Very interesting on-line Aikido book.
O Sensei would surprise us with how different he was from ordinary people. In his last year, he would have to be helped up the stairs and he said many times “I’m sick,” but as soon as he set foot in the practice hall, his back would straighten and he would look perfectly healthy as he gave an explanatory demonstration. But once again, as he stepped out into the hall, he would have to be helped by the deshi.
Then there were the times O Sensei would have to be helped to the toilet. We’d lift him up by his arms but it would take all our strength, it was like trying to move a giant stone.
“Sensei, we can’t move you…”
“Ah, I’m full of ki…” then he would stop extending ki and we could lift him off the bed. O Sensei was no ordinary person, that much I came to understand. He was 86.
http://www.cup.com/kobayashi-dojo/english/book/forward.htm