With Maximal Power Available (MPA) Analysis in hand, Xert enables these four concepts to now be measured, tracked and used with precision as part of an endurance training regime.

Each of these are built on the foundation of MPAMPA stands for Maximum Power Available. It is a measure of the maximum power an athlete can generate at a given moment... More and your fitness signatureIt is represented by three values: Threshold Power (TP), High Intensity Energy (HIE) and Peak Power (PP). The three fitness values are used...:

**StressSynonymous with work, this metric is measured in joules and is the total work performed over a given period or...**being the work you perform measured against your three energy systems**FocusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is...**being the ratios of the work you perform, interpreted as an Athlete TypeThese are categories that associate with a given Focus Duration point on the power-duration relationship and may or may not...**Specificity RatingThis is a percentage value that provides further detail on a Focus. With Focus Duration characterizing the duration along the...**being a measure of the variability in the work you do**StrainMeasured in joules, this quantifies how much work is performed close to MPA. As MPA drops with fatigue, strain increases...**being the measure of how stressSynonymous with work, this metric is measured in joules and is the total work performed over a given period or... is affecting you and your ability to produce power

### Work Allocation and Stress

StressSynonymous with work, this metric is measured in joules and is the total work performed over a given period or... comes from exercise. The more you exercise, the more stressSynonymous with work, this metric is measured in joules and is the total work performed over a given period or.... With Xert, we can allocate stressSynonymous with work, this metric is measured in joules and is the total work performed over a given period or... according to work allocation ratios. That is, we can look at the work you perform against the three fitness signatureIt is represented by three values: Threshold Power (TP), High Intensity Energy (HIE) and Peak Power (PP). The three fitness values are used... energy systems:

**Low Intensity Work**: Work performed at Threshold PowerAlso used as an acronym TP in Xert and sometimes described using the more colloquial term FTP, Threshold Power is... and below**High Intensity Work**: Work performed above threshold derived from high intensity energyAlso used as the acronym HIE, this is the amount of energy or work capacity an athlete has above Threshold...**Peak Intensity Work**: Work performed above threshold derived from peak power

This energy allocation applies to work performed over any period, even right down to a given second. When we perform work against these three energy systems, Xert cumulates these on your Progression Chart. An example of this chart is shown below:

### Focus

Inherently, focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... follows the same intuitive notions that you may already have: “What is my training focused on?”. To answer this question, we need to look at your work allocation ratios and infer* *how your fitness signatureIt is represented by three values: Threshold Power (TP), High Intensity Energy (HIE) and Peak Power (PP). The three fitness values are used... is being put under stressSynonymous with work, this metric is measured in joules and is the total work performed over a given period or... by the work you perform. The value is determined as a * duration *in Xert, as it maps the work allocation ratios, to power, to a duration based on your fitness signatureIt is represented by three values: Threshold Power (TP), High Intensity Energy (HIE) and Peak Power (PP). The three fitness values are used.... It does so as a matter of convenience and comparison.

To make interpretation of FocusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... easier, each duration is given an **Athlete TypeThese are categories that associate with a given Focus Duration point on the power-duration relationship and may or may not...**:

**Power Sprinter**: 20s**Road Sprinter**: 2 minutes**Pursuiter**: 3 minutes**Puncheur**: 4 minutes**Breakaway Specialist**: 5 minutes**Rouleur**: 6 minutes**GC Specialist**: 8 minutes**Climber**: 10 minutes**Sprint Time-Triallist**: 20 minutes**Time-Triallist**: 1 hour**Century Rider**: 2 hours**Triathlete**: 3+ hours

FocusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... is applied to everything in Xert, right down the work you perform every second. Xert determines your work allocation ratioSometimes referred to as Work Contribution Ratios, these ratios divide work and strain into peak, high and low. Since the three... for every joule of work and cumulates them to give you focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... values for activities, workouts and for time periods such as in your Progression Chart.

