Triathlon Bike Intervals: Key Workouts Guide
Complete guide to bike intervals for triathlon. FTP-boosting workouts, threshold sessions, and race-specific intervals for every distance.
Triathlon bike intervals improve your FTP, lactate tolerance, and race-pace sustainability through structured efforts ranging from 30-second sprints to 20-minute threshold blocks.
Intervals are where fitness is built. While endurance rides build your aerobic base, intervals raise your ceiling and teach your body to sustain higher power outputs. This guide covers the key bike intervals every triathlete should know.
Understanding Interval Training
Why Intervals Work
Physiological benefits:
- Raise FTP (functional threshold power)
- Improve lactate clearance
- Increase VO2max
- Enhance muscular endurance
- Develop race-specific fitness
Training Zones Reference
| Zone | % FTP | Purpose |
|---|---|---|
| Zone 2 | 56-75% | Base endurance |
| Zone 3 | 76-90% | Tempo |
| Zone 4 | 91-105% | Threshold |
| Zone 5 | 106-120% | VO2max |
| Zone 6+ | >120% | Anaerobic |
Find your zones: FTP Calculator
Threshold Intervals (Zone 4)
Purpose
Build sustainable race power by training at or near your FTP.
The Classic 2x20
Warm-up: 15 min building
Main Set:
2 x 20 min at 95-100% FTP
10 min easy recovery between
Cool-down: 10 min easy
Total: ~65 min
Key points:
- Even pacing throughout each interval
- Should feel "comfortably hard"
- Can hold conversation in short bursts
3x15 at Threshold
Warm-up: 15 min building
Main Set:
3 x 15 min at 100% FTP
7 min easy recovery between
Cool-down: 10 min easy
Total: ~70 min
4x10 Threshold
Warm-up: 15 min building
Main Set:
4 x 10 min at 100-105% FTP
5 min easy recovery between
Cool-down: 10 min easy
Total: ~60 min
Good for: Athletes new to threshold work
Progressive Threshold
Warm-up: 15 min building
Main Set:
15 min at 90% FTP
15 min at 95% FTP
15 min at 100% FTP
5 min easy between each
Cool-down: 10 min easy
Total: ~80 min
Sweet Spot Intervals (88-93% FTP)
Purpose
Maximum training adaptation with manageable recovery requirements.
Standard Sweet Spot
Warm-up: 15 min building
Main Set:
2 x 20 min at 88-93% FTP
8 min easy recovery between
Cool-down: 10 min easy
Total: ~65 min
Extended Sweet Spot
Warm-up: 15 min building
Main Set:
3 x 20 min at 88-93% FTP
6 min easy recovery between
Cool-down: 10 min easy
Total: ~85 min
Sweet Spot + Threshold Combo
Warm-up: 15 min building
Main Set:
20 min at 90% FTP
5 min easy
10 min at 100% FTP
5 min easy
15 min at 92% FTP
Cool-down: 10 min easy
Total: ~80 min
VO2max Intervals (Zone 5)
Purpose
Raise your aerobic ceiling, improve oxygen utilization.
Classic 5x4
Warm-up: 15 min building
Main Set:
5 x 4 min at 110-120% FTP
3 min easy recovery between
Cool-down: 10 min easy
Total: ~55 min
Execution:
- Start strong but not max
- Even or slight fade acceptable
- Full recovery between intervals
6x3 VO2max
Warm-up: 15 min building
Main Set:
6 x 3 min at 115-120% FTP
3 min easy recovery between
Cool-down: 10 min easy
Total: ~55 min
Pyramid VO2max
Warm-up: 15 min building
Main Set:
2 min at 115% FTP, 2 min easy
3 min at 115% FTP, 3 min easy
4 min at 115% FTP, 4 min easy
3 min at 115% FTP, 3 min easy
2 min at 115% FTP, 2 min easy
Cool-down: 10 min easy
Total: ~55 min
Over-Under Intervals
Purpose
Improve lactate clearance and ability to recover at threshold.
