Tempo-Threshold Run: 3×15 Minutes at Half-Marathon Pace

Session Overview

Three 15-minute blocks at half-marathon pace with short recoveries. This is a classic lactate threshold session — challenging but controlled, and one of the most effective ways to build the run capacity you need for 70.3 racing. Intermediate athletes targeting a sub-2:10 half marathon will benefit most, and it translates directly to holding 70.3 run pace off a long bike leg.

What You’ll Need

• Road running shoes or your race day shoes (a good opportunity to practise in them)
• GPS watch with heart rate monitoring
• A flat or gently undulating route — avoid technical terrain for threshold work

Warm-Up (10 minutes)

10 minutes easy jogging at conversational pace. Follow with 4 × 20-second strides — fast but controlled accelerations — with 40 seconds easy jog recovery between each. This primes your neuromuscular system for the sustained effort ahead.

Main Set

Target your goal half-marathon pace, or the run pace you aim to hold off the bike in a 70.3. RPE should be 7–8 out of 10 — hard but sustainable. You should be able to speak a word or two but not hold a conversation.

• 15 minutes at half-marathon / 70.3 run pace, 2 minutes easy jog recovery
• 15 minutes at half-marathon / 70.3 run pace, 2 minutes easy jog recovery
• 15 minutes at half-marathon / 70.3 run pace — hold your form through the final minutes

Cool-Down (10 minutes)

10 minutes very easy jogging. Let your heart rate fall before stopping. Light hip flexor and calf stretching can follow after you’ve fully cooled down — never stretch immediately while your body temperature is still elevated.

Coaching Notes

• Use heart rate as your primary check: you should sit at Zone 4 (roughly 80–90% max HR) through each block
• The third block is the most important — if you’re blowing up, you started block one too fast
• To make it easier: reduce to 3 × 10 minutes with 2 minutes recovery; to make it harder: extend to 3 × 20 minutes with 3 minutes recovery
• Run this session once per week during a 70.3 build cycle; replace with a race-specific brick session in the two weeks before your event