When I heard about double threshold training, I thought it was a crazy method that could only be handled by the most intense athletes. I saw Jakob Ingebrigtsen’s training details and realized he was doing very high mileage with five workouts a week! Then I started to learn more about the method and implement it within my own training. I was surprised by how easy it actually is if done correctly. Throughout high school and early college, I was used to classic hard workouts that felt like an 8/10 effort. These double threshold sessions often felt closer to a 5/10 effort, but that’s the beauty of it.
The biggest challenge for athletes doing this training correctly is staying controlled and trusting the long-term development it brings. The athlete’s ego has to go away, and the long-term adaptations will come from controlled training.
What are threshold, double threshold, and the Norwegian method?
Threshold terminology can be confusing because there is an array of definitions and contradictions. I like the explanation that there are two distinct threshold points: LT1 and LT2. The first lactate threshold, LT1, marks an initial sustained rise in blood lactate above baseline. The second, LT2, marks a higher-intensity turnpoint. They are individual physiological markers; neither is defined by one universal lactate number. When doing threshold sessions, you run at a controlled workout pace that correlates with one of these targets.
Double threshold training and the Norwegian method are heavily tied together and mean relatively the same thing. With double threshold, instead of doing one workout a day, you split it up into two shorter sessions. The “classic” approach is doing longer interval repetitions in the morning and doing shorter repetitions in the afternoon. It’s stated that the approach should just be one long workout with a break in between.
The background that shaped the approach
My approach has been heavily influenced by Marius Bakken, who shaped the Norwegian approach through years of experimentation throughout his own running career. Born in Norway, he received early guidance from Olympian Per Halle before spending a year at York High School in Illinois. There, coach Joe Newton exposed him to high mileage and aerobic development influenced by Arthur Lydiard (a legendary New Zealand coach who influenced Bill Bowerman’s training approach). Through Newton, he met Peter Coe, the father and coach of Sebastian Coe (1:41 in the 800m), who introduced him to short double threshold sessions.
Bakken later attended Indiana University, training under Sam Bell and alongside Bob Kennedy. When he went back to Norway, he worked with physiologist Frank Evertsen and helped him develop systematic lactate testing. He went on to compete in two Olympics and ran 13:06 in the 5000m.
What changed in my own training
In high school and college, I cared about leading workouts and impressing myself with splits. I was doing what was prescribed, but oftentimes coaches push their athletes too hard to get the most out of them. This just isn’t the best long-term approach and fails to develop the lactate threshold.
I wanted to try something new, so during summer 2025, I used two double threshold days each week, plus an “X” session that might include 200-meter hills or faster track work. I built a much stronger aerobic foundation, and in the following winter and spring seasons, my mile improved from 4:10 to 4:03.
However, during that season, I was unable to keep up the threshold work, and I felt increasingly dependent on speed and less supported by the strength I had developed over the summer. I did not run another personal best after April.
Why going harder can miss the purpose
That’s not to say hard training doesn’t have its place. It definitely does, and for some athletes, doing very hard sessions is very beneficial. As I see threshold training gaining traction, I see close to all programs and athletes doing it incorrectly. They treat it as two hard workouts, not two true threshold workouts. It is important when taking on this training to maintain control. It will seem counterintuitive, but the benefits are massive.
This training also felt counterintuitive to me. I had associated a successful workout with being exhausted. Now I want to finish smoothly, in control, and capable of more. I have seen the pace I associate with LT1 move from about 5:50 to 5:15 per mile. Keeping my lactate within the zone is what I care about now, not the pace of the session.
What my double threshold days looked like
One example from my summer training was:
- Morning: 10 × 3 minutes at about 5:40 per mile, with 60 seconds of recovery.
- Afternoon: 12 × 400 meters in 72 seconds, with 45 seconds of recovery.
I had a preseason test to establish starting points, but I was not taking lactate measurements during those summer sessions. I was estimating the effort from that baseline, telling myself to go easier than I thought threshold effort should feel.
How to keep the effort controlled
For a runner serious about this approach, a lactate meter is a worthwhile investment. It gives you information you otherwise have to estimate. The number keeps you honest during training.
Without a meter, combine perceived effort, breathing or a talk test, and heart rate. For me, I know I am in the LT1 zone when my heart rate is between 165 and 175, I can say a sentence, and the effort is a 5–6/10.
Train to train
Being skeptical of this training method is normal because of how easy it is compared to other training methods when done correctly. Talking to other athletes and watching them make huge leaps with this training helps me keep trusting it.
Save your all-out efforts for a race. That is the true test. Working harder is not better. The discipline is trusting the work when you know you could run faster. Train to train.
Carson is a coach with Team RunRun, to learn more about him or to work with him, check out his coach profile.