Someone asked on my Twitter feed today what ‘FTP’ is. I had recently mentioned it in a tweet. Since I use that term a lot it’s probably a good idea to define it. A little background first…
Anaerobic threshold. Lactate threshold. Ventilatory threshold. These are terms used to describe points in the intensity spectrum when the athlete is on the verge of or is already accumulating lactate and hydrogen ions in the body’s fluids. This means that the body is rapidly becoming acidic. Scientists attempt to define the above terms very precisely and see each as having unique conditions. Despite their best efforts even they fail to be in complete agreement on what each means.
As athletes we seldom get involved in such discussions. We tend to see these terms as interchangeable and meaning roughly the same thing – you are “redlining.” And for all intents and purposes, that is reasonable since these thresholds occur at roughly the same point and are seldom exactly the same from one day to the next due to variations in fitness and fatigue.
Magazines and books written for the athletic market use these terms when talking about training for endurance sports, also often interchangeably. So we have come to accept and generally understand what they mean, especially 'anaerobic' and 'lactate' threshold. They are less clear on 'ventilatory' threshold since this term is used much less frequently than the other two. In fact, you can simply use the word 'threshold' when speaking with other athletes and they will usually take that to mean a high effort with an RPE of about 7 or 8 on a 10 scale.
Now there is a new term being used to describe this level of intensity – 'functional' threshold. This is largely due to the work of Andrew Coggan, PhD, and Hunter Allen and their book, Training and Racing with a Power Meter (VeloPress, 2006). I like this term for field work because it removes all of the mystery associated with scientific concepts such as hydrogen build up, lactic acid, lactate, aerobic, anaerobic, RER, ventilatory rates, and the like. Very few really understand these terms. Functional threshold solves this problem by defining redlining based on actual output in a field test or race.
Functional threshold power or pace (FTP) is the highest mean average power or pace you can maintain for one hour. That’s quite precise, clear and logical. It even fits nicely with what we know about AT, LT, and VT. When you are in good shape these various measures of intensity can be maintained for about an hour. So rather than trying to describe this phenomenon with biological conditions, we simply define it based on a common output denominator.
Once you know FTP your training zones may be established based on power or pace. WKO+ software does this for you. All you do is plug in your FT power (cycling) or pace (running) and the zones are automatically calculated. Then workout intensity is determined based on pace or power zones. WKO+ will also determine heart rate zones using the system described in my books. Just enter your average heart rate for a one-hour race effort. Of course, this software goes well beyond simply setting zones. It also allows you to see a visual representation of the pace- or power-based workout and graph the workout/race data into several different charts for analysis.
All of this analysis data is based on FTP so it must be kept updated with periodic testing to make sure you have it right. Over the course of a season FTP will change a lot if your training is affective. And it is one of the best indicators of how your fitness and race readiness are progressing. While heart rate remains rather steady throughout the season, power and pace change considerably. That’s obvious since becoming more fit provides several benefits including being faster and more powerful. Training is all about accomplishing these goals. That’s why I keep a close watch on FTP for the athletes I coach and highly recommend that self-coached athletes do the same.