How to Train for a Marathon PB

Understanding the physiology behind a faster time

VO₂ max describes the maximum rate at which the body can take up and use oxygen during exercise. It provides an important measure of aerobic capacity, but runners with similar values can produce different race performances. The proportion of that capacity they can sustain and the energy required to run at a given speed also matter. Bassett and Howley, 2000

Running economy describes the oxygen or energy cost of running at a submaximal speed. A runner with better economy needs less energy to maintain that speed. It reflects interacting metabolic, mechanical and neuromuscular factors. Barnes and Kilding, 2015

These distinctions make the training question more specific. A runner may have improved shorter-distance performance but still slow markedly late in a marathon. Another may pace consistently but lack the speed required for the next target. Prescribing more of the same training to both runners misses the difference between their performances.

Begin with the previous race and the block that led to it. Compare early and late splits, training consistency, long-run preparation and the fuelling used on the day. Weather and course profile belong in that review too. The aim is to identify a plausible priority for the next block, then monitor whether the change produces the intended response.

Building enough volume to support the target

Higher weekly running distance, greater training frequency and longer runs are associated with faster marathon performances. The relationship is consistent enough to make training volume an important consideration, but it remains an association rather than proof that a particular mileage increase will improve every runner. Doherty et al., 2020

For an experienced runner whose training is stable, increasing easy running can be a sensible starting point. The first question is where that additional work fits. Extending two shorter runs or adding a short easy day may distribute the workload more effectively than continually extending the longest run. The choice depends on the existing programme and the time the runner can protect for recovery.

The increase should remain in place long enough to assess it. If ordinary running begins to feel progressively harder, key sessions deteriorate or the runner repeatedly needs unplanned days off, the new workload needs review. A peak weekly total is useful only when considered alongside how often it can be completed and what happens afterwards.

We also look at the balance of effort. Research on distance-running programmes supports a substantial proportion of lower-intensity training alongside a smaller amount of threshold and higher-intensity work. Kenneally et al., 2018 Adding volume by turning easy days into moderately hard runs changes both the amount and intensity of training. Keeping easier sessions controlled preserves the intended distinction between them and the demanding sessions.

Threshold training and marathon-specific work

Blood lactate rises and changes its pattern as exercise intensity increases. Threshold assessment uses that response to identify physiological landmarks and inform training intensity. Different threshold methods describe different boundaries, which is why a fixed blood lactate value or a watch’s default zone should not automatically be treated as an individual threshold. Jamnick et al., 2020

In a marathon programme, controlled threshold work and marathon-pace work have different purposes. Threshold sessions develop sustained work at a higher intensity; marathon-pace sessions provide practice at the intended race demand. The session’s duration, recoveries and position in the week matter alongside the pace itself.

For a runner already accustomed to interval training, a session might contain three eight-minute efforts at an individually established intensity, separated by easy recovery running. A marathon-specific session might instead include two controlled blocks at the proposed race pace within a longer run. These examples show how session structure can change with its purpose. The appropriate amount follows the runner’s training history and response.

A faster target time should not be used to force every session faster immediately. Establish the workload the runner can currently complete, then progress it as performance improves. Repeatedly straining to hold the intended marathon pace early in a session is information about the target, not a reason to ignore the effort.

Sustaining performance as the run gets longer

Durability describes the onset and extent of changes in physiological characteristics during prolonged exercise. The capacity measured in a rested assessment can decline as exercise continues, altering what the same pace demands from the runner. Maunder et al., 2021

That gives long runs a clear role in a PB programme. They provide sustained exposure and an opportunity to observe how effort, pace and fuelling develop over time. Once the basic long-run duration is well established, selected sessions can include portions at marathon effort. Other long runs can remain easier so that the weekly programme remains manageable.

Review the later stages of those sessions in context. A rising heart rate alone does not identify the reason a run became difficult. Consider conditions, fluid and carbohydrate intake, perceived effort and the preceding training. Compare several relevant runs before treating one successful or unsuccessful session as a verdict on marathon fitness.

Fuelling should develop alongside this work. The intended race products and timings need to be usable at the intended effort. A long run in which pace and nutrition are both well controlled provides more useful preparation than a fast session that leaves the race fuelling question unanswered. The carbohydrate guide explains how to build that part of the plan.

Strength training and the energy cost of running

Strength training can improve running economy. A systematic review and meta-analysis found benefits from high-load and combined strength methods, with the response varying according to the training method and running speed examined. Llanos-Lagos et al., 2024

The aim is to add a useful stimulus without repeatedly compromising running. We recommend introducing unfamiliar strength work before the heaviest marathon weeks, allowing time to learn the movements and establish a manageable dose. As running demands increase, strength training should be coordinated with the key sessions rather than added wherever there is an empty space in the diary.

Exercise selection and loading should reflect the runner’s experience and assessment findings. Heavy resistance work requires preparation in the relevant movements and gradual progression towards the intended loads. Exercise execution and recovery over the following days help determine when that progression is appropriate.

At DVOTION, movement and force assessments can inform those coaching decisions. They do not directly measure running economy, which requires an appropriate submaximal gas-analysis protocol. Keeping that distinction clear allows each assessment to answer the question it is designed to address.

Converting the training into a race performance

A PB target becomes more credible when several sources of information agree: recent race performance, consistent training and longer sessions at an appropriate effort. Laboratory findings can clarify aerobic capacity and training intensity, while the training block shows how those qualities translate into running outdoors. Our marathon testing article explains the relationship between those measurements and race preparation.

Use that evidence to settle the target before the final taper. The pacing plan should describe an opening effort that can be controlled and an adjustment for conditions that make the original target less appropriate. The taper should provide room to recover from the work already completed.

The next PB is pursued through the accumulated effect of the programme. The important changes are those that make the intended pace more sustainable, improve the runner’s ability to maintain it and allow those gains to be expressed on race day.