Standard Over-Under
Warm-up: 15 min building
Main Set:
4 rounds of:
3 min at 95% FTP (under)
2 min at 105% FTP (over)
5 min easy between rounds
Cool-down: 10 min easy
Total: ~60 min
Extended Over-Under
Warm-up: 15 min building
Main Set:
3 rounds of:
4 min at 93% FTP
2 min at 108% FTP
4 min at 93% FTP
6 min easy between rounds
Cool-down: 10 min easy
Total: ~65 min
Criss-Cross
Warm-up: 15 min building
Main Set:
2 x 15 min continuously alternating:
1 min at 95% FTP
1 min at 105% FTP
8 min easy between sets
Cool-down: 10 min easy
Total: ~55 min
Tempo Intervals (Zone 3)
Purpose
Build muscular endurance, race-specific for Olympic/Sprint.
Tempo Blocks
Warm-up: 15 min building
Main Set:
3 x 15 min at 80-88% FTP
5 min easy recovery between
Cool-down: 10 min easy
Total: ~70 min
Extended Tempo
Warm-up: 15 min building
Main Set:
45 min continuous at 82-88% FTP
Cool-down: 10 min easy
Total: ~70 min
Good for: Race-pace practice for Olympic distance
Race-Specific Intervals
Sprint Triathlon Prep
Warm-up: 15 min building
Main Set:
3 x 8 min at 90-95% FTP
(Sprint triathlon race effort)
4 min easy recovery
Brick Run: 15 min off bike
Total: ~60 min
Olympic Triathlon Prep
Warm-up: 15 min building
Main Set:
2 x 20 min at 85-90% FTP
(Olympic triathlon race effort)
8 min easy recovery
Brick Run: 20-30 min off bike
Total: ~90 min
Half Ironman Prep
Warm-up: 20 min building
Main Set:
60-90 min at 75-80% FTP
(70.3 race effort simulation)
Practice race nutrition throughout
Brick Run: 30-45 min
Total: 2-3 hours
Ironman Prep
Duration: 4-5 hours
Structure:
Warm-up: 30 min easy
Main: 3-4 hours at 68-75% FTP
(Full Ironman race simulation)
Full race nutrition practice
Brick Run: 45-60 min
Total: 5-6 hours
Interval Progression
Building Interval Capacity
| Weeks | Interval Type | Volume |
|---|---|---|
| 1-4 | Sweet spot | 2 x 15 → 2 x 20 |
| 5-8 | Threshold | 2 x 15 → 3 x 15 |
| 9-12 | Add VO2max | 4 x 3 → 5 x 4 |
| 13-16 | Race-specific | Per goal distance |
Weekly Interval Distribution
| Level | Quality Sessions/Week |
|---|---|
| Beginner | 1 |
| Intermediate | 2 |
| Advanced | 2-3 |
Rule: Never back-to-back hard days
Execution Tips
Warm-Up Properly
Minimum warm-up for intervals:
- 10-15 min easy spinning
- Include 2-3 builds to target power
- Heart rate should be slightly elevated
Pacing Intervals
Common mistakes:
- Starting too hard
- Fading in final interval
- Inconsistent pacing
Better approach:
- Slightly negative split each interval
- Same average power across all intervals
- First interval should feel "too easy"
Recovery Between Intervals
During rest periods:
- Keep pedaling (easy)
- Don't coast
- Let heart rate drop
- Prepare mentally for next interval
When to Stop
Cut workout short if:
- Can't hit target power
- Power drops >10% from target
- Form breaks down significantly
- Feeling unwell
Common Interval Mistakes
1. Too Much Too Soon
The problem: Starting with high volume/intensity The fix: Progressive buildup over weeks
2. Not Enough Recovery
The problem: Insufficient rest between hard sessions The fix: 48+ hours between interval sessions
3. Wrong Intensity
The problem: Intervals too hard or too easy The fix: Use power meter, know your zones
4. Inconsistent Pacing
The problem: Hard start, big fade The fix: Start conservative, even pace
5. Skipping the Warm-Up
The problem: Jumping into intervals cold The fix: Minimum 10-15 min build
Sample Interval Week
Build Phase
| Day | Session |
|---|---|
| Mon | Rest |
| Tue | Threshold: 3x15 at FTP |
| Wed | Easy endurance 60 min |
| Thu | VO2max: 5x4 at 115% |
| Fri | Rest or easy 45 min |
| Sat | Long ride with tempo blocks |
| Sun | Long run |
Related Resources
- FTP Calculator - Find your threshold
- Triathlon Bike Training Guide - Overall bike training
- Indoor Cycling for Triathlon - Indoor intervals
- Triathlon Training Zones - Zone definitions
- Triathlon Bike Pacing - Race execution
- Threshold Training Triathlon - Threshold details