The ramp test has been regaining popularity for the past couple of years, and for good reason: it takes less time, is slightly less painful, and yields similar results. However, is it a better way predict FTP compared to the 20 minute version? Why do some people have a drastically different ramp test results compared to their 20 minute results? Which one should you use? This blog post will attempt to answer all of those questions, and provide some of the science behind ‘why’ there is a difference.
What is a Ramp Test?
A ramp test is exactly what it sounds like – an athlete starts at a given wattage (typically 100w) and ‘ramps’ up their power every 1 to 3 minutes (typically in 20w increments) until failure is reached. Here is what I do with my athletes:
- Warm up for 10-15 minutes.
- Having a smart trainer makes life much easier here.
- I start my athletes off at 60% of their FTP, and increase by 8% every minute or 2 (based on athlete fitness), until failure is reached.
- Once you settle into a cadence of your choice you must maintain that cadence, or pedal faster, throughout the rest of the test. For instance, if you ride at 90 RPM for the test you can’t then have your cadence fall off to 85, 80 and eventually 75 RPM in the final stages. Once you can’t maintain your cadence the test is over, but you must push to the point of failure and not give up!
You are looking for a heart rate inflection point for this test. The inflection point signals the anaerobic threshold (FTP) and can be very hard to see in my experience. Another way is to take the last COMPLETED step of the test, and multiply this by .75. This test is also called a Conconi Test.
This seems simple enough to get right, but the research around the ramp test is inconclusive. Furthermore, the majority of the “results” are inaccurate with Carey (2002) finding “a rather low correlation coefficient (r = 0.458), high standard error of estimate (SEE = 10.7 b·min-1), and high total error (TE = 16.7 b·min1)” compared to a computer-assessed decoupling point.
So, the ramp test has issues in terms of validation, and overall accuracy for some athletes, but why is that?
A Crash Course in Energy Systems
The 2 main energy systems at work during an FTP test are the aerobic and anaerobic – also called oxidative and glycolytic. Well-trained endurance athletes have a very high VO2 max (aerobic system), which enables them to ‘oxidize’ fat at a very high percentage of their FTP. There is always a flip side to the coin though – having a well developed aerobic system results in a down regulation of the anaerobic system. This anaerobic system, or the maximum rate of energy production by the ‘glycolytic’ system is sometimes designated by the term VLamax, or maximum production of lactate. In reality this is the maximum rate of production of pyruvate and lactate but since lactate is what is measured “La” has been used for this term. Clear as mud, right?
You’ll remember from a recent article about the Sweet Spot vs. Zone 2 debate in which I detail the change in lactate production from aerobic to anaerobic energy production:
In exercise where lots of oxygen is present (aerobic) your body will produce more pyruvate and less lactate. When you continue to push yourself into the higher power zones and above your lactate threshold, oxygen levels in the cells will decrease and you will go into anaerobic energy production, thus producing increased lactate and decreased pyruvate. Continue to push harder and the levels of lactate produced will continue to increase while pyruvate levels decrease. I.e. the fuel ‘mixture’ (substrate) of fat (pyruvate) to carbohydrate (lactate) changes as an athlete works closer to their individual lactate threshold.
This down-regulation of the anaerobic system means an aerobically dominant athlete will not be able to sustain supra-threshold work for long, but can sustain around FTP for upwards of 60 minutes. In comparison, an anaerobically dominant athlete will be able to push much further over FTP, and not crumble due to their ability to produce a ton more ATP (energy) via glycolysis. Think of a Tour de France climber compared to a track sprinter – they both ride bikes, yes, BUT are completely different ‘under the hood’.
Fortunately, we now have an ability to closely model the amount of work an athlete can perform above their FTP via WKO4. This is called FRC, or functional reserve capacity.
What is FRC?
FRC can be defined as:
Dr. Andrew Coggan
The total amount of work that can be done during continuous exercise above FTP before fatigue occurs.
We measure this ‘work’ in kilojoules (kJ), or J/kg. Below, are the approximate standards for FRC.
