Power Curves and W/kg Benchmarks: Evaluating Riders by the "Shape of Ability" Rather Than a Single Data Point

One Curve Beats a Single FTP

A single FTP number cannot describe a rider’s capability structure. The power curve—best power across durations from seconds to hours—reveals the “shape of capability.” Its shape alone tells you whether a rider is a sprinter, an all-rounder, or a pure endurance specialist.

Power Curve Shape and Rider Type

Why You Must Look at Both “Absolute” and “Relative”

Absolute power (watts) dominates on flats and in time trials, but climbing is governed by weight-relative power (W/kg)—because climbing primarily fights gravity, and the power required to overcome gravity is proportional to body weight. At the same 400 W, a 60 kg rider and an 80 kg rider perform vastly differently on steep climbs. Evaluating a rider requires looking at both the absolute curve and W/kg.

The Right and Wrong Ways to Use W/kg Benchmark Tables

W/kg benchmark tables (W/kg ranges for various durations corresponding to different levels) have reference value, but they are often misused: they are a rough classification tool, not a verdict on your personal ceiling. Forcing yourself into a category, or self-labeling with a single W/kg data point, ignores the curve shape—the more important information. Benchmarks are a map, not a destiny.

Using the Power Curve to Guide Training

• Find the “dips” in the curve—those are usually relative weaknesses and training opportunities
• Align training with the durations required by your target events (e.g., 20–40 min for GC, 5–15 sec for sprinting)
• Track both absolute and W/kg curves to distinguish flat-road and climbing strength
• Retest the curve in a fatigued state to assess durability (echoing the decline-rate theme)

Connection to the Entire Data-Driven Training System

The power curve is the capability-side counterpart to load models (TSS/CTL), the visualization of the FTP/W’ two-parameter model, and the baseline for durability testing. It is not an isolated metric but the “capability map” that ties together all the data topics discussed previously.

Evaluating a rider with a single FTP number is like evaluating a basketball player by height—it matters, but it is far from enough. The power curve gives you the “shape of capability”: where you are a beast and where you are a weakling. Add W/kg to translate the truth of gravity, and only then can you see clearly who you really are and where you should train. Benchmark tables can tell you where you stand, but only your curve shape can tell you where to go.

Related Reading

• Interpreting the Power Curve: Find Your Weak Zones
• Cycling Power Curve Interpretation: The Training Significance of Power Output at Different Durations
• Weight Management for Climbers: The Relationship Between W/kg Ratio and Climbing Speed
• Power Output Optimization: How W/kg Determines Climbing Rankings