How to Use Strava’s Fitness & Freshness Tool

Fitness and Freshness enables you to track your levels of fitness, fatigue, and form over time, which can both help you peak for races and prevent you from overtraining, as Chris Case explains.

Imagine if Strava offered a tool that visually illustrated how all of your training linked together to produce fitness gains. Pretend this magical tool could help you find your peak form and, just as importantly, help you ride the edge of fitness without tipping over.

Well, look no more. The Fitness and Freshness feature has been available to Strava subscribers for years, but many people don’t know exactly how to use it. Let’s change that.

In essence, this simple chart enables you to track your levels of fitness, fatigue, and form over selected periods of time, graphing this information to be used as a guide for optimizing your training.

FITNESS AND FRESHNESS: Check out your graphs today

“This tool helps to tell an athlete’s training story, especially when it’s viewed over multiple seasons,” says Ryan Kohler, founder of Rocky Mountain Devo Coaching. “Being able to see that natural variation from season to season, that tells me crucial things about how they’re training, how they’re periodizing. Then you can look more closely to detect the things that worked or didn’t work in past seasons.”

What is Fitness, Fatigue and Form?

In reality, what this tool attempts to do is illustrate a rather complex concept: fitness. In simplistic terms, fitness is an accumulation of training. Understanding how form and fatigue yield fitness takes a more involved explanation.

Your Fitness score is calculated using Training Load (based on factors including power and duration) and/or Relative Effort (based on heart rate or Perceived Exertion input), to produce a score for your daily training. A so-called impulse-response model is used to quantify its effect over time.

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Conceptually, your Fatigue score is easier to understand—we all know that achy-legs-on-the-stairs feeling that limits our performance. Fatigue is modeled the same way as Fitness, but on a shorter timescale. You'll notice the score rises quickly after consecutive hard days, but it also drops quickly if you take rest days.

Form is simply the difference between Fitness and Fatigue. Being in form, or "peaking," happens when one has very high fitness but low fatigue.

For the nerds out there, Strava’s method for calculating Fitness, Fatigue, and Form is based on an impulse-response model first developed by Dr. Eric W. Banister in 1975. It was later applied to cycling by Dr. Andy Coggan.

Tips for using the Fitness & Freshness tool

The Fitness and Freshness chart is especially useful if you are using a periodized training plan. When employing this method, training goes through various phases as you improve fitness toward the season’s goals. A block of training might include a three-week build-up, followed by a recovery week. This will be clearly illustrated as a staircase-like ramp in your Fitness and Freshness chart.

What’s happening is that your Fitness score rises stepwise over the three weeks of training impulses. Simultaneously, your Fatigue accumulates faster, which leads to a decline in form. However, if you back down, Fatigue drops quickly, while Fitness is largely maintained during the recovery week. Voila, you’ve allowed your Form to peak.

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In general, the overall numbers in your chart aren't as important as the general trends you identify. One of the more powerful things you can do with this information is to compare where you are now to past periods when you were fit. This can help you determine your current fitness, appropriate training loads, and how to improve even more.

When using the Fitness and Freshness tool on the website, there are several things you can do to refine the graph to your liking.

• You can select the range of time represented by the graph, as well as enable plotlines to track your Fatigue and Form.

• Clicking on any point in the graph will “focus” on that time interval—and show your specific Fitness, Fatigue, and Form values on that date.

• Below the graph, you'll see the relevant activities that contributed to your Fitness values, as well as their Training Impulse. Simply click again anywhere in the chart to “unfocus.”

• Races are marked in red to help you analyze fitness over longer chunks of time. The fitness delta (change) next to the fitness score will show how your fitness has changed over the last seven days.

There's more information on how to refine your Fitness and Freshness graph here.

When one line goes up, the other comes down

For the novice, the Fitness and Freshness feature is one of the more complicated tools on Strava. However, it is also one with great potential, since it can be used to closely track and improve your fitness, as well as prepare for events. In fact, this type of analysis is modeled after a similar tool found in TrainingPeaks, which is the benchmark of training data analysis software. The company’s Performance Management Chart (PMC) is based on concepts that have been in training for many decades.

RELATED: Power Meter Guide: The Power Curve, Fitness and Freshness and Hitting Your Peak

Regardless of the name, there are universal concepts that apply to both tools. First, the line that most people will naturally gravitate toward is the Fitness line, or chronic training load (CTL) in the parlance of the PMC. The problem with focusing on that single line is that it drives people to try and push it as high as possible. Higher number equals a fitter athlete, right? Not exactly. Again, it’s a more complex relationship.

“Be very careful about focusing on that line,” says physiologist Trevor Connor, founder of Fast Talk Labs. “As with so many things, it’s all relative based on the level of the athlete. And it’s simply more complex than that. There’s a lot of interplay with other factors, and there are limitations to the tool.”

The importance of 'good' data

The limits of the Fitness and Freshness tool, as with the PMC, are significant. Knowing what they are will help you use the tool more effectively. These limits include:

• The various scores are calculated based on your FTP. Therefore, if your FTP is inaccurate, all of the data in the graph will be inaccurate. To prevent these errors, it’s helpful to conduct an FTP test every 6-8 weeks in the midst of serious training. Keep the FTP up to date.

• Fitness is relative. It’s simply a representation of your data, and is not comparable to your training buddies, since it is a function of your FTP. Therefore, it is imperative not to “chase” a high Fitness score solely because your friend’s is higher. A higher score does not necessarily make you a better rider.

• Likewise, building up to a Fitness score that feels “right” and fits with your routine is great, but if you then simply try to hold that Fitness score indefinitely, you will plateau and sacrifice optimal Fitness. Sometimes losing a bit of Fitness (through rest and recovery) is essential for rebuilding to an even higher level.

• The graph is only as good as the data you put in, which means that you need to be consistently feeding it good data for it to be able to calculate scores accurately. Make sure your power meter and/or heart rate monitor are in good working order. Or, if you are using Perceived Exertion, make sure to answer the question “How did that activity feel?” consistently.

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Ultimately, the Fitness and Freshness tool is great for identifying trends. Look for steep ramps, upward or downward, to understand the nature of your training. Look for times when Fitness is high, Fatigue is low, and Form is rising. This should correspond with some of your best performances. If it doesn’t, look a little deeper at the causes.

“The tool can be used broadly enough that you don’t get bogged down in the details,” Kohler says. “The big picture actually tells us more about what we need, generally speaking. It’s all about identifying trends.”