Lactate Threshold Training for Triathletes

Lactate threshold represents the exercise intensity at which lactate begins to accumulate faster than it can be cleared from your bloodstream. For triathletes, improving this crucial physiological marker across swimming, cycling, and running can dramatically enhance race performance and the ability to sustain higher intensities. This comprehensive guide provides discipline-specific strategies to develop your lactate threshold and race at faster, more sustainable paces.

Understanding Lactate Threshold

Lactate threshold (LT) is the highest exercise intensity you can sustain before lactate accumulation causes fatigue. It's also known as the anaerobic threshold, though these terms have subtle differences. For practical training purposes, LT represents the intensity you can maintain for approximately 45-60 minutes in a single discipline.

The Science of Lactate

Lactate is produced when your muscles break down glucose for energy. At low intensities, lactate is easily cleared and recycled. As intensity increases:

• LT1 (Aerobic Threshold): First rise in lactate (~2 mmol/L)
• LT2 (Anaerobic Threshold): Rapid lactate accumulation (~4 mmol/L)
• Beyond LT2: Lactate accumulates faster than clearance, causing fatigue

Why LT Matters for Triathletes

Lactate threshold is crucial for triathlon performance because:

• Race Pace Sustainability: Determines how fast you can go without "blowing up"
• Transition Quality: Higher LT means less fatigue carrying over between disciplines
• Pacing Strategy: Helps establish sustainable intensities for each leg
• Training Efficiency: Targets specific adaptations for endurance performance

Lactate Threshold Training Principles

Training Zone Determination

LT training typically occurs in these zones:

• Zone 3 (Tempo): 85-95% of LT - builds aerobic power
• Zone 4 (Threshold): 95-105% of LT - improves lactate clearance
• Zone 5 (VO2 Max): 105-120% of LT - develops maximal aerobic power

Adaptations from LT Training

Consistent threshold training produces several key adaptations:

• Improved Lactate Clearance: Better ability to process and recycle lactate
• Enhanced Buffering: Muscles become more resistant to acidity
• Mitochondrial Efficiency: Increased aerobic enzyme activity
• Cardiac Output: Improved heart's ability to pump oxygenated blood
• Capillarization: More blood vessels deliver oxygen to muscles

Swimming Lactate Threshold Training

Determining Swimming LT

Swimming threshold is typically determined through:

• Time Trial Method: 1500m-3000m time trial pace
• T-Pace: Best 1000m time ÷ 1000 × 1.05
• CSS (Critical Swim Speed): Based on 200m and 400m times

Swimming LT Workouts

Steady State Sets:

• Threshold Pace: 10-20 minutes continuous at LT pace
• Broken Swims: 3 × 1000m at threshold with 15-30 seconds rest
• Ladder Sets: 400-800-400m at threshold pace

Interval Sets:

• Mid-Distance: 8 × 200m at threshold with 10-20 seconds rest
• Pyramid: 100-200-300-400-300-200-100m at threshold
• Descending: 5 × 300m descending 1-5 at threshold pace

Open Water Considerations

• Sighting Practice: Include bilateral breathing and sighting
• Draft Training: Practice swimming in groups
• Navigation: Straight-line swimming efficiency
• Wetsuit Training: Practice threshold pace in race gear

Cycling Lactate Threshold Training

Determining Cycling LT

Cycling threshold can be determined through:

• FTP Test: 20-minute test × 0.95
• 60-Minute Test: Best sustainable power for one hour
• Ramp Test: Progressive test to failure × 0.75
• Lactate Testing: Lab test for precise threshold

Cycling LT Workouts

Sustained Efforts:

• Sweet Spot: 20-60 minutes at 84-97% FTP
• Threshold Intervals: 2 × 20 minutes at 95-105% FTP
• Race Simulation: 40-90 minutes at threshold power

Interval Training:

• Classic Threshold: 3 × 15 minutes at threshold with 5-minute recovery
• Over-Unders: Alternating above/below threshold
• Tempo Intervals: 4 × 12 minutes at 85-95% FTP

Specialized Triathlon Sets:

• Aero Position: All threshold work in race position
• Cadence Focus: Practice optimal cadence (85-100 RPM)
• Brick Preparation: End rides with short threshold run

Running Lactate Threshold Training

Determining Running LT

Running threshold can be determined through:

• 30-Minute Test: Best pace sustainable for 30 minutes
• 15K-10 Mile Race: Average pace from recent race
• Heart Rate Method: 85-90% of maximum heart rate
• Perceived Effort: "Comfortably hard" sustainable effort

Running LT Workouts

Tempo Runs:

• Steady Tempo: 20-40 minutes at threshold pace
• Progressive Tempo: Building from 85% to 105% of LT
• Broken Tempo: 2 × 20 minutes at LT with 2-minute recovery

Threshold Intervals:

