Metrics & Scoring

Coach Watts tracks a variety of physiological and performance metrics to give you a complete picture of your fitness and recovery.

Training Stress Metrics

We use standardized metrics to quantify the "cost" of your training sessions.

TSS (Training Stress Score)

TSS is the primary way we measure workout volume and intensity. It is calculated based on:

1. Power Data: Using Normalized Power (NP) relative to your FTP.
2. Heart Rate (Fallback): If power is unavailable, we use HRSS (Heart Rate Stress Score) based on your Lactate Threshold Heart Rate (LTHR) and Heart Rate Reserve.

Fitness, Fatigue, and Form

• CTL (Fitness): A 42-day rolling average of your daily TSS. It represents your long-term training capacity.
• ATL (Fatigue): A 7-day rolling average of your daily TSS. It represents the immediate stress on your body.
• TSB (Form/Freshness): The difference between Fitness and Fatigue (CTL - ATL). A positive number usually indicates you are "fresh" and ready to race.

AI Performance Scores

Coach Watts goes beyond raw numbers by using AI to generate Performance Scores (1-10). These scores provide context to your data.

Athlete Profile Scores

• Aerobic Capacity: Your ability to sustain sub-threshold efforts.
• Recovery Capacity: How well your body adapts to stress (based on HRV and sleep).
• Consistency: How well you stick to your planned training volume.

Workout Performance

After every session, the AI evaluates:

• Execution Quality: How closely you followed the prescribed intervals and zones.
• Physiological Response: Whether your heart rate and perceived exertion matched the expected intensity.

Actionable Explanations

Every score in Coach Watts comes with a detailed AI explanation. When you click a score card, you'll see:

1. The "Why": A breakdown of the factors (e.g., low HRV, high sleep latency) contributing to the score.
2. Actionable Improvements: 2-3 specific steps you can take today to improve that metric (e.g., "Prioritize 8 hours of sleep" or "Add a dedicated recovery day").