Procedure

1. Macrocycle Setup and Assessment

   • Determine the user's current fitness baselines (FTP, Z2 heart rate, swimming pace) using get_user_history or get_user_preferences.
   • Use compute_hr_zones to establish training zones based on the Polarized Training Intensity Distribution (TID): Zone 1/2 (Low Intensity) and Zone 4/5 (High Intensity).
   • Explain the 16-week structure:
     • Block 1 (Weeks 1-6): Aerobic Foundation.
     • Block 2 (Weeks 7-12): Lactate Threshold & Power.
     • Block 3 (Weeks 13-16): Race Specificity & Taper.

2. Mesocycle Construction (3:1 Loading Ratio)

   • Initialize the program in 4-week blocks using create_week.
   • For weeks 1-3 of each block, apply a build phase. Use the 10% volume increase rule to ensure the Acute:Chronic Workload Ratio (ACWR) stays between 0.8 and 1.3.
   • For every 4th week, schedule a deload:
     • Reduce total volume by 30–50%.
     • Eliminate Zone 4/5 intensities; keep all sessions at Zone 1/2.
     • Reduce strength training frequency by 50%.

3. Weekly Workout Programming (80/20 Split)

   • Distribute 80% of volume to Low Intensity (Z1/Z2) and 20% to High Intensity (Z4/Z5).
   • