FTP Is a Yardstick, Not a Score

FTP is a yardstick, not a score

If you train with a power meter, functional threshold power is the number everything else hangs on. It sets your training zones, and it tells you whether a block of work actually did anything. To explain it properly, we went to Ian Gibson of Dialed Performance Coaching. Ian is a USA Cycling certified coach, he co-hosts the Dialed Podcast with us, and he is the road captain of the Dialed Cycling Team, so he is the person we wanted explaining this.

This post walks through Ian's take on what FTP is, how far to trust the tests, and how to raise it. He covers all of it in more depth in his own article, A Cyclist's Guide to Functional Threshold Power, which is worth reading in full.

What FTP actually means

Ian builds his explanation around thresholds. In his telling, as you ride harder, aerobic energy alone can no longer cover the demand, so your body leans more and more on glycolysis, which breaks down stored carbohydrate quickly. Lactate builds up, the blood grows more acidic, and at some point a harder effort simply cannot be held.

If you plot blood lactate against effort, the line stays fairly flat for a while, starts to lift, and then bends sharply upward once your body can no longer clear lactate as fast as it makes it. Ian explains that the first lift is called the first lactate threshold, and the sharp bend is the second lactate threshold, which some people call the onset of blood lactate accumulation. The power you can produce at that second threshold is your threshold power.

The "functional" part, as Ian puts it, means estimating that point out on the bike instead of in a lab. Coaches and researchers define FTP as the highest power you can hold steadily for roughly an hour, which is why you need a power meter to find it.

Coach Ian Gibson is clear that threshold is a gradual line, so you cannot ride forever just because you are a few watts under your FTP.Riding at 95 percent of FTP still hurts, and how long you can stay there comes down a lot to how much discomfort you will put up with.

The 20 minute test is an estimate

Ian is the first to admit that hardly anyone wants to ride a full hour all out, and nobody wants to do it often, so most riders use a shortcut. The common one is a 20 minute test, where you ride as hard as you can for 20 minutes and take 95 percent of your average power. Ramp tests, which add resistance in steps until you cannot keep going, are the other popular choice. Ian's caution is that these tests, and the conditions you ride them in, only get you an estimate, and that most riders who test this way cannot actually hold the result for a full hour.

The research backs him up. A 2018 study in the International Journal of Sports Medicine had 23 trained male cyclists ride a 20 minute time trial, a 60 minute time trial and a lab test. On average the two time trial estimates landed close together, but for individual riders the gap could run as wide as about 60 watts either way, and the authors concluded the two should not be swapped for each other for any one person. A 2022 study in the Journal of Science and Medicine in Sport took FTP from the 20 minute test and had riders hold it until they could not, and the typical rider in every group fell short of an hour.

Better trained and more experienced riders lasted longer at their own FTP. That fits Ian's warning that someone else's number is a poor yardstick for your own, and it is a good reason to compare each test with your last one.

Indoors and outdoors

Ian also points out that the power you can hold on a trainer and the power you can hold on the road or trail are not always the same, and that how far apart they land depends on the setup and on the rider. Our take: if your indoor number reads low, check the setup before you blame your fitness. Make sure the room is not too hot, a fan is actually on you, and the trainer reads the same as the power meter on your bike. Then test in the same place and the same way every time, so the trend means something.

A good FTP depends on your weight and your riding

Ian's view is that unless you only ride flat roads, raw FTP matters less than most riders think. On a climb, gravity charges you for every extra kilo, so a heavier rider with big watts can still get dropped by a lighter one once the road starts going up. That is why watts per kilogram is the number he watches for hilly riding. In a flat time trial it flips, and the rider with more lean muscle and more absolute power has the edge if everything else is equal.

For a benchmark, Ian's rule of thumb is that something around 4 watts per kilogram is a good number to work toward if you want to be competitive in an amateur Category 3 road race. He is just as clear that genetics put limits on how high any one rider can go.

Muscle fiber type is one of those limits. Ian explains that slow twitch fibers are built for long, steady output and run mostly on aerobic energy, while fast twitch fibers bring the explosive power but rely more on glycolysis and tire sooner. Training can shift the mix somewhat, but riders born with more slow twitch fibers start with an advantage for sustained power. The research agrees that a good share of this is inherited: a 1995 review in the FASEB Journal estimated that about 45 percent of the variation in slow twitch fiber share between people is tied to inherited factors, and about 40 percent to environment, which includes how the muscle gets used.

