Originally Posted by
bbbean
You're playing a little fast and loose with the terminology there. First and foremost, FTP is a measurement of power. If you aren't using a power meter, then you don't know what your FTP is, and you obviously can't determine training zones that depend on power. It is possible to train to HR, albeit not as effectively, but you need to use the proper terminology so people can understand what you're doing.
I know my FTP, and I know what it feels like to put out that much power for a sustained timeframe. Although I don’t have power metering on my bike, I do on my trainer, and I ride it a lot in the winter. So I’m pretty familiar with the relationship between HR and power production for me.