Track Run: 8 x 400m Repeats for Speed Development

Session Overview

400m track repeats are the classic speed development session for runners at every level. For triathletes, they develop running economy and neuromuscular power at intensities above race pace, making your race-day pace feel more comfortable and sustainable. This 45-minute session is best done on a running track but can be adapted for roads with a GPS watch.

What You’ll Need

• Access to a 400m athletics track (free at most leisure centres during off-peak hours)
• GPS watch or stopwatch for timing each rep
• Lightweight running shoes or race flats
• Water bottle at trackside

Warm-Up (12 minutes)

Jog 2 laps of the track at easy pace, then complete a dynamic warm-up: leg swings, high knees, butt kicks, and lateral shuffles (1 minute each). Finish with 4 x 80m strides at 85% effort, walking back to the start each time. You should feel loose, fast, and ready to push hard.

Main Set

Each 400m repeat should be run at a consistent, hard effort — roughly 1 mile race pace, or around 95–100% of max effort. The goal is even splits, not a fast first lap and a dying fade.

• 8 x 400m at 5K race pace effort (RPE 9/10), with 90 seconds standing recovery between each rep
• Record each 400m split — aim for variation of no more than 3–4 seconds between your fastest and slowest rep
• If you blow up badly on rep 5 or 6, reduce to 6 reps and use the extra time for cool-down

Cool-Down (10 minutes)

Jog 2 easy laps of the track, then walk 1 lap while doing shoulder rolls and gentle trunk rotations. Follow with quad, hamstring, and calf stretches. Speed sessions create micro-tears in fast-twitch muscle fibres that repair stronger — but only if you recover well. Prioritise sleep and a protein-rich meal within 30 minutes of finishing.

Coaching Notes

• The most common 400m mistake is running the first 200m too fast (the “400m death march”). Run the first 200m at controlled effort and accelerate the back straight — you’ll run faster overall.
• Focus on relaxed arm drive and high cadence (90+ steps per minute) — these are the technique cues that directly improve your triathlon run economy.
• Scaling for beginners: reduce to 6 x 400m with 2 minutes recovery. Scaling harder: add a 5th rep to your base set, or reduce recovery to 60 seconds.
• Schedule this session no more than once per week, with 48 hours of easy training either side. Speed work requires full recovery to adapt properly.