first of all Shamrock was an accomplished Pancrase champ well before the UFC I dont see him or Severn being intimidatd by anybody...secondly I dont think Tyson has any huge strength advantage if any over a seasoned grappler, and lastly takedowns are just as much about technique as strength....My experience is that pound for pound top wrestlers are some of the strongest atheletes I've ever encountered....Male Gymnasts at NCAA and Olympic level are studs as well.