Sprint Triathlon Training: 10 Threshold Brick Sessions
Summary
Threshold brick sessions combine bike and run efforts at a challenging but controlled intensity — perfect for building speed, endurance, and race-day execution. These workouts target your lactate threshold: 87–93% of max heart rate, 91–105% of FTP or a 7–8 RPE. By training both disciplines back-to-back at this level, you’ll improve fatigue resistance, sharpen pacing and run stronger off the bike. These 10 sessions are built to help you train smarter and perform better in sprint triathlon racing.
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.
Threshold Intensity Guidelines
Threshold efforts sit just below your redline — tough but sustainable. Here’s how to gauge intensity:
Heart Rate (HR): 87–93% of max HR
FTP (Cycling): 91–105% of FTP
RPE (Perceived Effort): 7-8
Use the FLJUGA Zone Calculator to dial in your training zones.
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: Threshold Brick Sessions
What is a brick session in triathlon training?
A brick session combines two disciplines back-to-back—usually cycling followed immediately by running—to simulate race-day conditions and improve transition performance.
What does “threshold” mean in these workouts?
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.
How often should I do threshold brick sessions?
Once per week is ideal for sprint triathletes during build phases. Include recovery weeks to avoid overtraining.
Are threshold bricks suitable for beginners?
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!
They teach you how to hold pace under pressure, recover just enough to go again and run hard off the bike — even on tired legs. Over time, that’s what builds real racing confidence. Rotate these sessions weekly, stay consistent and you’ll arrive at the start line sharp, strong, and ready to perform.
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.
