Fatigue (Xert)

In Xert, fatigue refers to a reduction in your ability to produce power and is modeled as either short-term (within a ride, tracked by MPA) or long-term (over hours, affecting your Fitness Signature). Xert uses fatigue modeling to personalize training, adjust workout intensity in real time, and quantify strain during workouts.

Summary Generated by AI

Definition

In Xert, fatigue describes a reduction in your ability to produce power.

Fatigue is separate from Training Status, which summarizes your readiness to train.

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What It Means

Xert models fatigue in two main ways:

• Short-term fatigue (within a ride): shown by a decrease in MPA (Maximum Power Available). This type of fatigue can recover during the activity when you ease off & recover.
  • Xert is the first model to quantify short term fatigue during intermittent exercise using MPA
• Long-term fatigue (over hours): shown by declines in your Fitness Signature during long rides using Durability modeling. This type of fatigue recovers slowly and typically requires rest.

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Why It Matters in Xert

Fatigue is central to how Xert works:

• As fatigue increases, strain (XSS) accumulates faster at the same power. This means workouts performed under fatigue can deliver a stronger training stimulus in less time - though they often feel more challenging.
• Riding near your limit (near MPA) is inherently more demanding. If you’ve ever held a hard effort to failure, you know the final minute feels much harder than the first. Xert accounts for this and assigns more strain to those “near-the-limit” moments.
• Xert uses fatigue modeling to personalize training in real time. SMART intervals dynamically adjust as you fatigue and recover, keeping the workout targets aligned with your actual capacity.

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Where You’ll See It

• MPA Charts for Workouts & Activities
• Real-time MPA data & Xert's "Rainbow Gauge"
• Durability assessments on long rides

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Related Terms

MPA

Durability Score

Fitness Signature

XSS

SMART Intervals