CTL vs. FTP - Aerobic capacity vs. Power ...

Andy SG

I've been reading this forum for almost 6 months, and change my training based on what I've read here and in litterature, such as Morris' book. I have increased my power output significantly since I started, and feel I have learned a lot, but there's one thing I can't understand.

Pure power addicts, seem to focus on increasing their power levels, and use power output as a measure, and in many cases that means high intensity intervall training, with intervalls of different length. I've seen blogs where people focusing on power output increase, state that they need a certain amount of load/training time to benifit from training, but in many cases many people focus on straightforward intervall programs, where they rely on higher watts, rather than time, to increase workload.

On the other hand there are these guys speaking of CTL, lenght vs. intensity trade-offs between L4 intervalls or building CTL, etc. They seem to focus more on aspects that is hard to measure, but is often refered to as Aerobic capacity, or similar.

I personally think the two views must be highly related, since it must be better to generate 200W over say 2 hours if it is 70% of your capacity, than if it would be 85%. On the other hand, the time put into training each week doesn't feel like totally irrelevant, and the more you train, the more you should be able to train, so it sort of indicates a good spiral ...

Question(s) then

1) Is there anyone that is willing to claim that the FTP is good enough as indicator of capacity over a longer race. Meaning that two riders with same FTP level (and everything else similar) but with different CTL level should generate the same result in a race?

2) Is there anyone that can give an example of where the person, in the example above, with higher CTL would have an advantage?

Thanks

Steve_B

If it's a road race, there are too many variables going on to say definitively. In theory, a lower CTL would indicate lower endurance though.

In a one-day race, endurance theoretically should be better and recover faster. In a stage race, in theory, you should recover faster with higher CTL.

rmur17

some good comments there. I think it would take one of Dr.W's long posts to address them properly. I'm definitely in the CTL-FTP, FTP-CTL balance camp. Focus too much on one or the other and you're not going to be at your best (at least not for very long!).

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rmur

dkrenik

There's another "Rick" that posted this and it seems appropriate here as well:
FTP=How Fast You can Go
CTL=How Long You can Go Fast

As Rick says above, "balance" is key to being at your best as one needs both CTL/FTP to achieve good form.

Dave

daveryanwyoming

O.K. since rmur dropped the gauntlet, I guess I'll have to take a crack at this. There are a lot of questions buried in your post Andy, but it seems you're looking for an irrefutable and scientifically validated answer to your questions. You won't get that. There's still a lot we can't prove regarding the ways the human body adapts, how it fatigues, the best ways to encourage specific adaptations, etc. People are also different in terms of the time they can dedicate to training, how well they recover, the nature of their target events, the climate in which they live... Basically there's a reason so many different and sometimes conflicting training philosophies can exist side by side. And coaches aligned with one school of thought can always point to athletes who've enjoyed great success, often at a professional or top amateur level, using their preferred methods.

Very long winded and rambling post warning, read at your own risk.....

You can't deny that LSD base training put many europros on the podium, Lydiard had great success in the running world with his methods and I don't doubt that the High Intensity Training folks can point to champions that trained nothing but short intense intervals. So you're going to find staunch advocates for each of these approaches and very little peer reviewed literature that proves that one method is superior to the rest. So some of this has to be taken on faith or IOW you sort of have to pick a horse and ride it for a while to find out what works for you within the overall context of your life and your athletic goals.

If you've followed these forums for a while you probably know that I strongly believe in the SST/Lydiard style approach. That basically means building a base of sustainable aerobic power through sustained submaximal efforts. That base is built and maintained year round with very little down time and only as the competition season approaches do I specialize with directed high end work targeting specific weaknesses. This approach has really changed my cycling for the better compared to the LSD winter training approach I tried for many years with little success. I also gravitate towards this in part because I live in a place with very long, very cold winters and SST work lends itself to indoor training. That and I'm a masters athlete with a wife and a job and lots of other demands on my time. A regular diet of 4 to 6 hour training rides just wouldn't work for me even if the weather allowed it.

That's where I'm coming from and the rest of this is just rationalization towards that approach, but rationalization that I definitely believe in. Others will probably post conflicting views and justify their training philosophies. Fair enough, it's an open forum but I'd be very suspicious of anyone offering the ultimate answer without acknowledging where they're coming from and what training philosophy they've bought into.

Reading between the lines it seems you're basically questioning the time/intensity relationships and how to use that in training. I see this on two levels, the micro level defining appropriate durations to target specific metabolic adaptations and the macro level looking at the CTL/FTP balance you asked about directly.

Time/Intensity tradeoffs on the micro scale

One of the biggest revelations that I've had since moving to training with power is the understanding that there are specific time ranges associated with the different metabolic processes and that you need to sustain efforts of appropriate intensity for certain minimum times to target the appropriate adaptations. The specific processes aren't really discrete and overlap heavily in a continuum but there are durations related to moving from primarily burning phosphocreatine to say primarily buring sugars anaerobically.

