Functional Threshold Power (FTP): What It Represents, What It Doesn’t, and Why Duration Matters

Functional Threshold Power (FTP) is one of the most widely used metrics in cycling — and one of the most frequently misunderstood.

It is commonly described as “60-minute power,” treated as a fixed physiological point, or inferred directly from short maximal tests. While these simplifications are convenient, they obscure what FTP is actually intended to represent and why its interpretation must be contextual.

This article explains what FTP represents, why duration matters, how it relates to other performance metrics, and where common misconceptions arise.

What FTP is intended to represent

Functional Threshold Power (FTP) is best understood as the highest power an athlete can sustain for a prolonged period without continual accumulation of fatigue.

Crucially, FTP is a functional construct rather than a single physiological breakpoint. It reflects the highest workload at which an athlete can remain in a quasi-steady metabolic state for an extended duration.

FTP is therefore about sustainability, not maximality.

FTP is not inherently a 60-minute value

Although FTP is often equated with 60-minute power, this is a convention rather than a physiological rule.

In practice, the duration over which an athlete can sustain FTP varies meaningfully between individuals. For some riders, FTP may align closely with 60-minute power. For others, it may correspond more closely to 40–50 minutes, depending on factors such as fatigue resistance, durability, efficiency, and training history.

This variability does not invalidate FTP — it defines it.

Treating FTP as a fixed-duration value introduces error, particularly when comparing athletes or prescribing training without context.

FTP is not a direct physiological threshold

FTP is often conflated with specific physiological thresholds, but it is not synonymous with any single laboratory marker.

It does not directly equal:

lactate threshold
maximal lactate steady state
critical power
ventilatory threshold

While FTP is related to these concepts, it is not interchangeable with them. It exists as a practical performance proxy, designed for applied training use rather than precise physiological classification.

This distinction explains why different testing methods can produce different FTP estimates for the same athlete.

How FTP relates to MAP

FTP and MAP describe different regions of the performance spectrum.

MAP reflects the upper ceiling of aerobic power.
FTP reflects the highest sustainable fraction of that ceiling.

The relationship between the two is strong but variable. Two athletes with the same MAP can have very different FTPs, and changes in MAP do not always translate directly into changes in FTP.

This is why FTP cannot be reliably derived from MAP using a single fixed percentage without considering individual characteristics.

A detailed explanation of MAP and its interpretation is available on the dedicated MAP reference page.

How FTP is commonly estimated

Because FTP cannot be measured directly without long-duration maximal efforts, it is often estimated using indirect methods.

Common approaches include:

long steady-state time trials
short maximal tests with modelling
incremental or ramp-based protocols
retrospective analysis of training and racing data

Each method involves assumptions and trade-offs. None produces a definitive value in isolation.

FTP estimation is therefore an interpretive process, not a measurement outcome.

Common misconceptions about FTP

Several misunderstandings recur frequently:

FTP is not a fixed physiological point
FTP does not guarantee race performance
FTP does not describe fatigue resistance
FTP should not be compared between athletes without context
Small FTP changes are not always meaningful

FTP is best used as a training anchor, not a performance verdict.

What FTP is genuinely useful for

When applied correctly, FTP remains a highly useful construct.

It is particularly valuable for:

anchoring training intensity distribution
monitoring changes in sustainable performance over time
guiding pacing in steady efforts
structuring workload progression

FTP works best when treated as a range-informed reference, refined through observation and experience rather than enforced as a rigid truth.

FTP, durability, and performance

FTP describes the maximum sustainable power under relatively fresh conditions. It does not describe how that power decays with fatigue, time, or repeated efforts.

This distinction explains why athletes with similar FTPs can perform very differently in long races or late-race scenarios.

Understanding FTP therefore requires considering durability and fatigue resistance alongside it, rather than expecting FTP to explain performance on its own.

A note on interpretation

FTP is a tool, not a verdict.

It should be interpreted alongside:

MAP
long-duration power outputs
training density
fatigue state
race and time-trial data

Used thoughtfully, FTP remains one of the most practical anchors in endurance training. Used rigidly, it becomes misleading.