“What Is Functional Threshold Power (FTP)?
The term “threshold” has become synonymous with the word “confusion” in the minds of many athletes. There are many different words for essentially the same concept: anaerobic threshold (AT), lactate threshold (LT), maximal lactate steady state (MLSS), onset of blood lactate (OBLA), and just plain old “threshold.” It seems that there are just as many possible quantitative definitions, with different versions of the concept based on heart rate (HR), blood lactate, wattage, and so on. As a result, even in many scientific articles the authors have to present their own definition to clarify what they are talking about.
For more than thirty years, exercise physiologists have known that the exercise intensity at which lactate begins to accumulate in a person’s blood—that is, his or her LT—is a powerful predictor of that person’s endurance performance ability. This is because although an individual’s cardiovascular fitness—that is, his or her maximal oxygen uptake (VO2max)—sets the upper limit to his or her rate of aerobic energy production, it is the individual’s metabolic fitness—that is, LT—that determines the percentage or fraction of this VO2max that he or she can utilize for any given period of time.
“The physiological factors determining LT are complex, but essentially blood lactate levels serve as an indirect marker for biochemical events within exercising muscle. More specifically, a person’s LT reflects the ability of his or her muscles to match energy supply to energy demand, which in turn determines the fuel “mix” (i.e., carbohydrate versus fat) used and the development of muscle fatigue. Consequently, LT is the single most important physiological determinant of performance in events ranging from something as short as a 3 km pursuit to a stage race lasting as long as three weeks. This is especially true when LT is expressed in terms of power output, which also takes cycling efficiency into account. Because the effort that is experienced by an athlete when exercising at any given intensity is dependent upon his or her power output relative to power at LT, this parameter provides a physiologically sound basis around which to design any power-meter-based training program.
However, few athletes have ready access to lactate testing on a regular basis. What’s more, even those who do are still generally dependent on the person performing the test to first design an appropriate protocol, and then to correctly interpret[…]”
Excerpt From: Hunter Allen & Andy Coggan PhD. “Training and Racing with a Power Meter, 2nd Ed.” iBooks.
As one of my New Year’s Resolutions, I have resolved to re-read some of the best and most respected books on the subject of fitness, training, and exercise physiology.
I’m starting this re-education with a book that many in the cycling world consider the “Bible” of training with a power meter, Training and Racing with a Power Meter, 2nd Ed. – Hunter Allen & Andy Coggan PhD.
As I read I’ll share excerpts that I believe are pertinent in the world of indoor cycling and the ever growing use of power meters and group display.