As a triathlon coach and fitness trainer, I'm constantly reading and studying about these subjects. It's a continual thing, and I enjoy it.
This is what I'm working on right now. Nearly 600 pages filled with cycling goodness! But still, 600 pages. Yikes. And this isn't for a certification, it's just keeping my own learning going. Just one of the swim, bike, run, yoga & fitness books I read in my spare time. (By the way, I recommend this book for anyone interested in cycling. It's comprehensive)
So, if you wonder if it's worth hiring a triathlon coach or personal trainer remember, this kind of thing is one of many books & study materials, not including the certifications we have to get. Not to mention the continuing education we must do regularly. We learn and study things that aren't mandatory to be the best we can for our clients. We love what we do! It's worth getting a triathlon coach, even if it's for a few sessions, even if it's consulting with them. We're in a constant state of learning so you can get the best training possible!