The aerobic engine: Why today’s trendy training systems aren’t as new as you think

To quote Robert Johnson of Let’s Run at www.letsrun.com, “The average runner does not run enough. They also do not sleep enough. Focus on that – not weights,” this is correct and not a revelation.

He appears to have written the article advising those who believe that lifting weights is important for a distance runner’s performance.

It is debatable at best.

Johnson cited Marius Bakken and John Kellogg, two well-known coaches who have performance records that stand up against almost any coach in the world.

Johnson wrote, “Marius Bakken agrees.”

“I’m not the only one who thinks that strength work is vastly overrated. Marius Bakken – the former Illinois state champion and two-time Olympian who brought double threshold training to the masses and whose system is used by Jakob Ingebrigtsen – agrees as well. In his new book, the Norwegian Method Applied, chapter 10 talks a lot about weights and the negative impact they can have.”

Bakken wrote in his book, “Strength training comes with hidden costs that rarely get discussed … Runners become consumed by everything surrounding training rather than the training itself. They convince themselves that intelligent programming is not enough, that they need strength circuits, stretching routines, foam rolling protocols, and recovery gadgets. The list grows. The focus scatters. I understand the impulse. These rituals feel like diligence. They create the satisfying sense that you are leaving nothing to chance. I have fallen into that trap myself, more than once. The lesson took years to fully absorb.”

The article asks, “Why so many coaches prescribe extensive weight protocols? Because it makes them feel important.”

This may seem harsh, but not an untrue indictment. In fact, the ego often gets in the way of the best-laid training plans.

Have you noticed training groups at various levels and their weekly meet-ups? Every week, 52 weeks of the year, they meet for a road or track session. Often, the emphasis is on going harder, faster, digging deeper and competing against teammates or one’s own best times. Meanwhile, overall volume is typically lower.

The coach feels that the athlete needs to feel as though there is deep thought going into the session, and the meeting of fellow athletes keeps them socially entertained – makes them feel as though they are part of a team. However, relentless pursuit of so-called speed in weekly anaerobic sessions causes injury and cannibalization of the aerobic engine’s mitochondria, which otherwise does over 90 percent of the work in a race.

Let’s Run often reports on and its chat forum contributors talk about the currently trendy Norwegian double-threshold system of training.

The Norwegian double-threshold system, as described by Marius Bakken and later employed and refined by Gert Ingebrigtsen with his sons, is fundamentally a method of accumulating a large amount of aerobic work at or just below lactate threshold while carefully avoiding excessive fatigue.

Interestingly, the Arthur Lydiard method of training was developed during the 1950s and evolved slightly, but never strayed far from the overarching premise. Note the similarities to the training weeks of a base period to the Norwegian double threshold method. Lydiard was clear that running volume is preferably built by running singles, rather than splitting runs. At the same time, he was good with the notion of extra running done at easy efforts (doubles and triples):

Typical Lydiard base week schedule

During the aerobic base period, the Lydiard method allows easy additional mileage on soft surfaces in a nearly unlimited way. His sessions above did not include easy warm-up and warm-down running volumes. While 160-plus kms per week is ideal, for non-elite runners, going by time rather than volume is sensible.

Whereas, the central idea of the Norwegian double-threshold system is similar: Run more kilometres at threshold pace than traditional training allows, but divide the work into two sessions on the same day. The basic structure. A typical week described by Bakken and associated with the Ingebrigtsens looks something like this:

The famous feature is on Tuesday and Thursday by all three methods.

Norwegian
Morning: Longer repetitions. Slightly lower intensity.
Evening: Shorter repetitions. Slightly faster pace.

Lydiard
Morning is easy, shorter.
Evening, 90 minutes at a strong effort.

The Norwegian sessions are usually separated by six to eight hours.

Lactate control is perhaps the most important aspect, not the doubles themselves. Bakken repeatedly emphasizes that the real secret is intensity control. Athletes frequently measure blood lactate during sessions, attempting to remain approximately 2.0–2.5 mmol/L in easier threshold work. 3.0–4.0 mmol/L in harder threshold work. The goal is to stay below the point where lactate rises sharply, and muscular fatigue becomes difficult to recover from.

Example sessions

A classic Tuesday might look something like:

Morning: 5 × 2,000 m 60–90 seconds recovery.
Evening: 10 × 1,000 m 60 seconds recovery. Or: Morning: 6 × 6 minutes.
Evening: 20 × 400 m The evening session is usually faster but still controlled.

Neither workout is meant to become a race. Why repetitions rather than tempo runs? Both the Bakken and the Ingebrigtsen systems favour repetitions over continuous tempo runs. Instead of: 40 minutes continuously at threshold, they prefer: 10 × 4 minutes, 5 × 2 km, 8 × 1 km, with short recoveries. The short recoveries allow: more total volume, faster speeds, lower lactate, and less muscular damage.

This permits the athlete to return for the second workout later the same day.

Gert Ingebrigtsen’s contribution

Gert Ingebrigtsen has publicly stated that the training system used with his sons was his own development. In recent years, he has argued that it was not directly derived from Bakken’s work.

Bakken disagrees, pointing to substantial similarities in structure and methodology. Regardless of the debate, the commonly observed characteristics of the Ingebrigtsen training include: Two threshold days per week. Morning and evening threshold sessions. Extensive lactate testing. Good mileage (often 160–190 km per week).

One faster session involving hills, speed, or VO₂ max work. Easy days that are genuinely easy. Those characteristics align closely with Bakken’s earlier descriptions of the Norwegian model. And the basic premise is borrowed intentionally or not from Lydiard. A sample Ingebrigtsen-style week might be:

The key principles of Bakken’s description boil down to several rules: Train near threshold often. Stay below the red line. Control intensity objectively. Break workouts into repetitions. Cluster hard work on hard days. Make easy days truly easy. Accumulate years of consistent training.

He has written that the goal is to raise the speed that an athlete can sustain at their second lactate threshold rather than constantly chasing higher VO₂ max numbers. One of Bakken’s most concise descriptions is: Two controlled threshold sessions on the same day to accumulate more threshold work without any single session becoming too large.

You need to be in shape to be in shape

For most recreational runners, coaches such as Bakken — and many others influenced by the system — caution that double‑threshold training is appropriate only after years of high‑volume work and the development of a substantial aerobic base.

By contrast, Lydiard’s method introduces steady, threshold‑like running but only in the latter stages of the base period. The system also incorporates repetitions, but strictly as fartlek done by feel rather than structured sessions. Lydiard championed time‑based running over distance‑based prescriptions, a shift he adopted after early success with Olympic medals and world records. He went on to serve as national coach for five countries and helped pioneer what is now standard endurance training practice among East Africans and many of the world’s best athletes.

Although influenced by figures such as Jack Dolan and Emil Zatopek, Lydiard ultimately arrived at his method through self‑experimentation — at times running more than 300 miles per week, which he deemed excessive, and at other times testing low‑volume approaches, which he found insufficient. His conclusions formed the foundation of the system illustrated in greater depth here.

Each era seems to bring to the fore a popular method that borrowed from a coach who came before, such as Lydiard, Percy Cerruty, among others.