Training Metrics and Running Physiology: The Complete Reference Guide

Key Performance Metrics

• Power: Output of work over time, typically measured in watts.
• Normalized Power (NP): An estimate of the physiological cost of a variable-effort ride or run.
• Watts per Kilogram (w/kg): Power output relative to body weight.
• Distance per Stroke: Key swim efficiency metric, higher = better stroke efficiency.
• Strokes per Length: Swim metric for tracking stroke efficiency and fatigue.

Running Performance Terms

• Pace: Speed of a run, usually in min/mile.
• Cadence: Number of steps per minute.
• Stride Length: Distance between heel strikes of the same foot.
• Speed = Stride Length × Cadence
• Vertical Oscillation: How high you move off the ground per stride (ideal = 6–13 cm).
• Vertical Ratio: Vertical Oscillation ÷ Stride Length. Lower = more efficient.

Training Intensities & Purpose

• Easy Pace: 59–74% VO2max, 65–79% HRmax. Comfortable pace promoting aerobic base.
• Marathon Pace: 75–84% VO2max, 80–90% HRmax. Prepares athletes for sustained race efforts.
• Threshold Pace (Tempo): 83–88% VO2max, 88–92% HRmax. Improves lactate threshold.
• Interval Pace: 95–100% VO2max, 98–100% HRmax. Targets aerobic power with 3–5 min bouts.
• Active Rest: Low-intensity movement during rest periods or on recovery days.

Energy Systems

• Aerobic: Uses oxygen to generate ATP. Lower intensity (e.g., running, swimming).
• Anaerobic: High-intensity efforts using glycogen. (e.g., sprints, heavy lifting).

Common Training Concepts

• DOMS: Delayed Onset Muscle Soreness – soreness 24–48 hrs after intense effort.
• EPOC: Excess Post-exercise Oxygen Consumption – elevated metabolism after high intensity.
• HIIT: High Intensity Interval Training – short bursts followed by recovery.
• RPE: Rate of Perceived Exertion – subjective intensity scale (1-10).

Training Load & Stress (TSS Systems)

• TSS (Training Stress Score): Composite score of workout intensity and duration.
• NP (Normalized Power): Estimate of physiological demand with variable output.
• IF (Intensity Factor): Ratio of NP to Functional Threshold Power (FTP).
• rTSS: Running-based TSS using pace relative to Functional Threshold Pace (FTP).
• sTSS: Swim-based TSS using swim FTP, distance, and moving duration.
• hrTSS: TSS from heart rate data based on lactate threshold HR.
• tTSS: TRIMPS-based TSS using avg HR, duration, and personal HR metrics.

Training Intensity Factor (IF) Ranges

• <0.75 = Recovery
• 0.75–0.85 = Endurance
• 0.85–0.95 = Tempo / Intervals
• 0.95–1.05 = Lactate Threshold / Shorter Races
• 1.05–1.15 = Time Trials / Track Races
• >1.15 = Prologue TT / Track Pursuit

TSS Load Guidelines

• <150 = Low (full recovery next day)
• 150–300 = Medium (slight fatigue next day)
• 300–450 = High (residual fatigue up to 2 days)
• >450 = Very High (several days recovery needed)

Swim FTP Calculation Methods

• Timed 30 or 60-min effort: e.g. 1000m in 30min = 33.3 m/min.
• Adjusted for 60-min FTP = 2x 30-min pace - 2.5%
• Critical Velocity Test = (Dist2 - Dist1) ÷ (Time2 - Time1)

Calculating Swim TSS

• 1. Measure total moving time (exclude rest).
• 2. Get average pace = distance ÷ time.
• 3. NSS (Normalized Swim Speed) = m/min.
• 4. IF = NSS ÷ FTP.
• 5. sTSS = (IF³) × hours × 100

Normalized Graded Pace (NGP)

• Adjusts raw GPS pace for elevation and grade to reflect true physiological effort.
• Used to calculate rTSS.
• More accurate than average pace for hilly runs.