How was Robin able to stand despite being cuffed with Seastone?


In chapter 398 we can see how Robin has enough energy to stand straight, walk
around, tell a long story and shout across the ravine, despite being
handcuffed with Seastone handcuffs.

![enter image description here](https://i.stack.imgur.com/bNdsbm.jpg)

While in chapter 730 we can see how Luffy becomes completely immobilized after
touching the bars of the Colosseum.

![enter image description here](https://i.stack.imgur.com/C8wMsm.png)

Where does Robin get all this energy from? How come her energy isn't
completely drained as it was with Luffy's?




> Kairoseki(Seastone) is a naturally occurring (though apparently rare)
> substance that can drain the energy of Devil Fruit Users to the point where
> they can't consciously control their powers. Dr. Vegapunk has invented
> revolutionary ways to use this rare substance. The Marines appear to have
> vast quantities of it, using it for jail cells, handcuffs, weapons, and the
> bottoms of battleships.
>
> **The degree of "weakness" induced by the Kairoseki depends on its density
> and composition; for example, Kairoseki handcuffs rob the prisoner of their
> abilities, but still allow the prisoner to walk around normally.**

Source : <http://onepiece.wikia.com/wiki/Kairoseki>

