Double threshold: two hard sessions in one day without wrecking your recovery

Why two sessions instead of one long one

This article explores one part of the method in depth. For the full system and its adaptation, read our guide to the Norwegian method.

The value of threshold training comes from time spent in the target range: more minutes just below the second lactate threshold mean a greater training stimulus. A single prolonged threshold session eventually hits a ceiling. After 40–50 minutes, quality declines: pace is sustained by willpower, lactate climbs and recovery becomes more expensive.

Splitting the day into two sessions addresses this. A 5–7-hour gap allows time for food and sleep, glycogen is partially replenished, and another 20–30 minutes of high-quality threshold work becomes possible in the evening. The result can be up to an hour near threshold without a single all-out repetition. That is why Marius Bakken, followed by the Ingebrigtsens and triathletes Blummenfelt and Iden, made double threshold a central part of the training week.

Elite protocols

Morning: long intervals. A classic Ingebrigtsen session is 5–6 × 2000 m with about one minute of recovery. Pace is slightly slower than 10 km race pace, target lactate is 2.3–3.0 mmol/L, and measurements are taken after every repetition. If lactate rises above the target range, pace is reduced or the session is stopped. Another threshold day is coming tomorrow, so overshooting today is more costly than doing slightly too little.

Evening: short intervals. For example, 25 × 400 m with 30-second recoveries or 10–12 × 1000 m. Short repetitions with brief recoveries make it easier to keep heart rate and lactate in range than long repetitions: intensity rises in steps rather than drifting upward unchecked. Triathletes apply the same principle across disciplines, with threshold cycling in the morning to reduce impact on the legs and threshold running in the evening.

Three mistakes when copying the method

• Running too fast. An amateur’s perceived threshold is often 10–15 seconds/km faster than their true threshold. Lactate rises above 4 mmol/L, recovery takes two days and the structure falls apart. Use a pace you could race for about an hour as a reference, then make the training pace slightly more conservative.
• Doing it too often. Professionals may complete two or three double-threshold days per week after years of adaptation. An amateur scheduling two double days back to back is more likely to be injured than training by Friday.
• Ignoring poor sleep and life stress. Double threshold is for a well-recovered athlete. Suppressed HRV and inadequate sleep turn controlled work into accumulating fatigue. Reduce the planned load before your legs force the issue.

How amateur athletes can adapt it

The foundation is one threshold day per week: 4–6 × 1000–2000 m at a controlled pace. This already provides the method’s main benefit: regular threshold work without excessive fatigue.

An advanced option, for athletes with 3+ years of consistent training, 60+ km per week and stable sleep, is one double-threshold day every 7–14 days. Use long intervals in the morning and short intervals in the evening, not immediately before or after a long run. If evening heart rate is 5+ bpm above normal at the same pace, end the session: your body has already given you the answer.

A sample amateur double-threshold day

• Morning — 2 km warm-up, 4 × 1600 m at threshold pace with 60 seconds of recovery, then a 2 km cool-down.
• Between sessions — a normal day with carbohydrate-containing meals, a 30–60-minute nap if possible and time off your feet.
• Evening — 2 km warm-up, 12 × 400 m at the same pace or slightly faster with 30 seconds of recovery, then a 2 km cool-down.
• The following day — easy training only: 30–40 minutes in zone 1 or complete rest.

Control without a lactate meter

Amateur athletes can use three tools instead. Heart rate should sit near the top of zone 4 without climbing towards maximum by the end of each repetition. Benchmark repetitions of the same distance from week to week reveal progress more honestly than a single watch estimate. Morning HRV and resting heart rate then show whether the previous day’s recovery cost was reasonable.

SkolCoach automates this feedback loop. It analyses every interval session repetition by repetition, compares it with previous sessions and reviews recovery the following morning. If a double day proves unusually costly, your coach proposes a data-backed plan adjustment before fatigue develops into a performance plateau.

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