CTL - Chronic Training Load is a metric that helps guide your training in terms of your "fitness." It's not a pure science reality - but an attempt at a best guess on what is happening to your body through the process of Stress & Recover - as you get more and more fit. It is quite good at helping you know where your "fitness" stands - but I'm finding more and more that fitness does not necessarily equate to "fastness."
Okay - that's a made up word, but it keys in on an element that is important if your goal is to gain performance as a cyclist. I felt the very specific effect of the difference between "fitness and fastness" this week at OKC's Wheeler Criterium.
I've done several Road Race events this year and have felt great during them. Even at Cedar Hill in Texas which is a two mile circuit with a sadistic "Cry Baby-esch" hill in it - forcing you into 90 seconds of VO2 every lap - I was able to hang on and feel good. But criteriums aren't a hard effort every 4 minutes, they are surge, attack, chase, attack, surge every 10-60 seconds as you get to each corner. It's not just Vo2 efforts, but layered Anaerobic efforts of jumping back up to high speed.
Wheeler this week was my first, and even though my fitness is as good as its ever been, my "fastness" was certainly not there for a criterium. The intensity, and barrage of attacks and surges left my glutes and heart rate reeling. Once the race got past 20 minutes and the attacks started to subside a little, I was able to file in and feel great. In fact the longer the race went the stronger (vs everyone else) I started to feel - a sign of fitness. Being fit enough wasn't my problem - being able to ride at high speed and recover quick was, and at this time of year that's all that matters.
That is why CTL is great up to a certain point, BUT USING IT AS THE GUIDE POST THE FINAL 8-10 WEEKS TO A KEY EVENT IS USUALLY A MISTAKE. It still needs to inform, but only secondarily. I'm finding paying more attention to your IF score (intensity factor; it tops out at 1.0 at it's highest which indicates you went as hard as you could for that ride.) during the final 8-10 week ramp is very important. In Oklahoma that is three weekends, Bike the Bricks, OKC Pro Am and Tulsa Tough - all criteriums. This kind of training turns into a "hot/cold" approach.
In this final 2 month ramp up you are either riding very hard, with small recoveries, or you are riding very chill - recovering from the intense efforts. This is important because a CTL based system gives some credit to a ride with high intensity, but not enough for how it impacts your system. You can start to feel you need a lot of endurance miles to keep that CTL high - that usually makes you feel much more tired then your TSB (Training Stress Balance) would indicate.
These final 8-10 weeks simply maintain your Fitness with one weekly endurance ride of 2.5-4 hours to keep your cardio progress at the same level. Everything else needs to be focused on those race essential levels of intensity (**Threshold, Vo2, Anaerobic, Short Recovery) OR on Speed Skills (Form Sprints, Motor Pacing, Core Work/Stretching).
For the working athlete that's putting in 8-14 hours a week I've found that the CTL based system doesn't quite match reality of the stress impact and importance of IF in your race readiness. A new metric CIL (Chronic INTENSITY Load) is helping with that - and watching your IF trend over time is a good indicator of "fastness" as well.
**Threshold is a staple of any successful racer, but as our main events are criteriums, not road races, this should be something you "maintain" as well. The last 2-4 weeks before our big criterium weekends I'd put all your chips in Vo2, Anaerobic, Short Recovery (tabata) workouts. But if you plan on extending your season past June then start back on Threshold after this batch of key events.