Which race time should I use?

The most recent one, run all out, ideally between 5 and 21 km. A 10 km is the best compromise: long enough to be aerobic, short enough that pacing mistakes do not distort the result. Avoid a marathon if you blew up after 30 km.

My computed MAS does not match my track test

It is common, and the gap is informative. A test MAS higher than the one derived from a long race means you have speed but little endurance: holding a high percentage of MAS is your weak point. The opposite means good endurance and a lack of raw speed.

How often should I redo the test?

Every two to three months is enough. MAS moves slowly, and an all-out test costs you a quality session. In an Endu plan it is scheduled once, in the first two weeks, if you ask for it or have given neither a MAS nor a recent race time.

MAS, VO2max and VDOT: what is the difference?

VO2max is an oxygen flow (ml/min/kg), MAS the speed at which you reach it (km/h), and VDOT a Daniels performance index combining both. MAS is the only one of the three you can put straight onto a watch.

MAS calculator

Work out your MAS from a race time or a 6-minute test and get your five training paces. Method explained, no sign-up.

Updated 9 October 2026

In short

MAS is worked out in two ways. On a 6-minute all-out test, it is the distance in metres divided by 100: 1,500 m gives 15 km/h. From a race time, it is the average speed divided by the share of MAS held over the distance (about 90% over 10 km): 10 km in 50 minutes gives 13.3 km/h.

MAS — maximal aerobic speed (VMA in French, close to vVO2max) — is the speed at which you consume the most oxygen. Every training pace is derived from it: get it wrong and the whole plan is wrong.

Two ways to get it without a lab: a recent race time, or a 6-minute field test. The race time is more reliable if it is less than three months old and was run all out.

Distance

Time

min

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Your MAS from your 10K time

10K time	MAS	Pace at MAS	Easy pace
35 min	19.0 km/h	3:09/km	4:30 – 5:15
40 min	16.7 km/h	3:36/km	5:09 – 6:00
45 min	14.8 km/h	4:03/km	5:47 – 6:45
50 min	13.3 km/h	4:30/km	6:26 – 7:30
55 min	12.1 km/h	4:57/km	7:04 – 8:15
1:00	11.1 km/h	5:24/km	7:43 – 9:00
1:05	10.3 km/h	5:51/km	8:21 – 9:45
1:10	9.5 km/h	6:18/km	9:00 – 10:30

Computed with the %MAS table of our plans. Easy pace: 60 to 70% of MAS, in min/km.

How it is computed

From a race time the calculation inverts the sustainable-%MAS table: a 10 km is run at about 90 % of MAS, a half marathon at 85 %, a marathon at 80 %. Your MAS is your average speed divided by that percentage. It is the convention of the French tables, and it is what lets the predictor land back exactly on the time you entered.

From the 6-minute test it is direct: the average speed held for 6 all-out minutes IS your MAS. That is the test the engine schedules at the start of a plan. A 12-minute test does not work here: it is run below MAS and would under-estimate it.

The five paces then follow as a percentage of MAS: easy 60-70 %, marathon 78-82 %, threshold 83-88 %, intervals 92-100 %, repetitions 105-115 %. Those ranges are tighter than the original VO2max zones because they are calibrated on amateur runners.

The plans built from this number

Running Trail & ultra Triathlon Swimrun All plans

Now the plan that goes with it

These numbers are exactly the ones Endu uses to build a full preparation: phases, volume, detailed sessions, exported to your watch. 14-day trial, cancel any time.

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Frequently asked questions

Which race time should I use?: The most recent one, run all out, ideally between 5 and 21 km. A 10 km is the best compromise: long enough to be aerobic, short enough that pacing mistakes do not distort the result. Avoid a marathon if you blew up after 30 km.
My computed MAS does not match my track test: It is common, and the gap is informative. A test MAS higher than the one derived from a long race means you have speed but little endurance: holding a high percentage of MAS is your weak point. The opposite means good endurance and a lack of raw speed.
How often should I redo the test?: Every two to three months is enough. MAS moves slowly, and an all-out test costs you a quality session. In an Endu plan it is scheduled once, in the first two weeks, if you ask for it or have given neither a MAS nor a recent race time.
MAS, VO2max and VDOT: what is the difference?: VO2max is an oxygen flow (ml/min/kg), MAS the speed at which you reach it (km/h), and VDOT a Daniels performance index combining both. MAS is the only one of the three you can put straight onto a watch.