Your winter base is in the bank. The first events are on the calendar. You've done the work — the long zone 2 rides, the indoor sessions, the slow accumulation of aerobic fitness that coaches keep telling you matters more than anything else. And now you're asking the question every cyclist asks around this time of year: when do I start going hard?
There is a phase between base and build that has no proper name, no chapter in most training books, and almost no coverage in the cycling media. It sits in the gap between endurance riding and race-specific intensity. It lasts about four weeks. And skipping it — or rushing through it — is the single most common reason amateur cyclists arrive at their first event of the season feeling flat, heavy, and slower than their winter numbers said they should be.
This is the base-to-build transition. And I'm going to give you the exact sessions, the weekly structure, and the physiological markers that tell you when your body is actually ready to make the shift.
Why the transition exists at all
Joe Friel laid this out clearly in The Cyclist's Training Bible, and Dan Lorang has talked about it on the podcast: the base phase and the build phase target different physiological systems, and those systems don't hand off smoothly unless you bridge them deliberately.
During base, you've been building mitochondrial density, capillarisation, fat oxidation, and aerobic enzyme activity. Your body has adapted to sustained, low-intensity work. Your slow-twitch muscle fibres are efficient. Your cardiac output has improved. Your training load has been climbing steadily at low intensity.
The build phase asks something entirely different. Threshold work demands lactate clearance at high rates. VO2 max intervals require fast-twitch fibre recruitment. Race efforts need anaerobic capacity, neuromuscular coordination, and the ability to repeatedly surge and recover. None of that was stressed during base.
What happens when you jump from one to the other in a single week? The aerobic system that has been patiently developing can't support the new demands. Your heart rate spikes. Your recovery between intervals is slow. Your RPE is through the roof on efforts that should feel manageable. And because you feel terrible, you either push through — accumulating fatigue without quality — or you back off and lose confidence.
The transition exists to introduce your body to higher-intensity stress in a graduated way, so that when the full build phase arrives, your aerobic base can actually support the work it's being asked to do.
How to know your base is ready
This is where most advice falls apart. Coaches say "after 8 to 12 weeks of base, move to build." Calendar-based transitions are lazy coaching. Your body doesn't know what week it is. It knows what it can sustain.
Here are the three markers I look for before recommending a rider moves out of base.
Efficiency factor is stable or rising. Efficiency factor is normalised power divided by average heart rate for steady endurance rides. If this number has been flat or climbing over 3 to 4 weeks of consistent zone 2 riding, your aerobic system is responding to the training stimulus. If it's still trending upward steeply, there's a case for staying in base longer — you're still extracting gains from low-intensity work.
Resting heart rate is stable. Morning resting heart rate, measured before you get out of bed, should be consistent within a 3 to 5 beat range across the week. If it's elevated or erratic, your autonomic nervous system is still adapting. Adding intensity on top of an unstable baseline is a recipe for overreaching.
You can hold zone 2 for 90 minutes without cardiac drift. Cardiac drift is the upward creep of heart rate during steady-state exercise at constant power. If you can ride 90 minutes at your zone 2 power and your heart rate stays within 5 per cent of where it started, your aerobic base is robust enough to support harder work. If heart rate creeps up 8 to 10 per cent by the end of that ride, you need more time in base. The aerobic engine is not yet efficient enough to handle the added load of intensity sessions.
Andrew Coggan's work on training with power established these metrics for a reason. They are objective. They are measurable. They don't care about your ego or your calendar.
The first intensity sessions: tempo, not threshold
Here's where it gets really interesting. Most riders assume that "adding intensity" means threshold intervals. Two-by-twenty at 95 per cent of FTP. That's the session everyone knows. And it is absolutely the wrong place to start.
The first intensity sessions in a transition block should be tempo. Seventy-six to 88 per cent of FTP. This is the range that sits above endurance but below the sustained effort of threshold work. And it serves a very specific purpose.
