Book Excerpt: Fitness, Fatigue and Form


The following is an excerpt from the soon-to-be-released edition of The Training Bible book series. © 2007 Joe Friel

Despite all of the previous discussion on periodization sounding very scientific, training based on periodization is largely a leap of faith. You simply trust that organizing workouts in a certain way produces peak readiness on race day. Along the way it is possible to take “snapshots” of your fitness every four weeks or so by doing field tests. But since the physiological changes are generally quite small—on the order of one percent—variables such as weather, the warm-up and even a couple cups of coffee can easily make it appear there is no progress in the past few weeks. So you are back to trusting your instincts—am I fitter than I was a few weeks ago?

Now all of that is changing. With new software designed by Hunter Allen and Andrew Coggan, PhD it is possible to graph and manage the daily changes in your race preparation. The software is called WKO+® and is compatible with all power meters. Don’t have a power meter? You don’t know what you’re missing. If you think a heart rate monitor is a great training tool, wait until you have a power meter.

One of the most powerful features of WKO+ is its Performance Management Chart (PMC). This allows you to track periodization and progress toward your race goals. The accompanying graph is a screen shot of the PMC for the early season for one of the athletes I coach. This a good example of the direction training technology is going. If you are serious about your race performance such software will allow you to keep a close eye on progress and respond quickly when small periodization changes are necessary to stay on track toward your goals.

There are three aspects of training represented by the lines on the graph. All are derived from long, complicated formulae determined by certain power-based variables—normalized power, intensity factor and training stress score. These reflect the intensity, duration and frequency of your bike workouts. To learn more about these details see Allen’s and Coggan’s book, Training and Racing with a Power Meter.

The red line on the chart represents fatigue. It closely approximates what you are subjectively describing after a few days of hard training. Notice the spikes and valleys. These indicate alternating hard and easy workout days. The spikes show increased training stress from long, high intensity and/or frequent bike workouts. The valleys are short, easy rides or days off the bike.

The blue line is fitness. When this line rises, fitness is improving. Notice that it isn’t a straight line. Fitness is never static and is always changing, either positively or negatively. Also note that fitness only increases in response to increases in fatigue. They go hand-in-hand. This makes sense as fatigue means you trained hard, and hard training produces greater fitness. While a few days of extended rest is necessary every three or four weeks to prevent overtraining and burnout, you must be careful not to make it too long or too much fitness will be lost. The software allows you to monitor this. Effectively balancing rest and stress is a fine edge when it comes to fitness.

The black line represents form which may also be described as race readiness. The word comes from late Nineteenth Century British horse racing when bettors would review a page of previous race results—a form—of the horses entered in a race. A horse was said to be “on form” when racing well.

Form rises when you back off from hard training to rest more. It falls when you train frequently with high intensity or long workouts. On the left side of the graph, next to the word “form,” you see a 0 (zero) on the scale. When the black line is above this point the athlete is “on form.”

So now let’s take a look at my athlete’s early season periodization and how it worked out. Along the fitness curve I’ve indicated his early season periods: Prep, Base, Build, Peak and Race (circle). The “2nd Build” following the Race period is the start of his return to hard training in preparation for the next A-priority race on his schedule.

As described earlier, the Prep period is a time when the athlete is just getting back into training following a break at the end of the previous season. In this case, it was December through early January. He had a family vacation planned for the last three weeks of this period and would not have a bike available. Here you can see the steady drop in both fatigue and fitness since he wasn’t riding. Accompanying that drop is a rise in form. He was really rested—at least as far as the bike goes—but, of course, his bike fitness was becoming increasingly poor. In the Base period he returned to steady and consistent training with increasing time spent on the indoor trainer working on aerobic endurance, muscular force and pedaling speed skills. The steady rise in fatigue and fitness with a drop in form all indicate that training was going as expected.

During the “1st Build” period I began to increase the intensity of his training by including muscular endurance rides made up primarily of intervals and tempo while maintaining his three fitness abilities—endurance, force and speed skills—established in the Base period. Both fatigue and fitness rose at a greater rate and form dropped to a low point of the early season due to this increase in the training load. I made slight adjustments to stress and rest along the way as the chart revealed how he was responding to training.

In the short Peak period he did just a couple of hard workouts with lots of rest between them. Notice how fatigue dropped dramatically while fitness decreased only slightly. The most important change to see here is the rapid rise in form with an increase above the horizontal zero line mentioned above. At his “First Race” he was not only at a high level of fitness, he was also well rested. This was evident in his sense of being ready on race day and in his race performance. He was on form.

Following this first race of the season he went on a mountain biking vacation for a few days and resumed hard training on his return. As you can see on the far right side, he was well on his way to the second peak of the season which produced even better results.

About the Author

Joe Friel

Joe Friel is the author of The Triathlete's Training Bible, Your Best Triathlon and other books on training. For more information visit his website at You can also view and purchase Joe's training plans on TrainingPeaks.

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