Lactate Threshold Training: How to Find Your Critical Cycling Pace

Introduction

Many cyclists share the same frustration: despite logging plenty of miles, their legs still “blow up” on long rides and they can’t hold their target speed. The core issue often lies in insufficient Lactate Threshold (LT) training. The lactate threshold represents the highest intensity you can sustain for an extended period without rapidly accumulating lactate—commonly known as your “critical pace.” Train this zone well, and both your average climbing speed and time trial performance will improve significantly.

The Physiology Behind the Lactate Threshold

Working muscles produce lactate during exercise. At low intensities, the body’s rate of lactate clearance keeps pace with its production, and blood lactate remains stable. Once intensity exceeds a critical point, lactate begins to accumulate and the effort becomes unsustainable—that critical point is the lactate threshold.

In exercise physiology, there are actually two thresholds:

For cyclists, raising LT2 (the intensity corresponding to FTP) is one of the primary training goals. The higher your LT2, the faster you can ride while still operating “aerobically,” which translates to better climbing and long-distance performance.

How to Find Your Lactate Threshold Intensity

The 20-minute FTP test is the most common method. After a proper warm-up, ride all-out for 20 minutes and take 95% of the average power as your estimated FTP—this power roughly corresponds to LT2.

Rate of Perceived Exertion (RPE): At LT2 intensity, you should feel “hard but manageable,” with heart rate around 85–90% of max, and you can only squeeze out short phrases when speaking.

Zwift / TrainerRoad Ramp Test: Increase power in steps until failure, then estimate FTP as the average power of the final completed minute × 75%.

Lactate Threshold Training Methods

The most effective way to raise your lactate threshold is sustained output in the “Sweet Spot” to “Threshold” range:

• Sweet Spot Training: 88–93% FTP for 20–40 minutes continuously—one of the most time-efficient workouts. For example, maintain a steady output on the rolling climbs in Muzha or Xindian
• Threshold Zone (Zone 4): 95–105% FTP, 10–20 minutes × 2–3 sets, with 5 minutes of rest between sets
• Repeated Climbs: Find a steady 8–15 minute climb (such as Yangmingshan Road or Lixing Industrial Road) and repeat 2–4 efforts at threshold intensity

Scheduling 1–2 lactate threshold sessions per week, combined with sufficient Zone 2 base riding and rest days, is the best strategy for raising LT2.

Common Mistakes

• Spending too much time in the “grey zone”: Intensity between Zone 3 and Zone 4 neither effectively stimulates your aerobic base nor sufficiently raises your threshold—this is the most common mistake among amateur cyclists
• Neglecting the base phase: Without enough aerobic foundation, your LT2 improvement potential is limited—like building a house while skipping the foundation
• Testing too frequently: Doing an FTP test every two weeks compromises training quality; it’s recommended to test every 4–6 weeks

Practical Advice

• Use a power meter or heart rate monitor to ensure you’re training in the right zone, avoiding the “feels hard but isn’t actually intense enough” trap
• Taiwan’s Beiyi Highway, Lixing Industrial Road, and the eastern approach to Wuling are all excellent venues for threshold climbing workouts
• Doing threshold training on a trainer eliminates wind resistance and cornering interruptions, allowing more precise intensity control
• Lactate threshold training requires 24–48 hours of adequate recovery afterward

Conclusion

The lactate threshold isn’t a metric only elite cyclists need to worry about. Any rider looking to break through a plateau in climbing or time trialing should make raising LT2 a core training goal. Find your critical pace, train scientifically at that boundary, and progress will come naturally.

Related Reading

• Cycling Lactate Threshold Training: Sweet Spot 88–93% FTP Interval Design
• Lactate Threshold Improvement Methods: The Scientific Breakthrough in Cycling Endurance
• Running Lactate Threshold Training: Scientific Methods to Break Through the LT Speed Wall
• Cycling Lactate Testing: Applying Blood Lactate Concentration to Training Zone Setup