Speed Endurance Swim: 4x400m Race Pace with 60-Second Recovery

Session Overview

A demanding threshold pool set for advanced triathletes. Four 400m intervals at CSS pace with just 60 seconds’ rest between reps forces rapid recovery at race intensity — exactly the stimulus you need to hold pace for 1.9km or 3.8km on race day.

What You’ll Need

• 25m or 50m pool with a visible pace clock
• Waterproof stopwatch
• Swim goggles and cap
• Optional: swim fins for cool-down only

Warm-Up (10 minutes)

400m easy: 100m freestyle, 100m catch-up drill, 100m freestyle, 100m backstroke. Focus on long strokes and full hip rotation. Follow with 4 x 50m building pace from easy to threshold — each rep slightly faster than the last.

Main Set

4 x 400m at CSS pace (or 2–3 seconds per 100m faster if targeting a time goal). Take exactly 60 seconds rest between each rep. Record your split for every 400m to track fatigue:

• Rep 1: Hit target pace — establish rhythm and stroke count early
• Rep 2: Maintain the same pace — resist the temptation to bank time in the first 200m
• Rep 3: Hold on — this is where the session gets hard; focus on technique over power
• Rep 4: Race it — aim for the same split as rep 1 even under accumulated fatigue

Cool-Down (10 minutes)

400m easy with fins if available. Focus on long, passive kicks and slow arm recovery to flush lactic acid. Add 4 x 25m backstroke to release tension in the chest and shoulder girdle.

Coaching Notes

• CSS is typically the pace from: (400m time − 200m time) ÷ 200 — this gives seconds per metre
• The 60-second rest is intentionally short; if you’re more than 5 seconds off CSS by rep 3, extend rest to 90 seconds but note the modification
• Compare your slowest rep to your fastest — aim to keep the range under 5 seconds per 100m equivalent
• To scale down: reduce to 3 x 400m with 90-second rest
• To scale up: shorten rest to 45 seconds or add a fifth rep at your absolute limit
• Target RPE: 7–8 throughout, finishing at 9 on the final rep — this is a hard session