PACR
AI 5K training plan, rebuilt every morning.
Two runners want opposite things from the same distance: one wants to finish it, one wants twenty minutes. PACR builds either block from your own runs — and on the days you turn up flat, it writes a session you can actually complete.
reps
How a 5K block is built.
Six to ten weeks. Short enough that you can see the end of it, long enough for the aerobic side to move.
Easy running, at a pace that lets you talk. If you are starting out, this is run-walk — three minutes running, one walking — extended a little each session until the walk disappears on its own.
Volume grows gently, strides appear twice a week, and one steady run a week teaches you what controlled discomfort feels like without wrecking the next two days.
Race-pace reps: 8 × 400 m or 5 × 1 km at 5K effort, with recoveries long enough that each rep looks like the last. Speed you cannot repeat is not speed.
Two easy runs, a handful of strides, and one short session at race pace. Nothing that needs recovering from.
What a 5K week looks like.
A representative sharpening week for a runner going four days. A first-timer's week is the same shape with the hard day replaced by steady running.
Race a parkrun on Saturday and Sunday's long run is rewritten before you wake up — shorter, slower, and no worse for it.
What decides today's 5K session.
Rebuilt at 4am from your last run, your real pace and the air you are about to run through.
Your last run
How hard the last rep felt, and whether your splits drifted. Eight times four hundred metres is short, but it is not free — Thursday knows what Tuesday cost.
Your real pace
Your 5K target comes from your own sessions, not a chart. That matters most for new runners, whose pace can move by twenty seconds a kilometre inside a month.
Today's climate
Short races feel the heat too. The session carries a heat offset in seconds per kilometre so a warm evening changes the target instead of the outcome.
Short reps, called in your ear.
Four hundred metres is over before a watch is any use. The coach calls the effort while there is still time to fix it.
5K training questions.
From first-timers to the ones staring at 20:00 and refusing to blink.
How long does it take to train for a 5K?
Six to ten weeks covers most cases — a beginner building from run-walk, or an experienced runner sharpening for a fast one. PACR sets the length from your race date and what your current runs can support.
Can a complete beginner use this 5K plan?
Yes. The first weeks are run-walk intervals that lengthen as they get easier, and the coach's job on those days is mostly to slow you down. The block grows from what you can do now, not from week one of a generic template.
How do I run a sub-20 5K?
Sub-20 is 4:00 per kilometre, and it is built on threshold running with race-pace reps close to the race, not on running every session hard. The plan places two quality days a week and protects the easy days that make them possible.
What pace should I run 5K intervals at?
Around race pace for 1 km reps and slightly quicker for 400s — but only as quick as you can repeat. PACR sets those targets from your own threshold and adjusts them for the day's heat.
How is this different from a couch-to-5K programme?
A fixed programme runs to a calendar. PACR runs to you: if a week goes badly the next session is rewritten around it instead of assuming you completed the last one, which is where most fixed programmes quietly lose people.
Can I use it to train for parkrun?
That is the most common use of a 5K block. Saturday can be a rehearsal, a race, or an easy run, and the coach rewrites Sunday around whichever one you actually ran.
Training a different distance?
Same coach, same daily rewrite, different block.