CTL, ATL, TSB

↓ What is TSS in Cycling?
↓ Can’t I Just Count TSS Points And Look At CTL For Race Fitness?
↓ What’s A Good CTL On TrainingPeaks?
↓ How Can I Tell If My Riding Is “At Intensity?”
↓ Can I Use Polarized Training Numbers To Gauge Intensity?
↓ Am I Fit and Race Ready?
↓ How Driving Your CTL High Can Be Misleading Later
↓ Why focusing just on CTL or Fitness Scores Can Ruin Your Season

CTL, ATL, TSB - are you running your training schedule with these acronyms but not entirely sure how they effect your racing? Read on!

Once Strava started to incorporate their version of a Performance Manager Chart, calling it Fitness and Freshness, athletes started to dig into their data more and look at graphs of how fit they were.

While I like that Strava made the idea of Chronic Training Load (CTL), Acute Training Load (ATL), and Training Stress Balance (TSB) very easy to understand, there is one massive reason why you shouldn’t obsess over this curve and base your overall fitness solely on this one number.

What is CTL in TrainingPeaks? CTL is a combination of duration and intensity to describe how an athlete has trained historically. It is an exponentially weighted average of all the workouts over the past 42 days.

What is ATL in TrainingPeaks? ATL is the exponentially weighted average of the workouts from the past 7 days, so a much smaller snapshot of training.

TSB is the CTL minus ATL. Roughly speaking, a positive number means you are fresh, a negative number means you are deeper into a training block, and a number around 0 means you are well adapted to the training. There are a lot of nuances to this though, and CTL is only ONE metric to be looked at.

CTL is what Strava calls Fitness.

ATL is what Strava calls Fatigue.

TSB is what Strava calls Form.

What is a good TSS in TrainingPeaks? Ideally, you have a Fitness that is at or above 70 and a Form that is close to, or above 0.

How does Strava track Fitness Scores? The same way that TrainingPeaks calculates CTL; there is an algorithm that looks at each workout, scores it, and uses a weighted average, so that the most recent workouts have the largest affect on your Fitness Score.

When athletes start to rest, I hear people saying “My fitness is plummeting!” Well, not really.

You need rest, as this is when the body adapts to the stress you put on it (the riding), absorbs all of the training, and you come back stronger for the next block. You’re growing at this point in time.

What is TSS in Cycling?

TSS, or Training Stress Score, is a number that takes into account how long you trained for, and at what intensity. This will allow an athlete to be able to get a rough sense of the overall training load for one session, but it is not perfect. 100 TSS points from a one hour time trial will surely feel different than 100 TSS points from a two hour endurance ride.

Can’t I Just Count TSS Points And Look At CTL For Race Fitness?

There was a great question asked at one of our EVOQ.BIKE Live Sessions about Training Stress Score (TSS), and we discussed how you can count TSS points all day but they don’t actually show how race ready you are.

TSS doesn’t account for things like Repeatability or Race Specific efforts.

After the session, I decided to do a ton of base mile riding at zone 2 and zone 3 to build up my aerobic capacity.

While this will drive FITNESS according to Strava, am I really fit in the sense that most athletes are interpreting this as? What will riding a ton of base miles do to my CTL curve and Fitness Score?

If you want to skip the details, jump down to the section “Am I Fit and Race Ready”.

As you can see from the graph from WKO4, the Blue line is Fitness, the Purple line is Fatigue, and the Yellow line is Form.

What’s A Good CTL On TrainingPeaks?

A very general rule is that a good CTL score is about 65-70 or more to have a solid fitness for your event. Cat 1-2’s should be at 90 or more, and World Tour Pro’s often exceed 150. The same goes for Strava Fitness Scores: a good Strava Fitness Score is 65-70 for an amateur racer, or someone attending a gran fondo.

Don’t forget though that this score does not encapsulate what all of your training consists of, so do not bank a good performance on your CTL score.

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How Can I Tell If My Riding Is “At Intensity?”

From October to Late December I was just riding for fun and lifting in the gym a lot. My fitness hit a high of 84 but was mostly hovering in the mid 60s, which is very low for a competitive Category 1 racer. As you can see below, the mileage (SHOWN in percentages) was nearly ALL Zone 2 (light blue) and 3 (light green).

Let’s see what happens when I do a bunch more base mile riding to build my aerobic fitness. Here is the riding from 12/26/18 until 01/22/19.

