Look man my pops and two uncles all played DI college football in the late 50's and early 60's, and one uncle would have been drafted had he not blown out his knee. They all attest that weight lifting and speed training was not done and this is at Oklahoma State University/Missipi State University not some scrub school. Hell my pops says that water wasn't allowed at practice so that players got tough. His senior year they got to have ice during practice, and that was a huge deal. Of my 3 close friends who played DI football they all had big gains in just about every athletic characteristic over their 5 years in college. A typical DI college prospect gains 10-20(lineman sometimes gain even more) pounds of muscle during a college career and sees big improvements in speed and strength. The science of improving athletes speed, strength, agility etc has come leaps and bounds since Jim Brown played ball. It is almost sickening the efforts even at the HS level (in Tx at least) that players go through to chop a tenth of a second off their 40 time or add an inch to their vertical. After the OC and DC most HC will tell you that their strength/conditioning coach is the most important guy on staff. There really isn't a correlation between training in boxing and football. No boxer would want to carry around the type of bulk and muscle required for the power and fast twitch muscle needed in football. I dont recall seeing 40 yd dash times, bench press and squats listed under any boxer's stats. Would Jim Brown have such awesome stats had he played in the 90's to present? Maybe not, but he would still be at the top of the list somewhere hands down.