Most athletic boxer ever

Mom was infatuated with Ken Norton... much to my dad's chagrin

 

Roy Jones Jr.

 

Tyson is obviously up there.

 

Athletic?
Best stamina?
Power?
Explosiveness?
Speed?

Tyson, Louis, Ali, Jack Johnson, Langford spring to mind.

 

Assuming you're talking about Fast Twitch Athleticism:

Mike Tyson
Roy Jones Jr
SRR
Floyd Mayweather Jr (Pretty Boy era Floyd specifically)
Manny Pacquiao
Floyd Patterson
Muhammad Ali
David Haye
Tyson Fury
Joe Louis
All come to mind as standouts.

And before anyone loses their mind, yes, having insanely fast hands, feet, body movement and reflexes whilst also arguably being the physically strongest fighter in your division AND having 12 round stamina as a 6'8 250lbs Super Heavyweight makes Fury an ATG athlete. The notion that Fury is "unathletic" is 100% only said because he's fat and white lol.

 

Terry Norris and Roy Jones Jr.

 

Not to lose my mind on the issue, but whilst I agree Fury can reasonably be argued as having some exceptional athletic qualities for a man his size, his fast twitch muscle fibre, which is what you based your list on, is not close to being on a par with the others you list, which is why, p4p, he lacks their combination of explosive speed and power.

 

Mandingo!!!!!

 

Easily Jones

 

Super Southpaw Corrie Sanders

 

Is Fightbeat down? I can’t access it.

 

Ali, Pernell Whittaker, (young) Tyson Fury comes to mind.... M. Tyson??

 

It's a bit ironic you put Fury on the list of great fast twitch boxers, when what he excelled at was really slow twitch aerobic muscles. The ability to fight for an extended time and size and not lose too much endurance. It's a shame that he never treated his body like an athlete should though.

 

Ofc SRR and Hagler A level, right on top. With higher body weight it is starting to get a compromise of the main attributes:

speed / agility / explosiveness
punching power
general strength
stamina

When considering all factors i think young Ali and also Holyfield are A level.
Norton, young Foreman also a very good compromise. Marcianos conditioning was freakish...so also 1a for today's LHW to CW division.
Among the active HW i rank Wilder and Frank Sanchez pretty high in terms of all around athleticism.