Disable mapping of `Man`

I have this mapping in my ~/.config/nvim/mappings.vim (it’s included with source from the init.vim file):

noremap <S-k> 5gk
vnoremap <S-k> 5gk

I went through a part of the vim manuals and found this entry: :h find-manpage. I was always wondering why the help page popped, if I pressed Shift-k and now there’s the reason! But why does the default K binding still opens the manual page although I used noremap?