Tempo riding teaches your body to clear lactate at moderate production rates. It recruits a mix of slow-twitch and fast-twitch fibres without the deep fatigue of threshold work. It stresses the cardiovascular system enough to begin the upward adaptation toward higher intensities, but not so much that recovery is compromised for the next day's training.
Think about what's happening physiologically. A rider who's been doing nothing but zone 2 for 12 weeks has an aerobic system that is excellent at low power outputs and a lactate clearance system that is essentially dormant at anything above endurance pace. Jumping to threshold asks that dormant system to work at maximum capacity on day one. Tempo wakes it up gradually.
The sessions are simple. In the first week of the transition:
- Session 1: 2x20 minutes at 76 to 80 per cent of FTP, with 5 minutes easy between efforts. This should feel controlled. You should be able to speak in short sentences. If you can't, you're above tempo.
- Session 2: 3x15 minutes at 80 to 85 per cent of FTP, with 5 minutes easy recovery. Slightly higher in the tempo range, slightly shorter efforts.
Two tempo sessions per week. Everything else stays as endurance riding. Total weekly volume drops 5 to 10 per cent from late base to protect the quality of these new efforts.
Week by week: the 4-week transition block
I'm going to give you the exact structure. You can go and do them this week — or whenever your physiological markers say you're ready.
Week 1: Tempo introduction
Goal: Wake up the lactate clearance system. Introduce sustained effort above endurance pace.
- Monday: Rest
- Tuesday: 90 minutes endurance (zone 2) with 2x20 minutes tempo at 76 to 80 per cent of FTP embedded in the middle. Five minutes easy between efforts.
- Wednesday: 60 minutes easy endurance
- Thursday: 75 minutes endurance with 3x15 minutes at 80 to 85 per cent of FTP. Five minutes easy between efforts.
- Friday: Rest or 45 minutes very easy spinning
- Saturday: 2.5 to 3 hours endurance ride, steady zone 2 throughout. This is your long ride. No tempo today — the endurance base still needs feeding.
- Sunday: 60 to 75 minutes easy recovery ride
Total structured intensity: Approximately 75 minutes of tempo work across 2 sessions. Everything else is zone 1 to 2.
What to watch: Heart rate response to tempo efforts. In the first week, heart rate will likely sit at the upper end of your tempo range. That's normal. If it's spiking above threshold heart rate during tempo-power efforts, your base wasn't ready.
Week 2: Sweet spot introduction
Goal: Progress from tempo to sweet spot — 88 to 93 per cent of FTP. The power range that sits just below threshold and produces substantial training stimulus without the full recovery cost of true threshold work.
- Monday: Rest
- Tuesday: 90 minutes with 2x15 minutes sweet spot at 88 to 93 per cent of FTP. Five minutes easy between efforts. Note the shorter duration than the tempo efforts — sweet spot is harder, so the intervals are trimmed.
- Wednesday: 60 minutes easy endurance
- Thursday: 75 minutes with 2x20 minutes tempo at 80 to 85 per cent of FTP. One session stays at tempo while the other progresses to sweet spot. This prevents both sessions from being too demanding simultaneously.
- Friday: Rest or 45 minutes easy
- Saturday: 2.5 to 3 hours endurance with 1x30 minutes at upper tempo (85 to 88 per cent FTP) embedded in the second hour. This is a progression of the long ride — introducing sustained effort into your weekly volume anchor.
- Sunday: 60 minutes easy recovery
Total structured intensity: Approximately 30 minutes sweet spot, 70 minutes tempo across 3 sessions.
What to watch: RPE for the sweet spot efforts. They should feel hard but sustainable — a 6 to 7 out of 10. If you're rating them 8 or above, drop back to upper tempo for another week.
Week 3: Threshold exposure
Goal: The first true threshold efforts of the season. Brief, controlled, with plenty of recovery between.
- Monday: Rest
- Tuesday: 90 minutes with 3x10 minutes at 95 to 100 per cent of FTP. Five minutes easy between efforts. Short threshold intervals. Not two-by-twenty. Not yet.
