What is MAS?
Maximal aerobic speed (MAS) is the slowest running speed at which a player hits their maximal oxygen uptake — in plain terms, the top of their aerobic engine expressed as a speed. It matters to coaches for one reason: it turns a fitness test result into training speeds. Instead of "do runs", a session becomes "15 seconds at 120% of your MAS, 15 seconds off" — individual to each player, and honest about who is coasting and who is at their limit.
How the estimate works
Any continuous run of roughly four to six minutes approximates MAS: divide the distance by the time. A 1.5km time trial is the classic field version. The Bronco test (1,200m of 20–40–60m shuttles) works too, with one caveat: the turns cost time, so a Bronco-derived MAS reads slightly below a player's true value. That makes it a conservative estimate — training speeds built from it will be achievable rather than optimistic, which for a club squad is the right side to miss on.
Using the training speeds
The classic MAS session is intermittent running: 15 seconds on, 15 seconds off, at 100–120% of MAS, for blocks of 6–10 minutes. The calculator's "distance in 15s" column is the practical bit — mark that distance out with two cones and a player simply runs cone-to-cone on each work interval. Players with different engines get different cones, which is how one session trains a whole panel fairly.
Two habits make the number useful rather than a one-off curiosity. Retest on the same schedule as the rest of your battery — every 10 to 12 weeks, as covered in our complete guide to fitness testing for GAA clubs — and judge results against the right age band, because a strong U15 MAS and a strong senior MAS are different numbers.
Frequently asked questions
What is a good MAS score for a GAA player?
Adult male club players typically land somewhere around 4.0–4.7 m/s (14.5–17 km/h), with intercounty players higher again. Treat published figures as rough guides — age, sex and the test used all shift the numbers, which is why age-banded benchmarks beat one-size-fits-all targets.
Why is a Bronco-based MAS estimate conservative?
The Bronco includes turns every 20–60m, and every turn costs time that a straight run would not. So 1,200m divided by your Bronco time slightly understates true MAS. Treat the result as a floor: real MAS is a touch higher, and training speeds built from it will err on the manageable side.
Can I calculate MAS from a Yo-Yo test result?
Not directly with this calculator. The Yo-Yo is an intermittent test with built-in recovery walks, so its result does not convert to a continuous running speed the same way. Use a Bronco or a continuous time trial for MAS, and keep the Yo-Yo as its own benchmark.
How often should I retest MAS?
Every 10–12 weeks, the same rhythm as the rest of your testing battery — typically the start and end of pre-season, optionally mid-season, and end of season. One result is a snapshot; the change between two results is what tells you whether the training block worked.