That’s something I’ve considered also as I don’t know for a fact how the measurement is taken but it seems completely impossible that either Norton’s “tale of the tape” arm size is that on the hang, or Ali’s for that matter.
The figures would be way high for the arm being extended, though as a guess I would have thought Norton’s arms were about half an inch bigger than that.
16" on the hang would be about 18" flexed. Arnold’s arms were only approximately 19" (despite claims) since Oliva’s were an actual 20" and Arnold was noticeably less. There’s no way that Norton was within an inch of Arnold Schwarzenegger, as one comparison of why not.
Another reason I think it’s not flexed is because Lennox Lewis is listed at 18.5" and could not possibly be that on the hang, and a couple others are listed at 17" or 17.5" and likewise that would have to be flexed.
Either this or the measurements are just consistently wrong, which I guess could be the case. Though it does seem odd that all sorts of different officials making the measurements would consistently give truthful figures on for example chest size, but not bicep size. If they were going to lie about one, why not both? If anything, the public knows more about what a given chest size means, because of how their clothing fits, than they do arm size, which the general public has no reference on at all.
The apparent size in photos and video versus actual size is an interesting illusion, as none of the measurements of any of various heavyweight champions is what we would think is too impressive in the context of six-foot and taller men, including modern guys like Evander Holyfield or even Tyson, who looked pretty thick although not tall. In fact the only modern heavyweight champions with normal chest measurements over 45" are Riddick Bowe and Oliver McCall (both 46") and Frank Bruno (48".) Well also the old fat Foreman, but fat doesn’t count. Everyone else from Liston on was 40" to 45", most being about 42" or 43." Really not big. And that, being usually 6’2" or better.
Even Mike Weaver has an official chest measurement of only 44.5" at 6’1": and this guy was called “Hercules” and did look like it. Seems amazing, I agree.
(For a complete list of official measurements of heavyweight boxing champions: http://www.ibhof.com/ibhftape.htm )
I suppose we must all or mostly suffer from body dysmorphia and perceive ourselves smaller than really is the case, and so can see these men who may be no or little better built or even not as much and find it extremely hard to believe we are that size. Yet I suppose others do see it that way, or at least relative to if they saw these men in person. (It’s possible that as is commonly said the camera adds apparent weight – supposedly 10 lb for the average person so perhaps 15 lb for a bigger person isn’t impossible.)