As much as Mary is into physical fitness, she has to already experienced that each progressive boob expansion makes certain exercises and machines less viable, whether it is because your boobs are in the way or they interfere with your arm movements. Everyone remembers Beshine mentioning these things, even saying her boobs were too heavy for even triple bras on the treadmill, so she had to give that up and go for the non-bouncy elliptical. Of course with her new style bras, I doubt she worries about bra straps, just the stress on the cups. The thing is, it takes a special attitude to want bigger and bigger boobs when they are going to cut back on your gym abilities; obviously, Mary has that attitude. That is not to say you cannot be physically fit with huge boobs; they almost require it if you are going to try to live a somewhat normal life and that extra boob weight does strengthen muscles much more than the average person would ever experience. Like my comment above about sit-ups; Foxy has already mention feeling like a turtle on its back as she can no longer sit up with using her arms to push her as she wiggles her butt to the side of the bed so that she can sit up. But when you love huge boobs, I seriously doubt you mind doing these extra things at all.