Sweet spot is the zone just under threshold. Hard enough to drive real fitness, easy enough to repeat. For riders short on time, it is one of the most useful tools there is. Used well, it builds FTP fast. Overused, it turns every week into the same grind. Here is how to get it right.What is sweet spot?Sweet spot sits at roughly 88 to 94% of your FTP, just under threshold. It feels like a solid, controlled effort. Breathing is deep but steady, conversation comes in short phrases, and you could hold it for a good while if you had to. On a 1 to 10 scale it is a 6 or 7.The name comes from the idea that it gives you the best return for the effort: a lot of training stimulus without the deep fatigue of riding at or above threshold. Not sure where your zones sit? Use our FTP and zones calculator.Why it worksTime efficientIf you have 6 to 8 hours a week, you cannot ride 15-hour weeks of easy miles. Sweet spot packs a lot of aerobic and threshold work into a short session, which is why it suits riders fitting training around work and family.Builds thresholdLong blocks just under FTP push it upwards. You spend more time close to threshold than you could in a true threshold session, and you recover faster afterwards. See how to increase your FTP.Builds durabilityHolding steady power for long periods is exactly what sportives, time trials and long breakaways ask of you. Sweet spot trains the muscles, the head and the fuelling for it.Classic sweet spot sessionsGetting started: 3 10 minutes at 88 to 94% of FTP, 5 minutes easy between.Building: 3 15 minutes, then 2 20 minutes.Long: 2 30 minutes, or 60 to 90 minutes of total sweet spot in a session as you get fitter.Over-unders: 10-minute blocks alternating 2 minutes at 95 to 105% with 2 minutes at 85 to 90%. Teaches you to recover while still working hard.Outdoors: a steady climb or long, quiet road. Ideal for time trial practice in your TT position.Progress by adding time before adding intensity. Going from 3 10 to 2 20 is real progress, even at the same power.The catchSweet spot is tiring. Not destroyed-tired, but tired enough that doing it four or five times a week adds up. Do too much of it and every week turns into the same moderately hard grind. Easy days stop being easy, hard days stop being hard, and progress stalls. This is one of the most common patterns we see in self-coached riders.Polarised and 80/20 trainingStudies of endurance athletes show that most of their training is genuinely easy, often around 80% of their time, with the rest split between moderate and hard work. That pattern keeps you fresh enough to make the hard work count.Sweet spot fits into that 20%, alongside threshold and harder intervals. It is a tool in the box, not the whole box. Riders with very few hours might do a bit more of it. Riders with more time should lean on easy volume and save sweet spot for one or two key sessions a week.When to use itBase phase: one or two sweet spot sessions a week alongside lots of easy riding. Builds the platform for harder work later.Time-crunched weeks: the most useful single session when you only have an hour.Before long events: sportives, gran fondos and 25-mile TTs reward the ability to hold sustained power. See how to pace a 25.Less useful close to short, punchy races: crits and road races need repeated hard efforts and sprints. Shift towards those as race day approaches.Fuel itA 90-minute sweet spot session burns a lot of carbohydrate. Eat beforehand, take a bottle with carbohydrate in it for anything over an hour, and refuel after. See carbs per hour.Track the progressWatch your heart rate and feel at the same power over a few weeks. If heart rate drops and the effort feels easier, you are getting fitter. Our guide to feel, heart rate and power explains how to read the signs, and power testing shows when to retest.Next stepThe right mix of sweet spot, easy riding and hard work depends on you and your goal. That is what we do with our riders every week. See how coaching works, or book a free call.More like thisHow to increase your FTPCycling intervals: types, zones and why we use themHow to sprint faster on the bikeHow many carbs per hour when cycling?Saddle up.