Is there a guide to how many hours per zone are needed for adaptation?

Finding this site very interesting and because it’s very easy to use, I’ve been able to come up with some anomalies by playing around with dates and time in zone.

It has me wondering about something now. I’ve seen a significant best effort in the 8 to 12 min range, well above anything I’d done before. But it was done coming off the back of an 8 month period when I’d quit riding. Then I’d started again in July and the best effort was mid-October.

Thats 3.5 months of riding unstructured and then doing an all time PB in that 8 to 12 min range.

I think anyone would raise an eyebrow at that. Now some things did make sense when I went back over the period. I had week off before the effort (which would be like a rest week I suppose) and then just one smaller, but reasonably hard ride the day before (which would be a pre-race warmup/activation day).

So now I’m down to looking at how many hours at endurance, tempo and threshold I had in those 3.5 months with must have raised my FTP or VO2 to at least previous highs (it’s quite possible I could have done that best effort before but never tried - I really never liked that 8 to 12 min range).

So that’s the question - can I use time in zone from intervals to make judgements about how training affects me personally? Then use that in future if I have a big detraining period to mimic that.

Or is there already well studied and generally accepted hours per zone that coaches understand will generally raise power in detrained, moderately trained and highly trained riders?

You may have considered this already, but you need to be careful not to read to much into peak power outputs if they are not typical of your efforts. For example, you may only do climbs that take about 6 minutes to complete or about 30 minutes, but none that last 10 minutes. this could also happen if you only do certain types of intervals.