Plan interval workout times and rest.
The number you actually need at the track is the target time for each repetition, which is the rep distance in kilometres multiplied by your target pace. Total fast distance is the session's volume — 3 to 5 km at interval pace is a typical range for distance runners — and the work-to-rest ratio tells you whether the recovery is generous or deliberately incomplete.
Interval target times
Rep time in seconds = rep distance / 1000 x target pace x 60; main set = total work + rest x (repetitions - 1)
These figures are population-average estimates for training and recreational planning only and are not medical advice. Individual responses vary widely. Consult a qualified health professional before starting or significantly changing an exercise programme, particularly if you have any medical condition. Official dimensions, rules and timings should be confirmed against the governing body for your sport.
For classic VO2 max work, roughly equal to the repetition time. Shorter recoveries make the session more aerobically demanding; longer ones let you hold faster paces.
Three to five kilometres of fast running for most distance runners, which is why eight by 400 m or five by 1 km are such common sessions.
No. The point is repeatability — the last rep should match the first. Starting too fast turns a controlled session into a time trial.