In that example you'll primarily burn phosphocreatine in the absence of oxygen for maximal efforts lasting less than 15 to 30 seconds depending on how heavily you've trained that system and how much phospocreatine you have stored. Try to sustain that effort much longer and your power will drop and your body will shift to primarily burning sugars anaerobically through anaerobic glycolocis. The time course of those relationships can be affected by specific training and fueling but the relationships are well understood and maximum times exist, no matter how hard you train you won't fuel your efforts for a full two minutes via phosphocreatine.

You can work down through to the slower but longer lasting metabolic processes in the same way. Try to hold a near maximal effort for more than 3 minutes and a primary reliance on anaerobic glycolocis gives away to a primary reliance on aerobic metabolism and you're working at a VO2 max intensity. Try to hold it for 8 to 10 minutes and your body has to back off again to a slower but more sustainable process that can be maintained with a bit less oxygen.

Well you can turn those maximum times on their heads and view these as minimum times(at sufficient intensity) necessary to target a specific metabolic process. If you want to target your ability to sustain L4(Coggan's levels) or "Threshold" efforts then you'd better hold those efforts for at least 8 to 10 minutes. Hold that same intensity for much less and your body can rely on more oxygen, utilize more of its anaerobic capabilities in the mix and get through the effort with a different metabolic system. Similarly if you want to train VO2 Max it doesn't pay to do minute long intervals. Sure you'll get some adjacent level crossover but you'll be targeting anaerobic glycolocis(L6) and not VO2 Max(L5) with these efforts.

So how does this relate to your questions? This is the first problem I have with a pure High Intensity Training(HIT) approach to building fitness. I've seen HIT plans where the longest intervals were in the 4 to 6 minute range with authors claiming anything longer is unecessary. From a certain perspective I can see what they're saying. VO2 Max represents the top end of your predominantly aerobic system(there's definitely a lot of anaerobic contribution going on at that level but you're still predominantly aerobic when working VO2 Max). Conventional wisdom says "raise VO2 Max and everything else will follow". This pull up method definitely has its advocates but there's an awful lot of published and reviewed work demonstrating that in addition to a relatively high VO2 Max and even power at VO2 Max there's still the question of power at LT(FTP in Coggan's system) as a percentage of P-VO2 Max. IOW, raising VO2 Max by itself may not be enough, there's still the question of how high you can raise FTP relative to P-VO2 Max. Longer intervals that target sustained primarily aerobic metabolic processes are the ticket to raising FTP with or without raising VO2 Max. So those efforts of at least 8 to 10 minutes are essential to increasing sustainable power if you buy into the SST/Lydiard school of thought.

Realistically 8-10 minutes represents the bare minimum for these SST/L4 intervals so most folks go to something like 20 minute to hour long efforts when targeting their sustainable aerobic metabolism. If you think of those first 8 minutes as the price of entry or priming the pump then it makes sense to hold these efforts longer so you don't have to pay that entry fee too many times in a given session.

Anyway, on the micro scale there are definitely durations associated with specific metabolic processes so one answer to your question is that efforts should be held long enough to target the appropriate processes.

Time/Intensity tradeoffs on the macro scale

You've already given the short answer to this one: "the more you train, the more you can train" but there are other ways of looking at the need for some reasonable duration in your training. In a simplistic way I think it's pretty easy to see that there are some minimum durations you need to train just to be able to complete longer rides. Assuming you meet the minimums discussed above you'd still need some saddle time to manage say your first century ride. So the question isn't whether you need some duration, the question is "how much?".

Everyone has a Mean Maximal Power (MMP) curve that characterizes the power they can put out for various durations. Power meters and power analysis software like WKO+ have allowed us to easily visualize this curve but we all have some relationship between time and the intensity we can sustain. Monod and Scherrer developed a simple two element model in 1965 that estimates this curve based on Anaerobic Work Capacity or an individual's purely anaerobic energy reserve and Critical Power or their long term sustainable metabolic power. It's a pretty good model for moderate durations but falls apart for very short or long durations. In particular it tends to grossly overpredict the power an athlete can generate for durations much over an hour. But the general idea and even rough shape of this power/time curve is similar to a rider's MMP.

Andy Coggan proposed the use of FTP or power for approximately one hour under ideal conditions as the anchor point for his training levels and as the primary metric for gauging an athlete's sustainable power. This metric has caught on and been widely accepted among folks and coaches using power based training but it represents only one point on the MMP. It also represents a point that is more often estimated than truly measured. Folks tend not to do a lot of 40 km TTs under ideal conditions including appropriate rest and race day motivation. So in general FTP is an estimate of one point on an athlete's MMP, but how does the rest of the curve look, and what does that say about an athlete's readiness for a particular event?

