The screenshot of this workout from Xert’s Workout Designer, including the interval definitions, are shown above. The key pieces of information you should pay attention to are the Total XSS (117), Difficulty Rating (4 diamonds – Tough) and both the MPA (Maximal Power Available) line on the graph as well as the Difficulty Score line, which reaches 114.

For this athlete, the MPA line doesn’t look too challenging. MPA manages to dip below 800W but never comes close to reaching the Target Power value. In Xert, when the MPA line reaches the red Target Power line, it signifies that the athlete is at their limit – the first type of fatigue identified above (A. The power targets are impossible.)

However, the Difficulty Score rises to 114. Reaching a 114 Difficulty Score is rare in workouts (less rare when racing) as it requires a considerable amount of training and motivation on the part of the athlete. This score of 114 translates to a Difficulty Rating of 4 diamonds – Tough and would be recommended to athletes that have been training for a least a couple of months and have reach a Training Status of Elite in Xert (4-Star Training Load).

Modeling a Similar Workout using Smart Intervals

The Xert Workout Designer offers alternative methods to define intervals, which can be made to cater to the athlete more precisely. They can also offer the same amount of training strain (XSS) without the same level of difficulty. For example, here is a workout similar to the VO2max workout that Xert users may be familiar with, called Smart – Closer 200 (slightly adjusted to match the VO2max workout in terms of XSS).

The workout definition and accompanying interval targets are shown above. The workout has exactly the same warmup and overall duration. It also offers the same XSS as the VO2max workout above. However, the workout has a Difficulty Rating of 3.5 Difficult (Difficulty Score reaches 109), lower than the VO2max workout. What this means is that the benefit of the workout (XSS, including the breakdown into low, high and peak) is identical to the VO2max workout, but it’s easier, making it more likely to be completed. Anything that can help you complete a workout without compromising your training is a good thing!

What Would Make You Unable to Complete These Workouts?

Examining the charts, we can see that in both cases the workouts are not impossible for the athlete. (The blue MPA line does not cross the red target power line.) This means that they have enough power to complete these workouts, so reason A. The power targets are impossible, is not the reason. But they both reach high levels of Difficulty. Performing these workouts requires a considerable training for the majority of athletes. Reason B. The intervals are too painful, could very well be the reason they were not able to complete this workout. The Smart – Closer 200 is slightly easier according to the Difficulty Score and this is because the intervals become easier as you do them, due to their changing power targets. Doing these intervals as Smart intervals offers a very unique feeling for athletes since the interval targets decline as MPA is reduced. The sensation is that the same level of effort is sustained rather than experiencing an increasing effort with flat, fixed wattage intervals.

If you’re doing this workout, it shouldn’t be attempted until you’re sufficiently recovered from previous training sessions. If you experience reason C. Feels like you have no energy, you haven’t given yourself enough time after your last workout to be able to complete this tough workout.

What Happens When We Consider A Different Athlete?

The examples we used above are based on an athlete with a Fitness Signature of 310W TP, 23kJ HIE and 1200 PP. What happens though if the athlete has a lower High Intensity Energy of 14kJ? (Note: High Intensity Energy or HIE represents how much power an athlete can sustain above their TP.  Even with the same Threshold Power, athletes have different values for this). Let’s plug those numbers into the Workout Designer, click Refresh and see what happens:

For this athlete, with the same Threshold Power of 310W, the workout is impossible (Reason A. The power targets are impossible). The last few seconds of the 115% intervals would bring MPA below that of power (the blue MPA line passes the red target power line). In this case, the workout is simply not something the athlete would be able to complete, at any training status level. The Difficulty Score reaches a much higher level as a result of the added effect on MPA, reaching over 150. Here, the Xert Workout Designer can help you see if a given set of intervals are possible with your individual Fitness Signature.

Xert’s Smart Intervals in Action

If we instead apply the same unique Fitness Signature to the Smart – Closer 200 workout, we get an very different result:

As you can see, if we change the Fitness Signature and Refresh this workout, the results are identical to the Smart – Closer 200 workout above. This is one of the main benefits of using Smart intervals in your workout definition. Workouts can be designed such that they offer the athlete the identical benefits (XSS) independent of their Fitness Signature.  It doesn’t matter what your Fitness Signature is, whether you are aerobically gifted or blessed with a lot of high end power, this workout will have the same benefit and Difficulty Score. As an athlete or coach, this ensures that you will know exactly what benefit the workout will provide and how difficult it will be no matter who does it.

