Sprint Triathlon Training: 10 Threshold Brick Sessions

What Is a Threshold Brick Session in Sprint Triathlon Training?

Threshold brick sessions are your secret weapon. These workouts push you near your lactate threshold to build race-day speed, strength, and endurance.

By combining sustained efforts on the bike and run at or just below your threshold, these sessions simulate the intensity of sprint racing while improving your ability to manage fatigue. They train your body to hold a strong pace under pressure, sharpen your mental focus, and improve your efficiency across both disciplines. Threshold bricks help you develop the control and toughness to stay fast when others start to fade — giving you the edge you need to run strong off a hard ride and finish with confidence.

Below are 10 key threshold brick sessions to elevate your performance.

1. Short Threshold Brick

Purpose: Build intensity tolerance at sprint race pace

Bike Warm-Up: 10 min spin + 3 cadence lifts
Bike Main Set: 3 x 8 min @ Zone 4 (3 min spin between)
Transition Jog: 5 min easy jog
Run Main Set: 3 x 4 min @ Zone 4 (2 min jog recoveries)
Cool-Down: 10 min jog

2. Fast-Finish Brick

Purpose: Practice strong finish off high-end aerobic load

Bike Warm-Up: 10 min spin
Bike Main Set: 20 min @ Zone 3, 10 min @ Zone 4
Transition Jog: 5 min easy jog
Run Main Set: 10 min @ Zone 3, 5 min @ Zone 4
Cool-Down: 10 min jog

3. Over-Under Threshold Brick

Purpose: Handle pace changes and recover just below threshold

Bike Warm-Up: 12 min spin
Bike Main Set: 4 x (3 min @ Zone 3 + 4 min @ Zone 4)
Transition Jog: 5 min easy jog
Run Main Set: 3 x (2 min @ Zone 3 + 3 min @ Zone 4)
Cool-Down: 10 min jog

4. Repeating Brick Intervals

Purpose: Develop repeatable race-intensity efforts under fatigue

Bike Warm-Up: 10 min spin
Bike Main Set: 3 x 10 min @ Zone 4 (3 min spin between)
Transition Jog: 5 min easy jog
Run Main Set: 3 x 6 min @ Zone 4 (2 min jog recoveries)
Cool-Down: 10 min jog

5. Progressive Brick Builder

Purpose: Increase intensity through each phase of the session

Bike Warm-Up: 12 min spin
Bike Main Set: 10 min @ Zone 3, 10 min @ Zone 4
Transition Jog: 5 min easy jog
Run Main Set: 5 min @ Zone 3, 5 min @ Zone 4
Cool-Down: 10 min jog

6. Big Gear Threshold Brick

Purpose: Build strength and muscular control at threshold

Bike Warm-Up: 12 min spin + cadence work
Bike Main Set: 3 x 8 min @ Zone 4 (big gear, low cadence) (3 min spin between)
Transition Jog: 5 min easy jog
Run Main Set: 2 x 8 min @ Zone 4
Cool-Down: 10 min jog

7. Double Threshold Set

Purpose: Train both bike and run at race-specific intensity with minimal recovery

Bike Warm-Up: 10 min spin
Bike Main Set: 2 x 15 min @ Zone 4 (5 min spin between)
Transition Jog: 5 min easy jog
Run Main Set: 2 x 10 min @ Zone 4 (3 min jog between)
Cool-Down: 10 min jog

8. Split Brick Format

Purpose: Stack bike-run efforts with partial recovery to simulate late-race fatigue

Bike Warm-Up: 10 min spin
Bike Main Set: 15 min @ Zone 4 (5 min spin), 10 min @ Zone 4
Transition Jog: 5 min easy jog
Run Main Set: 10 min @ Zone 4, 5 min @ Zone 3
Cool-Down: 10 min jog

9. Threshold Tempo Combo Brick

Purpose: Blend controlled pacing with sharp efforts under fatigue

Bike Warm-Up: 12 min spin
Bike Main Set: 30 min @ Zone 3, 10 min @ Zone 4
Transition Jog: 5 min easy jog
Run Main Set: 10 min @ Zone 3, 5 min @ Zone 4
Cool-Down: 10 min jog

10. Race Simulation Brick

Purpose: Mimic full sprint-distance pacing and intensity

Bike Warm-Up: 10 min spin
Bike Main Set: 20 min @ Zone 4
Transition Jog: 5 min easy jog
Run Main Set: 15 min @ Zone 4
Cool-Down: 10 min jog

Mini FAQ

Q: What is a brick session in triathlon training?

A: A brick session combines two disciplines back-to-back—usually cycling followed immediately by running—to simulate race-day conditions and improve transition performance.

Q: What does “threshold” mean in these workouts?

A: Threshold refers to training at or near your lactate threshold—an intensity you can sustain for about 60 minutes. It improves endurance, pacing, and fatigue resistance.

Q: How often should I do threshold brick sessions?

A: Once per week is ideal for sprint triathletes during build phases. Include recovery weeks to avoid overtraining.

Q: Are threshold bricks suitable for beginners?

A: Yes—with modifications. Beginners can reduce the duration or intensity to stay within their current fitness level while still gaining benefits.

Final Thoughts

Threshold bricks are key to developing race-day speed, strength, and endurance. Add these to your training plan, and you’ll be ready to crush your next sprint triathlon!

Ready to turn legs of lead into legs of steel?

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.