Running speed training on road

Threshold Run with Surges: 40-Minute Speed Endurance Builder

Session Overview

This 40-minute run session combines sustained threshold effort with short, sharp surges. It develops your ability to change pace mid-race — a crucial skill for responding to course terrain, overtaking competitors, or pushing through difficult patches during a triathlon run leg.

What You’ll Need

  • GPS watch or running app for pacing
  • Flat to gently rolling route with good footing
  • Road or trail running shoes

Warm-Up (8 minutes)

Jog easy for 6 minutes at Zone 1-2. Include 3 x 15-second accelerations building from jog to fast running pace, with 45 seconds easy jog between each. Finish with 2 minutes steady jogging to prepare for the main set.

Main Set

Run 20 minutes at threshold pace (RPE 7 — hard but sustainable for 20 minutes). Within this 20-minute block, add surges as follows:

  • Minutes 0-5: Settle into threshold pace. Find your rhythm and breathing pattern.
  • Minute 5: Surge for 30 seconds at 5K effort (RPE 9), then return immediately to threshold pace.
  • Minutes 5:30-10: Hold threshold pace. Focus on smooth form despite the accumulated fatigue from the surge.
  • Minute 10: Surge for 30 seconds at 5K effort, then return to threshold.
  • Minutes 10:30-15: Hold threshold. This section is the mental crux — your legs want to slow down but you must hold.
  • Minute 15: Surge for 30 seconds at 5K effort, then return to threshold.
  • Minutes 15:30-20: Hold threshold to the end. If you feel strong, finish with a final 30-second surge in the last minute.

Cool-Down (7 minutes)

Jog easy for 5 minutes, gradually reducing speed. Walk for 2 minutes with gentle quad stretches, calf raises and hip flexor stretches.

Coaching Notes

  • The surges should feel hard but brief — 30 seconds at 5K effort is enough to spike your heart rate without derailing the threshold block
  • The key skill is recovering your rhythm quickly after each surge. In a race, this mimics going over a hill or responding to another athlete’s move.
  • Beginners: reduce to 2 surges and extend recovery between them. Advanced: increase to 5 surges or extend the threshold block to 25 minutes.
  • Heart rate will lag behind effort during surges — use pace or RPE to guide the surges, not heart rate.

Training at your own risk. The information provided is for general guidance only and is not a substitute for professional medical advice. Please consult a doctor before starting any new exercise programme, especially if you have any pre-existing health conditions.