Original episode & show notes | Raw transcript
In the world of cycling, Functional Threshold Power (FTP) has become the dominant metric for assessing and tracking endurance fitness. As the podcast explains, its popularity stems from its relative ease of measurement and its power as a single, motivating number that athletes can track. It effectively marries the physiological concept of a sustainable “threshold” with the quantifiable output from a power meter.
However, as any racer knows, a race is rarely won by holding a perfectly steady power output. The highest FTP doesn’t guarantee a win. This leads to a crucial question: What lies beyond FTP? This guide will unpack the podcast’s conceptual framework for understanding the multifaceted nature of endurance, exploring the physiology, training methods, and tracking techniques for building a truly robust and race-ready engine.
Before moving beyond FTP, we must first understand what it represents and where its explanatory power falls short.
Definition: FTP is an estimation of the highest power output a cyclist can maintain in a quasi-steady state for approximately 30 to 75 minutes without fatiguing.
Its Role: It serves as an excellent predictor of performance in steady-state events like time trials and provides a baseline for overall aerobic fitness.
The Limitations: The podcast highlights several critical limitations of relying solely on FTP:
It’s Not One-Dimensional: An FTP of 300 watts held for 35 minutes (TTE, or Time to Exhaustion) is a different physiological state than 300 watts held for 60 minutes. Context is key.
It Ignores Non-Steady States: It fails to capture performance in disciplines defined by stochastic (highly variable) efforts, such as criteriums, cyclocross, and mountain biking. It doesn’t measure sprinting or the “punchiness” required for repeated accelerations.
It Overlooks Sub-Threshold Durability: It doesn’t describe how long an athlete can hold a high percentage of FTP. One athlete might hold 90% for an hour, while another can hold it for two.
The Critical Flaw - Motor Units: Most importantly, FTP does not encapsulate what happens in our largest, most powerful motor units. Training at or below FTP primarily stresses smaller, slow-twitch dominant motor units that are already highly aerobic. It neglects the physiological development of the larger, fast-twitch units required for race-winning moves.
The podcast proposes a framework for endurance built on two distinct but complementary pillars.
This is the classic form of endurance that FTP attempts to measure. It’s the ability to sustain work for long periods without significant fatigue.
Physiology & Adaptations: Riding at a steady state primarily recruits smaller motor units. The goal of this training is to make these units, and the entire aerobic system, more efficient. The key adaptations include:
Increased plasma volume, which enhances cardiac output.
Increased muscle capillarization for better oxygen delivery.
Increased mitochondrial density and function for greater ATP production.
Enhanced fat mobilization and oxidation, sparing precious glycogen stores.
Increased muscle glycogen storage capacity.
Measuring Improvement: Since FTP is just one snapshot, we need better tools to track improvements in steady-state endurance:
Power at a Given RPE: If your “all-day” perceived effort (RPE) yields a higher average power over time, your aerobic engine is improving.
Heart Rate Decoupling: For a given steady power output, a lower degree of upward heart rate drift over the course of a long ride indicates improved fitness. (Note: This can be confounded by heat, hydration, and stress).
Efficiency Factor (EF): Calculated as Normalized Power / Average Heart Rate. The podcast highlights this as a favorite metric. An increasing EF for similar types of rides shows that you are producing more power for a given cardiovascular cost. This is a superb way to track aerobic fitness over a training block.
This is the ability to handle and recover from repeated, high-intensity efforts above FTP. This is the cornerstone of the “Beyond FTP” philosophy.
Physiology & Adaptations: To produce high power for sprints, accelerations, or steep climbs, the nervous system must recruit larger motor units, which are typically composed of more fast-twitch muscle fibers. By default, these motor units are powerful but not very aerobic; they fatigue quickly.
The revolutionary concept here is that these large motor units can be aerobically trained. The podcast cites a study on cross-country skiers whose Type II (fast-twitch) fibers developed fat-oxidizing capabilities comparable to their Type I (slow-twitch) fibers. This demonstrates that metabolic adaptation is not inextricably linked to fiber type; it is driven by training stimulus.
The goal of stochastic training is to repeatedly demand ATP from these larger motor units, signaling them to develop their own aerobic machinery—more mitochondria, more aerobic enzymes, and a better capacity to use fat for fuel.
Training Methods:
Stochastic Tempo: Riding on rolling terrain with the goal of covering the course as fast as possible. This involves pushing harder on climbs (recruiting larger motor units) and recovering on descents, mimicking the demands of a breakaway.
Over-Unders: Intervals that alternate between being just over your FTP and just under it (e.g., 1 minute at 110% FTP, 3 minutes at 90% FTP). This forces the body to process lactate and work under fatigue while keeping larger motor units engaged.
Intermittent Intervals: Short, repeated “on/off” efforts, such as 15 seconds hard and 15 seconds easy, for extended blocks (e.g., 10-20 minutes). The key is not to go “all-out” but to pace the efforts so they are repeatable for the entire duration. This accumulates significant time stressing the target motor units.
Repeated Sprint Training (RST): Short, maximal sprints with brief recovery (e.g., a 5-second sprint every minute). This targets the very largest motor units to improve their fatigue resistance.
Measuring Improvement: Tracking this fitness is tricky. Normalized Power (NP) is often misleading, as a very punchy race can yield an artificially high NP that is not a new FTP. Better methods include:
Fixed Test Course: The gold standard. Periodically perform a maximal effort on the same loop of road or trail. Tracking your time, NP, and EF on this course provides a true apples-to-apples comparison of your stochastic fitness.
Workout and Race File Analysis: Analyze your power file from a race or a hard workout. Does your peak power in sprints or accelerations drop off significantly from the beginning to the end? As your stochastic endurance improves, you will see less decay in these efforts, indicating enhanced fatigue resistance in your larger motor units.
The ultimate goal is to integrate these two pillars. A high FTP provides the foundation to stay with the group, but a well-developed stochastic endurance engine provides the ability to win the race.
The key benefit of training your larger motor units to be more aerobic is glycogen preservation and enhanced freshness. When these powerful units can contribute to efforts using fat or by oxidizing glucose more efficiently (yielding ~30 ATP instead of 2 via glycolysis), they spare their limited internal glycogen stores.
This means that when the critical moment arrives—the final sprint, the race-winning attack—those large, powerful motor units are not already depleted. They are “fresher” and have the fuel needed to produce maximal power, giving you the kick that others who have “burned their matches” will lack.
This resolves the apparent “irony” mentioned in the podcast. The advice is not to do exhausting anaerobic capacity workouts all year. Instead, it is to perform targeted, sub-maximal but high-force efforts designed to build the aerobic machinery of your fast-twitch fibers, making you a more durable and formidable racer.