Training Zones: The Limits of FTP

To All Riders

Many of you are likely familiar with the concept of Functional Threshold Power (FTP), which has become a popular method for setting training zones. It’s simple and widely used, but it has significant limitations when it comes to accurately defining your true physiological capabilities. Today, I want to explain why relying solely on FTP is insufficient and introduce a more advanced and comprehensive method for understanding your metabolic profile: the INSCYD system.

The Limitations of FTP-Based Training Zones

FTP is typically defined as the highest average power output you can sustain for approximately one hour. Based on this value, many training plans create power zones to guide different types of training. While this seems logical, FTP offers only a small window into your overall metabolic system. Here’s why using FTP to define your training zones can lead to ineffective or inefficient training:

1. FTP Measures a Single Threshold
   FTP focuses only on your aerobic threshold, assuming this value can predict your entire performance spectrum. However, your body has other key thresholds—such as your anaerobic threshold and recovery efficiency—that are equally important for different types of efforts. FTP doesn't account for these.  
2. FTP Ignores Anaerobic Contributions
   Many riders have strong anaerobic capacities (think short, sharp efforts like sprints), but this power comes from different energy systems than those used in endurance riding. FTP doesn’t account for the energy contributions of the anaerobic system or how well you can recover between anaerobic efforts.
3. No Insight into Carbohydrate and Fat Utilization
   FTP gives no information about how your body uses different fuel sources—carbohydrates and fats—at various intensities. Knowing how your body utilizes fuel during rides is essential for optimizing endurance and performance. Are you burning too much glycogen in the early stages of a long ride, leading to fatigue? FTP won't tell you.
4.  Inconsistent Training Results
   Different riders have different physiological makeups, even if they have the same FTP. A training zone based solely on FTP could result in undertraining for some riders and overtraining for others because it doesn't consider individual metabolic nuances like lactate production and clearance rates. For example: Two riders with the same FTP may have vastly different metabolic profiles: one might have a high anaerobic capacity (VLaMax), making them excel in short, intense efforts, while the other could be more aerobically efficient, ideal for sustained endurance efforts. By basing zones purely on FTP, both riders would be prescribed the same training intensity for endurance, tempo, and interval work, despite their different energy systems. This leads to overtraining for some—especially those with higher anaerobic capacity, who may struggle to sustain efforts intended for aerobic improvement—or undertraining for others, like those with strong aerobic systems who need higher intensities to stimulate gains. Without considering variables like lactate production, fat utilization, and recovery dynamics, FTP-based zones fail to offer the precision needed for tailored, effective training across different rider profiles.

Introducing INSCYD: A More Comprehensive Approach

At Soulor I use the INSCYD platform to test and create training zones. INSCYD is a scientifically backed performance testing and analytics tool that overcomes the limitations of FTP by offering a far more detailed view of your metabolic profile. Rather than focusing on a single data point (like FTP), INSCYD provides insights into the multiple systems that contribute to your performance. Here’s why INSCYD testing offers a superior approach:

1. Complete Metabolic Profiling
   INSCYD doesn’t just measure your power output; it assesses how your body produces energy, providing information on both aerobic and anaerobic energy systems. This allows you to understand your strengths and weaknesses in each energy domain, whether you're doing long endurance efforts or explosive sprints.  
2. Lactate Dynamics
   One of the key features of INSCYD is its ability to measure how efficiently your body produces and clears lactate. FTP doesn’t assess lactate production rates, but lactate is crucial for understanding your performance limits and recovery ability. Knowing your lactate dynamics helps you pinpoint the exact intensity at which you can train to maximize aerobic gains without burning out.
3. Fuel Utilization (Carbohydrate vs. Fat)
   INSCYD provides detailed data on how much fat and carbohydrate your body uses at different intensities. This is critical for endurance athletes, as it allows you to train in a way that optimizes fat metabolism and conserves glycogen stores. Knowing how your body uses fuel also helps with race-day nutrition planning.
4. VLaMax: The Anaerobic Component
   VLaMax (Maximum Lactate Production Rate) is a key metric in the INSCYD system that measures your anaerobic power. While FTP ignores anaerobic capabilities, INSCYD helps you balance both your anaerobic and aerobic systems. Lowering VLaMax, for example, is crucial for long-distance riders, while increasing it may benefit sprinters. Training tailored to these specific goals becomes more effective with such insights.
5. VO2max and Recovery Insights
   INSCYD also calculates your VO2max—your maximum aerobic capacity—and integrates this with your lactate threshold to give a full picture of how well you can sustain high efforts. It also offers insights into your recovery process by showing how quickly your body can clear lactate after hard efforts, something FTP alone cannot measure.
6. Highly Personalized Training Zones
   With the metabolic data from INSCYD, your training zones will be tailored to your unique physiology. Instead of basing your zones purely on FTP, you'll have zones that reflect your anaerobic capacity, lactate thresholds, and fuel utilization patterns, leading to more targeted and effective training sessions.

FTP Is Just the Beginning

While FTP has been useful starting point, it’s only a piece of the performance puzzle. As a more sophisticated system, INSCYD will help you to: 

• Train with precision based on your individual metabolic profile.
• Maximize fat metabolism for endurance, preserving glycogen for when it’s needed most.
• Understand how your body recovers and how to improve recovery rates between efforts.
• Balance aerobic and anaerobic training to meet your specific performance goals.

By integrating INSCYD into testing and zone setting we can customize training to target the exact areas where improvement is needed most. Whether it's building aerobic endurance, increasing sprint capacity, or optimizing recovery, this method ensures that every ride has a specific purpose. 

Hope that helps.

So, as ever, ride hard, be brave, have fun,

Peter