Procedure

1. Initial Assessment and Goal Setting

   • Determine the user's current fitness level. Use get_user_history to find recent cardio performance.
   • If needed, calculate the current baseline using compute_vo2max.
   • Use compute_hr_zones to establish target intensities:
     • Low Intensity (Z1): 60-70% HRmax.
     • High Intensity (Z3): 90-100% HRmax.

2. Phase 1: Base Building (Weeks 1–4)

   • Implement a Pyramidal (PYR) distribution (~70% Low / ~20% Moderate / ~10% High).
   • Use plan_week to schedule:
     • Majority of sessions as Moderate-Intensity Continuous Training (MICT).
     • One session per week of moderate-intensity intervals to prepare the musculoskeletal system.

3. Phase 2: Intensification (Weeks 5–12)

   • Shift to a Polarized (POL) distribution (~80% Low / ~20% High).
   • Use create_workout to implement 2 high-intensity sessions per week using one of the following evidence-based protocols:
     • Norwegian 4x4: 4 mins at 90-95% HRmax, 3 mins active recovery at 60-70% HRmax.
     • Micro-Intervals (30/30s): 30s at high effort, 30s easy recovery, repeated for 20–30 mins.
     • Billat’s vVO2max: 3 mins at vVO2max velocity, 3 mins recovery.
   • Ensure the remaining volume is strictly low intensity to prevent overtraining.

4. Progressive Overload and Recalibration

   • Monitor adherence and perceived fatigue weekly.
   • Every 4 weeks, review training logs to ensure the intensity distribution matches the POL or PYR model.
   • After Week 12, perform a re-evaluation of VO2 max.
   • Use update_preferences or compute_hr_zones to recalibrate target heart rate zones and paces based on the new "aerobic ceiling."

5. Safety and Recovery

   • Monitor for signs of overtraining, especially during Phase 2.
   • If the user reports excessive fatigue, use plan_week to insert a deload week with reduced volume and high-intensity frequency.