Over-Under Training: Lactate Clearance Workouts Alternating 5% Above and Below FTP

Introduction

Among all the training methods for raising FTP, Over-Under (O-U for short) is arguably the most “uncomfortable” yet the most effective. Its design logic stems from racing reality: real races never let you hold a steady power output comfortably. Gradient changes, wind shifts, and surges from the pack all force you to fluctuate repeatedly around your threshold. Over-Under training simulates exactly this reality, teaching your body to keep producing efficiently even while lactate accumulates rapidly.

The Physiological Mechanism of Over-Under

When power exceeds FTP (the Over phase), lactate production outpaces clearance, and lactate begins to accumulate in the muscles. When power drops back below FTP (the Under phase), the body gets a chance to activate lactate clearance mechanisms—lactate is converted back into glucose (the Cori cycle) or directly oxidized by other muscle fibers.

Training effects of repeated switching:

• Increased lactate clearance enzyme activity: MCT (monocarboxylate transporter) density increases, improving lactate shuttling efficiency
• Higher lactate threshold (LT2): The body adapts to maintaining lactate balance at higher intensities
• Enhanced muscle buffering capacity: Increased bicarbonate buffering capacity in skeletal muscle
• Improved mental toughness: Getting used to continuing output while “uncomfortable”

Standard Over-Under Workout Design

Beginner Workout (for those trying O-U for the first time)

Warm-up: 15 minutes (ramp to 85% FTP in the final 5 minutes)
Set 1: 3 min × 95% FTP → 1 min × 105% FTP (repeat 3 times, 12 minutes total)
Rest: 6 minutes easy riding
Set 2: Same as Set 1
Cool-down: 10 minutes

Advanced Workout (for riders with O-U experience)

Warm-up: 15 minutes
Set 1: 2 min × 95% FTP → 2 min × 110% FTP (repeat 5 times, 20 minutes total)
Rest: 5 minutes
Sets 2–3: Same as Set 1
Cool-down: 10 minutes

Execution Tips

Tip 1: Don’t “surge” during the Over segment
When switching from Under to Over, slightly increase your cadence (+3–5 RPM) rather than stomping on the pedals, allowing power to rise smoothly to the target. Power spikes exceeding 20W above target will unnecessarily deplete anaerobic capacity.

Tip 2: Don’t completely relax during the Under segment
The purpose of the Under phase is lactate clearance, not full recovery. 95% of FTP is still a relatively demanding intensity—you need to stay mentally focused and maintain a cadence of 85–90 RPM.

Tip 3: Use a metronome or alarm for timing
The precision of your switching points affects training quality. Set a repeating 2–4 minute alarm on your phone rather than relying on feel to judge time.

Tip 4: The final set is what matters
The adaptive stimulus of O-U comes primarily from the ability to maintain power under high accumulated fatigue. The earlier sets are relatively “easy”—it’s holding power in the last set that truly determines the training effect.

Training Frequency and Periodization Recommendations

Best phase: Base/build period (spring, 8–16 weeks before race season)

Frequency: 1–2 sessions per week, no more than 2 (high risk of fatigue accumulation)

Weekly combination:

• Tuesday: Over-Under (primary intensity workout)
• Thursday: VO2max intervals or SST
• Saturday: Long climbing ride (aerobic volume)
• Sunday: Easy recovery ride

Common Problems and Solutions

Problem 1: Blowing up before completing the scheduled Over duration
Possible causes: FTP overestimated, insufficient warm-up, or the previous high-intensity workout was too recent. Verify that your FTP setting is accurate and ensure full recovery in the 48 hours before testing.

Problem 2: Severe burning sensation in the muscles after finishing a set
This is normal, especially in the quadriceps. Over-Under is by design a lactate-stimulating workout, and moderate burning means the training hit the mark. However, if you still have noticeable muscle soreness the next day, increase rest time between sets.

Problem 3: Still feeling fatigued 2–3 days after O-U
Over-Under accumulates more fatigue than SST. If you feel persistently tired after two consecutive weeks, reduce the number of sessions or add more easy days. Schedule a deload week every 4 weeks.

Practical Recommendations

1. Use ERG mode: Power is controlled automatically, letting you focus on rhythm and breathing rather than manually adjusting resistance
2. Pair with music or video: The monotonous switching of O-U can easily cause you to give up mentally; external stimulation helps maintain motivation
3. Record the “final Over segment power” each session: Use it as an indicator of adaptation—if after several weeks you can still hold target power in the last Over segment, your fitness is improving

Conclusion

Over-Under training is uncomfortable, but that discomfort is exactly why it works. By repeatedly oscillating between lactate accumulation and clearance, the body gradually learns to maintain balance at higher intensities. Every time you grit your teeth through an Over segment, you’re investing in a higher FTP.

Related Reading

• Over-Under Threshold Intervals: The Secret Weapon for Breaking Through FTP Plateaus
• Cycling Lactate Threshold Training: Designing Intervals at the Sweet Spot of 88–93% FTP
• FTP Improvement Strategies: Annual Periodization of Sweet Spot, Over-Unders, and VO2max Intervals
• Zone 4 Lactate Threshold Training: How to Precisely Hit the Sweet Spot to Raise FTP