Full Marathon Periodized Training: The Four Phases of Base, Build, Race, and Taper

Introduction

Many runners train the same way year after year: a fixed weekly mileage, a fixed schedule, yet they expect improvement every year. In reality, the body’s adaptation mechanism tends to plateau under fixed stimuli. To keep improving, training stress and recovery must be alternated in a planned, progressive manner—this is the core concept of “periodized training.” Whether your goal is to finish, break four hours, or break three hours, periodization is the backbone of effective race preparation.

What Is Periodized Training?

Periodized training originated in Soviet sports science, initially applied to weight training and later widely adopted by endurance sports. Simply put, it divides the training year (or race preparation cycle) into time blocks with different goals, where each phase has different training intensity, volume, and focus, creating a spiral of progress: “stress → adaptation → new stress → higher adaptation.”

A full marathon preparation cycle typically lasts 16–20 weeks and can be divided into the following four phases:

Detailed Explanation of Each Phase

Phase 1: Base Phase

The purpose of the base phase is to build the aerobic engine. Training consists mainly of easy aerobic runs (80% or more), with weekly mileage increasing gradually and intensity kept in a range where conversation is comfortable.

Key training elements:

• 5–6 easy runs per week, 75–90 seconds/km slower than marathon goal pace.
• One long run per week, starting at 16–18km and adding 2km every two weeks.
• Incorporate running strength training (squats, lunges, bridges) to strengthen the glutes and core.

The most common mistake in the base phase is “running too fast,” rushing to test results and ending up overtired before the build phase even begins.

Phase 2: Build Phase

The build phase introduces “quality workouts” with the goal of raising lactate threshold and improving marathon pace efficiency. Training intensity becomes clearly differentiated: easy runs get slower, quality sessions get faster.

Key training elements:

• One threshold run per week (8–12km, 30–40 seconds/km faster than marathon goal pace).
• One marathon pace long run per week (maintaining goal pace for the final 8–12km).
• One “cutback week” every two weeks, reducing mileage by 20–25% to allow the body to fully absorb the training.

Phase 3: Peak Phase

The peak phase is the highest point of training volume and intensity in the entire preparation cycle, typically lasting 2–3 weeks. The goal of this phase is to integrate all training into complete race-ready ability.

Key training elements:

• Long runs reach their peak (28–34km, adjusted according to goal level), with the latter portion executed at race pace.
• Maintain threshold run intensity but slightly shorten the distance (to avoid carrying accumulated fatigue into the taper).
• Include one simulation race or an all-out half marathon time trial.

Phase 4: Taper Phase

The taper phase is the hardest phase for many runners to execute: mileage drops significantly (to 40–60% of peak), yet the “quality” of training must be maintained. The taper is not rest—it is about letting fatigue subside and allowing training adaptations to surface.

• Week 1: Mileage drops to 70% of peak, keeping one threshold run.
• Week 2: Mileage drops to 50% of peak, long run shortened to 16–18km.
• Week 3 (race week): 6–8km easy runs on Monday through Wednesday, rest Thursday and Friday, race Saturday.

Common Periodization Mistakes

• Treating the taper as a chance to catch up: “Using this cutback week to make up for missed mileage” is the most common mistake, often leaving legs feeling heavy on race day.
• Introducing too much intensity in the base phase: Adding interval sessions too early results in accumulated fatigue that degrades training quality by the build phase.
• Ignoring cutback weeks: There should be a volume reduction week every three weeks to allow the body to supercompensate.

Practical Advice

• Work backward from race day with a 16-week plan: After confirming your target race date, plan each phase backward from race day to avoid still doing high-intensity work right before the race.
• Taipei Marathon preparation timeline: The Taipei Marathon typically falls in the third week of December, making late August or early September the ideal starting point—conveniently avoiding the hottest part of summer.
• Adjust flexibly rather than rigidly following the plan: If you get sick or face special circumstances, proactively adjust that week’s schedule instead of forcing training just to “hit the numbers.”

Conclusion

The essence of periodized training is “applying the right stress at the right time.” It gives your body ample time to adapt, enough stimulus to keep progressing, and full preparation to perform at your best on race day. Think of your next preparation cycle as a piece of music: the base phase is the prelude, the build phase is the development, the peak phase is the climax, the taper is the resolution, and race day is your final bow.

Related Reading

• Half Marathon Training Periodization: Transitions Between Base, Build, and Race Phases
• The Complete Guide to Periodized Training: How to Scientifically Plan Your Annual Training Program
• Road Running Periodization Basics: Time Allocation Across Base, Build, Peak, and Recovery Phases
• Mileage Periodization: Stacking Base, Build, Peak, and Recovery Phases