Omloop Het Nieuwsblad goes on February 28th. Kuurne-Brussels-Kuurne the day after. The 2026 Spring Classics season has started, and unless you’re lining up in Belgium next weekend, these races mark something more useful than spectator entertainment: a hard deadline for your own season prep.

Most amateur cyclists either ignore the Spring Classics calendar entirely or use it as a source of vague dread. “The pros are already racing and I’m still doing zone 2.” Right. But there’s a smarter way to use this moment.

If you’ve been building a base since November or December, late February is exactly when the transition should happen. Not because the calendar says so. Because your aerobic foundation is ready—or as ready as it’s going to get before the first local races hit in late March.

Quick Answer

Pre-block: FTP retest before starting — power zones drift over base phase

Week 1 (7.5-8.5 hrs): Threshold reintroduction — 3x10 min threshold, sweet spot, over-threshold

Week 2 (8-9 hrs): VO2 max enters — 5x4 min VO2, threshold, race simulation

Week 3 (8.5-9 hrs): Race-specific power — over-unders, punch-and-hold, long race effort

Week 4 (5-6 hrs): Sharpen — openers, sprints, race simulation

Best for: First races in late March / early April Skip if: You haven’t done 6+ weeks of base training yet Weekly hours: 6-9 hours (Week 4 drops to 5-6) Requires: Power meter or RPE discipline

What the Base-to-Build Transition Actually Means

“Base to build” sounds clean in theory. In practice, it’s the phase where most riders either hold on too long to zone 2 or blow their legs apart with interval overload in the first two weeks.

The transition is a bridge, not a switch.

Your body has been running on aerobic volume—long rides, steady zone 2, maybe some sweet spot work. The aerobic engine is solid. What’s missing is race-specific stress: short power, repeated anaerobic efforts, the capacity to respond when someone accelerates without burning everything you have.

The goal over four weeks is to layer race-ready neuromuscular capacity on top of that aerobic base without destroying the base in the process.

One thing that makes this window specific to 2026: if your target events fall in late March or April—Ronde van Vlaanderen amateur editions, local spring criteriums, gravel races with punch-fest finishes—you have roughly six weeks from Omloop weekend before you need to be genuinely race-sharp. This four-week block gets you there.

Before Week 1: The FTP Test You’ve Been Skipping

You probably haven’t tested since January. Maybe longer.

A late-February FTP test isn’t optional if you’re serious about calibrating your training zones before the race-pace blocks begin. Using power zones based on a December FTP means you’re either sandbagging intervals or burning matches in the wrong places.

The test protocol doesn’t need to be complicated:

Option A (Ramp Test):

• 10 min easy warm-up
• Increase power by 20W every minute until failure
• FTP estimate = approximately 75% of peak 1-minute power

Option B (20-Minute Test):

• 45 min progressive warm-up with 2x30 sec all-out openers
• 5 min full recovery
• 20 min maximal effort
• FTP estimate = 95% of average 20-minute power

Do this before Week 1 training begins—ideally the Sunday before, or Monday with Tuesday as a rest day. Everything that follows depends on accurate zones.

My experience: tested at 248W in early January, retested late February at 261W. Thirteen watts of honest improvement from consistent base work. Those 13 watts changed which training zones were hard and which were genuinely brutal. The retest matters.

No power meter? The whole block is doable on RPE. The percentage targets throughout map to: threshold = 7.5-8/10 RPE, sweet spot = 6-7/10, VO2 max = 9/10. Over-unders and punch-and-hold sessions should hit 8.5 and 9-10/10 respectively during efforts. You’ll lose some precision on the VO2 sessions, but the structure is sound.

Week 1: Reintroduce Threshold, Don’t Rush

Volume stays close to base-phase levels this week. The change is intensity distribution.

Monday: Rest or 30 min easy spin

Tuesday: 75 minutes threshold reintroduction

• 15 min progressive warm-up
• 3x10 min at 95-100% FTP (new FTP from test)
• 5 min easy recovery between
• 15 min cool-down

RPE: 7-8/10 during efforts. You should be able to speak in short sentences, not freely.

Wednesday: 60 min zone 2

Thursday: 75 minutes sweet spot

• 15 min warm-up
• 2x20 min at 88-93% FTP
• 5 min recovery
• 10 min cool-down

RPE: 6-7/10. Controlled discomfort.

Friday: Rest

Saturday: 90 minutes mixed

• 20 min warm-up
• 4x5 min at 100-105% FTP (just over threshold)
• 4 min recovery
• 20 min zone 2 cooldown

Sunday: 2-2.5 hours

• First 90 min zone 2
• Final 30-40 min at tempo (80-85% FTP)

Weekly total: 7.5-8.5 hours Intensity focus: Threshold and sweet spot only. No VO2 yet.

