Threshold Power (TP) – Knowledgebase

Threshold Power (TP) is the highest power you can sustain without accumulating short-term fatigue, meaning your MPA does not decline at that intensity. Xert determines TP dynamically from real-world performance data, not just tests, and it evolves over time. TP is a key part of your Fitness Signature and differs from traditional FTP concepts.

Summary Generated by AI

Definition

Threshold Power (TP) is a core component of your Fitness Signature. It represents the highest power you can sustain without accumulating short-term fatigue — meaning your MPA does not decline while riding at that intensity.

In simple terms:

TP is the highest steady power you can maintain without “burning matches.”

For most athletes, TP can typically be sustained for anywhere from 40 minutes to over an hour. Athletes with higher Peak Power & HIE values tend to be on the shorter end of that range.

What It Represents

Threshold Power defines the boundary between:

Efforts that can be (theoretically) sustained indefinitely
Efforts that begin to place strain upon your High and Peak energy systems

When you ride above TP:

MPA begins to decline
Short-term fatigue accumulates
Sustainability decreases

When you ride below TP:

MPA can recover
Fatigue stabilizes

Importantly, TP is not necessarily fixed during a long ride — it can decline due to durability effects of accumulated fatigue. Learn more about Durability, here.

How Xert Determines TP

Xert determines Threshold Power from your maximal efforts - especially Breakthrough or Near-Breakthrough performances. Your signature parameters, including TP, also will adjust up and down over time as you train & detrain using your selected signature decay setting.

Unlike traditional systems, Xert:

Does not estimate TP from a percentage of a single time trial
Does not rely on protocols like certain fitness tests (ramp or 8min/20min tests)

Instead, TP is extracted from your real-world performance data — including intermittent race efforts — using MPA modeling.

This means your TP reflects how well you actually perform, not just how you test.

Where You’ll See It

As a core component of your Fitness Signature, you will see Threshold Power displayed throughout Xert

In your Profile Header, as part of your Fitness Signature
On Activity Dashboard & Details pages
In Workouts Preview & Designer

Common Misunderstandings

TP is not just “FTP.” While similar in concept, TP is dynamically derived from your full Fitness Signature.
TP is not based on a single test. It evolves through ongoing Signature Extraction & Signature Decay.
Riding right at TP or slightly below it does not reduce MPA. MPA only declines when riding above TP.

Related Terms

Fitness Signature
MPA
Breakthrough
Lower Threshold Power (LTP)
Signature Decay