User blog comment:Pacifista15/Changing Gears: Part 2/@comment-4498721-20120102214220

Well, this one is really hard to fit in real world logic :D Gear Second is basically speeding up the blood stream, but Gear Third has a lot more variables to think about.

Biting through a bone is hard enough, and he is also inflating his bones. Since he is made of rubber, lungs should be more powerful than a normal human. But the bones are hard to figure out. I think he can adjust the hardness of his bones, like when he extends his arms probably bones extend too. So when he is using G3rd he makes his bones softer and bites through, fills with air and makes them harder again when attacking. And there's the question about what happens to hole he just used to inflate, is he using the same hole every time he inflates his arm, or is it somehow heals after he took his teeth off. Bones aren't directly connected and that's another problem, he seems to be able move the air through his bones but for a normal human(but still, we don't know what's 'normal' in OP universe) that should be impossible (aside from being rubber and inflating your own bones).

Only part I have a logical theory is shrinking. Think it like a balloon. When you inflate a balloon, it's not stretching from start. You can inflate it a little before it starts to stretch to it's -let's call it- 'normal limit', when you continue inflating then it stars to stretch. And when you let the air out, you can get it smaller than the 'normal limit'. That's basically how I think about shrinking. Since he's letting out too much air, he couldn't control it and get a little smaller. Then his body adjusts to normal size after a while. He probably mastered on returning normal after G3rd, so he's no longer shrinking.

I don't remember it in manga but in anime before "elephant gun"ing the kraken in the face, he is clearly biting his thumb.(end of ep524, beginning of 525). Actually he could just inflate his jaw, all he has to is biting his lip(or more like his chin) then move the air to his chest as usual xD (gomu gomu no jay leno xD LOL)

And again, I hope all this makes sense :D