Olympic Triathlon Swim Training: 10 Threshold Sessions

Why Threshold Swim Training Is Critical for Olympic Triathlons

Swimming efficiently and powerfully at threshold intensity is key for a fast 1500m swim — without draining energy you’ll need for the bike and run. Threshold training focuses on swimming at the edge of your sustainable effort — improving aerobic capacity, speed endurance, and race-specific pacing. By working around your critical swim speed (CSS), you teach your body to swim hard without tipping into unsustainable fatigue — perfect for the demands of an Olympic triathlon. If you haven’t tested your CSS yet, complete a 400m and 200m time trial and use an online CSS calculator to find your ideal training pace.

These 10 essential threshold swim sessions will help you build endurance, efficiency, and speed so you can dominate your race day!

1. Classic Threshold 100s

Purpose: Build pace discipline and threshold endurance

Warm-Up: 300 easy + 4 x 50 build
Main Set: 10 x 100 @ Zone 4 (15 sec rest)
Cool-Down: 200 easy

2. Broken Threshold 200s

Purpose: Accumulate threshold work with manageable rest

Warm-Up: 400 swim + 4 x 25 fast
Main Set: 5 x 200 @ Zone 4 (20 sec rest)
Cool-Down: 200 choice

3. Descending Threshold Ladder

Purpose: Sharpen pacing with decreasing distance under pressure

Warm-Up: 300 easy + 4 x 50 drill/swim
Main Set: 400 – 300 – 200 – 100 @ Zone 4 (20 sec rest)
Cool-Down: 200 pull

4. 50s + 100s Combo Set

Purpose: Blend pace control with short recovery

Warm-Up: 300 swim + 4 x 25 fast
Main Set: 6 x 50 @ Zone 4 (10 sec), 4 x 100 @ Zone 4 (15 sec)
Cool-Down: 200 easy

5. Long Threshold Intervals

Purpose: Sustain high effort for longer durations

Warm-Up: 400 easy + 4 x 50 strong
Main Set: 3 x 400 @ Zone 4 (30 sec rest)
Cool-Down: 200 easy

6. Broken 300s

Purpose: Maintain quality at threshold over mid-length sets

Warm-Up: 300 swim + 4 x 50 build
Main Set: 4 x (2 x 150 @ Zone 4, 20 sec rest)
Cool-Down: 200 easy

7. Tempo into Threshold

Purpose: Build from steady pacing into threshold fatigue

Warm-Up: 300 easy
Main Set: 2 x (200 @ Zone 3 + 200 @ Zone 4) (15 sec rest)
Cool-Down: 200 swim

8. Threshold Pacing Challenge

Purpose: Test consistency across a mixed block

Warm-Up: 400 pull + 4 x 25 drill
Main Set:

  • 4 x 100 @ Zone 4 (15 sec)

  • 2 x 200 @ Zone 4 (20 sec)

  • 4 x 100 @ Zone 4 (15 sec)
    Cool-Down: 200 backstroke

9. Short Threshold Ramps

Purpose: Sharpen aerobic power with quick reps

Warm-Up: 300 swim + 4 x 50
Main Set: 12 x 75 @ Zone 4 (15 sec rest)
Cool-Down: 200 easy

10. Broken Threshold Pyramid

Purpose: Sustain high effort across varying reps without overloading

Warm-Up: 400 swim + drills
Main Set: 100 – 200 – 300 – 200 – 100 @ Zone 4 (20 sec rest)
Cool-Down: 200 easy

Final Tips for Threshold Swim Training

  • Use a Tempo Trainer: Lock in your pacing without relying on wall clocks.

  • Focus on Technique: Smooth strokes save more energy than brute force.

  • Test and Retest Your CSS: Adjust your training paces every 4–6 weeks for accuracy.

Consistent threshold training sets you up to swim fast, finish fresh, and race your best on Olympic triathlon day!

FAQs

How often should I swim threshold workouts?

Typically 1–2 threshold sessions per week, combined with easy endurance and technique work.

What is CSS and why is it important?

CSS (Critical Swim Speed) represents your sustainable race pace — training at this pace improves endurance without overwhelming fatigue.

Can threshold swim sessions be done in open water?

Yes! If you have a measured course, you can adapt most threshold sets to open water for even better race-specific preparation.

Final Thoughts

Threshold swim training is your key to swimming stronger, pacing smarter, and starting your Olympic triathlon ready to dominate.

Which threshold swim session will you dive into first to boost your race performance?

Always consult with a medical professional or certified coach before beginning any new training program. The information provided is for educational purposes only and is not a substitute for personalized advice.

Previous
Previous

Olympic Triathlon Run Training: 10 Tempo Sessions

Next
Next

Olympic Triathlon Bike Training: 10 Threshold Sessions