Interval Run

Execution

1. Warm up with 5 minutes of brisk walking, 10 minutes of easy jogging and 4-6 short 20-second accelerations.
2. Run 400 meters at an effort where words barely come out, faster than tempo but still not an all-out sprint, about the pace you could hold for a 5-kilometer race.
3. Walk or jog very easily for 90 seconds between reps until the breathing comes back.
4. Do 4-6 reps in your first session and add one rep every two weeks at most.
5. Keep a quick cadence around 175-185 steps a minute and hold your form together on the last rep.
6. If a rep comes in more than 5 seconds slower than the first, end the session there, because quality beats volume.
7. Cool down with 10 minutes of very easy jogging and 5 minutes of walking rather than stopping dead after the last rep, then stretch the legs and calves.
8. In hot, humid weather run early morning or late afternoon and cut the reps. Chest pain, dizziness or unusual breathlessness means stopping and seeing a doctor.

Quick cues

• Fast, but the form holds.
• The recovery is for breathing.
• Last rep matches the first.
• Arms swing front to back.
• Much slower means session over.

Common faults

• Fault: Sprinting the first rep all out and crawling through the rest

  Fix: Set a target time for the first rep a few seconds inside your best and hold every rep to it.

• Fault: Cutting the recovery short because you still feel fine

  Fix: Keep the full 90 seconds by the clock, because a complete recovery is what keeps the next rep fast.

• Fault: Doing interval sessions two or three times a week

  Fix: Cap it at one interval session a week and keep the rest of the running easy.

• Fault: Skipping the short accelerations in the warm-up

  Fix: Do 4-6 accelerations of 20 seconds before the first rep so the legs meet the speed gradually.