3 × 800m Descending Pace Pool Swim Session

Session Overview

Three 800m repeats with descending pace — each rep faster than the last — trains you to run on a negative split, save something for the final 400m, and execute race pace under accumulated fatigue. An intermediate pool session building aerobic capacity and pace discipline.

What You’ll Need

• 25m or 50m pool
• Swim watch or poolside clock for pacing
• Optional: pull buoy for warm-up

Warm-Up (15 minutes / ~600m)

400m easy: 100m full stroke at a conversational pace, 100m catch-up drill (pause one hand at your hip while the other reaches forward), 100m side kick (on your side, kicking), 100m easy full stroke. Then 4 × 50m at CSS pace with 20 seconds rest — these prime your pacing system for the main set without pre-fatiguing you.

Main Set

3 × 800m with 2:30 rest between reps. Each rep descends in pace — you should feel comfortably challenged on rep 1 and working hard by the end of rep 3.

• Rep 1 — CSS + 8 sec/100m: If your CSS is 1:50/100m, target 1:58. Comfortable threshold effort, RPE 7. This should feel like the start of a race, not the finish.
• Rep 2 — CSS + 4 sec/100m: Target 1:54. Controlled effort, RPE 8. Breathing should be rhythmic but purposeful. Every 200m, check your split — many swimmers find they speed up unintentionally.
• Rep 3 — CSS pace: Target your 400m time-trial pace ÷ 2. RPE 8.5–9. This is the rep that matters. By now you’ve earned the pace — hold it from the first 100m, not just the final 100m.

Cool-Down (10 minutes / ~300m)

300m easy backstroke or mixed stroke (backstroke 50m, breaststroke 50m, repeat three times). No effort required — just flush the lactate, let your heart rate return to normal, and stretch your shoulders poolside before leaving.

Coaching Notes

• If you don’t know your CSS, do a 400m time trial first (separate session) or use your 400m race-best pace as a proxy.
• 2:30 rest between 800m reps feels generous — resist the urge to shorten it. The point of the session is descending pace across three good reps, not accumulated fatigue from insufficient rest.
• To make it harder: reduce rest to 2 minutes between reps, or add a fourth 800m at CSS pace.
• To make it easier: swim reps at CSS + 12 / +8 / +4 instead of +8 / +4 / CSS.