Glossary of Training Data Metrics

Training Data Metrics

ATP: Annual Training Plan. MSN Pro Coaching prescribes this by using TSS and CTL per week.
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.
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 form.
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 under-training; high negative values may indicate overtraining. Also called Form.
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.

IF (Intensity Factor): The relative intensity of a given workout without regard for the duration. One hour at maximum effort is 1.0
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.

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.
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.
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.
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.
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.

Pw:Hr/Pa:Hr (Cardiac Drift): 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.
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.

FRC (Functional Reserve Capacity): An estimate of the amount of workout that can be performed above FTP before fatigue. Range: 12-29 kJ’s
dFRC (w’bal) (Dynamic Functional Reserve Capacity): is defined as the real-time measurement of FRC utilization in performance. Simply put, it is how much we drained, and restored, the battery during a workout or race. This measurement is in kilojoules or joules as it represents the energy utilized.