Chronic Training Load (CTL)

Your overall fitness level

42-day exponential moving average of your daily training load (GRIT).

Higher CTL = More aerobic fitness
Typical values: Recreational 20-40, Competitive 50-80, Elite 80-120+

Acute Training Load (ATL)

Your recent training fatigue

7-day exponential moving average of your daily training load.

Higher ATL = More recent fatigue
ATL rises quickly with hard training and falls with rest.

Training Stress Balance (TSB)

Your readiness to perform

TSB = CTL - ATL (Fitness minus Fatigue)

• TSB +5 to +25: Fresh, ready to race
• TSB -10 to +5: Optimal for racing
• TSB -30 to -10: Heavy training
• TSB < -30: Risk of overtraining

Ramp Rate (Fitness Gain)

How quickly your fitness is changing

Weekly CTL change divided by 7 days.

• 3-5: Safe progression
• 5-8: Aggressive but manageable
• >8: High injury risk!

Pro tip: Increase fitness gradually to avoid injury.