Establishing Critical Power

First, if you can ride any more after the failure point of the Ramp test, you didn’t do the test properly. I have to get off the bike and lay on the floor after I get to my failure point on the Ramp test. I can’t ride for 1 more second at that power target. The whole point of the ramp test is to go until you just can’t even turn the pedals.

As to the rest, I’m a little confused as to why you want to find W’ or other Critical power targets.

If you want to improve your indoor curve, you could just try to do some all out efforts. There is a free ride option in TR, just load the Freeride workout and do a warm up, and then hit your max effort for your time.

You are saying that you use TR indoors, so all your workouts will be based off of FTP, which is already estimated with the Ramp test. So why not just make your life easy and follow the workouts?

So, basically my question is, what are you trying to achieve with knowing your critical power values?

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Thanks, but having read this it leaves me none the wiser. I’m not experienced enough to interpret the calculations and explanations fully from this paper. How does this translate into a workout that I can run? I know that the Ramp Test FTP is not the same as my CP - is there another calculation I can overlay to calculate CP from my past tests, or is there a different type of Ramp to complete? The calculations in the paper require other measures that I do not know.

Sorry if I’m missing something obvious - can I still claim noob status :pray:

You have to realise that the efforts needed for the calculation are max efforts, as in, you will only be able to do one in a session. They should be unpaced so forget about starting steady and eeking it out, the power curve for a 3 min max effort should start high and drop away rapidly as the hurt kicks in then it’s a grovel to the end. If you can raise your power in the last 30 seconds you did it wrong.

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I think I could keep going, but just not at the target power. It may not be much, but I’m betting I could sustain 80-90% of FTP for a few minutes. I feel like I’m mentally and physically toughing the tests out, but perhaps not :man_shrugging:

I didn’t know this existed - might have to give this a go. Great idea!

I’m happy with my indoor training and do want to follow the workouts. I just want to estimate my power curve potential so that I can probe different effort times and explore my fitness/power outside of the structured workouts. Why? Because curiosity makes us do and doing makes us faster :slight_smile:

I’m at the start of a new chapter in my biking, and having only followed the structured TR workout plans properly for the past 3/4 months with some great gains, I want to learn more and explore. I want to get faster, ultimately.

By knowing my CP, I can more accurately calculate my AWC, and by knowing both I can determine my theoretical power curve potential…giving more targets to aim for :slight_smile: Always looking for targets to keep training interesting!

Thanks for the reply :+1:

Ok @ValeCyclist , so hit hard from the start and just keep going until three minutes. Got it. I guess it’s a good idea to have someone on hand to catch me, just in case I drop :laughing:

To everyone else - I’m grateful for all of the advise on this thread. I get that the 3 minute test may not be as accurate for an elite cyclist, but given that I’m just an enthusiast, I think it will be a good starting point without over complicating things! I can always look to other tests later, once I understand more.

I use intervals.icu - I didn’t know that re the eFTP, so good to know. I’d better get on to getting some good data! :slight_smile:

As everyone will say, this should just not be possible. It defeats the purpose of the test if you can do this and it’s wasting time and effort if you can do this.

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I wouldn’t say that :yum:

It is definitely possible to drop the power and continue working after “task failure” at the end of a ramp test. Task failure only means you cannot continue to push the target workload. In a race if I can’t follow the wheel, I don’t simply stop. I’m able to continue riding, just not at the target power required by the race. task failure is not necessarily the same as exhaustion.

btw, this is where I think Xert has an advantage over W’ for realistically modelling ‘work capacity’ and task failure constraints.

Whether there is any value in continuing to work at a submax workload after task failure on a ramp test? :man_shrugging: I’ve actually seen something similar in the literature. One cruel experiment comes to mind where the subjects were asked to ride to task failure on an incremental ramp test as usual. Then the power was immediately decreased to something like 105 or 110% of power at ventilatory threshold 2 (VT2, a proxy for FTP/CP/“threshold”) and essentially they continued as a TTE time to exhaustion test until a second task failure… sounds painful.

