Peaking for Races: Six Weeks to Your Best Form

Most endurance athletes train for months towards a goal and still arrive on race day short of their best. The reason is rarely total training volume — it is the last six weeks. Peaking is the craft of placing the fitness you already have on one specific day. Approach that block without a plan and you arrive either tired or flat, leaving five to eight percent on the table that was built weeks earlier.

Peaking, tapering, periodisation — what is the difference

The three terms get mixed up constantly, but they describe three different levels. Periodisation is the whole arc of a season: base, build, peak, transition — several months, often with multiple target races. Peaking is the final phase of that arc, where load is deliberately shaped towards the goal: six to eight weeks in which volume and specificity shift so that form reaches its maximum at the right moment. Tapering is the end of the peaking block — the 10 to 14 days where volume drops by 40 to 60 percent while intensity stays.

The practical consequence: tapering can only work if the peak block before it did the right work. Two quiet weeks do not create fitness, they merely uncover what is already there. And a peak block without race-specific sessions leaves you fresh but unspecific — something you feel in the second half of the race. Where the races themselves sit in the calendar is covered in race season planning.

How long the block lasts — and what changes it

For marathon, half marathon and gran fondo, six to eight weeks is standard. Length depends on three factors:

• Race distance: a 10K needs four to five weeks of specific work, a marathon eight. The longer the race effort, the more time the body needs to adapt to exactly that load.
• Starting level: someone already running 60 to 80 kilometres a week can become specific faster than someone at 35. With a lower base, a longer block makes sense — but with more base work inside it.
• Experience with the format: a first marathon needs room for long runs and fuelling practice; the fifth needs the shorter version.

A common mistake is the over-long peak: ten weeks of nothing but race pace erodes the aerobic base that carries that pace. Six weeks with a clear progression beat ten weeks of steady distribution almost every time. How load is built across weeks is explained in periodisation.

The six weeks in detail

A peak block splits into three two-week blocks, each with a different job:

• Weeks 1–2 — hold volume, introduce specificity: total volume stays at build-phase level, but the share of race-specific work rises from roughly 15 to 30 percent. For a marathon that means marathon-pace segments inside the long run; for a gran fondo, longer blocks at target power.
• Weeks 3–4 — highest specific load: everything now points at race pace. Two quality sessions per week plus the longest specific session of the block — for a marathon, 30 to 35 kilometres with 15 to 20 at goal pace. Total volume drops 10 to 15 percent because intensity rises.
• Weeks 5–6 — sharpen and taper: volume falls clearly, intensity stays in short precise doses. Week 6 is where the official taper begins with a 40 to 60 percent volume reduction.

Direction matters more than absolute numbers: the block does not get harder week by week, it gets more specific. The heaviest week is typically week 3 or 4 — never week 5. Put the last hard session ten days out and you import fatigue exactly where it costs most.

TSB as a steering tool: what value matters on race day

Form is not a feeling, it is a number — at least approximately. The Banister model separates fitness (CTL, decays slowly) from fatigue (ATL, decays fast); the difference is TSB (Training Stress Balance). Positive TSB means fatigue has fallen away faster than fitness: you are fresh. Negative TSB means you carry residual fatigue.

Race-day corridors that hold up in practice:

• Marathon and gran fondo: plus 5 to plus 20 TSB. Within this window fatigue is largely gone while fitness is fully intact.
• Half marathon and 10K: plus 10 to plus 25. Shorter races tolerate more freshness because neuromuscular sharpness matters more than durability.
• Olympic-distance triathlon and shorter: plus 5 to plus 15, with emphasis on short fast touches during race week.
• Warning zone: above plus 25 you are detraining, below minus 5 you start carrying fatigue.

TSB is a corridor, not a precision instrument. Raise CTL from 70 to 85 during the peak and taper for two weeks, and you land in the target range almost automatically. The maths behind CTL, ATL and TSB is explained in CTL, ATL and TSB.

Race-specific work: what "specific" actually means

Specificity is the heart of peaking — and where most plans stay vague. "Race-specific" does not mean "run fast", it means reproducing the load the race actually imposes:

• Intensity: marathon pace, not 10K pace. Peak with intervals only and you have trained for a different race.
• Duration: segments of 15 to 25 kilometres at goal pace inside a longer session — not 5 × 3 minutes.
• Terrain: a hilly marathon needs hills in the peak, a flat one needs flat. Hills in training that are missing on race day cost you late in the race.
• Fuelling: gels, drinks and on-course nutrition get tested now, not during the race. Practise 60 to 80 grams of carbohydrate per hour in the peak and your stomach will not revolt. Details in our fuelling article.
• Gear: race shoes, kit, cycling shoes — everything worn on race day gets worn in at least two sessions first.

A practical test for specificity: if you cannot state after the block which pace, which terrain and which fuelling the race demands, the block was not specific. For the race week itself, the race day checklist covers the logistics.