For anyone that’s ever been prescribed a conventional 5×5 VO2max workout, they can attest that they can often be very challenging.  Getting the right interval targets often cannot be done without a coach’s involvement.  With Xert, both the athlete and the coach are empowered by using the Workout Designer.

Workout Tapering

A you try a variety of Xert’s SMART workouts, you will discover that many of the harder & higher-intensity workouts progressively decrease in intensity throughout the workout. Below, you’ll see the SMART – Bangarang workout, a workout with sweetspot intervals done under fatigue, with the 8 min intervals in the first half done at 92 XSSR and the 8 min intervals in the second half done at a slightly easier 88 XSSR:

The difficulty tapering of Xert’s SMART workouts is done intentionally to help reduce the overall difficulty of the workout, while minimally impact the overall training strain (XSS).  Tapering the workout difficulty also increases workout compliance – you can be confident after the first couple of intervals/repetitions that the workout will only get easier. Alternatively, if  you’re feeling strong on a particular day, you can always increase the workout difficulty using the Xert EBC apps or the Garmin workout player!

Accounting For Freshness and Tiredness

One of the tenets of Xert is “Training improves fitness as well as your ability to express it.”  What this means is that as you train, you get better at bringing MPA down and generating fatigue on a more repeatable basis.  With the Adaptive Training Advisor, workouts are recommended based on your Training Status (both number and colour of stars in your profile).  The number of stars helps you see which workouts would be suitable.  If you’ve been aggressively training towards an event and have reached a 3 star Training Status, you might see Smart – Closer 200 workout prescribed.  It would be a great workout to do as part of your Build Phase or in your Peak Phase with a GC Specialist Athlete Type.  You could attempt this workout with a Training Status of 2 stars but it would be very challenging and may likely lead to you abandoning it.

Given the demands this workout has on your 3 systems, you would need to be Fresh or Very Fresh (blue or green) Training Status in order to be recovered enough.  Xert will only recommend this workout, or other high-intensity workouts, when your Training Status is blue or green.

When Are Harder Workouts Better?

A workout can intentionally be designed to be hard in order to have you prepare for the suffering you will be subject to during racing.  The goal of such workouts isn’t to apply strain to benefit your fitness but to increase the difficulty of the workout so that you can practice and be prepared for the race.  In Xert, we have “Hardness Tests” that enable you to test how deep you are prepared to go.  They are great workouts in and of themselves but they’re designed to determine how much difficulty you can endure.  Making every workout a test in hardness however is a formula for disaster as you will struggle to complete workouts and thus impact the benefits you could obtain from your training.

Working with The Xert Workout Designer

Xert’s Workout Designer provides a unique and powerful environment to help coaches and individuals create workouts that offer flexibility, universality and precision unavailable in other workout design tools.  You can see, in advance, what MPA is predicted to be as well as get an appreciation for the Difficulty of the workout.  Workouts can be designed that offer the right balance of training strain, are achievable and won’t be abandoned because they are too hard.

What To Look For in a Workout

1. Check the MPA and ensure that the workout doesn’t lower MPA to a point where you cannot complete the workout.  If you’re more of an aerobic athlete, this problem can occur more often with workouts that are based on %FTP.
2. Avoid long intervals of easy pedaling while you’re already recovered… Seeing these in workouts is a sure sign that you’re wasting valuable training time in the workout, not accumulating improvements when you could be.
3. Maximize your XSS, not the Difficulty.  If you have the harder intervals near the end of the workout, they’ll be more difficult and more likely to be abandoned.  Unless this is the intent of the workout, it’s better to have the hardest intervals nearer the beginning.

Note that the amount of fat and carbs calculated does NOT include your basal metabolism.  It is derived from the work you perform that gets recorded by the power meter.

