Knowing your FTP is essential for power meter users seeking better performance. Stages' power education expert Benjamin Sharp shows you how to prepare for the pain

Functional Threshold Power (FTP) is probably the single most important power training term. For Benjamin Sharp, former USA Cycling National Team coach and Stages' power education expert, the value of knowing your FTP is simple: "Functional Threshold Power is a basic way to gauge fitness," he says. "Over the course of a season, an increase in FTP is an indication that aerobic fitness has increased."

Equivalent to the maximum power you can sustain for an hour's riding, FTP is also key in setting training zones and can be used to help pacing in road racing, triathlon events and sportives.

Testing Your FTP

While the thought of an FTP test strikes fear into the heart of many a power meter user, it's an essential part of getting the most out of your power meter and your cycling performance – and you don't even have to ride for a full hour.

"The 20-minute test protocol asks for a full-gas, 20 minute effort," says Sharp. "After the effort, subtract five per cent from the average power to estimate FTP.

"I prefer the 20-minute test over the 30-minute test, especially for newer athletes, because the shorter the test, the less critical pacing is. Further, staying focused for a 30-minute effort can be challenging and the longer test might be a bit more disruptive to training as it requires a bit of recovery before and after the test to assure the
best possible result."

"Regarding pacing, this is the strategy I like to give my athletes," says Sharp. "There are any number of mental or physical strategies you might want to employ for a 20-minute time trial. One option is to think of the test as 4x5min TT efforts. A full 20-minute test can be a bit daunting and many athletes find it more manageable to break the effort into smaller pieces.

"Further, focusing on five minutes at a time orients the chance of pacing properly more in your favour. If using this method, have an average wattage goal for each five-minute segment. As you get to the end of each five-minute segment, take an assessment based on your rate of perceived exertion. Can you keep at this intensity? Can you increase the intensity for the duration of the test? For the next five minutes?

"Trying to increase the average power for each five-minute segment (compared to the segment prior) will go a long way to helping you achieve proper pacing. When it comes to the last few minutes, you should be at full effort, eking out every last bit of energy to assure that you have averaged the highest power possible."

Tips for indoor testing

Performing the test on an indoor trainer removes many of the variables associated with riding outdoors and gives more repeatable results when re-testing, but can lead to slightly different figures than on the road.

"Just like riding a bike in a different position (e.g. TT versus standard road versus mtb), it's not uncommon to see values that differ slightly when training indoors on a turbo trainer versus outdoors. In my experience, most people, if they see a difference, see a slightly lower power output for the same perceived effort and / or heart rate, when training indoors versus outdoors.

"This can be caused by any number of factors. A big contributing factor to inflated perceived exertion and heart rate can be that evaporative cooling is nearly non-existent indoors. I therefore recommend setting up an indoor training environment with plenty of air flow and possibly with access to cool air (e.g. a very large fan in a window in the winter)."

Various variables

While FTP is a crucial number to know, testing isn't completely foolproof and neither is your body's reaction to different bikes and alternative riding positions.

"The word 'functional' is in the definition of FTP," says Sharp. "It's important to acknowledge that we are estimating FTP in a real world setting, not in a human performance laboratory. There are a myriad of factors that might influence FTP, particularly when comparing bike-to-bike and position to position.

"For example, FTP will vary depending on if a rider is testing on a road bike in a standard road position versus on a time trial bike in an aerodynamic position. If it's noted that there is a difference, it's perfectly acceptable to have a different FTP depending on the bike or position being utilised."

What to do with your FTP

With your FTP figure in hand, you can set your training zones, enabling you to get the most benefits from your training sessions (see panel). "It's important to realise that each of the training zones more or less represents a different physiological energy system," says Sharp. "Depending on what the demands of your discipline are, an athlete will want to spend time developing the appropriate energy system. For example, a BMX athlete, who must produce a high amount of power in the opening few pedal strokes, will spend much more time developing Z7 power than an Ironman-distance triathlete who is relying on aerobic development for success."

How often should you re-test FTP?

If your fitness changes, your FTP will do too. Training by power allows you to train in a way that's tailored specifically to you as a rider, so it's important to keep that figure current.

"The classic answer for how often you should test is, 'it depends'. For newer athletes that are (probably) going to see big changes in their fitness, quickly, they might want to test as frequently as every six weeks to two months. More established athletes that might not be seeing those swings in fitness might be best served by testing every three months or so.

"Testing can be perceived as being disruptive to training and athletes might postpone testing because they don't want to interfere with their training schedules. However, it's important to keep in mind that testing is training! There are benefits to doing the testing, including but not limited to, the stimulus of doing the test itself, as well as an opportunity to practice good pacing strategies for time trials and other steady efforts."

Training Zones

These zones will allow you to get the most from your training plan – or help you write one depending on your goals and event type.

Z1 (active recovery) – up to 55% of FTP (0.55 Intensity Factor)

Z2 (aerobic endurance) – 56-75% of FTP (0.56-0.75 Intensity Factor)

Z3 (tempo) – 76-90% of FTP (0.76-0.9 Intensity Factor)

Z4 (lactate threshold) – 91-105% of FTP (0.91-1.05 Intensity Factor)

Z5 (VO2 max) – 106-120% of FTP (1.06-1.2 Intensity Factor)

Z6 (anaerobic capacity) – 121-150% FTP (1.21-1.5 Intensity Factor)

Z7 (sprint power) – more than 150% of FTP (1.5+ Intensity Factor)


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