For the main site, could you not try and get some pro sports people to write the odd article, like ' a day in the life off...' or an interview perhaps? Some young athletes or strongman competitors might be up for that as it'll get them a little exposure. Some of the older ones might as well if they have a book to promote too.
You can also get news tickers to run across the top of the site, has something similar and so does . Our one could be for fitness news. You could do these yourself or there are companies that provide a news stream for you, if you want to look into that then I have a contact for you
As for the forum, the content and people have been massively improved over the last month, the only thing I would want changed is the format.
We currently have areas like 'The F Lounge' and stuff which aren't very clear and descriptive, I was thinking it should have more of a fitness based theme like areas of a gym so the off-topic lounge could be 'The Locker Room', the nutrition area could be 'The Kitchen', the weights discussion could be 'The weights room' and cardio areas could be 'The studio'. Lots of possibilities there but I think it would make the layout more intuitive