- Wednesday: 60 minutes easy endurance
- Thursday: 75 minutes with 2x15 minutes sweet spot at 88 to 93 per cent. This stays below threshold — you don't need two threshold sessions in the same week during the transition.
- Friday: Rest or 45 minutes easy
- Saturday: 3 hours endurance with 2x15 minutes tempo embedded. The long ride maintains its endurance character with a moderate sustained effort.
- Sunday: 60 to 75 minutes easy recovery
Total structured intensity: 30 minutes threshold, 30 minutes sweet spot, 30 minutes tempo across 3 sessions. Notice the pyramid — each intensity level has been introduced in sequence.
What to watch: Power-to-heart rate relationship during threshold efforts. If you're hitting your target power but heart rate is 10 or more beats above your known threshold heart rate, you're overcooking it. Drop to 92 to 95 per cent of FTP and build from there.
Week 4: Race simulation
Goal: String different intensities together in a single ride. Replicate the variable demands of racing or a sportive. Test outdoor-specific fitness.
- Monday: Rest
- Tuesday: 90 minutes with 4x8 minutes alternating between sweet spot (90 per cent FTP) and threshold (100 per cent FTP) every 2 minutes within each block. Three minutes easy between blocks. This teaches your body to manage changing intensities — which is what racing actually demands.
- Wednesday: 60 minutes easy endurance
- Thursday: 75 minutes with 2x12 minutes at threshold (95 to 100 per cent FTP). Six minutes easy between. These are longer threshold efforts now — your body has had three weeks to prepare.
- Friday: Rest
- Saturday: 3 to 3.5 hours endurance ride with a race-simulation section: 45 to 60 minutes of mixed-intensity riding in the second half, including 3 to 4 surges of 2 minutes at 110 to 120 per cent of FTP mixed with tempo and sweet spot between surges. This is the closest thing to racing without actually racing.
- Sunday: 60 minutes easy recovery
Total structured intensity: Approximately 60 minutes at or above threshold, 30 minutes sweet spot. This is a meaningful step up from weeks 1 to 3 — but notice that the progression was gradual.
Bridging indoor fitness to outdoor riding
Here's a piece that gets overlooked constantly. If you've spent your winter on a smart trainer — on Zwift, on TrainerRoad, on a Wahoo Kickr in the garage — your fitness is real. The watts are genuine. The aerobic adaptations are there. But indoor fitness transfers imperfectly to outdoor riding, and failing to account for that difference is one of the most deflating experiences in early-season cycling.
What's different outdoors? Almost everything about the execution.
Road surface variability. On a trainer, resistance is constant. On the road, you're adjusting power output continuously to account for rolling resistance changes, gradient shifts, and road texture. Your neuromuscular system has to manage a variable load, not a fixed one.
Wind. Training indoors eliminates aerodynamic drag as a variable. Outdoors, you're producing more power into a headwind and less on a tailwind, which means your pacing strategy has to be active, not passive. Riders who've only trained indoors tend to ride too hard into headwinds and too easy with tailwinds — the opposite of efficient pacing.
Thermoregulation. Most garages and pain caves are cool. A spring day at 18 degrees with a tailored kit is a different thermal challenge. Your body has to divert blood to the skin for cooling, which means less blood available for the working muscles. Heart rate rises. Perceived effort increases. The same watts feel harder.
Bike handling under fatigue. Cornering, descending, riding in a group, navigating traffic — none of these are trained on an indoor setup. And they all add cognitive and physical load that compounds the metabolic cost of the ride.
Fuelling logistics. On a trainer, your bottles are on the desk, your gels are in the drawer. On a four-hour outdoor ride, you need to manage fuelling while riding, which means eating in the rain, opening wrappers with one hand, and timing nutrition around climbs and descents.
The fix is simple but needs to be deliberate. Plan 3 to 4 outdoor-specific sessions before your first event. These don't need to be additional volume — replace indoor sessions with outdoor equivalents. Do your tempo efforts on the road. Do your sweet spot on a local climb. Do your long ride outside. The goal is to re-familiarise your body and your brain with the demands of real-world riding before the first event forces you to deal with all of them simultaneously.
