Target MPA (TMPA) – Knowledgebase

Target MPA (TMPA) is a workout design feature that lets an interval's end condition be defined by your MPA(Maximum Power Available) rather than by a fixed duration or fixed power target.

An interval built with TMPA finishes when your MPA reaches the specified value — allowing the workout to adjust in real time based on your current fatigue.

How TMPA Is Used

TMPA supports two interval types:

Variable Duration — the target power is fixed; the interval ends when your MPA reaches the TMPA value. If your MPA declines faster than expected, the interval ends sooner. If it declines more slowly, the interval lasts longer.
Variable Power — the interval duration is fixed; the target power adjusts throughout the interval to bring your MPA to the TMPA value by the end.

Both interval types work for hard efforts (where MPA declines toward TMPA) and recovery efforts (where MPA rises toward TMPA).

How TMPA Is Specified

Workout designers can specify TMPA in four ways:

Absolute value in watts (e.g., 800 W)
% of Threshold Power (e.g., 120% TP)
% of Peak Power (e.g., 90% PP)
% Reserve — calculated as TP + [X% × (PP – TP)] (e.g., 60% Reserve)

Note: TMPA can't be set below the interval's target power. For example, an interval with a 500 W target power can't have a TMPA lower than 500 W — MPA cannot decline below the power being sustained.

Where TMPA Works

TMPA intervals are only supported in Xert's own workout players:

Xert EBC (Android and iOS)
Xert Workout Player (Garmin Connect IQ)

Other platforms (Zwift, TrainerRoad, etc.) don't support the dynamic behavior TMPA depends on. Workouts with TMPA intervals will still export to these platforms, but the intervals will play as fixed duration/power rather than adjusting to your MPA in real time.

Related Terms

Learn More

For designing workouts with TMPA intervals, see the Advanced Workout Design guide.