If you’re a fitness buff and have the right combination of charisma and business sense, working as a part-time online personal trainer can be both physically and financially rewarding. Once you build up a reputation and client base for yourself, it could easily turn into a full-time endeavor for you. Check out this interview with several fitness blog owners who are making a living online, from MonetizePros. As well, I'd recommend checking out this resource if you want to take this business idea seriously and get started with a business plan for your personal fitness trainer business today.
Build your audience on a course community: If you’re just getting started building an audience for yourself and want to leverage communities already actively looking for content you can choose to host and sell your online course on a site like Skillshare or Udemy. These are easy, cost-effective ways to build an audience and test your niche to see if there’s demand for it.
If you have pop-ups and optins on every page, I would have to think that it would be a lot harder to convince someone to link to it. Especially since the pages where you have your optins (and probably receive the most traffic) are probably the same pages that you have your best content on as well that you'd be hoping to pitch in your outreach campaign.