Power (Wattage)
Our second training language is based on an objective measure of cycling intensity known as power.
Our power-based system uses zones constructed around a rider’s “threshold”.
The term “threshold” is generally synonymous with other common exercise physiology terms like lactate threshold (LT), anaerobic threshold (AT), and Maximal Lactate Steady State (MLSS) [1].
The graph shown is from a typical blood lactate test in a laboratory setting.
Our Y axis (vertical) shows blood lactate concentration while our X axis (horizontal) shows intensity in watts.
In this example, a sample of blood is collected every minute at the completion of each stage (on each stage, the intensity is bumped up by 5w).
On average, riders see an exponential increase in blood lactate in a wide ballpark of 4 mmol/L. In this example, the rider’s power at lactate threshold would be approximately 285w.
In general, lactate threshold testing attempts to pinpoint the deflection point where your body is no longer able to balance the production and clearance of lactate in the blood, leading to an exponential rise in blood lactate [2].
In an effort to more conveniently utilize lactate threshold concepts from the laboratory, Dr. Andrew Coggan and others came up with the concept of Functional Threshold Power (FTP) [3].
FTP translates to the mean max (average maximal) power a cyclist can produce for about one hour. This “functional” application of the lactate threshold concept makes “FTP” a convenient and practical method for describing and prescribing cycling training [4].
Of course, the FTP framework isn’t perfect, but no training system is. When choosing a language of power to guide our training, we aren’t after perfection, we’re after usefulness.
In this context, FTP’s convenience and reasonable accuracy at quantifying cycling fitness make it the preferred anchor for most power-based training systems.
Here are two examples of using the FTP concept (assuming an FTP of 300w) to construct two training zones:
- Zone 4/Threshold would range from approximately 273 (.91*300) to 312 (1.04*300) watts.
- Zone 2/Endurance would range from approximately 180 (.60*300) to 237 (.79*300) watts.
Viewed together, you can see how using power and RPE zones help to form a fuller picture of training intensity.
You can learn more about the language that describes the engine of human performance by clicking on page four.
References
- Klitzke Borszcz, F., A. Ferreira Tramontin, and V. Pereira Costa, Is the Functional Threshold Power Interchangeable With the Maximal Lactate Steady State in Trained Cyclists? Int J Sports Physiol Perform, 2019. 14(8): p. 1029-1035.
- Kenney, W.L., J.H. Wilmore, and D.L. Costill, Physiology of sport and exercise. 2020, Champaign, IL: Human Kinetics.
- Allen, H.C.A.R.M.S., TRAINING AND RACING WITH A POWER METER. 2019, [Place of publication not identified]: VELOPRESS.
- McGrath, E., et al., Is the FTP Test a Reliable, Reproducible and Functional Assessment Tool in Highly-Trained Athletes? International journal of exercise science, 2019. 12(4): p. 1334-1345.
