They were:
Perspectives #18: Overcoming Historical Inertia, with Andy Coggan
Perspectives #19: Adaptation, Signaling, and Performance, with Andy Coggan
I totally enjoyed both of these episodes. There’s some history about Coggan’s involvement with WKO and about Racing and Training with a Power Meter. It’s also a mythbuster episode: first threshold, VLAXmax, fatmax, polarized, sweet spot, etc.