Running Economy: The Real Secret Behind Endurance

Maximum Aerobic Endurance (MAE)

Maximum Aerobic Endurance (MAE) is often considered one of the hidden drivers of endurance performance because it determines how long a runner can sustain the highest possible percentage of their Maximum Aerobic Speed (MAS/VMA). While MAS (VMA) reflects the maximum power of your aerobic engine, MAE represents how efficiently you can convert that power into sustainable race pace over long distances.

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1. The Physiology Behind MAE

MAE sits within the critical aerobic-to-anaerobic transition zone.

The Aerobic Threshold

In physiological terms, MAE corresponds roughly to an exercise intensity where blood lactate concentration reaches around 2 mmol/L.

At this point, your body produces energy primarily through aerobic metabolism while keeping lactate accumulation low enough to avoid excessive fatigue.

The Sustainable Fraction of VO₂max

MAE reflects your ability to maintain a high percentage of your VO₂max for an extended period.

A well-trained marathon runner can typically sustain 80–85% of their MAS (VMA) throughout a marathon.

The higher your MAE, the faster you can run while remaining predominantly aerobic.

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2. One of the Most Trainable Performance Factors

One of MAE's greatest advantages is its enormous potential for improvement.

Significant Room for Progress

While VO₂max generally improves by only 15–20% through training, Maximum Aerobic Endurance can improve by as much as 45%.

This means many runners have far greater potential to improve endurance than aerobic capacity itself.

The Endurance Index (EI)

MAE can be evaluated using the Endurance Index (EI), which measures how quickly your running speed declines as exercise duration increases.

• An EI close to -2 indicates exceptional endurance.
• An EI around -12 reflects very poor endurance.

A stronger Endurance Index means you're able to preserve a higher percentage of your MAS over increasingly long efforts.

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3. How to Improve Maximum Aerobic Endurance

Building MAE requires more than simply accumulating easy mileage.

Training should target specific intensities that improve your ability to sustain high aerobic outputs.

Recommended Intensity

Most MAE workouts are performed between 80% and 90% of MAS (VMA).

This intensity provides enough physiological stress to improve endurance without generating excessive fatigue.

Workout Structure

MAE training typically consists of long intervals lasting:

• 10–20 minutes for most runners.
• Up to 30–40 minutes for experienced athletes.

These sustained efforts develop your capacity to maintain a high aerobic workload for extended periods.

Example Sessions

Typical MAE workouts include:

• 6 × 4 minutes at 80–85% MAS, with 75–120 seconds of easy jogging recovery.
• 3 × 10 minutes at 80–85% MAS, with short active recoveries.

These sessions teach your body to tolerate prolonged aerobic work while remaining below the level where fatigue rapidly accumulates.

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4. Why MAE Matters for Real-World Performance

Improving MAE effectively shifts your fatigue thresholds.

As your aerobic endurance increases, you can sustain a faster pace while expending the same amount of energy.

This is one of the biggest factors behind improvements in races such as the half marathon and marathon.

Rather than increasing your maximum speed, MAE allows you to maintain a greater percentage of your existing aerobic capacity for much longer, delaying fatigue and improving race performance.

Ultimately, that's what enables runners to set new personal bests over long distances.