[Deleted previous response to paste it properly in the reply chain]
All fair points.
However, in that FasCat link, I don’t see anywhere where they mention that the TiZ in their plans is in a continuous interval. Do you? That 240-min TiZ could be in 15-min intervals, no?
Which I guess bears the question (as always) of what the ROI is of fewer but longer intervals vs. more but shorter intervals. There has to be some kind of diminishing return where there’s little/no training benefit to be gained from increasing interval length. Especially when you consider in terms of race scenarios in which 60+ minutes of absolutely uninterrupted, no break, SS-level riding is generally very rare (no turns, no coasting, no drafting, no downhill tucks, no food/water sit up, etc.). A road TT is the only one that comes to mind, but that’s pretty specific (and would be at/near threshold), and that type of training would come into play with specificity, not just general base/build. Right?
Their example seems to follow exactly what TR is doing, with the obvious caveat that none of the TR plans have SS TiZ 90+ minutes:
For example, a 3 x 10 min (30 minutes total workload) would progress to 4 x 9 min (36 minutes total) and then onto 3 x 15 min (45 minutes total).