Harrison offered a masterclass on defensive technique, debunking the myth that players must constantly hit the ground during practice to hone their tackling skills.Harrison drew a clear line between going "live" and practicing with technique in mind.What yall gotta understand is, you dont need to actually tackle somebody to the ground, Harrison explained. When youre live that means youre dropping somebody to the ground and were going full go. What we do a lot is thud up: hit, wrap, release.According to Harrison, "thudding up" isn't just a concession to prevent injuries during practice; it actually cultivates superior fundamentals compared to full-go tackling drills, which can often lead to reckless habits. By focusing on controlled contact, defenders are forced to rely on discipline and form rather than momentum or dive-bombing.I think thudding up actually gets you in a better position to be able to make more secure tackles because now you have to get in there, you have to bend down, you have to put your head exactly where it should be, Harrison noted. Its no longer let me get there and dive at it.By emphasizing proper head placement, pad level, and wrapping up before releasing, defenders build muscle memory that translates directly into game-day success. Harrisons insights serve as a compelling reminder that elite defense is built on technical precision, control, and sharp fundamentals, not just brute force.This article originally appeared on Steelers Wire: From Pittsburgh's scariest defender to technique guru: James Harrison explains why 'thudding up' works