Six weeks, three sports: peaking for triathlon

In triathlon, peaking is more complex because three disciplines need to peak at once — and swimming, cycling and running respond to training at different rates. A staggered approach works well:

• Swimming: hold technique and short fast sets. Swim volume barely drops during the peak because water does not load the musculoskeletal system and technique needs frequent short stimuli.
• Cycling: the longest ride sits four to five weeks out; after that it is replaced by shorter sessions with race-pace blocks.
• Running: the last long run with race-pace content happens 14 to 18 days before the start — not later. Running leaves the longest-lasting fatigue.

Add one or two brick sessions during the block (bike plus short run) to sharpen the leg-turnover feeling. More than that adds no adaptation, only fatigue. The full structure of triathlon preparation is in the triathlon training plan for beginners.

What the peak costs — and what it returns

Realistically, a well-executed peak with taper returns three to five percent performance compared with an identical build without form management. At a 3:30 marathon that is five to ten minutes; over a four-hour gran fondo, proportionally more. That is more than most athletes gain from four extra weeks of training.

The price is a modest fitness loss: CTL drops five to fifteen points during the taper. That is intended, not regrettable. The craft lies in limiting the decline — which is exactly why short intensity touches stay in the plan. Strip all intensity from the taper and you lose not only fatigue but also neuromuscular tension, arriving flat on the start line. This effect, commonly called the taper blues, is purely psychological and no reason to change the plan.

Common mistakes in the peak block

• Testing too much that is new. The peak is no laboratory. New shoes, new gels, a new bike position — anything added in the last six weeks is risk without benefit.
• Placing the last hard session too late. A long run with race pace eight days before the marathon is imported fatigue. The last genuinely demanding stimulus belongs 14 to 18 days out.
• Stopping strength work abruptly. Two short, easy strength sessions per week (trunk, calves, glutes) maintain tension and cost little recovery. Only race week drops strength entirely.
• Neglecting sleep. Adaptation happens in sleep — more so in the peak, because intensity and specificity are high. Under seven hours a night makes the block ineffective.
• Too much control, too little trust. Checking HRV, resting heart rate and TSB daily and rebuilding the plan on every deviation creates stress instead of form. A weekly review is enough.
• Peaking for B and C races. Only the A race gets the full block. B races are run out of training, C races are training stimuli.

Example: the last six weeks before a marathon

Starting from 70 kilometres per week and a goal pace of 4:50 min/km — a realistic structure, not a template to copy:

• Week 1 (70 km): long run 28 km with 8 km at goal pace at the end. One tempo session 3 × 3 km at half marathon pace.
• Week 2 (72 km): long run 30 km with 12 km at goal pace. Tempo session 4 × 2 km at marathon pace.
• Week 3 (68 km): long run 32 km with 15 km at goal pace — the key session of the block. Plus 5 × 1 km at half marathon pace.
• Week 4 (58 km): long run 24 km with 12 km at goal pace. One session 6 × 800 m at 10K pace for sharpness.
• Week 5 (42 km): taper begins. Long run 16 km with 6 km at goal pace, one short quality session 4 × 1 km.
• Week 6 (25 km): race week. Two easy runs, 3 × 1 min at goal pace as openers, race day.

On this trajectory TSB lands around plus 12 on race day — squarely inside the target corridor. Push volume higher in week 3 and you will not be fresh in week 6.

How Peakora plans the peak

In the Peakora engine, peaking is not manual arithmetic: from your A race, current CTL and race distance the engine builds the block backwards, aligning volume, specificity and taper. The recovery monitor shows daily where your TSB sits and whether you are inside the race-day corridor — including a warning when the planned load would push you too far negative or too far into over-freshness. Adjustments happen moderately and with confirmation, never as a silent rebuild of the plan.

Frequently asked questions about peaking

How long should a peaking block last?

The peak block starts six to eight weeks before your A race, with the final 10 to 14 days being the taper. During the block, race-specific intensity increases while volume stays stable until the very end.

What TSB should I aim for on race day?

For marathon, half marathon and gran fondo, aim for plus 5 to plus 20 TSB. Above plus 25 you have rested away fitness, below minus 5 you start with residual fatigue. Shorter races tolerate the upper end of that range.

Is peaking the same as tapering?

No. Tapering is only the final part of peaking: cutting volume by 40 to 60 percent while keeping intensity in the last 10 to 14 days. The peak block itself covers six to eight weeks of shifting training towards race specificity.

Can I peak more than once in a season?

Yes — two or three A races per year are realistic if they are at least eight to twelve weeks apart. Between peaks you need a maintenance phase with reduced volume, not a second full build.

How do I know the peak block is working?

Three signs: TSB rises steadily, a race-pace test feels easier at the same pace, and resting heart rate is stable or slightly lower. If test performance drops clearly, the block is too hard.