• Classic Set: 3 × 2 miles at threshold with 90-second recovery
• Lactate Clearance: 6 × 1 mile at threshold with 1-minute recovery
• Race Pace: 4 × 8 minutes at 10K-15K race pace

Triathlon-Specific Running:

• Brick Runs: Threshold running immediately after cycling
• Fatigue Resistance: Threshold pace on tired legs
• Negative Split: Practice running faster when fatigued

Periodization of LT Training

Base Phase (Weeks 1-12)

Focus on building aerobic capacity with limited threshold work:

• Frequency: 1 LT session per discipline per week
• Duration: Shorter threshold efforts (10-20 minutes)
• Intensity: Conservative threshold pace/power
• Volume: High overall training volume at lower intensities

Build Phase (Weeks 13-20)

Increase threshold training frequency and duration:

• Frequency: 2 LT sessions per discipline per week
• Duration: Longer threshold efforts (20-40 minutes)
• Intensity: Target race pace/power
• Specificity: Race-specific conditions and equipment

Peak Phase (Weeks 21-24)

Maintain threshold fitness while increasing intensity:

• Frequency: 1-2 LT sessions per discipline per week
• Duration: Race-specific threshold durations
• Intensity: Race pace with short faster intervals
• Recovery: Increased recovery between sessions

Competition Phase

Maintain threshold while focusing on race execution:

• Frequency: 1 LT session per discipline per week
• Duration: Shorter, sharper efforts
• Focus: Race pace familiarity and confidence
• Recovery: Full recovery between sessions and races

Multi-Discipline Training Strategies

Sequential Training

Train one discipline's threshold at a time:

• Monday: Swimming threshold set
• Wednesday: Cycling threshold intervals
• Friday: Running threshold tempo
• Benefits: High quality, discipline-specific focus

Brick Training

Combine disciplines for race-specific adaptation:

• Swim-Bike: Threshold swim followed by threshold bike
• Bike-Run: Threshold bike followed by threshold run
• Benefits: Practices transitions and fatigue management

Concurrent Training

Train multiple disciplines in one session:

• Morning: Swimming threshold
• Evening: Running threshold
• Benefits: Time-efficient, high training load

Monitoring and Testing

Performance Indicators

Track these metrics to monitor LT improvements:

• Pace/Power at Threshold: Primary indicator of improvement
• Heart Rate at Threshold: Should decrease as fitness improves
• Perceived Effort: Threshold should feel easier over time
• Recovery Time: Faster return to baseline between intervals

Regular Testing Protocol

Monthly Testing:

• Swimming: 1000m time trial
• Cycling: 20-minute FTP test
• Running: 30-minute tempo test

Race Performance:

• Split Analysis: Compare discipline paces to training
• Transition Quality: Assess fatigue carryover
• Pacing Execution: Evaluate race strategy effectiveness

Common LT Training Mistakes

Training Too Hard

Many athletes train above threshold when targeting LT:

• Problem: Excessive lactate accumulation reduces training quality
• Solution: Use precise pace/power targets and monitor effort
• Indicators: Unable to complete intervals, excessive fatigue

Insufficient Recovery

LT training is demanding and requires adequate recovery:

• Problem: Poor adaptation, increased injury risk
• Solution: 48 hours between hard LT sessions
• Monitoring: Track HRV, resting HR, and subjective fatigue

Neglecting Discipline Specificity

Each discipline requires specific LT adaptations:

• Swimming: Stroke efficiency and rhythm at threshold
• Cycling: Position-specific power and cadence
• Running: Economy and pacing on fatigued legs

Nutrition and Recovery for LT Training

Pre-Training Nutrition

• Carbohydrate Loading: Ensure adequate glycogen for quality sessions
• Timing: 2-3 hours before training for optimal digestion
• Hydration: Start well-hydrated, especially for longer sessions

During Training

• Hydration: Replace fluid losses, particularly in heat
• Fueling: Consider carbohydrates for sessions >90 minutes
• Electrolytes: Replace sodium losses during long sessions

Post-Training Recovery

• Immediate: Protein and carbohydrates within 30 minutes
• Rehydration: 150% of fluid losses from training
• Sleep: Adequate sleep for adaptation and recovery
• Active Recovery: Easy movement to enhance circulation

Conclusion

Lactate threshold training is a cornerstone of triathlon performance, providing the physiological foundation for sustained race pace across all three disciplines. By understanding the specific demands of each sport and implementing targeted training strategies, you can significantly improve your ability to race at higher intensities.

Remember that LT development requires patience and consistency. Focus on quality over quantity, ensure adequate recovery between sessions, and monitor your progress through regular testing. The improvements in sustainable pace and reduced fatigue will translate directly to faster race times and better overall performance.

Use our lactate threshold calculator to establish your training zones and begin implementing these strategies in your triathlon training program today.