The Science Behind Power Training Zones: An Analysis of FTP and the Six Training Zones

Introduction

A decade ago, only Taiwanese professional cyclists had access to power meters; today, entry-level power pedals have allowed many weekend Wuling challengers to see the world through “watt-tinted glasses.” However, having data does not equal knowing how to train. The core concepts of power training—FTP and the six training zones—are backed by solid exercise physiology, and are worth a deep understanding for every cyclist.

The Physiological Nature of FTP

Functional Threshold Power (FTP) is the maximum average power a rider can sustain for approximately one hour. It is not a precise physiological metric, but rather a practical approximation of “lactate threshold power.”

Below the lactate threshold, the lactate produced by muscles can be effectively cleared, keeping blood lactate stable (around 2 mmol/L); once this point is exceeded, lactate accumulation outpaces clearance, muscle acidification accelerates, and power output cannot be sustained for long.

Common FTP testing methods include:

• 20-minute all-out test: take average power and multiply by 0.95
• 8-minute test: take average power and multiply by 0.90
• Ramp Test: take 75% of the final completed power

For Taiwanese riders, using long climbs such as Wuling eastbound, Taipingshan, or Hehuanshan to conduct FTP assessments is a highly practical choice of venue.

The Six Training Zones Explained

Based on FTP, Dr. Andy Coggan proposed the widely used six-zone training model, with each zone corresponding to different energy systems and adaptation goals:

Training Applications for Each Zone

Zone 2: The Underrated Foundation

Zone 2 training is the foundation of endurance, yet it is also the zone most often neglected by Taiwanese cyclists. Many people head out and ride at Zone 3 or above, feeling quick progress in the short term, but in the long run they are prone to hitting a plateau. Zone 2 stimulates mitochondrial biogenesis in muscle cells, improves fat oxidation efficiency, and helps you spare glycogen on long rides.

Within total weekly training volume, it is recommended that Zone 2 accounts for 70–80% (polarized training model), paired with a small amount of high-intensity training.

Zone 4: The Core Training for FTP

Riding directly around FTP is the most effective way to raise threshold power. Typical training sessions:

• Sweet Spot training (88–93% FTP): 2×20 minutes, with 5 minutes recovery
• Threshold intervals: 4×10 minutes @ 100–105% FTP, with 3 minutes recovery

Zone 5: The Engine for Short-Term Explosiveness

VO2max training places maximal load on the cardiorespiratory system, stimulating stroke volume and oxygen delivery efficiency. Typical session: 5×4 minutes @ 110–115% FTP, with 4 minutes recovery.

Practical Advice

• Testing cycle: Reassess FTP every 8–12 weeks and update your training zones
• Avoid the “gray zone”: Zone 3 intensity is neither easy nor hard; it accumulates fatigue while offering limited training benefit, and beginners can easily get stuck there long-term
• Leverage Taiwan’s terrain: Yangmingshan and the Xindian hills offer natural Zone 4–5 climbing training, with the Fengguizui long climb especially suited for Sweet Spot training
• Recovery is equally important: Zone 1 active recovery rides (30–60 minutes of easy spinning) accelerate lactate metabolism—don’t skip them
• Data logging: Use Garmin, Wahoo, or mobile apps to record the power distribution of every session and review it regularly

Conclusion

The value of power training lies not in owning expensive equipment, but in understanding the physiological meaning behind the numbers. FTP is the ruler; the six zones are the instructions for use. What truly makes you faster is the discipline to invest sufficient training volume in the right zones. Before your next ride, ask yourself: “What am I training today?”—not just “How fast am I going to ride?”

Related Reading

• The Physiological Mechanisms of Functional Threshold Power (FTP): A Detailed Analysis of the Lactate Balance Point
• Cycling FTP Growth Curve: 12-Month Systematic Tracking and Analysis
• Power Meter Training for Beginners: A Complete Guide to FTP Testing and Five-Zone Workout Design
• Power Training for Beginners: Understanding FTP, TSS, and Training Zones from Scratch