What is 4DP?
Four-Dimensional Power® (4DP®) uses four key performance metrics—Neuromuscular Power (NM), Maximal Aerobic Power (MAP), Functional Threshold Power (FTP), and Anaerobic Capacity (AC).
The Four Metrics of 4DP™
Your 4DP™ profile displays your current peak average power in four key metrics:
- Neuromuscular Power (NM): This 5-second power result represents a combination of your raw sprint power and muscular coordination. This value is based on your best 5-second power across both sprints. Yes, sprinting on a trainer isn’t the same as sprinting outside, and you’d be able to produce a bit more power on the open road. However, this value is used to set Sprint targets in the app, so using your indoor sprint power is necessary.
- Anaerobic Capacity (AC): This represents your ability to deliver short, high-intensity efforts as well as your ability to recover from hard efforts. It’s calculated from the results of your one-minute effort at the end of the test. Based on your results in the other metrics, it gives a good indication of how quickly you can put down the hammer, recover, and go hard again. While you’d be able to achieve a higher 1-minute peak power when completely fresh, that ‘fresh’ value would not take your ability to recover into consideration. Knowing a combination of both absolute ability and ability to recover allows us to set accurate power targets for short, sharp, and repeated efforts.
- Maximum Aerobic Power (MAP): Taken from the five-minute section of the test, this shows us your upper ceiling for aerobic power production, a key predictor of endurance performance. This value acts as a ceiling for your FTP and often needs to be raised in order to improve your ability over longer sustained efforts. This metric will be used to set targets in most of the higher intensity sessions. We can also estimate this value based on your results in our Half Monty Ramp test. Half Monty can be a better test for those who struggle with pacing or aren’t sure what you could realistically hold for a 5-minute steady effort.
- Functional Threshold Power (FTP): Taken from your 20-minute power, this is the metric you’re probably most familiar with and the only target used by most training apps. Traditionally FTP is calculated as 95% of your peak 20-minute power. While that can be close for some people, a single 20-minute test usually over-estimates FTP. While Full Frontal still has a maximal 20-minute effort, because it comes after the 2 sprints and 5-minute max-effort we take 100% of that 20-minute value. Those previous efforts deplete your anaerobic capacity, making the 20-minute effort in FF a more accurate representation of your true threshold power. We can also estimate your FTP based on our Half Monty Ramp test. By using heart rate data, power data from the ramp, and including a heart-rate constrained effort after the ramp we are able to make a more accurate estimation of your FTP compared to other ramp tests.
These values are measured using the Full Frontal 4DP test that is found in the app. The Half Monty test will measure FTP and MAP. If you've never completed Full Frontal, Half Monty will give you estimated NM and AC values that will be more accurate than when based on FTP alone.
For more information about Full Frontal:
How to get your most accurate Full Frontal results
For more information about Half Monty:
How to get your most accurate Half Monty results
For more information about the science behind 4DP and other sports science-related content:
Going Beyond Threshold Power – The SYSTM 4DP Power Profile