It clearly a bunch more Zone 2 and Zone 3, with just some small bouts of intensity as I tested different anaerobic benchmark durations. Remember that these are percentages of the zones, so even a hard race will only have small sections of orange and red compared to the other zones. Here is the race season from 2018:

Clearly the orange and red is more visible, but I wanted to paint the picture that most of the lines will still be blue, green, and some yellow.

Can I Use Polarized Training Numbers To Gauge Intensity?

A different way of showing that I didn’t have much intensity is looking at the percentage of work above 85% vo2max. This is NOT percentage of FTP.

Currently my power at VO2Max is 461W, around 25W less than race season. To look at a polarized report, you can add a new column with an expression to tease out tempo wattage or below. To do this, insert the following:

“rev(sum(if(ewma(bikepower*0.0108+0.007*metric(weight),25)>0.00*athleterange(date-89,date,vo2max(meanmax(bikepower))) and ewma(bikepower*0.0108+0.007*metric(weight),25)<0.75*athleterange(date-89,date,vo2max(meanmax(bikepower))),deltatime),"week")/sum(if(ewma(bikepower,25)>=0,deltatime),"week"))”

When you do this, you’ll see the column with the blue arrow.

I’m averaging mid to high 90’s percentages for endurance and tempo; said differently, I’m not going hard at all for almost all of those months! NO SPRINTING.

I had done some PMAX intervals and a one hour test which made those two weeks’ percentages much lower on the top of the chart.

Now, let’s move forward….I want to build my aerobic capacity. Let’s see what kind of riding I did.

You can see loads of endurance and tempo, one day of a threshold effort (yellow), and some zone 5, but not much.

Have you noticed, there’s almost ALWAYS very little zone 1?

Okay so let’s double check the percentages:

The first week looks too hard but it’s just one ride where I did a 15 minute effort then tempo bursts, so that’s an outlier. I have 85% tempo or close by, and less than 5% at 85% of VOMax (FTP), so I’m not going hard. Anaerobic wattage is almost less than 10 minutes each week.

Okay, you get it, I haven’t been riding hard, but riding a lot. Again, I’ve been building my aerobic fitness. Here’s the CTL:

A zoomed out view does it more justice:

The blue arrows indicate periods of rest, and between the red arrows is the previous graph.

See how important it is to step back and see the forest vs the trees? When the purple dips below the blue, you’re getting rest. When the purple climbs for a while, you’re NOT resting, and while you’re building Fitness, don’t forget that you are ALSO getting TIRED (yellow).

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Am I Fit and Race Ready?

Fitness peaked at 112, and I’m currently at 106, with a Fatigue at 127 (peaked at 190) and Form at -39 (peaked at -80).

112, I’m fit!! Actually, NO!!!!! Look at how long I’ve been fatigued for!

Even if I rested a few days and come to zero, I’ve been riding a ton and will be tired.

A full on rest week is in order, and most people HATE rest weeks.

When I provide free power file analyses for athletes, many people NEVER take a rest week. They just ride and ride and ride.

This is a recipe for being overtrained, plateauing, a combination of both, and less than your best riding performance. I can help you change that.

Related Post: Peaking for Your Bike Race

How Driving Your CTL High Can Be Misleading Later

I want to show you what happened to me this season in regards to chronic training load and why you need to continually look at the big picture; SEE THE FOREST, not just the trees.

If I was only looking at CTL metrics and not really understanding WHY the numbers were where they were, I could have dug myself into a huge hole months after a big build.

Is your excitement for racing and big spring build setting you up to ride through periods where you should truly be resting? Read on to see what I’m talking about. I was at 0 TSB and exhausted!!!

Athletes often think that when the CTL is falling, their fitness is falling. We’ve talked about why this isn’t true (you’re just tapering or resting).

Just focusing on your CTL can really screw up your racing, it's not race readiness. You could just be getting tired. It's really how much work you've been doing, your chronic training load.

If you go through a huge build, the numbers get kind of wonky later on, and I'll show you this in the video.

When you think about the season, you're getting ready for spring, you're getting pumped up for races, you follow your training calendar really well. YOU BUILD.

Once you start racing, it's not uncommon or wrong to have CTL somewhat plateau because you really racing and recovering.

This year was slightly different with COVID. I went ham on training and really was just trying to see how much my body could take in terms of training load.

Below is the Performance Manager Chart that we’re all accustomed to seeing.

I want to show you why in August, there's this huge portion where my TSB goes positive.

