The five paces
Daniels' system uses five intensities. Easy (E) builds the aerobic base and should make up most of your week. Marathon (M) is goal race pace. Threshold (T) is comfortably hard, around the pace you could hold for an hour. Interval (I) is 3–5 km race pace and trains VO2max. Repetition (R) is short, fast and fully recovered, for economy and speed.
Workouts, not just numbers
Knowing that T pace is 4:15 per kilometre is only useful if you know what to do with it. The workout table converts that pace into concrete sessions: mile repeats with a minute's jog, an 800 m set at I pace with three minutes' recovery, or 200 m repetitions at R pace with a full walk-back. Volumes are deliberately modest — the quality comes from the pace, not the accumulation.
Where runners go wrong
The most common error is running easy days at M or T pace, which turns three easy runs into three mediocre workouts. The second is extending interval sessions until the last reps are far slower than the first; in Daniels' system you stop the set when you cannot hold the target, because the adaptation comes from the speed, not the fatigue.
Frequently Asked Questions
Do I need a recent race?
Yes — the paces are only as good as the input. A time trial over 5 km on a measured loop works if you have not raced recently.
What is the difference between I and R pace?
I pace is 3–5 km race pace with 3 minutes' recovery; R pace is faster than 1500 m pace with full recovery. I trains the engine, R trains economy.
How much of my week should be quality?
Around 20%, or two sessions. The other 80% belongs at E pace, including the long run.
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