Original episode & show notes | Raw transcript
This document provides a detailed analysis of the concepts discussed in the “Empirical Cycling Podcast” regarding the use of Erg Mode in cycling training. It is intended for an educated audience seeking a nuanced understanding beyond simplistic “for or against” arguments. We will explore the tool’s utility, its significant drawbacks, and the overarching coaching philosophy that prioritizes athlete development through sensory feedback.
Erg Mode (Ergometer Mode) is a feature on smart trainers that automatically adjusts the resistance to maintain a specific target power output, regardless of the cyclist’s cadence. If the rider’s cadence drops, the trainer increases resistance to keep the wattage constant, and vice-versa.
The central debate, as framed by the podcast, is not whether Erg Mode is “good” or “bad,” but rather how its use impacts the development of a crucial athletic skill: the ability to self-regulate effort based on internal feedback. The core thesis is that over-reliance on Erg Mode can disconnect an athlete from their Rate of Perceived Exertion (RPE), hindering their ability to pace, adjust to fatigue, and perform optimally in real-world conditions.
The podcast acknowledges several scenarios where Erg Mode can be a distinct advantage:
Simulating Specific Terrain: For athletes living in flat regions, Erg Mode, particularly when paired with platforms like Zwift or RGT, is invaluable for simulating the low-inertia, high-resistance demands of climbing. This allows for targeted physical and neuromuscular adaptation that would otherwise be impossible to achieve.
“Set it and Forget it” for Low-Intensity Work: When the goal of a session is simply to accumulate low-intensity volume (e.g., recovery rides, some endurance work) and mental focus is required elsewhere (e.g., doing office work), Erg Mode can be beneficial. It ensures the athlete doesn’t stray into higher intensity zones.
A Remedial Pacing Tool: For novice athletes who struggle to hold a steady power output, Erg Mode can serve as “training wheels.” It helps them learn what a specific wattage feels like, acting as an introductory tool for developing pacing skills.
Fartlek-Style Workouts on Virtual Courses: Using a smart trainer on a rolling virtual course creates a dynamic workout that mimics the variable demands of a race or group ride. This “Fartlek Tempo” is a favorite workout mentioned in the podcast, as it breaks the monotony of indoor training and engages the athlete in a more stimulating way.
This section represents the core of the podcast’s argument. The consistent use of Erg Mode presents several significant disadvantages that can stunt an athlete’s long-term development.
This is the most critical point. Training is not just about executing numbers; it’s about building a sophisticated internal feedback loop between the brain, body, and power meter.
What is RPE? Rate of Perceived Exertion is the subjective feeling of how hard you are working. A well-trained athlete can accurately link their RPE to specific physiological states (e.g., “this feels like FTP,” “this is my all-day endurance pace”).
Why it Matters: This connection is fundamental. It allows an athlete to:
Adjust on the Fly: On any given day, fatigue, stress, and nutrition will alter how a specific wattage feels. An athlete tuned into their RPE will know to back off a workout that feels excessively hard, preventing overtraining.
Race Intelligently: In a race, there is no Erg Mode. Success depends on the ability to pace climbs, respond to attacks, and manage efforts based on feel, especially when power numbers fluctuate with terrain and tactics.
Track Progress: The shortest feedback loop for confirming that training is working is RPE. When an effort at a certain power level begins to feel easier, it’s a direct sign of improving fitness, often detectable long before a formal test.
The GPS Analogy: The podcast likens using Erg Mode to driving with a GPS. You get to your destination, but you don’t learn the route. Similarly, you might “complete” the workout, but you don’t learn how your body produces and sustains that power.
Erg Mode can engender a rigid, binary view of training: either the workout was completed at the prescribed wattage, or it was a failure. This is a flawed perspective.
Training is a Process, Not a Test: A workout that is barely completed by “muscling through” is often a physiological failure. It likely generated more fatigue than adaptation and compromises subsequent training days.
Ignoring Critical Information: An athlete who has to stop an interval early because the RPE is too high has gained valuable information: they are likely fatigued. The pass/fail mentality encouraged by Erg Mode tempts the athlete to ignore this signal and push through, which is counterproductive.
Physiological thresholds are not static numbers. They fluctuate daily based on recovery and overall stress.
Lactate Threshold 1 (LT1): This is the top of the “endurance” zone. As the podcast highlights, this can range from 50% to 85% of FTP depending on the athlete’s physiology and current state of fatigue. Setting an Erg Mode target based on a generic percentage (e.g., “70% of FTP”) is a shot in the dark. On a fatigued day, this could be a tempo effort, accumulating unnecessary fatigue and stunting long-term adaptation.
Functional Threshold Power (FTP): If an athlete’s FTP is set too high, Erg Mode will force them to complete intervals that are supra-threshold (VO2 max). This changes the stimulus of the workout entirely and leads to burnout. Without the RPE feedback loop, the athlete may not recognize that the “FTP” effort feels impossibly hard for the wrong reasons.
Erg Mode is particularly ill-suited for short, maximal-intensity efforts for several reasons:
Pacing and Power Decay: A true maximal effort (e.g., a 30-second sprint) involves a peak power followed by a natural decay. Erg Mode cannot replicate this; it would force a steady wattage, which isn’t how the body produces maximal power. This prevents the athlete from learning how to pace these efforts.
Skill Development: Skills like gear selection, cadence control, and body position are critical for sprinting. Erg Mode removes the need to practice these essential components of high-power production.
Hard-Start VO2 Max Intervals: While one could program a hard start followed by a fade in Erg Mode, the podcast argues this is suboptimal. The appropriate power level to “fade” to depends on the depth of the initial effort and the athlete’s recovery status. A pre-programmed workout cannot account for these daily variations. The goal of a VO2 max interval is a maximal effort for the duration, which requires self-pacing and listening to your body’s limits in real-time.
The overarching message of the podcast is one of balance and intention. Erg Mode is not an enemy to be avoided at all costs, but its limitations must be understood and respected.
The recommended hierarchy of training tools is:
Primary: Rate of Perceived Exertion (RPE). An athlete’s primary focus should be on cultivating a deep understanding of how efforts feel.
Secondary: Power Meter. The power meter should be used as an objective tool to provide feedback on that feeling. It validates the RPE and tracks long-term progress.
Tertiary/Situational: Erg Mode. This should be used sparingly and for specific purposes, such as those outlined in Section 2, but it should not be the default mode of training.
Ultimately, the goal is to develop a self-sufficient, intelligent, and adaptable athlete. This is achieved when the rider, not the trainer, is in control of the effort.