As you can see from above, the range of ability to perform work above FTP is massive from one athlete to another. With the range in males being 9.0 kJ-35.1 kJ, and females being 6.2 kJ-24.2 kJ. Also, this range can change over the course of a season, which is why it is important to track it, as well as manipulate your training to up-regulate or down-regulate it based on the demands of your target event. You want a relatively low FRC for more aerobically demanding events, and vice versa for more and anaerobically demanding events.
Putting it Together
Hopefully you can see why some athletes ramp tests are extremely low compared to their 20 minute FTP tests, and also why some athletes 20 minute FTP tests are much lower compared to their ramp test. Let’s create an example athlete to drive this point home, but first let’s talk energy conversions:
The energy E in kilojoules (kJ) is equal to the power P in watts (W), times the time period tin seconds (s):
E(kJ) = P(W)× t(s) / 1000
So, kilojoules = watts × seconds / 1000
or, kJ = W × s / 1000
Our athlete, Manny Watts (get it?!), has an FRC of 20 kJ with an FTP of 260w. This means once he breaks the 260w barrier, he has 20 kJ of work he can do before fatigue sets in, OR once he surpasses 260w on a ramp test, he will feel fatigued after performing 20 kJ of work. To make things simple, let’s have the ramp test increase by 20w increments every 1 minute, and let’s come into the test at 270w right after he bumps up from 250w:
270w x 1 minute = 270 x 60s /1000 = 16.2 kJ
So, Manny will feel fatigued around 18 seconds into the 290w step. This doesn’t necessarily mean total failure, just fatigue. At what point total failure will occur is hard to predict as there are a lot of factors at play, especially psychological, but this shows the size of the glycoloytic engine makes a huge difference for the ramp test results.
Utilize the Correct Test
If you have absolutely no clue what your FTP is, or are returning from injury or a long hiatus off the bike, you can use the ramp test results to predict a sustainable pace for the 20 minute FTP test. If you are testing what your Maximum Aerobic Power (MAP) is – which is beneficial to predict how well you would perform during a lead out, long sprint, or short ‘power’ climb – then the ramp test is also beneficial. Knowing what your MAP is, you will be able to better predict how hard you can push at the end of a race (when to start your sprint, and what power to target based on time til the line), how much power you can lay down and for approximately how long to create a breakaway, and if you can utilize the short and steep climbs during a race to your advantage.
However, if you are looking to see what your anaerobic threshold is (FTP) then the ramp test isn’t the way to go as it doesn’t take into account the individuality of what an athletes power is at their VO2 Max, and as discussed above, can overestimate FTP for the anaerobically strong cyclist, and underestimate FTP for the aerobically strong cyclist. Said another way, why would you use a test to predict your short duration power and try to extrapolate that out to what you can sustain for a longer duration?
The best testing protocol would be to incorporate all of the energy systems, test them individually, and create training zones based off the results – which is possible with a skilled Coach and using software like WKO4. The ‘perfect’ test has been attempted by many physiologists and coaches, but has not been perfected yet. However, I must give credit to Apex Coaching for their Sufferfest ‘4DP Test’ as that test is, in my opinion, the closest protocol yet to being able to get a look under an athletes ‘hood’ in less than an hour. Just like anything though, individualization of training, and testing protocols, makes the difference. So, I will test my sprinter-phenotype athlete’s short power more frequently, and my TT-phenotype athlete’s long duration power more frequently to ensure the training zones are correct based upon their individual metabolic system strengths. And, if I am brand new to an athlete with minimal data (which is rare these days) I will use a multi-day testing protocol to ensure they can perform each test at their maximal effort – but even this has conditional caveats like sleep, nutrition, stress, etc. from one day to the next.
The ramp test has its place, but in my opinion, it is not the best way to predict what your FTP is due to the myriad of factors discussed above, but mainly because of the individual variation for shorter duration power outputs. Besides that, the ramp test was designed to see what an athlete’s Maximum Aerobic Power (MAP) is. However, as discussed above there is no ‘perfect’ test, even in a laboratory, as everyone is different and can change by the day, week, month, and year. The best testing protocol is the one that provides the most accurate representation of the metabolic system you’re looking at, and the ramp test isn’t the best option for predicting anaerobic threshold – in my humble opinion of course.