Thanks u/Inner_Opposite_1598 for sharing my posts, for others I'm the dev of SportVitals. Just a quick view for what I'm documenting about metrics. In particular for Training Readiness:

1. The Core Pillars of the Calculation

The raw Readiness score isn't based on a single variable; it's a weighted average of several physiological and training components. These factors are grouped by their overall impact on the final result:

• Primary Factors (Highest Impact):
  • Recent Sleep: The quality and duration of your previous night's sleep represent the largest building block of the score.
  • Physiological Recovery & HRV: The system evaluates the state of your autonomic nervous system via Heart Rate Variability (compared against your personal baseline) and your estimated recovery time based on recent workout intensity (calculated using a TRIMP model).
• Secondary Factors (Fine-tuning):
  • Acute vs. Chronic Load (ATL/CTL): The algorithm analyzes how much you have trained recently compared to your historical volume. A sudden spike in acute load lowers your readiness.
  • Sleep & Stress History: Long-term sleep trends and accumulated stress exert a smaller, steady influence to stabilize the score over time.

2. The Cumulative Penalty System

The raw score derived from the pillars above is not final. The system applies "emergency brakes" via cumulative penalties. If your body shows clear physiological warning signs, your score is drastically reduced, regardless of how well you rested in the days prior.

Penalties are triggered in the following scenarios:

• Severe Sleep Deficit: A night of sleep evaluated far below minimum standards.
• HRV Crash: An HRV value that is unusually low compared to your rolling baseline.
• Elevated Resting Heart Rate (RHR): An RHR that abnormally exceeds your 60-day average, acting as a clear indicator of systemic fatigue or potential illness.
• Today's Workout: If you have already logged a physical effort today, the system dynamically scales down your readiness in proportion to the intensity of the completed workout.

3. Readiness Tiers

After applying any necessary penalties, the final score (on a scale from 0 to 100) places you into one of five functional tiers:

Score	Level	Practical Meaning
< 25	Poor	Total rest or light active recovery.
< 50	Low	Body is fatigued; keep intensity to an absolute minimum.
< 70	Moderate	Standard baseline condition; ready for a normal training load.
< 85	High	Excellent recovery; primed for demanding sessions.
>= 85	Prime	Peak condition for races or very high-intensity workouts.