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MAS Running Intervals (2026): The Complete Guide to Maximum Aerobic Speed Training
- Greg Dea
- Mar 5
- 5 min read
Interval running is one of the most effective ways to improve aerobic fitness, running speed, and endurance. One of the most precise methods used by coaches and athletes is Maximum Aerobic Speed (MAS) training.
MAS running intervals prescribe training intensities based on an athlete’s individual aerobic capacity. This allows every athlete to train at the correct physiological intensity rather than guessing pace or following generic interval programs.
In this guide you’ll learn how MAS running intervals work, how to calculate your MAS, and how to structure MAS workouts.
What Is Running Interval Training?
Running interval training involves alternating periods of faster running with periods of recovery. These workouts are widely used to improve aerobic fitness, endurance, and running speed. While traditional interval training often prescribes fixed distances such as 400m repeats, MAS running intervals use Maximum Aerobic Speed (MAS) to prescribe training intensities relative to an athlete’s fitness level.
What Are MAS Running Intervals?
MAS running intervals are structured running workouts performed at percentages of an athlete’s Maximum Aerobic Speed.
Maximum Aerobic Speed is the running speed associated with maximal aerobic capacity. Once MAS is known, training intensities can be prescribed relative to that speed.
This means two athletes with different fitness levels can perform the same workout structure, but at different running speeds.
MAS training is widely used in:
football codes
court sports
endurance sports
high-performance conditioning programs
Because MAS intervals are based on physiology rather than arbitrary distances, they provide highly targeted training adaptations.
How to Calculate Your MAS
Before performing MAS running intervals, you first need to determine your Maximum Aerobic Speed.
The simplest way to do this is the 5-minute MAS test.
Step 1 – Warm Up
Complete a 10–15 minute warm-up including light jogging and mobility exercises.
Step 2 – Run for 5 Minutes
Run as far as possible for 5 minutes at a consistent maximal effort.
Step 3 – Record Distance
Record the total distance covered in metres.
Step 4 – Calculate MAS
Enter your distance into the MAS calculator to determine your MAS and training targets.
MAS Training Intensities
Once MAS is known, running workouts can be prescribed using percentages of MAS.
Different intensity ranges target different conditioning adaptations.
Training Adaptation | Intensity |
Aerobic capacity | 85–95% MAS |
Aerobic power | 95–100% MAS |
High-intensity aerobic | 100–110% MAS |
Speed endurance | 115–130% MAS |
Using MAS ensures athletes train at the correct intensity for their current fitness level.
Examples of MAS Running Intervals
There are many ways to structure MAS interval training. Below are several common formats used in conditioning programs.
Long MAS Intervals
Long intervals develop aerobic power and running economy.
Example session:
3 minutes @ 95% MAS, then 3 minutes @ 45% MAS recovery
Repeat x3These sessions are ideal early in a training program to develop aerobic capacity.
Rectangle Intervals
Rectangle intervals alternate between higher intensity running and controlled aerobic recovery.
Example session:
15 seconds @ 103% MAS then 15 seconds @ 70% MAS
Repeat continuouslyThese sessions develop aerobic power while maintaining running rhythm.
Eurofit Intervals
Eurofit intervals develop repeat high-speed running ability.
Example session:
15 seconds @ 120% MAS then 15 seconds rest
Repeat continuouslyThe passive recovery increases intensity and places greater demand on anaerobic capacity.
Tabata MAS Intervals
Tabata intervals are extremely intense sessions used later in conditioning programs.
Example session:
20 seconds @ 120% MAS then 10 seconds rest
Repeat continuouslyThese workouts improve high-intensity running tolerance and repeat sprint ability.
Running Interval Training vs MAS Intervals
Running interval training typically involves alternating periods of faster running with periods of recovery. Many traditional interval programs prescribe fixed distances such as 400m or 800m repeats.
While this approach can improve fitness, it does not account for differences in an athlete’s aerobic capacity. Two athletes performing the same interval workout may experience very different training intensities.
MAS interval training solves this problem by prescribing running speeds based on percentages of Maximum Aerobic Speed.
This means:
• athletes train at the correct physiological intensity• workouts scale automatically to fitness level• interval sessions target specific conditioning adaptations
For example, instead of prescribing:
400m repeatsMAS training prescribes:
1 minute @ 100% MASThe exact running distance depends on the athlete’s individual MAS.
This approach allows interval training to remain individualised and precise, which is why MAS training is widely used in modern high-performance conditioning programs.
To calculate your personal MAS training speeds, use the calculator below.
Why MAS Training Is Effective
MAS training improves performance by targeting several key physiological qualities.
Aerobic Power
MAS intervals improve the speed athletes can sustain using aerobic metabolism.
Repeat Effort Capacity
Athletes develop the ability to repeat high-intensity efforts with shorter recovery.
Running Efficiency
Training at precise speeds improves running mechanics and energy efficiency.
These adaptations are essential for both endurance athletes and team sport athletes.
Who Should Use MAS Running Intervals?
MAS training is effective for a wide range of athletes including:
football players
soccer players
rugby athletes
basketball players
triathletes
endurance runners
Because MAS training scales to the athlete’s current fitness level, it works equally well for recreational athletes and high-performance competitors.
Structured MAS Training Programs
While MAS intervals can be performed individually, the best results come from structured progression.
A well-designed MAS program gradually increases intensity and volume while managing fatigue.
The MAS Running System is an example of a structured MAS conditioning program that includes:
MAS testing and re-testing
aerobic interval development
rectangle interval sessions
Eurofit conditioning
Tabata running sessions
View the full program here:
Turn MAS Knowledge Into Real Conditioning Gains
Learning how MAS running intervals work is only the first step. The real improvements come from following a structured progression of sessions that gradually increase intensity and workload over time. The MAS Running System provides an 8-week progression of interval sessions designed to develop aerobic power, repeat speed, and high-intensity running capacity using MAS-based training.
Start the MAS Running System
Final Thoughts
MAS running intervals provide one of the most precise methods for developing aerobic fitness and running performance.
By prescribing running speeds based on an athlete’s Maximum Aerobic Speed, training sessions become more effective, scalable, and measurable.
If you want to start MAS training, begin by performing the 5-minute MAS test and calculating your running speeds.
Use the MAS calculator below to determine your training targets.
FAQ
What is MAS in running?
MAS stands for Maximum Aerobic Speed, the running speed associated with maximal aerobic capacity.
How often should I do MAS intervals?
Most programs include 2–3 MAS sessions per week depending on the athlete’s training schedule.
How often should MAS be tested?
MAS is typically re-tested every 4–8 weeks to track improvements in aerobic fitness.
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