The Retainable Power Index (RPI™)
Retainable Power Index (RPI™)
A measure of how much output an athlete can maintain across sets relative to their peak output.
RPI™ shifts evaluation from:
• How high performance peaks
to:
• How well performance holds under repeated exposure
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First Principle
If output cannot be retained, it cannot be relied on.
Peak output reflects potential.
RPI reflects usable performance.
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Why RPI™ Exists
Most performance systems emphasize:
• Peak output
• Max velocity
• Single-rep performance
But training and sport demand:
• Repeatability
• Stability under fatigue
• Consistent output across efforts
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RPI answers:
• “Can this output be repeated?”
• “Will this performance hold under load?”
• “Is this level of output actually usable?”
RPI helps quantify output behavior.
To determine when changes are needed:
👉 Drop-Off Threshold Rule™
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How RPI Works
RPI evaluates how output is retained across multiple sets, using the first set as a reference point.
RPI is calculated by comparing average output across sets to peak output, expressed as a percentage.
Each subsequent effort is assessed relative to that baseline, and the system determines:
• How much output is maintained
• How quickly it declines
• How consistent performance remains
👉 The result is a single value (RPI %) that reflects:
• Overall retention of output across the session
Want to measure this in your own training?
→ RPI Output Scoring System ($19)
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Measurement Methods
RPI can be assessed using different methods depending on available tools and training context:
• Direct Measurement (Velocity / Power)
– Uses objective output data
– Most precise representation of output retention
• No-Tech Scoring (0–1–2 System)
– 2 = Full output maintained
– 1 = Slight degradation
– 0 = Clear breakdown
*Provides a practical estimate of retention without technology
The method used does not change the principle:
• RPI measures how well output is reproduced across efforts
Interpretation thresholds may vary slightly depending on movement sensitivity and measurement precision.
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RPI Classification System
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Interpretation Layer
RPI provides a performance signal, not just a number.
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High RPI
• Output is stable across sets
• Load is appropriate
• Performance is transferable
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Moderate RPI
• Output is beginning to degrade
• Fatigue is accumulating
• Monitoring is required
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Low RPI
• Output is not sustainable
• Fatigue is limiting performance
• Adjustment is required
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Pattern Recognition
RPI is evaluated alongside how output changes across sets.
The system identifies patterns such as:
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Early Drop
• Sharp decline immediately after the first set
Indicates:
• Excessive initial intensity
• Insufficient readiness
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Gradual Decline
• Progressive reduction across sets
Indicates:
• Fatigue accumulation
• Volume/load imbalance
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Inconsistent Output
• Fluctuating performance across sets
Indicates:
• Instability or control limitations
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Tight Clustering
• Minimal variation across sets
Indicates:
• Strong repeatability and control
To apply this within training:
👉 Output Retention Programming (ORP™)
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Decision Framework
RPI drives clear training decisions:
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High Retention
👉 Progress
• Increase load or intensity exposure
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Moderate Retention
👉 Hold
• Maintain current structure
• Monitor trend
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Low Retention
👉 Adjust
• Reduce load
• Modify structure
• Improve recovery strategy
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RPI Across Sessions
Single session = snapshot
Multiple sessions = trend intelligence
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Improving RPI
• Adaptation is occurring
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Stable RPI
• Current load is appropriate
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Declining RPI
• Fatigue or overload accumulating
To understand how retention evolves over time:
👉 Power Retention Model
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Integration Within the EVZ System
RPI is the foundation of:
• Session Quality Score
• Zone Classification
• Drop-off Diagnostics
• Coach Reports
• Certified Recommendations
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What RPI Replaces
• Peak-only evaluation
• Subjective fatigue assessment
• Guess-based progression
• Spreadsheet-driven analysis
Key EVZ Definitions:
• Retention Profile: pattern of how output is maintained, declines, or stabilizes across exposures
• Output Decay Rate: rate at which output declines across repeated exposures
• Output Stability: consistency of output across repeated exposures with minimal fluctuation
• Output Variability: degree of fluctuation in output across repeated exposures
👉 See full EVZ Definitions Framework
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System Philosophy
Performance is not defined by what you can produce once—
but by what you can reproduce consistently.
RPI measures how much output an athlete can maintain across sets.
High RPI = stable, repeatable performance
Low RPI = early fatigue and drop-off
It tells you whether performance will hold—or break down.
RPI is context-dependent — the sensitivity of output loss varies by movement and environment.
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Important Note
RPI is derived from structured retention analysis across sets and sessions, using proprietary logic to evaluate:
• Retention levels
• Performance consistency
• Fatigue patterns
