Interval session builder
Choose what you want out of the session. Your FTP turns it into watts you can set on the trainer, step by step, including the recoveries.
Build a session
Your FTP, and what you want out of the session. The watts come out ready to set on the trainer.
Sessions are written as a percentage of FTP so they mean the same thing to every rider. Threshold work is 91 to 105 per cent, sweet spot 88 to 94, VO2 max 106 to 120. If you cannot finish the last interval every time, your FTP figure is a few watts too high.
## Why sessions are written as percentages
Every structured session you will ever be given is expressed as a share of your FTP, and the reason is simple: it is the only thing that makes a session mean the same to two different riders, or to you in March and you in October.
"Four by eight minutes at 240 watts" is an instruction for one person on one day. "Four by eight at 100 per cent" is a session. When your FTP moves, the session moves with it and stays the same session.
Which is also why an out-of-date FTP quietly ruins a good plan. Set your numbers from a figure that is twenty watts too high and every interval becomes a failure; twenty too low and nothing ever adapts.
## Pick by purpose, not by how hard it sounds
The temptation is always to choose the hardest session you can face. Resist it. Each of these does a different job and doing only the brutal ones makes you tired rather than fast.
Threshold work — the 4 × 8 and the 2 × 20 — raises FTP directly. These are the sessions that move the number, and they work precisely because they are hard but *repeatable*. If you cannot complete the last effort at the target, the target is wrong, not you.
Sweet spot sits just below threshold and buys most of the benefit for considerably less cost. It is the session to do midweek when you have a hard weekend planned.
VO2 max — the 5 × 4 and 6 × 3 — raises the ceiling rather than the threshold. These hurt in a different way: the first interval feels manageable and the fourth does not. Hold the prescribed number rather than chasing a bigger one; blowing up in interval three means you did a worse session, not a harder one.
Over-unders alternate above and below threshold inside a single block, which teaches you to keep working while clearing lactate. They are the closest thing to what actually happens in a race.
Endurance is the one everybody skips. It should feel almost too easy, and the benefit comes from the volume rather than the effort. If you are breathing hard, you are doing tempo by accident and getting less out of it.
## How to actually ride them
Warm up properly. Fifteen minutes of easy riding with two or three thirty-second lifts in it. A cold start into the first interval makes the whole session worse.
Pace the first effort as though there are two more than there are. The most common mistake is going too hard early, fading through the set, and recording a lower average than an even ride would have produced.
Take the recovery seriously. The numbers between the intervals are part of the session. Soft-pedalling at a hundred watts when the plan says fifty will cost you the last effort.
In ERG mode, pick a small gear. The trainer will hold the power whatever you do, but a lighter flywheel responds faster and makes the spiral of death less likely when your cadence sags.
If the last interval falls apart every single time, drop your FTP by five watts and try again. That is information, not failure.
## A word on the load figure
The number shown next to each session is a rough training load, calculated on the usual intensity-squared basis where an hour at threshold scores 100. It is useful for comparing two sessions before you choose, and for noticing when a week has quietly become much harder than the one before it.
It is a comparison tool, not a target. Chasing the number is how people end up doing a very hard week followed by three poor ones.
Questions people ask
What is the best session to raise FTP?
Threshold intervals — four by eight minutes at 100 per cent, or two by twenty at 95 per cent. They work because they are hard enough to drive adaptation but repeatable enough to complete, which is the whole trick.
How many hard sessions a week?
Two is plenty for most riders, three at the very most, with easy riding between them. The adaptation happens during the recovery, not during the interval, so a third hard session usually costs more than it earns.
What if I cannot finish the last interval?
Your FTP figure is probably a few watts high. Drop it by five and try the same session again. Failing the last effort every time is information about the number, not about you.
Should I use ERG mode for intervals?
It helps a great deal for threshold and sweet spot work, because it removes the pacing decision entirely. For very short, very hard efforts it can lag, so many riders switch to level or simulation mode for anything under a minute.
How long before I see a change?
Six to eight weeks of consistent work is a reasonable first checkpoint. You will usually feel it before you measure it: the same session at the same watts stops hurting in the same way.
Still bored of the turbo?
That is the problem we are actually trying to solve. Turbo Trainer Games turns your watts into the controls of a browser game — your power flies the aircraft, climbs the mountain, pulls the sledge. Nothing to install, and it works with a smart trainer you already own.
It is in closed testing at the moment, so there is nothing to play yet. But you can put your name down.
Ask for early access