This article will help you understand what ‘Fitness Score’ is and give you an idea of what a normal CTL or Fitness Score might be.
First a Reminder of Training Stress Score (TSS)
TSS is a training load metric that combines the volume (time) and intensity (power) of your workouts into a single number for each workout you do. It is calculated based on your (hopefully accurate) functional threshold power (FTP). Accuracy is important if you are going to use TSS or CTL. If you are missing hours, have a mis-reading power meter (or do not use a power meter), or cross-train a lot, or do not have an accurate Threshold Power then you might look at other metrics (like hours) rather than Fitness Score.
Example: A 100 TSS endurance ride for an elite rider and a beginner might take about 2.5 hours in either case if they rode on their own at a similar percentage of their own threshold. The pro rider would cover more distance / put out more power across that same duration of ride. If the two riders rode together, side by side and on similar bikes though that same 2.5 hours would result in more TSS for the beginner rider while the pro rider would likely get a low TSS score as much of the ride would be at a very light output (low % of FTP)
What is Fitness Score (CTL)
CTL or Chronic Training Load is a rolling 6 week (42 day) average of your daily recorded TSS. So whatever your Fitness Score is today is just the average of your last 6 weeks of training. I like to tell clients that it is a quick measure of your ‘average day’. If you have a Fitness Score of 50 then it tells me you ride for around an hour a day *on average* and if you have a 100 TSS / day CTL then you likely ride between 2-3 hours per day *on average*.
Example: Expanding on this caution is often necessary so I will provide another example. You have one rider who trains only on their road bike on flat roads at a very low output for 4 hours a day and another who mixes their training between intense rides on their mountain bike and steady road rides in zone 2 for around 90-180min a day. The first rider always rides alone while the second rider gets 1-2 rides with other people and sometimes includes a practice race or spirited group ride. Both riders are going to race in the same mountain bike race. Who would you bet on? Why? The answers you give will help get you started on ways to assess your training and race preparedness more than TSS!
JUST TELL ME HOW HIGH MY FITNESS SCORE SHOULD BE!
In most cases, I find I can group athletes *who have accurate data* based on their Fitness Score (CTL). I took that idea from an idea Joe Friel had and added a few things to it over the years. I think for adults with families, working full time, this sort of helps us decide on what to focus on. It is important that regardless of your skill/experience you might find yourself at ‘frequency’ limited after a long period off of training for injury, rest, illness.
- Beginners or Frequency limited – if you aren’t riding very often, then riding more often will generally help. These people are typically under 30 Tss/Day for CTL
- Intermediates or Volume Limited: if you aren’t riding long, you can simply ride longer and get better. Most adults with full-time jobs and families end up in the 30-70 tss/day for fitness score. There is a gap between this and the next category. I just don’t see many people there for long.
- Advanced: if you are riding frequently and long, we need to then be careful that intensity is controlled and relevant to your goals and limiters. These athletes are typically around 100 tss/day or more. These athletes often struggle with ‘intensity discipline’ to ride easy on easy days and at the ‘correct’ intensity on hard days.
Where the CTL ends up for most working adults is going to be largely a product of their available time, not necessarily their abilities. We can try and cram more into our training by riding moderately in the limited hours we have but this is only possible in short periods. It is worth pushing towards a big race but it is also normal to let the load decrease for periods as well. In the below image you can see the red arrows roughly marking the fall / off period for an expert/elite mountain biker with peaks in BLUE CTL/fitness score around 90-110 tss/day typically at the end of the base phase (spring) and then a gradual decrease through race season. You can also see on the right a flatter pattern (smaller peaks in CTL) around the restrictions with Covid19 for the last 2 seasons AND as the athlete gets older, works more and trains less.
Who are you and what are you trying to do and how far away is it. If you are a pro with no other responsibilities and youth on your side while training for an Ironman then rack up all the TSS and Fitness Score that you can. The rest of us though have other things in our cup. You do a lot in a day and there are only so many hours each day. While TSS is ‘training stress’ there are other things that take up your time and energy, and so they should.
During the base or ‘accumulation’ phase of the year, we would expect some increase in CTL. Then during the competitive season, it is normal to see flatter or decreasing trends. This emphasizes that you should prepare many months ahead of events, especially ones that will be very challenging for you or different than you have done. Another consideration is the duration of the event. Longer races will require a bit more riding to prepare for as will goals that involve winning expert or elite level races. This article from Training Peaks displays some of the ranges in TSS based on event distance and your goal category (*NOTE THESE ARE RANGES and on the Elite side of things.
How hard you ride, how you collect your data (power or HR?), different power meters, indoor vs. outdoor are only a few of the factors that make comparison between people difficult and that warrant caution and a variety of of other factors make comparison between people very hard.
CTL and Fitness Score have several great uses:
- It can help reflect that your increased training time or effort or focus is increasing your ‘normal day’.
- It (combined with ATL / TSB) can help you flag if you are training too much, too soon. This typically only happens when the weather improves (e.g. spring) or when someone goes on a training camp. It isn’t perfect but the idea is that if you increase this week’s load (7-day average) over the ‘chronic’ there is an increased risk of injury. Pros and Cons of the ‘Acute:Chronic Ratio’ are discussed in our episode with Greg Lehman
- TSS is relatively easy to track and maintaining good data is a good practice. Having your own record of your yearly CTL seasonality is actually quite helpful to see what approximate load you carried in your best (and worst) years. This is one of the first things I check with new athletes (who have any data) because it gives you an idea. If someone has done many years at 100tss/day that’s different than someone with a couple of 30 tss/day years. Even if they are doing similar training today, you have an idea of where they have been.
In closing, it is a great thing to understand and observe but make sure you are thinking about all the other ingredients that go into ‘fitness’. There is more to bike riding and racing than intensity and duration multiples and averaging them over 42 days.