Simple.
Create resources and content to help those coaches and teachers realize the benefit of packaging their knowledge. An excellent place is here on Clarity, MosaicHub, LinkedIn, and a number of other sites where experts hang out.
They may be an expert in underwater basket weaving, but not in packaging their product into a course.
I'd love to talk more since I am in this position right now and think we could identify your marketing strategy.
-Shaun