But if you're following me on Strava, you're probably thinking “Wait a minute! I don't remember you ever resting that much.” And this is why things can be very deceiving.

So I want to show you this is another Performance Manger chart that they have in WKO5, I think that color coding is really beneficial.

Make sure you watch the video as I walk you through the portion below. If you are wondering why your Fitness is decreasing on Strava, this could be one reason! (The most basic reason is that you are training less. If you have less training versus prior weeks, your Strava Fitness score will decrease.)

So I went through this massive build, and since I’ve been training a lot for over 10 years, I'm not worried about going super negative to a TSB of -50 or lower.

This is a really interesting addition that they've added where they call the green portion a plateau. Once I got up toward 190+ CTL, I was clearly doing a ton of training.

I did a lot of FTP stuff, a lot of intensive aerobic, a lot of high torque, basically a ton of 15 to 25 minute efforts.

If you're focusing only on chronic training load, once you ramp up, if you started racing, you're going to see it fall off, right? People see their CTL falling, which should and they say I'm losing fitness, I'm not as fit. And then what happens if you go to another race? Tt's going to fall a little bit more.

That's the whole point of overloading: you ramp it up, and then you let it fall (become fresher) and taper into your race.

Remember that if you don't have a lot of miles in your legs, and you go to “peak”, things can go awry, because in order to “peak”, you have to overload. If you overload too much since you don’t have many career miles in your legs, you're just gonna make yourself crack; you're not gonna absorb that training.

Then when you go to taper, you're not going to be faster; you would have been better off just doing a normal build and riding with the fitness that you've had. So you got to be careful about that.

But back to chart above, what happens is here, I want to highlight this.

We're at June 26:

I do a 20 hour week, 18 and a half on the bike
I do a 26 hour week of riding
I do a 22 hour week of riding

This is now through July, and I come up to this race. That is a ton of riding and because I drove my CTL so high before, I'm not really seeing big negative TSB numbers.

So I could get to the end of July and on July 20 have a TSB of Zero!! But you saw what I just did, all that you're telling me that I'm don't have a ton of riding in my legs? 20 plus hours over and over again.

If you're there, this is when a lot of people are thinking: “wait, TSB of 0? I haven't trained enough!” and they just drive themselves into the ground. Don't do that.

See the forest, the reason these numbers are skewed is because you just did a big build.

You don't have to be looking at a CTL number that's 192, you might be going to 92. And then you go to a race and if it's 70. And then you go through a training block, and you're still at 70. And you're like I gotta go more, it's not always that. Remember to look back, as you're planning to go forward.

After July, things still stay funny, I go and do an 18 and a half hour week of riding with two lifting sessions, 22 hours with two lifting sessions. I'm setting PR’s this time through August.

I'm going to be at -8 TSB. There's no way I'm not tired at this point. So I rested and my numbers got super, super positive. Take the full rest week!!! Don’t see +20 and just get back after it. The body needs the physiological and mechanical rest!

By the end of October, my numbers will be more normal.

The whole point is, is by the end of August, there's no way I wasn't exhausted and ready for rest. But if you look at just these numbers, and you're not looking at what you did before, it's not going to fully capture all the volume and intensity like it should.

You have to make sure you're looking at the whole picture. So don't be hard on yourself when you're like, Why are my numbers all screwed up, you might have just went through a big build, or there might have been something else that happened. You got to look at the big picture.

Why focusing just on CTL or Fitness Scores Can Ruin Your Season

The FITNESS score may be just AEROBIC Fitness, NOT Race Readiness

I haven’t worked ANY intensity

I haven’t worked ANY repeatability

I haven’t worked ANYTHING REMOTELY CLOSE to a race or event specific effort.

A few blistering attacks from someone with similar caliber of riding (cat 1-2 or a strong Cat 3) with only a fitness of 80, but who has been training interval specific efforts, has time at 95% VO2Max or higher, has done ANY tabata type workouts, or hit race specific efforts, would drop me like a hammer!

Said differently, while I’ve accumulated a lot of Chronic Training Load, OR FITNESS, I am NOT RACE READY and not RACE FIT. I’m actually TIRED!

Do not only use the PMC Chart to gauge whether you are ready for a race or truly fit. Use it to track what is actually tracks: Chronic Training Load and the balance between your Fitness and Freshness.

Interested to learn more? Let’s start a conversation. Respond with your thoughts in the comments or reach out to me directly! You can contact us online, view our testimonials, or learn more about our training programs and team members.

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