What is maximal aerobic speed?
Maximal aerobic speed (MAS) is the slowest running speed at which you reach your maximum oxygen uptake (VO2max). Run slower and you stay below your aerobic ceiling; run faster and you rely increasingly on anaerobic energy.
Most runners can hold their MAS for only four to eight minutes, which is why it is used as a reference intensity rather than a race pace. Because it is expressed as a speed rather than a laboratory value, every other training intensity can be set as a percentage of it.
The Cooper tests
Half-Cooper (6 minutes) asks you to cover as much ground as you can in six minutes. Six minutes is a tenth of an hour, so the distance in metres divided by 100 gives your MAS in km/h directly. It also sits inside the window most runners can hold at their MAS, which makes it the simplest accurate option.
Cooper (12 minutes) uses twelve minutes instead; divide the distance in metres by 200. It is harder to pace evenly and, because twelve minutes usually exceeds the time a runner can sustain true MAS, it tends to read slightly low.
VAMEVAL and time trials
The VAMEVAL and Léger-Boucher protocols use a progressive track test where speed increases at fixed intervals until you can no longer keep up. The speed of the last stage you complete in full is your MAS. These give the most reliable result but need a marked track and audio cues.
A 3000 m time trial can also be used. A maximal 3000 m is typically run at around 97% of MAS, so the calculator adjusts for that. Treat the result as an estimate rather than a measurement.
Using the percentages
Once you have a MAS figure, training intensities follow from it. Easy and recovery running sits around 60–70%, the bulk of aerobic base work around 70–80%, and threshold efforts around 85–90%. Intervals at 90–100% develop MAS itself, with shorter repetitions run at or slightly above it.
Retest every six to ten weeks, or whenever your usual sessions start to feel consistently easy. MAS improves quickly in less-trained runners and slowly in experienced ones, so small changes still matter.
Looking for VAM as a climbing speed in cycling (metres gained per hour)? That is a different metric — use the vertical ascent rate calculator instead. Vertical Ascent Rate Calculator
Frequently Asked Questions
What is maximal aerobic speed (MAS)?
MAS is the slowest running speed at which you reach your maximum oxygen uptake. Most runners can hold it for only four to eight minutes, so it is used as a reference intensity rather than a race pace.
How do you calculate MAS?
The simplest field test is the half-Cooper: run as far as you can in six minutes and divide the distance in metres by 100 to get MAS in km/h. Progressive track tests such as VAMEVAL give a more precise result.
What is a good MAS?
Recreational runners are often between 12 and 16 km/h, while trained distance runners commonly exceed 18 km/h. Compare your own result over time rather than against a general benchmark.
Is MAS the same as VAM in cycling?
No. In cycling, VAM usually means vertical ascent rate, the metres of elevation gained per hour. Maximal aerobic speed is a running speed, so the two describe entirely different things.
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