How Progression Works

How Pheidi safely increases your training volume over time.

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Adaptive Increase Rate

Pheidi adjusts your weekly mileage increase rate based on your current volume. At lower mileage your body can handle faster jumps; at higher mileage the rate decreases to prevent overuse injuries.

This replaces the rigid "10% rule" with a volume-aware approach backed by research (Aarhus University 2012, BJSM 2025).

3-Up-1-Down Pattern

Pheidi uses a 3-up-1-down progression pattern: three weeks of building volume followed by one recovery (down) week at 80% of the previous peak. This provides built-in recovery without needing separate deload scheduling.

Beginner Safety Cap

For beginners, week-to-week increases are capped at 50%. When this cap creates a gap between current volume and the target peak, Pheidi automatically inserts transition weeks (up to 4) to bridge the difference safely.

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Research & evidence

Science behind this feature from pheidi.training.

• Running Training Plan: The Complete Guide Pillar hub linking 48+ deeper dives — start here for the full picture.
• Mileage Progression: What the Science Actually Says A 2025 BJSM cohort study rewrote injury prediction for runners.
• The 10% Rule: Origin Story, Not Science Traces back to 1980s coaching, never to a controlled study.
• The 10% Rule Head-to-Head Trial 2008 trial of 532 runners found identical injury rates at 10% and 50% weekly increases.
• Why Running Apps Still Use the 10% Rule Safety-first product decisions outweigh nuanced research.
• The Weekly Volume Sweet Spot Injury rates minimize around 30–50 km/week for most runners.
• Step Loading and Bone Adaptation Why bones need 6–8 weeks at each new stress level to remodel.
• Build-Rest Cycle: Why Deload Weeks Matter 3-up-1-down weekly structure and supercompensation.
• Recovery Week Supercompensation How a 25–40% volume cut triggers fitness gain.
• The C25K Wall: Why Beginners Quit at Week 5 72.7% jump in continuous running is the real dropout driver.
• C25K Week 5 Dropout Wall The exact mechanics of why beginners quit a 300% increase week.

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See also

• How Load Distribution Works How Pheidi shapes weekly distance around your long run using a shape-based system that keeps the hierarchy of run lengths consistent across the week.
• How Safety Guards Work How Pheidi protects you from training load spikes and injury risk: ACWR monitoring, session spike limits, and weekly volume caps based on running research.
• How Plan Generation Works How Pheidi builds your personalized marathon training plan: periodization, phase splits, shape-based load distribution, taper math, and base building.