Research
The science of AMRAP training
What the published research actually shows about AMRAP training, with every claim cited and every gap admitted. Written by a certified Master Fitness Trainer working from the papers, not summarised from other people's blog posts.
How these pages are sourced
One rule governs this section: a claim ships with a citation, or it does not ship. Every number is linked to the paper it came from, so you can check it rather than take our word for it.
Where the evidence is thin, the study is small, or the field genuinely disagrees, the page says so. Exercise science around functional fitness is younger and smaller than the confidence of most articles about it suggests — sample sizes of nine to twenty-two are common, and participants are mostly trained men. Pretending otherwise would make these pages less useful, not more.
These are practitioner syntheses of published work. They are not original research, they are not peer reviewed, and they are not medical advice.
Published
- Energy systems and the time cap
Both systems run from the first second, the crossover sits around 75 seconds, and heart rate cannot tell a 4-minute AMRAP from a 17-minute one.
- Lactate is not what makes an AMRAP hurt
Lactate is fuel, not waste. It does not cause the burn or next-day soreness — and where the biochemistry is still genuinely argued over, this says so.
- Fatigue, holds and movement choice
You slow down in an AMRAP, and part of that is a decision rather than failure. What the format comparison shows, and why holds belong early.
- Pacing, and where our own metric sits
Effort is regulated against an endpoint you know is coming. What the evidence supports, what the 2025 meta-analysis complicates, and which parts of our Pace Variance Index are ours rather than the literature's.
What is not here, and why
One page was planned and will not be published: sex differences in fatigue during functional fitness training. The workout studies in this area run to nine, twelve, fourteen, twenty-two participants, mostly men, with samples too small to analyse women separately. Writing that page responsibly would mean extrapolating from research that does not exist yet.
It is a real question and it deserves an answer. It does not yet have one, and saying so is more useful than filling the gap with confident prose. If the evidence arrives, the page will.
Who writes this
Justin Fassio — Certified Master Fitness Trainer since 1998. Owned San Diego Core Fitness, co-founded gymgo and aiworkoutgenerator.com, and builds AMRAP With Friends.