The training method argument is the most exhausting conversation in amateur cycling. Sweet spot apostles tell you polarised wastes time. Polarised disciples tell you sweet spot is the grey zone in a fancy hat. Threshold purists tell you both are missing the point. The forums fill up. The opinions calcify. And the cyclist asking the original question is more confused than they started.
The honest answer is that all three methods can work and all three can fail, and the right one for you depends on your weekly hours, where you are in your season, and what's actually limiting your fitness. The cycling internet's mistake is treating this as a religious war when it's a question of context and prescription.
Here's what each method is, what the research actually shows, and a decision tree for which one fits your situation.
What each method actually is
Sweet spot training. Intervals at approximately 84–94% of FTP. Long enough to be challenging (typically 20–40 minutes per interval), short enough to be sustainable in series (sets of 2–4 intervals with 5–10 minute recovery). The aim is accumulating large volumes of training stress at an intensity high enough to drive adaptation but low enough to absorb in the same week.
Threshold training. Intervals at 95–105% of FTP. The intensity band where lactate production and clearance are balanced. Typical formats: 2×20 minutes, 3×15 minutes, 4×10 minutes, with 5–10 minute recovery. Higher recovery cost than sweet spot, more specific stimulus to the lactate-clearance system.
Polarised training. A distribution across the week, not a session type. Approximately 80% of sessions at low intensity (Zone 1–2), 20% at high intensity (Zone 4–7), minimal time in the middle band (Zone 3). The hard sessions can be threshold, VO2max, or race-specific work — the structure is the distribution, not the specific session content.
These aren't equivalent options. Sweet spot and threshold are session prescriptions. Polarised is a weekly distribution. You can run polarised with sweet spot sessions as your hard days, but you can't run "sweet spot" as a distribution because that puts you at moderate intensity every day. The conversation often confuses these levels.
What the research actually says
Stöggl and Sperlich's 2014 study is the most cited comparison study. They put 48 well-trained endurance athletes through nine weeks of four different distributions: polarised, threshold, high-volume, and high-intensity. The polarised group produced the largest gains in VO2peak, time to exhaustion, and peak power output. The threshold-dominant group showed smaller gains. The high-volume group had moderate gains. The high-intensity group plateaued early.
Professor Stephen Seiler's broader research across decades documents that elite endurance athletes — cycling, rowing, cross-country skiing, distance running — independently converge on roughly the polarised distribution. The convergence is the strongest evidence the model captures something real about adaptation. Different sports, different countries, different coaching cultures, same intensity ratio.
The sweet spot research is more limited but suggests faster initial gains. Several studies of time-crunched cyclists running sweet spot blocks show meaningful FTP gains in 4–6 week windows. The trade-off is that the gains tend to plateau earlier than polarised approaches over longer periods, and the cumulative fatigue is higher.
The threshold research is mostly older. Threshold-focused training was the dominant model in the 1990s and early 2000s before polarised research displaced it. The evidence shows threshold work produces meaningful gains short-term but accumulates fatigue rapidly and plateaus faster than polarised over a season.
The honest summary: polarised wins over long periods, sweet spot can win short-term for time-crunched riders, threshold has narrow specific uses.
The case FOR sweet spot
Sweet spot training has a legitimate case in specific situations.
Time-crunched cyclists. If you have 5–6 hours a week and need to maximise training stress per hour, sweet spot intervals produce more measurable adaptation per session than easy Zone 2 riding. The cyclist who has only 4 hours a week and runs them all at sweet spot will typically beat the same cyclist running polarised at 4 hours — there isn't enough easy volume in 4 hours for the polarised distribution to express its benefit.
Mid-build focused blocks. A 4–6 week sweet spot block layered into the middle of an annual periodisation cycle can produce meaningful FTP gains. The intensity is high enough to drive adaptation, sustainable enough to repeat across sessions, and produces the kind of muscular endurance that translates well to race situations.
Indoor training. Sweet spot intervals on the trainer are mentally easier to execute than long Zone 2 sessions. For riders doing significant indoor training, sweet spot blocks earn their place because the alternative is often abandoning the session entirely.
Specific race demands. Cyclists training for events with sustained moderate intensity demands (long climbs, gran fondos, time trials with relatively flat profiles) benefit from sweet spot specificity in race-prep blocks.
The case against sweet spot is that it stops being sweet spot when it becomes everything. Running sweet spot every Tuesday and Thursday for 6 months turns the rider into a moderate-intensity machine with no top-end and no deep aerobic base. The plateau usually arrives at month 4–6.
The case AGAINST sweet spot (Schrot's warning)
When Dr Christian Schrot at Team Jayco was on the podcast, he was clear about why pros mostly don't use sweet spot as a default. His framing — the "mixed metabolism zone" — captures the underlying physiology. The detail is in why pros train so easy and the mixed metabolism zone.
Moderate intensity, sustained over weeks, puts the body into a confused state. The fat oxidation system is partially active but not fully optimised because the intensity is too high for clean fat metabolism. The carbohydrate system is partially active but not fully recruited because the intensity is too low for clean glycolytic work. Both fibre types are recruited at quality below what either pure aerobic or pure anaerobic training would deliver. The fatigue accumulates without clean targeted adaptation.
The pros mostly avoid this zone for the same reason. Schrot's prescription at Team Jayco is closer to polarised than sweet spot — long volumes of properly easy riding, with specific hard sessions when the calendar calls for them. The "make every minute count" instinct that drives amateur sweet spot use isn't how high-level cycling actually trains.
The case for threshold
Threshold work has narrower but real applications.
