Below is a list of the most commonly used abbreviation and terms related to the advanced metrics in TrainingPeaks. Any metrics with a trademark symbol Ⓡ were developed and are owned by TrainingPeaks.
| Term | Definition |
| Pw:Hr/Pa:Hr (Aerobic Decoupling) | A measure of how much your power or pace changes relative to your heart rate from the beginning of a ride to the end. A lower value (<5-8%) for long, steady rides may indicate improved aerobic endurance. |
| ATL (Acute Training Load) | A weighted average of daily Training Stress Score for the last seven days. Used to represent acute training load and its short-term contribution to Fatigue. Also called Fatigue. |
| CTL (Chronic Training Load) | A weighted average of daily Training Stress Score for the last 42 days. Used to represent training load and its long-term effects on fitness. Also called Fitness. |
| EF (Efficiency Factor) | The ratio of Normalized Power or Normalized Graded Pace to average heart rate for a given workout. A drop in this number over time for similar workouts indicates a higher power or pace for a given level of effort and an increase in fitness. |
| Fitness | See CTL (Chronic Training Load) |
| Fatigue | See ATL (Acute Training Load) |
| Form | See TSB (Training Stress Balance) |
| Freshness | See TSB (Training Stress Balance) |
| FTP (Functional Threshold Power) | The power output below which an athlete can sustain for a longer duration (>one hour) and above which fatigue will occur quickly. Estimated by 60-minute max power or 95% of 20-minute max power. |
| IF® (Intensity Factor®) | The relative intensity of a given workout without regard for the duration. One hour at maximum effort is 1.0 |
| kJ (Kilojoules) | A unit of work. Riding 200 watts for one hour would accomplish 720 kJ of work. For cyclists, Kilojoules are approximately equivalent to calories expended. |
| NGP (Normalized Graded Pace) | A correction for pace to account for running uphill and downhill to show what the pace would be if the terrain were flat. |
| NP® (Normalized Power®) | An algorithm to estimate the physiological cost of a workout or longer effort within a workout. Higher-intensity efforts are weighted to represent the physiological cost of using high-intensity energy systems. |
| Pa:Hr (Pace-Heart rate decoupling) | See Aerobic Decoupling. |
| PMC (Performance Management Chart) | A chart of Fitness (CTL), Fatigue (ATL), and Form (TSB) over time. Used to plan and track periodization, training load, and event readiness. |
| Pw:Hr (Power-Heart Rate Decoupling) | See Aerobic Decoupling |
| Ramp Rate | The change in CTL over time, usually the last seven days. A ramp rate that is too high may lead to overtraining or injury; too low may not gain fitness quickly or effectively. |
| Threshold | A level of effort above which an athlete will fatigue very quickly and below which can be sustained for a longer duration (>one hour). Can be defined by heart rate (LTHR) for all sport types, power (FTP) for running and cycling, and pace (T-Pace) for swimming and running. |
| TSB (Training Stress Balance) | Compares the training load for the past week to the typical training load over the past six weeks (CTL-ATL). Used to represent readiness to perform at peak potential. High positive values may indicate undertraining; high negative values may indicate overtraining. Also called Form. |
| TSS® (Training Stress Score®) | The training load of a given workout is based on duration and intensity. Can be calculated from power, heart rate (hrTSS), or pace (rTSS). One hour at maximum sustainable effort is 100 TSS. |
| VI (Variability Index) | The ratio of Normalized Power to Average Power for a workout. Indicates how steady the power output was. Time trials and long course triathlon bike legs may have low VI’s (<1.05) workouts, or races with a mix of sprinting and coasting (criterium, track, cyclocross) will have higher VIs. |