To help you resolve these issues, you can use the flag feature.  You can find the flag on many of the screens you use on Xert:

When an activity is flagged the system will not try to analyze it to look for a breakthrough; the extraction process that looks for breakthroughs (i.e. changes to your Fitness Signature) is skipped. Note that when an activity is flagged, the system will recalculate the progression data from that point forward. This is to ensure that the error in the activity signature isn’t propagated to the rest of your progression.

Note that the system will automatically flag activities when data anomalies are detected.

Ignoring Near Breakthroughs

Another application of the flag feature is to ignore a ‘near’ breakthrough. If you feel that the near breakthrough wasn’t a true maximal effort and feel that your signature declined erroneously, you can flag the activity so that the near breakthrough is ignored. The near breakthrough will no longer appear on your progression chart and your signature will not see a reduction from the activity.

Follow the steps below and you’ll be ‘Xerting’ before you know it! However, there are some things you should know ahead of time:

• ‘SMART’ workouts will no longer be adaptive/dynamic – All the correct wattages and durations are calculated when you export the workout file, but the workout player in Zwift  (or any other platform) isn’t capable of adjusting workouts on the fly in real-time like Xert’s workout players. If you have a smart trainer, you will hardly know the difference, since the trainer will control your power throughout the workout. For a more advanced approach, follow this guide if you wish to use Xert’s SMART intervals while riding in Zwift.
• Xert’s Curvilinear Intervals are Exported as Ramps – The Xert XSSR Intervals, with their iconic shapes can only be exported as ramps. This can make the workouts harder or easier than they were intended in Xert. Workouts with these intervals are best performed using an Xert workout player.
• Workout targets in Zwift are defined as %FTP – The ZWO exporter uses %FTP rather than specific wattages in the definition. This means that your FTP in Zwift should be set equal to your Threshold Power from Xert in order for the workout targets to be same.  There are a few important things to note about this:
  • If you are finding the workout too difficult to complete for whatever reason, you can change the overall workout intensity by either choosing a lower FTP before you start the workout, or adjusting the FTP Bias in Zwift.
  • As your fitness improves, you can adjust the FTP in Zwift to correspond to the increases in Xert (refer to your Fitness Signature in Xert). Under most circumstances this should work well, although if you’re using a workout that was exported with a very different signature, you may want to re-export the same workout again to get updated values and more precise targets.
  • Even though the workouts are based on %FTP, they are not easily transferrable from one athlete to another. As all good Xerters know, using %FTP as workouts targets has its limitations, so you should not use someone else’s file if you want to benefit from Xert’s high precision workouts.

Loading Xert Workouts to Zwift

1. Log into your Xert Account and navigate to the Training tab of the My Fitness page. You can view  recommended workouts on the right-hand side of the page. As you scroll through the recommended workouts, you will see buttons appear for Play Now, Schedule, as well as exports to ZWO, TCX, or ERG file formats. Click the ZWO option and save this file to your computer. You can also go to your Workouts page, open any workout from the Standard, Coach, or Personal list, and select ZWO in the upper right corner to download the file.
2. Move/Save the ZWO file to Documents > Zwift > Workouts > ###### (this is your Zwift ID number) on your computer.
   
3. Start the Zwift app on the device you use for Zwift rides and navigate to the ‘Workouts’ screen. Select the ‘Custom’ category and search for the Xert workout you’d like to perform. That’s all!

Note: if you’d like to maintain the SMART features of a workout, you can use the Xert Workout Player for Garmin, Android or iOS to ‘play’ the workout while letting Xert ‘listen’ to the power data and power you through the virtual world. Here are a couple helpful resources to help you achieve this:

• How to set up the Xert Remote Player
• The Ultimate Guide to Training with Xert and Zwift

Focus Type in the Adaptive Training Advisor provides guidance on what the Focus needs to be for the workout at this point in your training program.  It also factors in whether you are Tired or Very Tired.  The guidance is not meant to provide a workout structure but provide some simple guidelines you can apply when just riding and using the apps that show Focus and XSS. Training with Xert doesn’t need to be so precise since we’re capturing all your strain, even with semi-random power data. It is the reason why our workouts are not so repetitious and provide more interest. Following simple and rigid workouts is becoming a thing of the past.

