First question first. This is a difficult one. To begin, we have to ask, how are our two human miniboxers being shrunk down - ie. are we imagining two people who have ordinary-sized cells but simply far fewer of them? This seems to be the only interesting case, to me. We can't say that the cells themselves are shrunk down in size, because they wouldn't keep working, unless we shrink down their component atoms too. However this just means making every part of both people smaller equally, which actually wouldn't change anything at all (if we assume the entire universe is similarly shrunken, which we must do). I'm not even sure if the scenario of "ordinary-sized cells but miniature people" would work either, in fact I'm heavily inclined to believe it wouldn't. The numbers of brain cells inside a human and an ant differ by at least a factor of 105. I'm guessing the brain and central nervous system would have trouble working at one hundred-thousandth of their original neuron capacity. You might be thinking "What is the point of bothering with these questions" but it is important. I assume the purpose of this submission was to ask whether the appparent "super strength" of ants carries over to humans as a function (roughly) of their size, but this can't really be addressed without considering how we are changing the cellular make-up of the minihumans, because that's the whole reason behind the weird super-strength phenomenon in the first place. People are often happy to state that an ant's strength is due to its amount of muscle in terms of cross-sectional area being greater in relation to its volume (than other animals) - thus bringing the entire question down to the level of "x squared is smaller than x cubed" - but in your scenario this would be a silly answer. We would have to somehow ascertain if indeed things work this way between completely different organisms: an almost impossible task. In a way we could dispense with that avenue of investigation and just assume the "strength of an ant" exists in our minihumans, and then go on to make the conlusion that they do not have the same protective exoskeleton as ants, so we can answer your question in the negative. But even that is a bit of a letdown, due to the crazy level of assumption that was made, almost answering before the fact. This submission is a surprising pandora's box! I thought it would be more simple than it has become... I honestly don't really know where to begin with the first part of the question, let alone the giant-human scenario! It's interesting to think about though; I might come back later but I'll leave this here for now. This is such a good question that I really hope we get some experts in here to help out. Remarkably no one discipline is going to be enough to provide a good answer here; we'll need input from physicists and biologists, probably - if a satisfactory answer can be given at all. I'd love to hear what Randall Munroe would make of this.