Originally Posted by PeteHski

I watched the second video and found it a bit confusing to be honest. My current plan consists mainly of short VO2 max doses and Z2 rides in the 2-3 hour range. Total weekly volume averaging only 5-7 hours. It has been very effective for me this winter. I've done a few hard Zwift races up to 2 hour duration and set PRs everywhere. I've gone from a mid-high cat C at to a strong cat B over the last 3 months. FTP and VO2 max power has increased significantly - actually the highest I've seen in the last 3 years. It will be interesting to see how longer rides go in spring, but I think it will be good. I usually start doing longer Z2 outdoor rides (3-5 hours) and continue with higher intensity intervals and the occasional Zwift race to keep sharp and punchy.

I thought it was interesting what the GDN guy said about feeling a bit flat going into his Cross race. I find those VO2 max intervals very effective in the right dosage.

I don't know if this is a good idea or not, but if I'm short of time I might decide to sub a 3 hour Z2 ride for a slightly harder 1 hour Z3 effort. Intuitively it feels like a more effective use of an hour, but maybe it isn't. I guess the question is what is the minimum single dose of Z2 to see a benefit? Is it an hour, 90 mins or longer? For me 90 mins seems like the tipping point where I feel like a Z2 ride was worth it. Below that I feel like I might be better off going a bit harder. I've done this quite a lot this winter due to a busy family life and I feel good for it.