Normalized Graded Pace (NGP)

Normalized Graded Pace (NGP) is an intensity metric for running. It builds on GAP (Grade Adjusted Pace), and the logic is similar to cycling’s NP (Normalized Power).

In plain terms:

• GAP answers: “What flat-ground pace is equivalent to this uphill/downhill pace?” (instant/segment-level equivalence).
• NGP answers: “For this variable run (changes in grade and speed), what steady flat pace would have similar physiological cost?” (whole-run equivalence).

Core idea

Physiological cost (glycogen use, lactate accumulation, overall metabolic stress) is non-linear with intensity.

Example: A steady 5:00/km run is usually less stressful than “half the time at 4:00/km + half the time at 6:00/km”. Even though both average to 5:00/km, the second run’s NGP may be meaningfully faster, reflecting the higher physiological cost of the surges.

Computation

NGP is computed from a grade-adjusted intensity stream, then displayed back as a pace.

Normalization

Because pace is a time value (smaller means faster), Trainingload.ai converts GAP into a speed/intensity equivalent before weighting. Then it applies an NP-like normalization:

1. Convert: turn GAP pace into speed or intensity.
2. Smooth: compute a 30-second rolling average.
3. Weight: apply 4th-power weighting to emphasize harder segments.
4. Average + root: take the mean and then the 4th root.
5. Display: convert the result back to pace for readability.

NGP_intensity = 4th_root( (1/N) * sum_{i=1..N} (GAP_intensity_rolling(i))^4 )

Typical applications

1. Add context for trail and mountain effort

On hilly terrain, average pace can look very slow. NGP helps reveal that your actual effort may not have dropped.

• Example: a mountainous trail run averages 10:00/km.
• NGP: could be much faster, better reflecting the metabolic stress your body felt.

2. Basis for rTSS

Trainingload.ai uses NGP to compute rTSS (Running Training Stress Score). The formula structure is similar to cycling TSS:

When NGP and FTPa are displayed as min/km pace, convert them to speed first. In speed terms:

IF = Speed_NGP / Speed_FTPa

Using NGP helps keep running load comparable across different terrains.

Metric comparison

How Trainingload.ai uses NGP

• Use as a terrain-aware intensity reference: NGP is often more informative than average pace on hilly or variable runs.
• Compute running load: NGP is a key input for rTSS because it reflects terrain and intensity variation.
• Use with VI: compute VI (Variability Index) = NGP / Avg GAP.
  • If VI is close to 1.0, the effort was steady.
  • If VI > 1.05, it likely reflects intervals or very complex terrain.

Related docs

• Grade Adjusted Pace
• Pace Zones
• Training Stress Score

References

• TrainingPeaks: What is Normalized Graded Pace?
• Normalized Graded Pace (NGP) is a registered trademark of Peaksware, LLC.