The FTP trap: why testing too early costs you
The biggest early-season mistake, and I see this every single year, is testing FTP in week one of the build phase. Riders come off a strong winter of indoor training, step outside, do a 20-minute test, and the number comes back 10 to 15 watts lower than their indoor peak.
Panic. Disappointment. Frustration. And then either a spiral of confidence loss or, worse, a decision to set training zones based on that deflated number — which means every subsequent session is undercooked.
The good news: there's nothing wrong with you. Your FTP hasn't dropped. What's happened is entirely predictable. The first outdoor efforts of the season include all the variables I just described — wind, temperature, road surface, pacing errors — and those variables suppress your expressed power output relative to the controlled environment of a trainer.
Give it 2 to 3 weeks. Once your body has readjusted to outdoor riding, your power numbers will climb back to meet your indoor benchmarks and, if the base phase went well, exceed them. Friel's advice on this is characteristically blunt: test when you're ready to use the result, not when you're curious about the number.
If you must assess fitness early in the transition, use heart rate decoupling on a steady endurance ride instead. It tells you about aerobic capacity without the psychological baggage of a power test. Cardiac drift under 5 per cent on a 90-minute zone 2 ride means your engine is ready. That is a far more useful signal than an FTP number produced under conditions your body hasn't adapted to yet.
What most people do versus what actually works
Here is the pattern I see in the riders who email me, the riders in the Skool community, the riders who show up to their first event wondering what went wrong.
What they do: Finish base training on a Sunday. Do a threshold session on Tuesday. Add VO2 max intervals on Thursday. Race on Saturday. Spend the following week shattered, wondering why their legs felt like concrete at the first event.
What actually works: Finish base training. Spend a week on tempo. Spend a week introducing sweet spot. Spend a week adding threshold in small, controlled doses. Spend a week stringing it all together in race-simulation sessions. Show up at the first event with legs that have been progressively prepared for the demands they're about to face.
The difference is four weeks. Four weeks of patience. Four weeks of resisting the urge to skip ahead because the calendar is pressuring you and your training partners are posting threshold sessions on Strava.
The science has finally caught up to what good coaches have always known: adaptation is sequential, not instantaneous. Your body needs time to build the enzymatic, cardiovascular, and neuromuscular infrastructure that supports high-intensity work. That infrastructure doesn't appear overnight because you've decided it's time to go fast.
Common mistakes and how to avoid them
Starting intensity before the base is ready. If your efficiency factor is still climbing steeply, you're leaving aerobic gains on the table. Another 2 to 3 weeks of base riding will produce more long-term benefit than starting the build phase early.
Two hard days back to back in the transition. During the full build phase, consecutive quality days can work if recovery is managed. During the transition, your body is not yet adapted to intensity. One hard day needs at least one easy day — ideally two — before the next quality session.
Chasing last year's numbers in week one. Your FTP from October is irrelevant in February. Your body has spent months doing different work. Meet it where it is, not where you want it to be. The numbers will come.
Neglecting the long ride. Some riders get so excited about intensity that they drop their weekly long endurance ride. Don't. The aerobic base still needs maintenance. The long ride — 2.5 to 3.5 hours of steady zone 2 — should stay in the programme throughout the transition and into the build phase. It is the foundation everything else sits on.
Ignoring recovery quality. Your easy days need to be properly easy. If you're riding "easy" at 65 per cent of FTP because you feel good, you're bleeding into tempo and accumulating fatigue that compromises your next quality session. Easy means easy. Conversational pace. Zone 1 to low zone 2. Professor Seiler's research showed that polluted easy days are the most common failure pattern in endurance training at every level.
Not adjusting for age. Riders over 40 need more recovery between intensity sessions. Where a 28-year-old might absorb two quality sessions in three days, a 48-year-old typically needs a full 48 hours between hard efforts during the transition phase. This isn't a limitation — it's physiology. Plan accordingly and the adaptation is identical. Rush it and you're courting injury.