#### Current Focus

Using the Progression Chart, Xert establishes what your current focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... is based on exponentially-weighted averages. Using a 42 day time constant, the work you perform against each system is cumulated and displayed in the Progression Chart. The Progression Chart provides a value that represents what your average daily energy load is for each three systems. You can view this as the answer to the question “What is my *recent* training been focused on?*“.*

#### Recommended Focus

Based on your * Target Athlete TypeThese are categories that associate with a given Focus Duration point on the power-duration relationship and may or may not...* and your

*as defined in your profile, Xert makes a recommendation on the focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... you can have in preparation for your event. For example, you may have allocated most of your work over the off-season as a*

**Target Event Date***Triathlete*(a.k.a

*base*training). As your event nears, Xert will recommend that you change your intensity mix toward your target in order to prepare yourself for the event as the Target Athlete TypeThese are categories that associate with a given Focus Duration point on the power-duration relationship and may or may not... you selected. For example, if your current focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... is a

*Time-Triallist*and your

*is 1 month away, and with a*

**Target Event Date***of*

**Target Athlete TypeThese are categories that associate with a given Focus Duration point on the power-duration relationship and may or may not...***Breakaway Specialist*, Xert will recommend that you train as a Climber in order to prepare for your event.

#### Using your Target Event’s Focus

As described in our blog on Work Allocation Ratios, using the focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... from the event you’re targeting or from a similar event, provides a way to decide on the target athlete typeThese are categories that associate with a given Focus Duration point on the power-duration relationship and may or may not... you should train for. Some events require shorter duration fitness, such as criteriums, whereas stage races may require longer duration fitness. Identifying the focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... of the event together with your strengths and weaknesses, Xert provides the information you need to decide on which areas of your fitness to focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... on.

### Specificity Rating

Achieving your focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... can be accomplished in many ways. Those with very low variability, those with high variability and those in between. Low variability workouts and activities, target the power associated with your focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is... work allocation and *only that power*. These workouts/activities are termed * pure*. For example, interval training that only has intervals at a set intensity, with no intensity during rest-in-between periods, has by definition, a

**pure**specificity ratingThis is a percentage value that provides further detail on a Focus. With Focus Duration characterizing the duration along the.... Workouts that target the same work allocation but with very high and very low power targets, i.e. high variability, are termed

*. Those that combine various high, low and target power are termed*

**polar***.*

**mixed**### Strain

StrainMeasured in joules, this quantifies how much work is performed close to MPA. As MPA drops with fatigue, strain increases... is what creates change in your fitness. If your fitness is poor, strainMeasured in joules, this quantifies how much work is performed close to MPA. As MPA drops with fatigue, strain increases... will help generate adaptations to help you improve. If your fitness is strong, strainMeasured in joules, this quantifies how much work is performed close to MPA. As MPA drops with fatigue, strain increases... can help you maintain that fitness. If your fitness has the wrong focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is..., the right type of strainMeasured in joules, this quantifies how much work is performed close to MPA. As MPA drops with fatigue, strain increases... encourages your body to adapt to the new focusThis is a generalized concept that is quantified as duration value and categorized as an Athlete Type. The value is....

If work is the stressor for adaptation, the degree and type of adaptation depends on the strainMeasured in joules, this quantifies how much work is performed close to MPA. As MPA drops with fatigue, strain increases... it induces.

In Xert, strainMeasured in joules, this quantifies how much work is performed close to MPA. As MPA drops with fatigue, strain increases... is established through determining the affect stressSynonymous with work, this metric is measured in joules and is the total work performed over a given period or... has on your ability to generate power. That is, strainMeasured in joules, this quantifies how much work is performed close to MPA. As MPA drops with fatigue, strain increases... is the degree to which the work you do is affected by MPAMPA stands for Maximum Power Available. It is a measure of the maximum power an athlete can generate at a given moment... More.

StrainMeasured in joules, this quantifies how much work is performed close to MPA. As MPA drops with fatigue, strain increases..., like stressSynonymous with work, this metric is measured in joules and is the total work performed over a given period or..., gets associated with each energy system and thus can be accumulated to provide a perspective of where you are seeking change/improvement.