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HOW LONG SHOULD THE BASE PHASE BE?

By Anthony WalshRoadman CyclingUpdated

WHO THIS IS FOR

IS THIS YOU?

The rider planning their annual structure

You're deciding how to divide the year and want to know how much time to protect for base.

The rider who always cuts base short

You get bored of easy riding after six weeks and start intervals. Every year ends the same way.

THE ROADMAN VIEW

The Roadman view

Riders consistently underestimate how long the base needs to be because the payoff isn't visible during the phase itself. You don't feel faster. Your test numbers don't move much. You just feel... fine, and a bit bored. The gains from base training are running in the background, and they only become visible once intensity starts in the build phase.

Joe Friel's guidance is clear on this: don't rush to build. The base phase is not a waiting room before the real training starts — it is the real training. The mitochondrial density and fat oxidation you build in those 12–16 weeks are what allow threshold work to produce meaningful adaptation later. Cut the base to eight weeks and you'll get early build gains; cut it to four and you'll plateau by April wondering what happened.

If the calendar genuinely doesn't allow 16 weeks, protect 12. If it doesn't allow 12, protect 10. But never compress the base below 8 weeks and jump straight into full build intensity. You'd be better served staying in base a little longer and shortening the peak taper.

EXPERT EVIDENCE

WHAT THE EXPERTS SAY

  • Joe FrielAuthor of The Cyclist's Training Bible; co-founder of TrainingPeaks

    The base period is non-negotiable in length because the adaptations it builds — aerobic capacity, fat oxidation, structural resilience — accumulate on a time scale of weeks to months. Athletes who compress base phases typically see early build gains followed by stagnation or breakdown.

    Hear it: Joe Friel's Cycling Training Plan Structure | Roadman Cycling
  • Professor Stephen SeilerExercise physiologist, University of Agder

    Across elite endurance athletes studied longitudinally, the volume of genuine easy aerobic work done in the preparation phase is one of the strongest predictors of high-intensity adaptation later in the season. More base time doesn't just help — it amplifies what follows.

    Hear it: 80/20 Training to Ride Faster | Dr Stephen Seiler

PRACTICAL APPLICATION

DO THIS WEEK

  1. Block 12–16 weeks in your calendar first

    Before planning any build or peak phase, reserve 12–16 weeks from late autumn or early winter for base. This is your non-negotiable time investment in the season.

  2. Progress within the base phase

    Base isn't just riding the same volume for 16 weeks. Add 10% volume every three weeks, take a deload week at week four, then build again. Progressing within base keeps the stimulus moving without introducing premature intensity.

  3. Use the final 2–3 weeks of base for low-level intensity

    In the last 2–3 weeks of base, introduce one session per week of tempo riding (76–83% FTP) to begin bridging toward the build. This is not full build intensity — it's a controlled transition.

COMMON MISTAKES

WHAT CYCLISTS GET WRONG

  • MISTAKEStarting the build phase after only 6–8 weeks of base because progress feels slow.

    FIXThe gains are happening below what you can measure day-to-day. Commit to the full 12 weeks before assessing.

  • MISTAKEAdding multiple hard sessions 'just to maintain intensity' during base.

    FIXOne modest intensity session per week in the final base weeks is fine. More than that means you're not in base — you're in an undescribed limbo phase.

  • MISTAKEUsing the same 12-week base length regardless of event distance.

    FIXLonger events — gran fondos, ultras — benefit from longer base phases. A rider preparing for a 200km event needs 16 weeks; a rider targeting a 40km time trial can manage with 12.

FAQ

FREQUENTLY ASKED QUESTIONS

Can I do base training in 8 weeks?
Eight weeks produces some base adaptation, but it's the minimum. You'll see more limited gains and the build phase may feel harder than it should. If you genuinely have only 8 weeks, lower your build expectations and prioritise honest zone 2 throughout — don't try to compensate with intensity.
What should the base phase look like on a weekly basis?
Most weeks: two to four zone 2 rides, one longer zone 2 ride on the weekend, one optional easy strength session. No threshold or VO2max work until the final 2–3 weeks of the phase. Volume builds gradually across the 12–16 weeks.
Do masters cyclists need a longer base?
Generally yes. Recovery from intensity takes longer after 40, so the aerobic base needs to be more developed before the body can absorb hard build work. Sixteen weeks of base is a better default for masters riders than 12.
Should I ride indoors or outdoors during base?
Both work. Outdoors is easier for long zone 2 rides. Indoors is more efficient for controlled sessions and better for zone adherence in bad weather. Many riders use indoor riding for shorter weekday zone 2 and get outside for the longer weekend base ride.
What happens if I miss weeks during the base phase?
One or two missed weeks can usually be absorbed by extending the base phase slightly rather than skipping forward. If you miss four or more consecutive weeks, consider restarting the base phase from a lower volume rather than jumping to where you left off.

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