I think one of the first things we have to do in order to promote the site, is make sure we get an agreement on the scope. We can't promote the site if we don't know what we're promoting or who our core audience should be.
From my personal experience I think there are several groups that would be excellent users for our site:
The Dutch Olympic committee has set up a program where coaches and topathletes can ask questions and get them answered by a group of Kinesiologists. Now I'm sure no Olympic committee would want to 'share' such information on a public site, but I'm sure there are other organizations that focus don't focus on top sports, who would be very interested.
I studied Human Movement Science / Kinesiology and nearly everyone in my class was a highly active athlete. Furthermore, these are groups of experts when it comes to Fitness and Exercise, so are more likely to be able to answer questions. On top of that, their choice of sports is a lot more diverse than at a gym or even athletics club. Approaching the student organizations or the Universities themselves with a selection of our best content might get them interested in participating.
Trainers and coaches at your local sports club. These people have a one to many relation to a lot of potential users, so they are more likely to have a Scoble-effect than individual athletes. They also receive significant amounts of questions, which they could (partially) redirect to the site. This is a win-win for them, because they don't have to come up with an answer right away and rather than repeating the same advice over and over, they can point them here instead.
A problem for non-English speaking users is that its nearly impossible to convince organizations to start using an English site. They may be able to read English, but formulation questions in English is a bridge too far. Perhaps they would be more willing if they were following the example of their English counterpart, but I don't expect them to lead the pack. This means we should focus mainly on English-speaking countries until we get more traction.
Another issue is the quality of the questions. I'm not confident that the questions we have right now would entice to these groups, largely because they are as VPeric puts it:
the random-people want just one thing and the answer is almost always the same (take up a physical activity) with one slight variations.
As for the answers, here's an example of a skating question I 'answered'. Now I get to skate nearly every winter, but because I can stand on skates doesn't exactly make me an expert on skating. I could very understand that if a skating expert came along and saw my answer as the accepted answer would decide we're an ignorant bunch and not worth his time or effort. This problem get's worse when we move to the nutrition and injury related questions, because I don't think we have anyone here who's professional trained to vet these questions.
So when reaching out to these groups it will be very important to cherry pick the right questions and possibly clean up any content that doesn't meet a certain standard or fits our scope.
As for ideas for bloggers to contact, we often link interesting blog posts in the chat room, perhaps we should analyze those links to find some that fit our site well.