If you’re in the Base, Build or Peak phase of your Training Program, the Athlete Type category will be shown based the Program Phase and your Training Status.  In the above example, it is Endurance and this the general category for the workout/activity that is being suggested.  Focus is shown next. This is shown as a time value and represents the Focus Duration.  In the above example, it shows 24:06.  When using Xert Mobile, or the Focus and Strain Garmin CIQ app or if you have the Remote Player on screen during your workout, you’ll be able to see what this value is for your entire workout.  As your training nears your Target Event Date, the value will come closer and closer to that of your Target Athlete Type.

Note that his value does not represent the duration of the workout or intervals.  It represents that longest duration you would be able to sustain for the Interval Targets shown.  It should be used with our apps or in creating/choosing an Xert workout. 

The last value shown in your Interval Targets.  This value provides a rough estimate of the power target you should be looking to maintain during intervals, if you are planning on just riding and not following a workout.  The more time you spend at this intensity, the more you are training at the correct focus. Combining efforts above and below this intensity is also effective.

If your are Pre Base or Post Event, you’ll be offered a randomized Focus.  This means that the XATA will not periodize your training and will recommend workouts with varying Focus.

When performing unstructured workouts using the Garmin Focus field, you should aim to sustain the Interval Targets or slightly higher in order to reach the Focus Duration specified.  Ideally, the colour of the Garmin Focus field should be blue or green (See Specificity Rating) in order to get the most benefit towards the given Focus.  If the colour is black or yellow, it means that the workout is mostly Endurance / low intensity work.

The XPMC typically includes the following components:

1. Training Load: The solid black line represents the cumulative stress imposed on the body during training sessions over time. It is often quantified using metrics such as Xert Stress Score (XSS) or Training Load (TL).
2. Recovery Load: A measure of the recovery required to return the body to a balanced state after training stress. This metric is hidden by default since Xerters don’t need to keep track of Recovery Load directly.  Xert will summarize how much recovery you need and simplify this by using Training Status and Form.
3. Form: The multicoloured line indicates your training status over time. Form is derived from the balance between training load and recovery load.
4. Daily XSS (Xert Strain Score): The ‘Matchstick‘ for each activity reflects the strain or stress placed on each of your 3 energy systems during activities & workouts, providing a detailed view of daily training intensity.  Blue corresponds to low XSS, Orange corresponds to High XSS, and Red corresponds to Peak XSS.

Additionally, the XPMC also includes the following supplementary components for added context:

5. Threshold Power: Displays an athlete’s Threshold Power level, a key metric used in performance assessment and training intensity prescription.
6. Breakthrough Activities: The circles found in your XPMC highlight specific activities where you achieved significant improvements or breakthroughs in performance, helping to track progress and performance milestones.

Overall, the Xert Performance Management Chart serves as a comprehensive tool for athletes to monitor their training load, recovery status, form, and performance metrics, providing valuable insights to optimize training strategies and performance outcomes.

The Stars

As your training volume increases and decreases throughout the year, you might notice the number of stars in your profile increase or decrease, corresponding with your changes in training. To earn your first star, you must reach a training load of 25, which indicates that, on average, you have accrued 25 XSS/day recently. To earn additional stars, you must achieve Training Loads listed below:

0 Stars – Untrained: Training Load < 25
1 Star – Recreational: 50 > Training Load >= 25
2 Stars – Trained: 75 > Training Load >= 50
3 Stars – Competitive: 110 > Training Load > 75
4 Stars – Elite: 150 > Training Load >= 110
5 Stars – Pro Level: Training Load >= 150

Training Status

The colour of your stars is determined both by your long-term fitness & recent training activity.

• Very Fresh (Green): Low, High, & Peak intensity systems are ready to train. High Intensity training can be completed. Often happens after some additional recovery.
• Fresh (Blue): Low, High, & Peak intensity systems are ready to train. High Intensity training can be completed.
• Tired (Yellow): Low intensity system is ready to go, but High & Peak systems need additional recovery. Endurance activity can be completed, but be sure to avoid high-intensity efforts.
• Very Tired (Red): Low, High, & Peak intensity systems are too tired to train. Consider taking a rest day.

