I agree with Irish in that speed merchants will suffer more than punchers in their 40's --- where I disagree is his contention that the distinction between 70's Foreman & 90's Foreman wasn't massive --- it was, & old Foreman's success greatly belies this. Foreman used his perenially under-rated footspeed & general swiftness of assault to trap many foes, Frazier included, under his scope & pin them at the perfect range, one of many, many things old Foreman struggled mightily to affect, & routinely failed to. That's just one of a dozen areas he lost ground through age. Foreman was in his 40's & clinically obese during the 90's. Show me a fighter in the Universe who doesn't lose an absolute tonne of quality as a fighter under those circumstances. The guys prime was over at 25 years of age, for God's sake. I can't honestly believe 90's Foreman lasts any amount of time with his 70's self. It would be a total massacre.