Tempo Long Run: 2×5km at Half Marathon Pace

Session Overview

Two sustained 5km blocks at half marathon race pace, with a full easy warm-up and cool-down on either side — this session combines meaningful training volume with genuine lactate threshold stimulus. It is the cornerstone run session for athletes targeting Olympic triathlon or 70.3 and looking to build run-off-bike durability and race-pace confidence.

What You’ll Need

• GPS watch with pace alerts
• Flat or gently undulating road or path
• Running water bottle for hot days

Warm-Up (15 minutes)

Run 2km at easy conversational pace (Zone 1–2, RPE 4). Follow with 4 × 20-second strides at 5km race pace, with 40 seconds of easy jog recovery between each. The strides prime your running economy without accumulating lactate before the main set. End with 30 seconds of dynamic leg swings per leg — front-to-back and lateral.

Main Set

Two 5km blocks at your current half marathon race pace. Use your GPS watch to hold target pace — pace discipline across both blocks is the skill being trained here.

• 5km at half marathon pace (RPE 7–7.5, lactate threshold — conversational but hard)
• 3-minute easy walk/jog recovery
• 5km at half marathon pace (RPE 7–7.5) — aim to match or run 3–5 seconds per km faster than block 1 in the final kilometre

Cool-Down (10 minutes)

Run 1.5km at very easy pace (Zone 1, RPE 3–4). Follow with 5 minutes of static stretching: hip flexors in a kneeling lunge, standing single-leg hamstring stretch, and wall calf push. This session creates meaningful muscle micro-damage — do not skip the cool-down or you will feel the deficit the following morning.

Coaching Notes

• Half marathon pace means your current best half marathon time divided into per-kilometre pace — not your goal pace. Be honest with your current fitness rather than aspirational.
• Common mistake: running block 1 too fast and losing 10–15 seconds per km through block 2. A negative or even split across both blocks is the ideal execution of this session.
• Scale up: advanced athletes can increase to 2 × 7km or add a third 5km block with a 5-minute recovery between blocks 2 and 3.
• Schedule on fresh legs — avoid a hard bike or swim session the day before. This fits best on Tuesday or Wednesday in a standard seven-day training week.