The accompanying chart is a detailed summary of a road cyclist’s periodization leading to his first A-priority race of the season last Saturday (click to elarge). It shows the timeframe of October 5, 2009 through June 9, 2010. I’m not going to get into how the chart was generated from the power meter as that in itself would be an entire blog post. The bottom line here is that the athlete trains with a power meter and his daily data was uploaded into WKO+ software. The software generated the chart. If you’d like to see more such case studies and more on WKO+ see some of my previous blogs here, here, and here.
To orient you on the chart, notice that the X axis represents the timeframe mentioned above. The Y axis, on the right side, shows average daily stress levels (“TSS/d”) which serves as a proxy for determining fitness and fatigue, which I’ll explain shortly. The Y axis on the left side is used to determine the athlete’s form status (“TSB”).
The blue line on the chart is what is generally called fitness. In WKO+ talk it is “Chronic Training Load” (CTL). Essentially, this tells us how much of a training load the athlete can handle. The more he can handle the more fit he is. Notice the general rise with undulations in fitness over the course of the season. Our obvious purpose is to elevate fitness during this time. That was generally well done in this athlete’s case.
The red line is fatigue, or “Acute Training Load” (ATL) in WKO+-speak. As the daily training load varies the athlete’s body responds by becoming more fatigued (red line rises) or more rested (red line falls). Notice that fatigue is much more sensitive than fitness. It changes a great deal from one day to the next while fitness remains rather constant with only slight changes from day to day. Also notice that when fatigue is rising fitness also is. That by itself is a good lesson in what it takes to produce fitness – enough training load to cause fatigue to increase.
The black line is form, or “Training Stress Balance” (TSB) in WKO+ lingo. This tells you how race-ready the athlete is at any given point in the season. The black, dashed, horizontal line represents zero TSB. When form is above this line the athlete is “on form,” he is fresh and ready to race. When form is rising regardless of the zero balance point, the athlete is coming into form. The daily form data point is generated by subtracting fatigue that day from fitness that day. That makes sense since what you are trying to do in race preparation is to shed fatigue while maintaining fitness.
The dashed, purple lines that run vertically through the chart show the points at which his periodization mesocycles changed. Those periods are listed across the top of the chart (Transition, Prep, Base, Build, Peak, Race). You can tell the exact date that each period starts and ends by noticing where each purple line intersects with dates on the X axis.
Ok, now you should have an idea of what you are looking at in this chart. So let’s move on to the periodization of the athlete’s season and how he peaked for the A-priority race last Saturday.
From the start of the Prep period until late in the Base period his fatigue was generally high as fitness rose. The “valleys” in fatigue show when he rested. Notice the big drop in fatigue with a corresponding rise in form late in the Base period (circled in brown). This is one of those times every athlete experiences at least once in a race build up. He had to do a lot of business travel and was unable to train regularly. The spotty training allowed him to rest up so fatigue dropped along with fitness (remember: they always trend the same direction) while form became highly positive. In fact, form reached the highest point of the entire season, which is generally not good when there isn’t a race. Following this travel his training got back on track and all three metrics began to behave again. This was the start of the Build period.
During the Build period there is a steady rise in fatigue and fitness as form drops quite low. All of this indicates that training was generally progressing well. At the end of the Build period is another brown circle. This was week of R&R to shed fatigue and make sure he was fresh (“on-form”) and ready to start the Peak period with the final push to his first A-priority race of the season.
For this athlete my goal for form is for him to be at about +20 TSB on race day. So I manage the daily workouts of this period closely watching form and adjusting the workload to keep him on track for that form goal (some day I’ll explain this in another post). Notice that in the Peak period there are only slight changes in fatigue and that fitness plateaus. This is because he is doing a hard, race-like workout every 72 hours with two days of recovery riding between them. So rest is increasing. When rest increases fatigue falls and fitness follows the same trend. Recall that fitness minus fatigue equals form. So form is trending up and down right around the zero balance line as hard workouts and two very easy days are alternated for two weeks.
Finally, the Race period starts. This is the week of the race. But actually we extended his Race period by four days as he had a B-priority time trial the Wednesday after the road race. In Race week the training was cut back dramatically to allow for shedding of fatigue. You can see this happening with the fall of the red line. And since fitness always follows fatigue, notice that his fitness is dropping a little bit also. My goal here is prevent more than about 10% of drop in fitness at this time while getting rid of as much fatigue as possible. That was accomplished here by making the workouts short but including a decreasing amount of high intensity in each session as the week progressed.