Recovery Demands

User’s can make a system-wide adjustment to their calculated Freshness using the Recovery Demands Slider. For more information, check out the support documentation.

Technical Note: When the Recovery Demands slider is entered, the maximum sustainable ramp rate is limited to less no more than 4. With the slider moved all the way to the right, max sustainable ramp rate is below 2. And with the slider moved all the way left, maximum ramp rate is approximately 7.

To perform MPA Analysis on an activity, open the Activity Details – MPA tab for the activity.  On that page you have a chart showing both MPA and power.  Below the chart, you can click on the other activity data to overlay additional information that you might need for the assessment.

Progression calculations will automatically attempt to determine the fitness signature for the the activity. The results of this are shown as the Fitness Signature for the activity below the chart.  Xert automatically performs a signature extraction using the previous activity’s fitness signature as the starting point.   In the case where a long time has passed since your previous activity, Xert may have lowered your signature values as it will have expected a decline due to detraining.

To see what a different signature looks like in terms of MPA, enter in a given set of values and click Refresh Analytics.  This will use the signature you entered to determine MPA and plots these.  Where your MPA is at or below your power output are your maximal efforts.  If you MPA falls below your power, this indicates that one or more of your fitness signature values are too low.  If your MPA never meets your power data, this can either mean that the activity did not have any maximal efforts or that the signature used is too high to represent your fitness.

Using the Extract Fitness Signature button, Xert will run a process to determine what your signature was for the activity using the values in the boxes as starting points.  The values used are important since your fitness changes relatively and not all activities express your entire fitness.  For example, you may not express your Peak Power in an activity so using a low Peak Power value as the starting point for the extraction will likely lead to a low extracted value.

When an activity is rich with maximal efforts, Xert’s extraction process will have a much easier time determining your a three fitness signature values at the time of the activity.  When an activity has few, it relies more on the previous activity’s signature.

When you’re satisfied that the fitness signature is representative of your fitness at that time, Save the fitness signature to the activity.  Note that when doing so, subsequent activities may also be affected by the change.

1. Time zone discrepancies between the source of your activity file and your Xert account;
2. Double syncing i.e. you’re syncing your Xert account with both Strava AND Garmin Connect;
3. Your Planned Activity/Workout Time is keeping a planned workouts on your calendar after you’ve completed your activity/workout.

Let’s look at how to identify & solve each one of these…

Time Zone Discrepancy

Xert uses timestamps on activities to identify and omit potential duplicate activities. If your timezone has not been selected in Xert or if it differs from the source of your activity file (Strava or Garmin Connect), Xert will see these as different activities. To solve, make sure you’re time zones are correct and consistent between platforms you are using with Xert. In Xert, this can be found under Account Settings > Personal Info – Timezone.

Double Syncing

If you’re syncing activities from both Garmin Connect AND Strava duplicates can easily occur, especially if there are differences in time zones. To solve, enable only Garmin Connect or Strava as your activity file source and make sure your timezones are the same in both your Garmin Connect or Strava account and your Xert account settings. If  you see duplicates in the past you can manually delete them in Activities > Table.

Planned Activity/Workout Time

If you have a planned activity/workout scheduled for later in the day and you completed this scheduled activity in advance of its scheduled time, you will see two entries on today’s date for that activity using the Fitness Planner.  When the time of your scheduled activity has passed, it will be expired and you’ll only have one activity remaining for today.  Until then, you may possibly see two duplicate entries.

To have Xert do a progression recalculation, go to your Account Settings / Profile tab:

For best results, start by entering a Fitness Signature which is representative of your Fitness Signature for the very first activity in your progression history. Use the Fitness Signature Calculator to help or contact the support team if you’re not sure how to determine these numbers.

Once that’s done, click ‘Save’ and then click ‘Recalculation Progression and confirm.  Xert will then use the signature you entered as your very first Fitness Signature for your first activity, perform MPA Analysis to determine maximal efforts, XSS, Focus & Specificity rating and extract a fitness signature, if required.  This process then trickles-down through your entire activity history.

Note: during the recalculation process, any activities that have saved/locked fitness signatures will be unlocked and updated.