JP pointed out "I can tell where your socks used to be".
So I looked at Nora's ankles, and there were clear lines on her skin created by her not so elastic dress socks.

I don't know if I am explaining this very clearly...
Okay, so Nora was wearing a pair of dress socks probably until the beginning of afternoon pose, and then she changed her dress socks for her short sport socks to get ready for 'coaching'. The dress socks she was wearing, which were obviously not so elastic left lines on her ankles, and her sport socks were just not long enough to conceal them.

Nora was little embarassed I think.
Oh.. By the way, it was interesting to see her teaching in her coaching outfit; it was very new.