Remember that my goal was for him to be at about +20 TSB (on-form) on race day. He hit +19.7 that day and had an excellent race winning his category. Everything came together exactly as we wanted it.
After a few days of rest (Transition period) he starts the build up for his next A-priority race in August. He is now returning to Base period training as described in my book, The Cyclist’s Training Bible. I hope to report the same sort of success in this next A race.

That is pretty amazing stuff. As a non-competitive cyclist, I never knew how much balance and shifting there was for training schedules. I can't wait to hear how you adjusted his workload to keep his form on track.
Posted by: Jason Huselton | 06/11/2010 at 06:04 AM
Great information. The visual aid is extremely helpful, too. Terrific post!
Posted by: Matt Borowski | 06/11/2010 at 08:27 AM
Joe, I am almost on the same periodization as this rider..i.e. this was my transition week and I plan to do an HR/POWER test this weekend with late July as my next "A" race.
So, do I go back to Build1 or Base or what?
tks
Posted by: Super G | 06/11/2010 at 09:13 AM
Joe, great topic! Is there a way to calculate/estimate ATL and CTL with only a heart rate monitor?
Posted by: Jay | 06/11/2010 at 10:04 AM
Hi Joe,
Great post!!
The way I understand it your TSS score (which determine both your CTL and your ATL is based off of your volume and intensity relative to your functional threshold.
As an athlete such as the one you are coaching becomes more fit throughout the season his functional threshold will change. He should be able to produce a higher average power or faster average pace in 1 hour time trial.
This would essentially mean that the athletes TSS score for a ride (or run) would not be consistent throughout season.
For example an athlete with a TTS score of 100 for an hour bike ride early in the season (when his functional threshold is 200 watts)would be much different then TTS score of 100 for and hour bike ride in the build period (when his functional threshold is 220w).
It seems as though your CTL (fitness) could remain the same throughout the season even if you have made large improvements. Your CTL is highly dependent on how often you test your functional threshold.
Do you assume that a particular athlete has the same functional threshold throughout the entire season even though that might not be the case??
Posted by: Kyle Visin | 06/11/2010 at 01:19 PM
Kyle--I know people who do that. You'd be in good company. But you're merely comparing your current level of adaptation to a previous fitnss level, however.
Posted by: Joe Friel | 06/11/2010 at 01:28 PM
Jay--Good timing on his question. TrainingPeaks.com is working on just such a thing. Expect it have it up and running by the end of the month. In the men time reading this may help... http://home.trainingpeaks.com/articles/cycling/estimating-training-stress-score-(tss)-by-joe-friel.aspx
Posted by: Joe Friel | 06/11/2010 at 01:31 PM
Hi Super G--That rider will go back to base 3 training. That's usually best for most athletes at this point in the season.
Posted by: Joe Friel | 06/11/2010 at 01:32 PM
So what your saying is that your CTL is not really your fitness level. Correct?? For instance your fitness level could change drastically throughout the build period even though your CTL may remain constant due to an increases made in your functional threshold.
Is there a useful way to estimate your "fitness" where you could compare it to where you were earlier in the season or even previous seasons?
It seems to me that the best way to gauge fitness would be to find a useful way to relate pace (power) and duration to Heart Rate (as a percentage of threshold HR). But perhaps were not there mathematically yet!!!
Posted by: Kyle Visin | 06/11/2010 at 04:27 PM
I read on a forum that you should not increase your CTL by more then 4 TSS points from one 3 or 4 week phase to the next. I see that this athletes CTL goes up by a lot more then that in the base and build phases. What are your thoughts? How much of a raise in CTL is safe for MOST athletes?
Posted by: Nathan | 06/12/2010 at 02:12 PM
Nathan--It's very individualized Some athletes can manage rapid changes, especially in their base period, while others can't. There is no formula for this that fits everyone.
Posted by: Joe Friel | 06/12/2010 at 05:24 PM
If your life feels like it is lacking the power that you want and the motivation that you need, sometimes all you have to do is shift your point of view.
Posted by: coach purses | 06/27/2010 at 11:34 PM
Joe, earlier in this thread, I inquired about a way to calculate/estimate ATL and CTL with only a heart rate monitor. Has TrainingPeaks made any progress on this?
Thanks.
Posted by: Jay | 07/01/2010 at 09:02 AM
Jay--haven't heard. Will check.
Posted by: Joe Friel | 07/01/2010 at 12:51 PM