Marathon Training Blocks With Readiness Checks

A marathon build works best as three blocks with different jobs: base, specific, and taper. Each block has a fixed purpose and a fixed long-run pattern, and readiness decides how much of each individual session you run. The block structure keeps you honest about progression; the readiness layer keeps the peak weeks survivable.

Why blocks instead of a single 18-week plan

A single continuous plan asks every week to do everything: build volume, sharpen speed, rehearse race pace, and stay fresh. Blocks separate those jobs so each gets a clear window, which makes it obvious what to cut when a week goes badly.

Blocks also make progression measurable. In the base block you are watching weekly volume and long-run duration. In the specific block you are watching how much marathon-pace running you can hold late in a long run. In the taper you are watching nothing except whether you are staying rested. Three different questions, three different sets of evidence.

Block 1: base, weeks 1 to 8

Purpose: raise weekly volume, extend the long run, and build a threshold that makes marathon pace feel comfortably sub-threshold.

• Weekly structure: 5 to 6 runs, two quality sessions, one long run
• Quality 1: threshold work. 4 x 8 min at threshold pace with 2 min jog, progressing to 2 x 15 min or 25 min continuous
• Quality 2: aerobic support. Progression run of 50 to 70 min finishing at marathon pace, or a hill circuit of 8 to 10 x 60 s uphill
• Long run: 90 min rising to 130 min, entirely easy for the first four weeks
• Everything else easy, with 6 x 20 s hill sprints twice a week

Volume progression is the whole point of this block, and it is where builds are most often ruined. Nielsen and colleagues (2014) followed 874 novice runners for a year and found those who progressed weekly distance by more than 30 percent across a two-week period had a higher rate of distance-related injuries such as patellofemoral pain, iliotibial band syndrome, and medial tibial stress syndrome than those progressing by less than 10 percent.

Gabbett (2016) adds the other half of the picture: high chronic loads reached gradually appear protective, and reductions in workload are not always the safest response. The instruction that follows from both is simple. Raise volume in small steps, hold each step for a week, and reduce every fourth week by 20 to 30 percent.

Intensity distribution stays conservative here. Seiler (2010) found that competitive endurance athletes converge on roughly 80 percent of sessions at low intensity, with about 20 percent dominated by high-intensity work and little time spent at threshold. In a six-run week, that is two quality sessions and four easy runs.

Block 2: specific, weeks 9 to 15

Purpose: make marathon pace durable when you are already tired, and rehearse fueling.

• Weekly structure: 5 to 6 runs, one threshold session, one long run containing race pace
• Quality 1: threshold maintenance. 3 x 10 min at threshold with 2 min jog, once per week, kept short
• Long run: 130 to 165 min with progressively more marathon-pace work in the final half
• Midweek medium-long run: 75 to 95 min easy, the session that most distinguishes a serious marathon build
• Tune-up race: one half marathon or 10 mile race, 4 to 6 weeks out

The long-run progression is the block's engine:

Fuel every one of these as you intend to race: 45 to 75 g of carbohydrate per hour after the first 45 minutes, using the exact products and the same timing. Gut tolerance is trainable and race-day gastrointestinal failure is usually a training omission rather than bad luck.

Block 3: taper, final 14 to 18 days

Purpose: arrive rested without losing sharpness.

• Reduce weekly volume by roughly 30 percent in the first taper week and 50 percent in race week
• Keep two short sessions with race-pace content: for example 5 x 1 km at marathon pace eight days out, and 4 x 800 m at marathon pace four days out
• Last longer run 10 to 12 days out, at 90 to 100 min with 20 min at marathon pace
• Final three days: 30 min easy, 25 min easy with 4 x 200 m, then rest or 20 min shakeout

The taper is deliberately fixed, and this is the block where readiness data should be ignored. Volume drops, so HRV rises and resting heart rate falls, and those changes reflect reduced load rather than an invitation to add work. Runners who adapt their taper upward on the basis of good readiness scores arrive at the start line having trained through the one period designed to make them fresh.

The readiness layer, block by block

Readiness resizes sessions. It does not change what block you are in.

Three constraints keep this coherent:

1. Never reduce the long run in two consecutive weeks unless you are ill or injured. Long-run frequency drives the block.
2. Never move a long run next to a quality session as a result of rescheduling.
3. If three consecutive weeks are yellow or red, the plan is too ambitious. Cut peak weekly volume by 15 percent and continue rather than repeatedly failing the same week.

Foster (1998) supplies the underlying logic for the third rule. In 25 experienced athletes, illness clustered when individuals exceeded personal thresholds calculated from session load, monotony, and strain. A plan that generates repeated yellow and red days is producing strain you are not converting into fitness.

Vitadel Run applies this layer automatically: the block structure comes from your plan, and each day's session is resized against a readiness score built from sleep, HRV, and recovery data.

Weekly volume shape across the build

Peak weekly volume depends on history, not ambition. A runner whose highest previous week is 55 km should peak near 70 to 75 km, not 100.

Signals to change the plan rather than the session

• Easy pace at a fixed heart rate has slowed across three weeks with no volume increase.
• The marathon-pace block inside long runs is drifting slower week over week at the same effort.
• Resting heart rate 7-day average is more than 4 beats above your 4-week average for a week.
• Sleep 7-day average has dropped by an hour or more during peak weeks.
• Any localized pain that changes your gait, which outranks every other signal here.

The first four call for a reduced week and a lower peak. The last calls for a diagnosis before another long run.

Setting a goal pace you can defend

Derive goal marathon pace from the tune-up race, not from ambition or from a 5K time. A half marathon result four to six weeks out, adjusted by roughly 5 to 6 percent slower per kilometre, gives a defensible starting point for a runner with adequate long-run volume. Runners with lower weekly volume should expect a larger adjustment, because marathon pace decays with insufficient aerobic durability regardless of shorter-distance speed.

Then test it in training. If 50 minutes at goal pace at the end of a 155-minute long run is controlled and repeatable, the pace is real. If that block is a survival effort, the pace is aspirational and race day will make that clear at 30 km.