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.



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



Where does Robin get all this energy from? How come her energy isn't completely drained as it was with Luffy's?
Read that chapter (169) more carefully then...



Here, Luffy stands in Crocodile's Kairoseki cage.



Then he states that he has no power. Well, of course, since the cage is made of Seastone.



Then Smoker kicks his ass and nails him down. And I think regardless of Seastone any of us would have problems standing if Smoker pushed his weapon to our chest.

So to answer the question: Robin was in a weak state because of the Seastone handcuffs back then, but she could stand because nobody pushed her down.