Strength work in the transition
A note on strength training through this period, because I get asked about it constantly. If you've been doing gym work through the winter — and you should have been — the transition is where you shift the emphasis.
During base, strength work focuses on muscular endurance and stability. Body-weight exercises, resistance band work, single-leg movements, core stability. Two to three sessions per week alongside your endurance riding.
During the transition, reduce gym frequency to once or twice per week and shift toward maintenance loads rather than progression. Your body is now absorbing a new type of stress — intensity on the bike — and it cannot recover from simultaneous increases in both gym load and riding intensity. Something has to give. Let it be the gym.
Keep the core work. Keep the single-leg stability exercises. Keep the hip mobility routine. Drop the heavy loading. The strength you built over winter doesn't disappear in four weeks. It just needs maintaining while your body redirects recovery resources toward the new demands of higher-intensity cycling.
When to compress the transition
Not everyone has four weeks. Sometimes life, weather, or a late decision to enter an event compresses your timeline. Fixable — but you need to know what you're trading off.
Three-week transition: Combine weeks 1 and 2 from the block above. Run tempo and sweet spot in the same week — one session of each — then progress to threshold in week 2 and race simulation in week 3. You lose the clean separation of stimuli, but you still get a graduated introduction to intensity.
Two-week transition: One week of combined tempo and sweet spot (two sessions). One week of threshold and a race simulation ride. Accept that you will arrive at your event fit but not sharp. Treat the event as a training race and target your peak fitness at the next one.
One week or less: There is no meaningful transition you can do. Ride the event on your base fitness. Zone 2 is not nothing — it produces perfectly respectable endurance performances. You won't win the bunch sprint, but you'll finish strong if you pace yourself intelligently.
The important thing is not to manufacture intensity you haven't earned. A rider with a strong base and a rushed transition will always outperform a rider who spent their base phase doing unstructured intensity and arrives at the event with neither a foundation nor a peak.
Monitoring through the transition
Track three things daily through the four-week block.
Morning resting heart rate. A 5-beat elevation sustained over 2 or more days means you're accumulating more fatigue than your body can absorb. Swap the next quality session for an easy ride.
Session RPE. Rate every ride on a 1 to 10 scale. Tempo sessions should sit at 5 to 6. Sweet spot at 6 to 7. Threshold at 7 to 8. If your perceived effort is consistently one or two points above those ranges for the same power output, you need more recovery between sessions.
Sleep quality. Disrupted sleep during a build transition is an early warning sign of overreaching. If you're waking at 3 a.m. or struggling to fall asleep after quality sessions, your autonomic nervous system is stressed. An extra rest day costs you nothing. An overreaching episode costs you weeks.
These are simple, free, and more informative than any recovery gadget on the market. Use them.
The goal is race-ready, not race-fit
There's a distinction worth making. Race-fit means you have the physiological capacity to produce the power outputs racing demands. Race-ready means you have the capacity, the pacing skill, the fuelling practice, the group-riding confidence, and the tactical awareness to use that fitness in competition.
The base-to-build transition is about becoming race-ready, not just race-fit. The tempo sessions teach your body to clear lactate. The sweet spot sessions build muscular endurance. The threshold sessions develop the top-end you'll use in attacks and climbs. The race-simulation ride teaches you to manage changing intensities.
But beyond the physiology, the outdoor sessions teach you to fuel on the move, pace into wind, hold your line in a group, and manage effort across a variable course. The indoor trainer built the engine. The transition teaches you to drive it on a real road.
Give it four weeks. Follow the markers, not the calendar. And arrive at your first event knowing that the bridge between base and race day hasn't been skipped — it's been built, deliberately, one session at a time.
Want the weekly structure reviewed against your own power data? The Roadman Cycling community on Skool is where riders post their transition blocks, get feedback on pacing, and share what's actually working in early-season preparation. No guesswork, no generic plans — real riders building real form together.