Carbohydrate note: Threshold work burns significantly more glycogen than pure zone 2. You need at least 60-80g carbs per hour during Tuesday and Thursday sessions, not the 30-40g that was fine during base phase. Eat more this week than your body is asking for—you’re resetting your fueling baseline for the harder weeks ahead.

Week 2: VO2 Enters the Picture

This is where Spring Classics fitness gets built. Following an attack on a climb, holding that effort through the next 30 seconds before the road flattens out—that’s VO2 max territory.

The sessions are uncomfortable. That’s correct.

Monday: Rest

Tuesday: 75 minutes VO2 max

• 20 min warm-up with 3x30 sec builds
• 5x4 min at 108-115% FTP
• 4 min easy recovery between
• 15 min cool-down

RPE: 9/10 in the last 90 seconds of each effort. If you’re finishing easily, the power is wrong.

Wednesday: 60 min zone 2 (honest zone 2, not tempo)

Thursday: 75 minutes threshold

• 15 min warm-up
• 3x12 min at 97-102% FTP
• 5 min recovery
• 15 min cool-down

RPE: 7.5/10. Harder than last week’s threshold, shorter intervals.

Friday: Rest

Saturday: 2 hours race simulation or fast group ride

• If group ride: sit in for first hour, then respond to accelerations in the second
• If solo: 20 min warm-up, 4x6 min “punch efforts” (5 sec sprint + hold 110% FTP for remainder), 5 min recovery, 30 min tempo

Sunday: 2-2.5 hours with 6x30 sec surges

• Zone 2 base
• Every 20-25 minutes: one 30-second all-out surge
• Mimics race dynamics without accumulating threshold fatigue

Weekly total: 8-9 hours Key adaptation: Anaerobic capacity on top of aerobic base. This is the point of the block.

Carbohydrate periodization shift: By Week 2 you should be eating high-carbohydrate on every training day and dropping back to moderate carbs only on full rest days. VO2 work is almost entirely glycolytic. Trying to run VO2 intervals with depleted glycogen is like trying to sprint with flat tires. Aim for 7-9g carbs per kg body weight on Tuesday and Saturday.

Week 3: Race-Specific Power

The goal shifts from building systems to applying them in race-like patterns.

Spring Classics are not clean threshold efforts. They’re explosive, variable, punishing. Cobbled sectors, short punchy climbs, tempo riding to hold position then absolute max for 30 seconds to follow a move. Week 3 trains that chaos.

Monday: Rest or 30 min easy

Tuesday: 75 minutes—over-unders with sprints

• 20 min warm-up
• 4x8 min over-under: 2 min at 95% FTP, 2 min at 108% FTP (repeat twice per interval)
• 4 min recovery between
• 15 min cool-down

RPE: 8.5/10 by the fourth interval. The power swings are the point—your body is learning to clear lactate while still working.

Wednesday: 60 min easy

Thursday: 75 minutes punch-and-hold

• 15 min warm-up
• 6x3 min: 15 sec all-out sprint (max power), immediately hold 95% FTP for remaining 2:45
• 4 min recovery
• 20 min zone 2

RPE: 10/10 for the first 15 seconds, 8/10 for the hold. The sprint pre-fatigues the legs. That’s the exact scenario on a Classics climb.

Friday: Rest

Saturday: 2.5 hours—hardest ride of the block

• Include a challenging group ride if available
• If solo: structured race simulation with 3x15 min race-pace blocks separated by 10 min tempo (not rest)
• One extended effort of 20 min at 90-95% FTP near the end when legs are already cooked

Sunday: 90 min recovery

• Easy zone 1-2
• No intensity
• Let Week 3 adapt

Weekly total: 8.5-9 hours Fueling during hard sessions: 80-90g carbs per hour for over-under and punch-and-hold sessions. This is not excessive. This is what the effort demands.

Week 4: Sharpen, Don’t Dig

Week 4 is not a fourth week of loading. Volume drops by about 25%. The goal is arriving at race day feeling sharp and aggressive, not tired.

This is where riders make the most common mistake: seeing the big volume of Week 3 and thinking more will make them even better. More will make them flat.

Monday: Rest

Tuesday: 60 minutes openers

• 20 min warm-up
• 3x2 min at race pace (full effort)
• 4 min recovery
• 4x30 sec sprints (max power)
• 2 min recovery
• 15 min cool-down

Legs should feel crisp. If they don’t, you need more recovery, not more intensity.

