FTP vs 4DP: The Staggering Difference in Accuracy Explained

In a sport where athletes obsess over precise tolerances for power meters and smart trainers, it hardly makes sense doing workouts which aren't accurate. But when we compared the results of more than 30,000* 4DP power profiles to the assumptions FTP-based apps typically use to design workouts, our Sports Science Team found that FTP-based workouts can set targets which are inaccurate for up to 94% of athletes - a problem which training with 4DP avoids.

Physiology Primer: Power Comes In Many Forms

Before we get ahead of ourselves, let’s back up. To simplify things, there are four generally-accepted ways cyclists generate power: 

  • Threshold Power (FTP): Generally considered the highest average power you could sustain for about an hour.
  • Maximal Aerobic Power (MAP): The kind of power you use when doing an all-out, five-minute effort.
  • Anaerobic Capacity (AC): When you go flat out for a minute, you're digging maximally into your AC.
  • Neuromuscular Power (NM): Your pure sprint power, something you can hold for only a few seconds.

Regardless of what kind of cyclist you are or the types of events you target, you must spend time in each of these areas to achieve your potential. (Think you only need to work on FTP? You really need to read this). Importantly, performance in one area does not predict specific performance in another. Just as your AC does not predict your FTP, your FTP cannot predict your AC (even if FTP-based apps want you to believe that it can).

    How 4DP Sets Workout Targets

      Ask any experienced cycling coach and they’ll tell you how important it is to base workouts on the full power profile of an athlete. And that's what The Sufferfest does. Using our 4DP methodology, FTP efforts are based on FTP, MAP are based on your MAP, AC efforts are based on your actual AC and sprints are based on your NM. Every target is, therefore, automatically and accurately calibrated to your specific and unique abilities so you get the best training stimulus possible. If we want you to do an interval that targets 100% of your MAP, we can do that because we know what your MAP actually is.

      How FTP-based Apps Set Targets

      Most cycling training apps aren't sophisticated enough to do this. Their workouts are based only on FTP. So if you want to do an interval at 100% of your MAP, they have to make a guess based on a percentage of your FTP.

      To do this, they rely on physiological norms—or sometimes just crude estimations—of what the average person’s MAP, AC and NM are relative to their FTP. Generally, this means that MAP efforts are set at 120% of FTP, AC at 150% of FTP and NM at 250% of FTP. They're setting all your workout targets above FTP on, essentially, a guess about what you can do. They're even suggesting that you adjust the workout until it 'feels' about right to you (we think that science should do that for you).

      How Accurate are FTP-Based Workouts?

      But just how good is that guess? As mentioned, we took 30,000* 4DP power profiles and analysed how much a rider’s actual MAP, AC and NM varied from the estimated values FTP-based apps typically use. In doing so, they saw whether the targets were too high, too low or just right for the rider’s ability.** The results were astounding:

      • FTP targets based on FTP will be accurate for all athletes….obviously.
      • MAP targets based on FTP are inaccurate for 44% of athletes.
      • AC targets based on FTP are inaccurate for 82% of athletes.
      • NM targets based on FTP are inaccurate for 94% of athletes.


      Clearly, FTP is not an effective reference for efforts above threshold. Don't take our word for it, though. Look at the data and examine the incredible ranges in MAP, AC and NM power that athletes can produce relative to FTP. We've put our 30,000 test results into an interactive graph for you to filter by age and gender.

      • The x-axis (horizontal) shows power generated by people in our sample as a percent of FTP.
      • The y-axis (vertical) shows the percent of the sample that achieved that result.
      • The colored curves represent the spread of athlete ability, as a percentage of FTP,  for five-minute (MAP - yellow), one-minute (AC - red) and five-second (NM - blue) efforts. You can see, for example, that some athletes can only manage NM efforts of 150% of FTP while others can hit 700% (Clearly showing the folly of having sprints set to 250% of FTP for everyone).
      • You can also see three vertical lines, each representing where FTP-based apps typically set targets for MAP, AC and NM. This allows you to see where these assumptions sit within the full spread of what people in our sample can do.

      What About People With The Same FTP As You?

      Let's get personal. What’s the range in performance for people with your FTP? Let's take a look.

          • Enter your FTP in the calculator below.
          • We'll then show you the typical MAP, AC and NM targets a FTP-based app would set for you and everyone else with your FTP, regardless of what you can actually do.
          • We'll also show you the range in values for MAP, AC, and NM for people with your FTP, based on our 4DP Full Frontal results.***



      As you see, there are people with your FTP who can do far more, and those who can do far less, than an FTP-based app assumes. Where do you fall in that range? An FTP-based app can't tell you that - but The Sufferfest can. All you have to do is complete our 4DP fitness test. You'll get your 4DP profile, strengths and weaknesses as well as an idea of what kind of rider you are right now (which is the starting point to become the rider type you want to be).

      Get Started With The Sufferfest and 4DP

      Doing workouts based on FTP is old science. Those apps will tell you that everything is just fine as it is. But the world has moved on. You deserve the best fitness returns for the time you spend training. That means using the most advanced, accurate sports science available and using targets that precisely match what you can do.

      Get started with your 14-day free trial and experience the benefits of training with 4DP.



      * We analysed a sample of more than 30,000 tests from both male and female cyclists ranging in age from 18 to 82 years old. All files in the sample met specific criteria for inclusion, including the use of real power measurement (no virtual power), valid test results and other factors. Extreme outliers were removed from the sample. 

      ** What is 'just right?' To give those workouts every benefit possible, our team assumed that a target set by a FTP-based workout was 'just right,' when the reference metric (i.e., FTP) multiplied by the generally accepted physiological norm (e.g., 120% for MAP) was +/- 5% of the athlete's actual capability. Power-profile based workouts like 4DP, of course, don't need such leeway since they can precisely target the athlete's actual ability. It’s also worth stating that we are talking about setting the actual target within a workout itself. A further part of the art and science of performance improvement is how close an athlete needs to come that target in order to get a training stimulus (e.g., the athlete does not need to hit exactly 100% of their AC in order to drive AC improvement). The acceptable range varies by the desired training stimulus, the energy system targeted, the intensity and duration of the effort as well as other factors. It goes without saying, however, that if the accuracy of the target itself is wrong, then any deviation from that incorrect target will take the rider even further from the desired training stimulus.

      *** We use 5w 'buckets' for this analysis. So if you enter, say, 237w, we'll show you results for everyone with an FTP of 235-240w. We do this so competitors are not able to get a complete picture of how the power profiles break down in 1w increments. This does not significantly affect the relevance of the results for any particular individual. As well, while we have substantial data sets for most FTPs, extremely low or high numbers may have small populations. For this reason, the results shown may not capture the full range of human ability.


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