From the Coaches: What does your engine look like?

Let’s break some basic components of Endurance performance by comparing them to a car engine.

Maximal Aerobic Power = Max RPM (revolutions per minute). What is the maximum RPM your car can hit? This value acts as the ceiling for your aerobic power production. A Formula1 car can hit 15,000, while most commuter cars max out around 6,000.

Threshold Power= Redline RPM (revolutions per minute). You can only remain above that Redline for a limited amount of time. This is the balancing point between a sustainable output and a non-sustainable output. Two cars can have a Max RPM of 5,000, but car A might have a redline RPM of 4,800 while car B could be 4,000. In cycling terms, that would mean two people with the same MAP, but one has a significantly higher FTP than the other.

Economy = MPG (miles per gallon). How many miles can you travel for a single gallon of fuel? In this analogy, our fuel is oxygen. How fast/far can you go for the oxygen you are taking in? If you put that F1 engine inside a school bus, you will end up burning more fuel per mile traveled. At the same time, you can improve your miles traveled per gallon by sacrificing speed (driving well below Max RPM).

Ultimately your performance will be limited by a combination of these factors. The tricky part becomes recognizing which components will be the most limiting based on your goals. Are you looking to ride your best 10 mile TT, taking on a 200 mile Gravel Race, or set a new PB on your favorite climb? The “optimal engine” is different for each of these goals. And while you and a friend might be training for the same goal, your starting engines aren’t identical. The changes, your engine needs will be different compared to the changes your friend needs to make. Your training should take your starting engine into consideration when laying out the exact work that needs to be done to ensure you get that “optimal engine.”
This is why our training plans are based on your Rider Type and Weakness. For example, all of the 40k time trial plans have the same end goal. Getting you to that “optimal engine” for 40k TT, which is increasing your redline RPM (FTP) as much as possible. If your redline RPM is almost equal to your Max RPM (MAP), then the starting focus should be increasing your Max RPM, which means plenty of MAP sessions. If your redline RPM is 20% below your Max RPM, your training should be more focused on sustained threshold efforts.

At this point, it’s crucial to recognize that we are not just engines getting pumped out of an assembly line with identical specifications. We each have our own unique engine. Just look at how different and unique you are as a person, from height to eye color, arm length, foot size, hair type, etc. With all of those things being different, it makes sense that our insides, our engines, are just as unique. That is why it’s essential to get to know your own engine. Why you should check up on it from time to time to see how it has changed.
So for those who haven’t checked the engine in a while… you should start planning for your next Full Frontal!


Just checked my engine. My engine appears to need some work.


Really interesting post. Liked it a lot, except for that last sentence :hot_face:


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From a training perspective does the engine configuration for cycling have a different mode than for running for example? So if (when) I do Full Frontal again and get a new (or improved/reduced) rider type is this likely to broadly match similar output capabilities across different sports (running and cycling) or is it very sport specific because of the test being on a bike? @Coach.Mac.C

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Think my engine is somewhere between a Farrari, Transit Van and a Reliant Robin…depending on terrain🤣


My engine type has certainly changed since I started the Suff workouts. Instead of tying up after a couple of short hard efforts and be toast for the rest of the ride, I now absorb these efforts and enjoy them, however riding tempo has me blown off the back .I cannot get my head around why. The lightest reduction in effort produces a huge loss of speed, riding 35 watts below threshold, not breathing hard, HR sensible , fed and watered yet although all the ingredients are there to ride, I go bang

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I’d be interested to know what the coaches view the optimal engine is for the XC MTB plans. My experience is that it can include everything from long grinds up climbs, to short sharp nasty climbs to sprints to get to the next bit first, and so on. Highly variable! Do you aim for an all-rounder style?



Probably some kind of pulse jet - bang, pause, bang, pause. Fuel economy is miserable too.

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I highly doubt that about you, but a great photo!

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To an extent, these capabilities will translate to running from a purely aerobic point of view. But the Economy portion becomes more significant in running. For running, proper form can have a massive impact on how fast you can go for the oxygen you can use. You will still have an upper limit of oxygen intake (which will be slightly higher than cycling because running requires using more muscle groups that demand their own oxygen). And there is still a critical pace that represents that redline rpm. However, one thing that impacts these characteristics in running but not cycling is tendon stiffness. The easiest place to see this is at the Achilles tendon. It takes a long time to increase tendon stiffness, which essentially makes your Achilles more “springy.” So you can use less muscle force to get the same propulsion.


The XC MTB plans are aimed more towards that repeated efforts rider type, with more emphasis on muscular strength endurance, rather than just steady state power. The one component unique to the XC plans are the free ride sessions out on the trails. Ideally this days would be done on terrain similar to you target race has in store. Obviously this isn’t always possible, but the focus on continuing to improve your handling skills on these days is still very important.


Can you expand a bit one what you mean by blow up in this scenario? Is it muscular fatigue? General low energy feeling? And what sort of cadence are you riding at for tempo efforts like that?

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Thanks @Coach.Mac.C - appreciate your response. Interesting stuff. :sunglasses: :ok_hand:

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coach Mac. In the last 3-4 months, I notice that after a map effort, dropping to something 20-35 watts under ftp, I find my legs go dead and I cannot pedal at any cadence, even if I dial down to 40+ watts under my cadence can drop from 90 ish to 40 then down off the scale. I know oxygen is available because I am not breathing that hard, my HR is 25 under the level it gets really alarmed, This does not happen on short recoveries with repeated hard efforts.My rider weakness is sustained and apparently I am not too efficient at using oxygen.

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I know right. Why does there have to be suffering delivered even from a blog post. Geez.

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Sir Mac, I have a question for you;
Why is it that when I am running, I can hold 171 bpm for almost the duration of the run, but when on the bike, hitting 171 bpm leads me to feel like it’s time to scale back?

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So I am an Attacker with a VO2 Max weakness, and going along with what you have said above…My redline RPM is 222W and my Max RPM is 275W which means my MAP is about 124% of my FTP or 24% greater than my FTP. I am reading this as equal or less than 120%=MAP/FTP100 is Sustained Effort work and greater than 120%=MAP/FTP100 is raise aerobic power output.I feel like I am reading this wrong. Does this mean I should focus more on sustained efforts rather than MAP? Or do my other metrics play a role into into this as well too?

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You must have just finished Violator!

Either that or you completed the 9th Hammer without the break!


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