**Target MPA**, or **TMPA**, is used in the definition of some SMART intervals in the Xert Workout Designer. TMPA represents your ending MPA value for a given workout interval. TMPA can be used as a SMART variable-duration or a SMART variable-power interval. This allows Xert to modify the *power target* or *duration* of an interval in real-time while you’re doing the workout. For more detailed information, continue reading further below.

Target MPA based intervals can be used for both high intensity efforts (where MPA declines) and recovery intervals (where MPA rises), where the target power is above and below TP, respectively.

## Workouts with TMPA Intervals

Target MPA intervals are only supported for the Xert EBC apps and Xert Player for Connect IQ, which support the ability to manage fatigue in order to ensure the Target MPA is reached during workouts. Calculations are based upon whether the interval has a declining or rising MPA value.

For example, if an interval has a declining MPA to a given Target MPA level, the players will speed up interval time or decrease the target power if the athlete maintains a power above the target power (for SMART duration & SMART power, respectively). On the other hand, the apps will slow down interval time or increase the target power if the athlete maintains a power below the target power for the interval (for SMART duration & SMART power, respectively).

Conversely, during rising MPA intervals, interval time will speed up or increase the target power if that athlete maintains a power below the target power and will slow down the timer or decrease the target power if the athlete maintains a power above the target power. These dynamically managed fatigue intervals help ensure that the athlete achieves the goals as determined by the workout design.

SMART – Elastic Heart – 3.5 is a modified VO2max workout that uses *Target MPA* intervals rather than %FTP for the VO2max interval targets. As you progress through the interval, Xert will adjust the power target up (or down) such that you finish the interval at the Targeted MPA (60% Reserve – shown in the interval steps below).

For more information on SMART workouts, check out our blog post on SMART workouts, here.

There are 4 options when it comes to Target MPA:

- Absolute Target MPA (in W) – e.g. 800 W Target MPA 800 means that the interval will end when MPA is 800 W
- % TP TMPA – e.g. 120% TP TMPA means that the interval will end when MPA is equal to 120% of Threshold Power
- % PP TMPA – e.g. 90% PP TMPA means that the interval will end when MPA is equal to 90% of Peak Power
- % Reserve TMPA – e.g. 60% Reserve means that the interval will end when MPA is equal to TP + 60% * (PP – TP)

*Note*: It is not possible to reach at Target MPA that is below the target power. For example, if an interval’s target power is 500 watts, it is not possible to define a Target MPA of 400 watts since it would not be possible to reduce MPA below 500 watts at a target wattage of 500 watts. Once MPA reaches 500 watts, the target power cannot be sustained and so the lowest Target MPA that can be assigned to a 500 watt interval is 500 watts.

For more information on creating workouts using Target MPA, refer to our article on advanced workout design, here.

### Variable Duration

Rather than specifying a duration for an interval (e.g. 5 min), a Target MPA based duration interval calculates the time an interval needs to be based on the input interval target power & the athlete’s signature/MPA. An example of this in action is SMART – Uprising – Variable, which uses Target MPA recovery intervals.

### Variable Power

Alternatively, Target MPA can be used to set the intensity of an interval. For example, one could use 99% PP TMPA over 5 min for a recovery interval, which means that the power of the interval will adjust as needed such that your MPA would be equal to 99% of PP by the end of the 5 min interval. An example of this in action is the SMART – Iron Man series of workouts.