That guidance wasn't needed, really. It's refreshingly free of trendy design, and straightforward to use. And other things, like the ads not being in the way of the content. I'm sure you've got a list you're working on, but what's there looks great.

One minor suggestion...there are some paths that lead you to a "muscle not found" page, like this: https://musclewiki.com/Barbell/Female/Calves/. Some way of preventing landing there in the first place would probably be more intuitive. Like a popped hint when you hover over a calf if Female/Barbell is pre-selected. Or some semi-transparent overlay to suggest Calves can't be selected, etc.