I’d have to go find the paper, but I think the purpose was to demonstrate that W’ was being theoretically under-estimated from constant workload (and ramp) tests, if the riders were shown to be able to continue to work below the ‘task demand’ but above CP, therefore burning more kJ of W’.

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OK so maybe my wording wasnt great but what I was trying to convey is that “in general” most people who do a ramp test wouldn’t feel able or inclined to do much more work after their break point. Of course it is possible to continue at a much lower power but if you’re trying to identify a W’ value this isn’t going to help.

I was thinking of saying that doing a ramp test may not be the best method of emptying the tank and the experiment you cite appears to back this up.

Maybe you can help with what use we can make of a CP value? Would you plan sessions as a percentage of it as you would FTP?

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I’ve never tried I’m just agreeing with @SpareCycles in that you will be able to continue to produce power, I’m not too sure I want to carry out the test he describes either :joy:

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Then you always quit too soon.

I’m sorry, that’s not the original paper I thought it was. The equation you need is:

T = CP/s + 2*W’

To determine CP and W’, you would do at least three ramp tests with different rates of increase in power (s), plot time to exhaustion (T) against s, and fit the above equation using a computer program.

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So far, the ride that gave the me most data for CP/W’ was a 20min hill climb that started out easy (5-8%) and gradually got steeper (up to 15-20%). The final steep section actually makes it easier to maintain a high power even as you fatigue.

Also Xert has a workout designer that overlays MPA (analogous to W’ Bal but expressed in watts) on the graph of power vs time. So you can use it pretty easily to design your own test.

Based on playing around with this tool, the quickest test was by far a sort of reversed ramp test where you start deep in anaerobic and then let yourself fade overtime but never drop below CP/threshold power (i.e. hang on for dear life). The test is done when you can’t hold power over threshold anymore.

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That’s not how High Intensity Energy (HIE) works in the Xert Model.

As you deplete HIE you also reduce your Maximum Power Available (MPA), although they happen at different rates. When MPA reaches your current output you have to reduce the output to below MPA to be able to continue riding. This can continue at ever reducing power until you reach Threshold Power (TP) at which point you will have depleted HIE but will still be able to ride at TP. The point at which you were unable to continue in a ramp test is not the same as depleting HIE as the ramp test doesn’t allow you to continue at a lower output if you are in ERG mode.

I think what the opening post is suggesting is that by going to failure on the ramp test and then switching to slope mode you could effectively continue to ride at a power that would tend towards TP. You could do that with any test that ‘depleted’ HIE though. It wouldn’t be specific to a ramp test.

Mike

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I didn’t say anything about Xert or MPA?

You responded to someone who was making direct reference to Xert’s HIE.

Mike

Ah. I was actually referring to this comment: “a ramp test does not nearly feel as draining.”

If you’re not completely drained at the end of a ramp test, you quit early.

Fair enough. Just a misunderstanding.

Mike

I am just looking into Critical Power today (typically late to the party) but I found that this article explains it well Critical Power for cyclists explained | Better than FTP? - BikeRadar

And it’s got a useful link to a CP and W’ calculator.

https://www.highnorth.co.uk/critical-power-calculator

Interestingly (well for me anyway) just using intervals.icu calculations of my outdoors power curve based on a 3,5 and 12mins 0.94 of CP gives me what I think my FTP should be. When I add a 4th power value (20mins) there’s a high degree of uncertainty and my CP goes down probably highlighting a weakness there. Which agrees with what I feel too early I am dropping into a pace that I know will get me home regardless of it being a 50mile TT or a 10mile one :neutral_face:

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40 minutes? 30 minutes is what the literature suggest (see slide 8) and longer duration test is generally not recommended as you have indicated as it “is prone to fatigue/motivation and does not add any additional detail” (see slide 9). Dropbox - CP Model Explainer.pptx - Simplify your life

https://groups.google.com/g/wattage/c/nk2Y5S5b3nQ/m/_DPAvM2yAAAJ

Wattage Group - Series on Critical Power

Cycling-Physiology Group - “Critical Power Test Search”

Wattage Group - “Critical Power Test Search”

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