Synonymous with **Power-Duration Chart** and **Power-Duration Curve**, this describes the relationship between how long an athlete can sustain a given power, starting from fresh, at a steady-state, and ending with the inability to sustain the given power. Inability to sustain the given power is also termed a point-of-failure.

In Xert, your power-duration relationship is determined by applying a special use-case of MPA. *The duration that an athlete can sustain a given fixed work rate (i.e. state-state power) is determined by calculating how long will it take MPAMPA stands for Maximum Power Available. It is a measure of the maximum power an athlete can generate at a given moment... More to reduce from Peak PowerAs one of the three parameters that define an athlete's Fitness Signature, this is an athlete's highest possible power. Sometimes... until steady-state power equals MPAMPA stands for Maximum Power Available. It is a measure of the maximum power an athlete can generate at a given moment... More*. This calculation can be performed at any given intensity to determine duration or using a given duration to determine the steady-state power. Note that since the athlete’s Fitness Signature is used to formulate MPAMPA stands for Maximum Power Available. It is a measure of the maximum power an athlete can generate at a given moment... More, 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... can be depicted as a power-duration curve for visualization and to help interpret fitness.

An alternative approach to defining the power curve is to use Mean Maximal Power (MMPSee Mean Maximal Power....) data. Using MMPSee Mean Maximal Power.... generally results in similar values to steady-state, fresh-to-failure efforts as described above but can have more variance. A power curve defined using MMPSee Mean Maximal Power.... data, obtains the highest average power over a given duration from an athlete’s power data. There is a presumption that the efforts are started from fresh, didn’t have periods of rest or partial rest and ended with the athlete’s inability to sustain the average power over the period. *One must acknowledge that the occurrence of such data – where the athlete starts from fresh, doesn’t have any moments where power drops below Threshold Power and where the athlete’s inability to sustain the average power did not precede nor could have succeeded the end of the period – is rare in regular power data.*

Below are two power curves, the red curve is derived from MMPSee Mean Maximal Power.... data whereas the purple curve is derived by determining the Fitness SignatureIt is represented by three values: Threshold Power (TP), High Intensity Energy (HIE) and Peak Power (PP). The three fitness values are used... that expressed the MPAMPA stands for Maximum Power Available. It is a measure of the maximum power an athlete can generate at a given moment... More for the activity. Only when the red and purple coincide, was the corresponding MMPSee Mean Maximal Power.... effort started from fresh, didn’t have moments below TPSee Threshold Power.... and ended in a point-of-failure. In this sample activity, no MMPSee Mean Maximal Power.... efforts exhibited this.