Wednesday: 45 min easy spin

Thursday: 60 minutes maintenance threshold

• 15 min warm-up
• 2x12 min at 95% FTP
• 5 min recovery
• 3x20 sec sprints at end (stay neuromuscularly sharp)
• 10 min cool-down

Friday: Rest or 20 min very easy

Saturday: Race simulation or A-priority group ride

• Full effort in safe environment
• Test your nutrition strategy
• Practice positioning, tactics, responding to surges

Sunday: 60-75 min easy

• Done. You’re ready.

Weekly total: 5-6 hours

Fueling the Transition: Carbohydrate Periodization

Base training allowed some flexibility with nutrition. You could train fasted, ride with minimal carbs, use fat as primary fuel. Those days are over.

The shift to threshold and VO2 work means your muscles are demanding fast fuel. Glycogen. Race-pace efforts can’t run on fat adaptation—the aerobic-glycolytic overlap is what makes high intensity possible.

Practical approach for these four weeks:

Training day carbohydrate targets:

• Zone 2 day (recovery/easy): 5-6g per kg body weight
• Threshold/sweet spot day: 7g per kg body weight
• VO2/race simulation day: 8-9g per kg body weight
• Rest day: 4-5g per kg body weight

On-bike fueling targets by session type:

Session Type	Carbs Per Hour
Zone 2 (60 min)	30-40g
Sweet spot (75 min)	60g
Threshold intervals	70-80g
VO2 max intervals	80-90g
Race simulation	90g

One thing to practice now: Whatever drink mix or gel products you plan to use on race day, test them during Week 2 and 3 hard sessions. Gut issues at race pace are a training problem masquerading as a race problem.

What This Feels Like Week-by-Week

Week 1 feels almost manageable. The threshold work stings but you’re recovered by Thursday. You’ll wonder if you’re doing enough. You probably are.

Week 2 changes that. First VO2 session on Tuesday will feel fine for the first two intervals. Intervals three and four start to bite. Five is honest suffering. Correct.

Week 3 is the hardest week. The over-unders on Tuesday feel brutal in ways that straight threshold doesn’t. The punch-and-hold Thursday workout is genuinely unpleasant. Saturday’s long ride should leave you tired in the right way.

Week 4 feels like magic by comparison. Your legs are fresh but the power is there. Openers feel snappy. This is adaptation—the reason you went through Weeks 2 and 3.

Signs the Block Is Working

By the end of Week 3, you should notice:

• Heart rate recovery between intervals getting faster
• Power holding better through the back half of each VO2 interval
• Weekend group rides feeling more controlled at the front

By the end of Week 4:

• Legs feel fresher than Week 3 at the same warmup power
• Sprints come out sharp
• Race-pace doesn’t feel like emergency mode

If you’re more cooked at the end of Week 4 than Week 3, you overdid the intensity. Reduce Week 4 volume by another 15%.

Signs to Pull Back

Don’t push through these:

• Resting heart rate elevated 6+ bpm for more than two days in a row
• Power 7-10% below target on a well-rested day
• Joint pain (knees, hips)—not muscle soreness, actual joint pain

Respond to these by:

• Making the next day a complete rest day
• Replacing the following hard session with zone 2
• Eating more than you think you need for 48 hours

The block works because of progressive overload. It breaks if you push overload past your recovery capacity.

How This Connects to Your Year

This four-week block assumes you completed a legitimate base phase—at minimum 6-8 weeks of consistent zone 2 and sweet spot work. If your base was inconsistent, compress the threshold exposure in Week 1 before introducing VO2 in Week 2.

After this block, you’re not done building. This is race-ready fitness for early-season events. Your next step depends on target dates:

• Late March / early April races: This block delivers you there. One week taper, race.
• May target races: Run this block, 2-3 weeks of race-stimulus training, then a 10-day taper.
• June target: Run this block, then a second build block focused on event-specific demands (criterium vs. granfondo requires different emphasis).

For the base training that precedes this block, see the 8-hour base plan that covers the zone 2 and sweet spot foundation. For early season race tactics once you’re fit, the early season race prep guide covers February’s specific challenges.

The Bottom Line

Four weeks from now, you can be genuinely race-ready. Not “survived the first race” ready. Actually in the mix.

What it takes: an honest FTP test before Week 1, consistent execution in Weeks 2 and 3, and the discipline to go easy when the plan says easy. That last part is harder than the intervals.

The Spring Classics field is off the front in Belgium. Your field is whoever shows up to your first local race in late March. Get ready for that race, specifically.

Test your FTP. Start Week 1 this week. The season isn’t waiting.

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Training zones calculated from FTP test completed late February 2026. Adjust carbohydrate targets based on your actual body weight. Power targets are percentages—not absolute watts—so recalibrate after your test before starting Week 1 sessions.