Board Thread:Questions and Answers/@comment-118.211.8.204-20150302141811/@comment-6697950-20150908104022

It's not about "knowledge", it's about "being used to virtual realities". There are slight differences in the sense of gravity and balance between the virtual and real world. The more time you spend in the virtual world, the more you are used to these differences. And what on earth does physical skill have to do with virtual realities? The only thing that matters is how fast the brain can react to stimuli. Unless Yuuki had a brain illness (or something that could abruptly endanger her life and need immediate treatment), her condition in the real world wouldn't have much of an effect on her performance in-game.

There is no information about what Excalibur can do. Only lore-related things are known.