How to be successful in the body building niche?

Same way you are successful in any high potential niche --

1. Add value by helping people reach desired outcomes
2. Study and learn from what has worked and what has not worked in the past...learn from the top blogs, social networking leaders in this niche, top selling products on amazon, top videos on youtube, etc...
3. Create your own way of adding value (taking into account what has and has not worked in the past from #2)
4 Work harder, longer and more efficiently than your competition - are you ready to do that?

Jeff

While I'm not qualified to give any advice to the marketing stuff, maybe this could give you a different angle:
I'm an endurance guy who likes the "loneliness of the long distance runner". If you're doing this seriously (which I don't at the moment, but I did an ironman distance triathlon a few years ago), you have to get into strength training. If not for performance, then for injury prevention.
Back then, when I was serious, I searched the web and everything I found was about getting to x houndred pounds. I was having problems just keeping my weight because of the training load and would have been happy to get some (clean) supplements, so I didn't have to stuff all that pasta into me.
If you're "not big yet" and concentrate on the functional aspects, maybe that is not as overloaded.

Very good! Competition is a good thing and the marketplace can never get over saturated with a good product.

It takes consistency and speaking from the heart. From your own knowledge. Does not mean you can not stay up to date in your market and niche and see what is trending and learn about that and then provide value yourself through your blog.

After you have your blog and your generating on page seo post one important off page seo tactic for you to implement if your taking the blogging strategy is do create web 2.0 blogs on a part of your niche or a sub niche. These are sites like blogger, hubpages and others. I idea hear is to bridge people from these 2.0 sites over to yours with backlinks thus also helping with your seo.

Maybe also get a free report or something you can give away to help build a list. You can create a separate landing page for this as well and implement other traffic strategies like solo advertising or ppc or banner for some fast, direct traffic thus hopefully building yourself some front end cash flow while you grow your business.

Takes time...

Make up some goals, create plans and go to work and don't stop until your get there being open to see what is working and what is not!

My goal right now is to generate loads of unique content onto the blog. I am going to handle the social media pages most of the time, while I hire more knowledgeable trainers who could write posts. As I learn more I will generate content my self but for now Id be handling everything from website maintenance, seo, social media, advertising, etc.

No, haven't been in the body-building niche.

However, it's a great niche with huge potential