Double Threshold Training: How it Works and 5 Single-Session Alternatives

# What double threshold training is Double threshold training means running two threshold interval sessions in one day: a morning block and an afternoon block, usually separated by 4 to 6 hours. Coaches who use the Norwegian-style model control intensity with blood-lactate testing and aim to keep lactate roughly between 2 and 4.5 mmol/L during threshold work.

# Why coaches use it

# What elite double-threshold days look like Elites typically place different rep formats in each session so the two blocks complement each other:

• Morning: longer threshold reps such as 5 × 6 minutes or 5 × 2 km, run at the lower end of threshold (around 2–3 mmol/L), with about 60 seconds recovery.
• Afternoon: shorter threshold reps such as 10 × 1,000 m or 20–25 × 400 m, run at the upper end of threshold (around 3–4 mmol/L), with 30–60 seconds recovery.

Those sessions sit on top of very high weekly mileage (about 150–180 km per week in the Norwegian review) and are often scheduled twice per week.

# Why this isn't practical for many runners

# How to get the same benefit in one session You can get the threshold-splitting advantage—more usable minutes at threshold with lower drift—by structuring a single workout to mimic split blocks. Examples include tempo-interval formats that break the work into separate efforts with short easy jogs between them.

Practical single-session structures recommended:

• 2 × 3 miles with 3–4 minutes easy jog between. Matches the physiological effect of split threshold while fitting a single training window.
• Tempo intervals that break total tempo time into multiple blocks (e.g., 3 × 10 minutes with short recoveries) instead of one continuous tempo run.
• Combo workouts where threshold blocks are followed by a small number of 5K-pace reps to train running fast on tired legs. These compress the elite morning/afternoon objectives into one session.

# A 12-week progression Build gradually: start by splitting your current tempo run into two shorter blocks within a session. In weeks 5–8 add more threshold volume. In weeks 9–12 introduce short faster reps after threshold blocks (combo workouts) to develop speed on fatigue. The article presents this sequence so you gain volume and specific adaptation without jumping straight into two-a-day sessions.

# Practical takeaway for everyday runners You don't need two full training windows to get the main physiological benefit of double threshold training. Use split-style tempo intervals and progressive buildup across several weeks. Reserve true two-a-day threshold days for when your schedule, recovery, and weekly mileage match the elite context described in the Norwegian model.