Ian adds body geometry to the list, since where your muscles attach to your bones changes the leverage you have to work with. So if a friend your age has a bigger FTP than you, there may be good reasons you never match it, and that is fine.

Ian on racing

Where FTP matters most, and where it matters less

Ian says FTP matters most to triathletes, marathon runners and riders whose racing is mostly long time trials. In a typical road, gravel or mountain bike race where everyone starts together, holding a hard effort for an hour or more often is not what decides the result, unless the course has long climbs or you end up alone in a breakaway. The pace in a bike race changes every few minutes, so Ian trains all of a rider's energy systems, not only threshold.

1. Short, very hard surgesHanging on when the pace jumps is often worth more than a few extra watts of FTP.
2. A sprint after a long dayIan points to the finish that comes after hours of steady zone 2 and tempo riding, when you are far from fresh.
3. Racing smartTactics are their own skill, and no power number covers them.

The good news, in Ian's experience, is that riders who build threshold in a structured way usually see their five minute power come up along with it.

Threshold compared with your ceiling

Ian's preferred way to judge an athlete's fitness is not FTP on its own, but how close threshold sits to VO2max, the most oxygen your body can use. In cycling he compares power at threshold with power at VO2max. Many experienced riders are already close to their genetic limit for VO2max, he notes, but there is usually still room to push threshold up toward it.

Two riders with the same engine can ride very differently, depending on where their threshold sits.That is why Ian Gibson, our coach, judges fitness by how close a rider's threshold power sits to their VO2max power.

A classic study shows why that matters. In a 1995 review, exercise physiologist Edward Coyle described two groups of competitive cyclists with the same VO2max but different thresholds, 82 percent of VO2max in one group and 66 percent in the other. Riding hard, the low threshold group burned through muscle glycogen more than twice as fast and lasted about half as long. Coyle also noted that after the first two or three years of hard training, performance gains track improvements in threshold while VO2max barely moves, which lines up with Ian's view that threshold is where most riders still have room to grow.

How Ian raises it

Ian builds FTP work on two training principles. Specificity means training the system you want to improve, and progressive overload means raising the stress a little as your body adapts. At threshold your body is still using both aerobic and glycolytic energy, so riding at or near your current FTP improves both. As that work gets easier, it has to get harder for you to keep improving.

Lactate shuttle intervals

Rather than teaching your body to put up with rising acidity, Ian would rather improve its ability to clear lactate out of the working muscles. His main tool for that is what he calls lactate shuttle intervals. Each one opens with a short burst above threshold to spike lactate, then settles straight into a longer stretch just under threshold, where your body works to clear it while you keep pedaling. As your clearing gets better, he makes the intervals progressively harder. He leans on these heavily, and in his coaching they are a big part of how riders push FTP up.

Zone 2 underneath it

Ian's second tool is plenty of zone 2 riding. A stronger aerobic system holds off the point where glycolysis takes over until a higher intensity, which, as Ian puts it, shifts the lactate curve to the right and delays that sharp rise. He ran a full zone 2 masterclass on episode 351 of the Dialed Podcast, and he walked through FTP on the show back on episode 349.

VO2max work when the ceiling is low

Some riders already have a threshold close to their VO2max but modest watts overall. Ian's read on that rider is that the ceiling itself has room to rise, so he shifts the focus to VO2max intervals and lets FTP get pulled up behind it.

How Ian would have you use it

Ian's advice for putting the number to work comes down to a simple routine.

1. Test at the start of a training block.
2. Set your zones from that number and do a lot of your work at or around threshold, including lactate shuttle intervals.
3. Test again at the end of the block to see whether the training worked, and compare yourself with your own last number.
4. If you race in a pack, train surges and sprints alongside threshold.

FTP tells you where your steady ceiling is. Ian uses it to set zones and to check whether a block of training paid off.

It does not tell you how you race. Surges, sprints and smart tactics live outside it.

Use FTP to measure your own progress, not to compare yourself with other riders.

Want help raising yours?

Then go find out where your line is.