Two pieces of advice are given to riders every autumn, and they contradict each other.
The first says winter is for base, so ride long, ride easy and keep intensity out of it until spring. The second says most amateurs have too little time for that and should spend their few hours at sweet spot, where the return per minute is highest.
Both are right, for different riders, and the variable that decides which one applies to you is your hours rather than your ambition.
Why the traditional advice assumes hours you may not have
Low-intensity training works through volume. The stimulus per hour is modest by design, and the adaptations accumulate because there are many hours. A professional riding twenty-five hours a week gets an enormous aerobic stimulus from riding almost all of it easily, and would be destroyed by doing otherwise.
Scale that to five hours and the arithmetic changes, because five easy hours is a small total stimulus. It beats five hard ones comfortably, but a rider in that position who never goes near threshold all winter is leaving adaptation on the table, since their limiter is total work rather than recovery.
That is the case for sweet spot in a short week. It sits high enough to drive meaningful adaptation and low enough that you can do a reasonable volume of it without needing days to recover.
Why sweet spot is not simply better
Sweet spot costs recovery, it accumulates fatigue quietly, and a rider who fills every available session with it arrives in February stale rather than fit.
Polarised training keeps its advocates because the easy days have to be genuinely easy, and sweet spot riders frequently let their easy days drift up into the middle, at which point they get the fatigue cost of hard training with the stimulus of moderate training. What fails is a week with no genuinely easy riding left in it.
What WattPlan does with your week
The plan builder resolves this from your availability rather than from a philosophy.
| Your week | Hard days it schedules |
|---|---|
| Fewer than four riding days, or under four hours | 1 |
| Four or more days and four or more hours | 2 |
| A recovery week | 0 |
In the base phase that quality work is sweet spot rather than threshold or VO2 max, on one or two days depending on the table above, with the rest of the week aerobic.
Two details sit behind it. Sweet spot is treated as costing the same recovery as threshold or VO2 work, so the week never stacks it on consecutive days, and the remaining days stay genuinely easy rather than drifting upward, which is the failure the polarised argument is really warning about.
What this means in practice
Three days a week, five hours total. One sweet spot session and two steady rides. Do not add a second hard day because the week looks empty, because it is correctly proportioned for the recovery you have.
Five days a week, eight hours. Two quality days with genuine easy riding around them, and a long ride at the weekend if you can get one.
Ten hours or more. The traditional advice starts to apply properly, and a long, mostly easy base block will serve you well.
The thing to actually watch
Both approaches fail the same way, when the week stops being sustainable and the rider quietly stops completing it.
Watch Form through December and January, because drifting steadily negative for weeks is the signal that the shape is too hard for the hours, whichever philosophy produced it. Then count how many sessions you actually finished.