PACR
AI marathon training plan, rewritten every morning.
Most marathon plans are written once and then quietly stop being true — the week you travel, the week you get sick, the morning it is 33°C at 5am. PACR sets the block from your race date, then rebuilds each session on the day you actually run it.
long run
How a marathon block is built.
The shape is old and well understood. What PACR changes is that each session inside it is written on the morning you run it, not in January.
Aerobic volume and honest easy running, with the long run stretching towards 24 km. Strides twice a week so your legs do not forget what fast feels like while the mileage climbs.
Threshold work arrives — 2 × 20 minutes at a pace taken from your own sessions, not a race-time calculator. Long runs reach 28–32 km, and some of them finish honest rather than shuffling.
Marathon pace becomes the point of the week: 26–32 km with 10–16 km at goal pace, until race pace stops feeling like a guess and starts feeling boring. That is what you want it to feel like.
Volume drops by roughly 40% while intensity stays. Short race-pace blocks keep the legs sharp and let three months of fatigue drain out of them before the start line.
What a marathon week looks like.
A representative build week. Yours will differ — that is the point — but the skeleton holds: two hard days, one long day, and easy running that is genuinely easy.
If Sunday cooks you, Monday is not the interval set you planned in January — it is forty minutes easy. The plan absorbs the week you actually had.
What decides today's marathon session.
Every morning at 4am the session is rebuilt from three things, and nothing else gets a vote.
Your last run
Split drift, cadence, and how hard the end of the long run felt. Twenty miles on Sunday changes what Tuesday can usefully be, and a plan that ignores that is how marathon blocks end in physio waiting rooms.
Your real pace
PACR models threshold from your own sessions and sets marathon pace off it, moving in seconds week to week instead of dropping you into a tier from a race-time calculator.
Today's climate
Heat, humidity and wind on the exposed stretch. A 32 km long run in 81% humidity gets the same training stimulus at an honest pace instead of a broken one.
The long run, called out loud.
Marathon sessions are long enough that you stop making good decisions. That is roughly when the coaching starts to matter.
Marathon training questions.
The things runners ask before committing sixteen weeks of Sunday mornings to something.
How long should a marathon training plan be?
Sixteen to twenty weeks is the usual block for a runner who can already run for 45–60 minutes comfortably. PACR sets the length from your race date and what your recent runs say about your current fitness, then fills the block in one morning at a time.
Can AI really write a marathon training plan?
It can do the part a static plan cannot: react. The shape of a marathon block — base, build, race-pace specificity, taper — is well understood and not controversial. What breaks marathon plans is life, and life is exactly what PACR rewrites around every morning.
What happens if I miss a week of marathon training?
Nothing dramatic. Because the plan is rebuilt daily, a missed week is simply the state it builds from: volume returns gradually instead of dropping you into the session you would have been doing if nothing had gone wrong.
How does PACR set my marathon pace?
From your own sessions. It models threshold from what you actually run and moves the target in seconds, week to week, rather than assigning you a tier from a calculator you fed a five-year-old 10K time into.
How many kilometres a week does marathon training need?
Fewer than the internet insists, and more in the middle of the block than most runners expect. PACR builds weekly volume up from where you are now rather than from an idealised 100 km week you have never actually run.
Does the plan handle a hot marathon?
Every session carries a heat offset in seconds per kilometre, calculated from temperature, humidity and wind, so training stays honest in summer. That habit pays on race day: you will already know what 28°C does to your pace instead of finding out at 30 km.
Training a different distance?
Same coach, same daily rewrite, different block.