That is why. Can’t you tell?

The chart above is one of my favorite training analysis chart. It is called the Performance Management Chart. With it I can track my long term fitness improvement (the blue line), my short term average training effort (the pink line) and how rested I am at any given point (the pink bars). Based on that chart, I was convinced last night was going to be a good night, and it truly was.

According to TrainingPeaks, the developer of the software I use to generate the above chart – and obviously according to my CTS coach Tim – most coaches can get you somewhat fitter than before however the true challenge is not just to be fitter than before but to be way fitter than before and at the exact time that you need to be way fitter. That’s the true challenge.

I have used a power meter for several years. The great thing about using a power meter is that it gives me a complete record of my training, second by second. Because a power meter quantitatively measures the training load in watts – an objective measure of effort – each ride can be categorized in a numerical fashion by giving it what TrainingPeaks calls a “Training Stress Score” or “TSS”. TSS is the creation of Dr. Coggan and is a useful metric to quantify the training stress of each workout, from long hard training days to easy recovery rides. 

At a very high level TSS is based on the intensity (Intensity Factor or IF) of a ride and the length of the ride – in time not distance. IF is simply the ratio of the normalized power (average watts) for the ride to my threshold power – calculated as the average power in watts I can maintain on a full out 7 minutes effort uphill. For example, if my normalized power for a training ride early in the season is 210 watts and my threshold power at the time is 280, then the IF for that workout would be 0.75. However, if I did that same exact ride later in the year after my threshold power had risen to 332 watts, then the IF would be lower, i.e., 0.63. Intensity Factor therefore provides a valid and convenient way of comparing the relative intensity of a training session or race taking into account changes or differences in threshold power or increase in fitness. To simplify all this in the example above of an IF of 0.63 the TSS of this ride would be about 63 if it was an hour ride and about 126 if it was a tow hour ride – not quite but you get the idea. Or if you look at it the other way, I need to produce more watts during a ride as my threshold goes up in order to keep the intensity up and hence the adaptation. This also illustrates the fact that in order to create training stress and adaptation that leads to increased fitness we can play with duration and/or intensity.

Since I track metrics for each ‘dose’ of training, or training load, then my coach and I can begin to see the levels of training that are needed for improvements in fitness and apply those specific ‘doses’ as we need. This is the key to the system and my coach and I can exactly quantify my training load based on the TSS for each workout.

But what exactly is ‘fitness’ then? ‘Fitness’ is a response to training stress. A dose of training is given to an athlete, and then the athlete adapts and responds positively to that dose, which create improvements and efficiencies in the body. These improvements are cumulatively called an improvement in fitness. So, fitness is the creation from a training stress or a load of training. This load of training has to be more intense or more volume than before, or both, in order to create a greater adaptation.

While exercise intensity is clearly an important factor in determining the type and magnitude of physiological adaptations to training, exercise frequency and duration – which together determine the overall training volume – are important factors as well. However, there is obviously an interaction between training intensity and volume, i.e., at some point as intensity goes up volume must come down.

To quantify the overall training load, TrainingPeaks uses my power data to calculate a TSS for every workout, and it provides a graphical summary of my recent TSS. TSS takes into account both the intensity and the duration of each training session, and might be best viewed as a predictor of the amount of glycogen utilized in each workout. Thus, a very high TSS resulting from a single race or training session can be used an indicator that one or more days should be scheduled.

Since Tim and I know the TSS for each ride we can start tracking the TSS over time and analyze how well we are doing at creating more and more adaptation at the right time. TrainingPeaks calls the cumulative effect or impact of training stress that has been done over the last six weeks the ‘Chronic Training Load’ (CTL – the blue line, roughly a six weeks moving average of TSS). CTL can be shorter than six weeks or it may be longer, that is up for debate, however let’s just consider the fact that the workouts that I did six weeks ago are without a doubt impacting my performance today. The workouts that I did three weeks ago are impacting me as well and most likely with a slightly higher impact than those done six weeks ago. What about the workouts that I did this past week? We call these the ‘Acute Training Load’ (ATL – the pink bars, roughly a seven days moving average of TSS) and these too impact my performance today and into the future. In order words we want to increase training stress slowly over time to cause adaptation and increased fitness and track that progression.

In addition to the concepts of CTL and ATL, there is the concept of ‘form’. Form is the proper balance of fitness and freshness. Fitness is based on training stress or training load, so based on this simple equation, TrainingPeaks renames ‘form’ as Training Stress Balance (TSB – the pink bars).

  • Form=Fitness+ Freshness
  • Fitness is result of Training Stress
  • Freshness is the result of rest.

In this equation TSB represents the balance of training stress or how well I am juggling my training load and my rest periods. If  my TSB is a numerical value and it is ‘positive’ number, then this would mean I would have a good chance of riding well on during those ‘positive’ days, and would suggest that I am both fit and fresh. While if my TSB was a ‘negative’ number, then it would mean that I are most likely tired from a high training load, which could possibly consist of both my CTL and your ATL being high.

Before last night my TSB was at almost a year high and my CTL was also at almost a year high, so fitness + freshness = last night’s result.

Didn’t I tell you?

PS: some of the text above is an edit of text from TrainingPeaks.