TT specialists. Time trial performance is closely tied to the rider's sustainable threshold power. Threshold-specific intervals develop this directly. For cyclists targeting TT events, threshold blocks in the build and peak phases earn their place. Matt Bottrill's work covered in the pro rider TT techniques episode emphasises threshold specificity for TT preparation.
Late build / peak sharpening. Threshold intervals in the final 4–6 weeks before an A-race produce the race-pace specificity that lifts performance from "fit" to "race ready." 2×20 minutes at threshold or 3×15 minutes simulates many race demands directly.
Threshold-limited riders. Some cyclists have strong VO2max but weak threshold — they can spike hard for 4 minutes but can't sustain 95% of FTP for 20 minutes. For these riders, threshold-specific blocks address the actual limiter directly. The training diagnostic helps identify this profile.
The case against threshold as a default is the same as sweet spot. Run threshold work every week of the year and you'll accumulate enormous fatigue without commensurate gain. The published evidence shows threshold-dominant training plateaus faster than polarised over multi-month periods.
The decision tree
Three factors determine which method fits your situation. Walk through them in order.
Factor 1: Weekly training hours.
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Under 5 hours per week: sweet spot blocks have the strongest case. Run 4–6 week focused blocks of sweet spot work as your primary intensity. Layer in 1 short Zone 2 ride per week for variety. Polarised doesn't have enough easy volume to express its benefit at this volume.
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5–8 hours per week: polarised structure with sweet spot blocks layered in. Default distribution is 80/20 (one hard session, rest easy), with periodic 4-week sweet spot blocks during the build phase.
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8–12 hours per week: polarised with mixed hard sessions. The harder days rotate between threshold, VO2max, sweet spot, and race-specific work depending on the block focus.
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Above 12 hours per week: polarised becomes clearly superior. The easy volume needed to support multiple weekly hard sessions requires the polarised distribution. Sweet spot dominance at this volume produces overtraining within 4–6 weeks.
Factor 2: Current training phase.
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Base phase: polarised, regardless of volume. The aim is aerobic foundation; the wrong intensity here costs the foundation that everything else builds on.
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Early build phase: polarised with VO2max blocks. Lifting the ceiling.
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Mid build phase: polarised with sweet spot or threshold blocks. Layered specificity.
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Late build / peak phase: polarised with race-specific intensity. Threshold work earns its place here for cyclists racing against the clock; race-pace efforts earn their place here for cyclists racing in groups.
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Race phase: polarised with reduced volume. Race-specific intensity only.
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Transition phase: unstructured. The phase isn't about adaptation; it's about recovery.
Factor 3: Your specific limiter.
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Aerobic base limited: polarised. The diagnosis is usually high-end power feels okay but you can't hold it long. The fix is more easy volume.
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VO2max limited: polarised with VO2max blocks. The diagnosis is short hard efforts hurt disproportionately. The fix is concentrated VO2max blocks.
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Threshold limited: polarised with threshold blocks. The diagnosis is you can spike well but can't sit at threshold for sustained periods. The fix is threshold specificity blocks.
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Repeated-effort limited: polarised with VO2max and short-effort durability blocks. The diagnosis is the second and third hard efforts come apart. The fix is repeated-effort sessions in build phase.
The training diagnostic walks through this assessment in detail and produces a specific prescription. The decision tree above is the framework; the diagnostic is the actual diagnosis.
Why amateurs argue about this
The reason the training method debate is so heated in amateur cycling is that most amateurs aren't running any single method properly. They're running a confused mix that looks like sweet spot some days, threshold other days, easy on accident, and never really polarised. When their training stalls, they blame whichever method they thought they were running, switch to another, and stall again.
The underlying problem isn't the method choice. It's the structure execution. The cyclist who runs polarised badly (easy days not easy, hard days not hard) plateaus. The cyclist who runs sweet spot badly (intensity drifting, no recovery weeks) plateaus. The cyclist who runs threshold badly (no aerobic base under it) plateaus.
The fix isn't another method. It's executing one method properly for long enough to express its benefit.
What I run
For full disclosure: I run polarised as my default distribution with periodic sweet spot blocks in the build phase. Two hard sessions per week, three easy rides, one long ride. The hard sessions rotate based on the block focus: VO2max in early build, threshold in mid-build, race-specific in late build and peak. Recovery weeks every fourth week.
The structure works because it's repeatable and the principle is clear. I'm building aerobic capacity with the easy 80%; I'm lifting the ceiling with the hard 20%. The grey zone gets avoided because there's a deliberate cap on the easy days and a deliberate floor on the hard days.
For most amateur cyclists at 8–12 hours per week, this is the structure I'd recommend testing first. The polarised training guide covers the full prescription. If your volume is under 6 hours, sweet spot blocks with light Zone 2 surrounding them is the better default — the time-crunched training guide covers that case.
What to do next
Start with the Plateau Diagnostic — four minutes, free, returns the one change most likely to move your numbers. Most amateurs are training for the wrong limiter because they've assumed it's threshold when it's actually aerobic base. Plug your numbers into the FTP zone calculator so your sweet spot, threshold, and VO2max bands are accurate.
For deeper coaching support, the coaching pathways cover specific training models. The Not Done Yet community at $195/month is where most of these decisions get worked through in the weekly coaching call. For full one-on-one programming, the Roadman Method at $297-397/month is the structured 12-month programme with personal coaching through the method selection and execution.
The training method that works is the one you execute properly for long enough to see results. Pick the structure that fits your volume, your phase, and your limiter. Hold it for 12 weeks. Then assess. The cycling internet will move on to a new debate; the rider who runs the right structure consistently will keep getting faster.