Over time it's not hard to fill in a lot of shorter duration points on the MMP during training and racing. Most races give us a good chance to push for a best 3 to 5 minute power number and if an athlete trains sprints and L6 work they'll end up with decent estimates for very short durations(though a lot of folks don't hit their best 1 minute numbers unless they dedicate a session to 1 minute tests or race track). But those really long efforts tend to stay low relative to an athlete's potential unless they specialize in very long time trials. It's just hard to push for best possible power for two three, four or more hours. In mass start events we try hard not to race right up to our MMP by racing smart. Triathletes and other long TT specialists have a better chance of hitting best efforts for long durations but then only during competition.

If you buy into the SST/Lydiard way of thinking CTL can be used to estimate how flat your MMP is for very long durations. As rmur put it recentlyNope, it doesn't easily translate to exact points on your projected MMP and no one can tell you exactly how much CTL you need at a certain FTP to be competitive in a particular event. But it still provides a quantitative measure of overall training load in a way that takes into account intensity and duration of individual workouts.

The part I find most useful wrt CTL is that it quantifies the training load you've adapted to for the previous 3 or more months. That's true whether the makeup of that training was good, bad, or downright ugly. Do nothing for 3 months and your CTL will drop to a very low level and sure enough that's what you'll have adapted to. Do the wrong thing but a lot of it for 3 or more months and your CTL might be high but it will indicate that you've done a lot of and adapted well to the wrong thing. Engage in a well structured program for 3 or more months and your CTL will reflect both the volume of that well structured program and the fact that your body has had a lot of time adapting to that program.

This makes CTL a really interesting metric when combined with a well structured program targeting specific needs. It tells you for reasonably static training programs what you've adapted to over a substantial time period. Get your CTL fairly high on a well structured program and you can safely say that similar work that yields TSS much below your current CTL isn't too stressful. Similar work with TSS much above your current CTL means you're stressing your body to encourage further adaptations. Add in ATL and TSB and you've got ways to visualize how deep you dig your hard training holes, how you rebound and when you're likely to peak for events. It also helps you recognize unwanted peaks that result from training interruptions or that may come from a switch to high intensity short duration work that produces average daily TSS much below your current CTL.

So getting back to your questions.....

Let's say the race is a TT so tactics and pack dynamics don't come into play. Even then your question is too open ended, is it a two hour road race or a 10 hour gruelathon? How far apart is the CTL of the two riders? Is one holding a CTL of 120 and the other a CTL of 40? How fresh are the two riders, is one at TSB of -40 and the other at TSB of +8?

But in general, assuming similar prerace tapers and similar FTP, for events much longer than an hour the rider with the higher CTL will very likely have a flatter MMP out beyond an hour and very likely hold a higher percentage of that common FTP for the time trial. For events up to an hour it probably doesn't make much difference during the race(by definition they can both hold the same power for roughly an hour) but I'd put money on the high CTL rider to feel much better after the event and on subsequent days which allows that rider to resume training sooner. Again, the more you train, the more you can train(or race).

Long events, stage races, busy racing schedule, subsequent training to raise that FTP or work on other weaknesses......

Wow, that's even long winded by my standards. Be careful what you ask for rmur

-Dave

Piotr

I got to think about Rick's mantra and it seems perpetually unbalanced. Let me illustrate:

FTP=How Fast You can Go (for 1 hr)
CTL=How Long You can Go [at FTP]

Which brings me to my previous argument of CTL and FTP being sorely interdependent.

P.S. Holy crap, Dave I'll have to read your post some other time.

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rmur17

"How long you can go fast". There are a number of ways to read that. Something like "time flies like an arrow". you know what I mean?

I definitely didn't mean you long you can sustain FTP power in a workout ....

Re Dave, I'm waiting for the e-book to come out.

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rmur

Steve_B

As the locals around here might say, "Oh my Gauwd! That's a wicked lawt of text." I'll read it when I get home and be able to tell you if it's "wicked pissah" (the local sign of acceptance).

Steve_B

There's a book out called, "Eats, Shoots and Leaves". Reminds me of that title (but not the content).

rmur17

I think you have it Steve .

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rmur

rmur17

Dave, I thought they were good comments/questions that needed a proper reply and just who could deliver that .

Now about that Training Philosophy e-book .....

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rmur

Piotr

Yes, I understood it in the context of training philosophy (and don't disagree with it), but I thought that taking a more literal approach, e.g. "fast" being defined as FTP, illustrated a more complicated relationship between CTL & FTP. To use an extreme, what's the FTP of someone who can barely complete a 30 min workout?

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Steve_B

Yeah, I mean, to some extent I think that FTP and CTL can be independent (and I've seen situations in my own numbers where that is the case) but in an extreme case such as you've posed (which migh be a tad unrealistic?), they aren't fully separate. Bottom line: clearly there is to some degree an interrelationship but they aren't always "tightly coupled", if you ask me.

Alex Simmons

Like all good Kiwis, "eats roots and leaves"

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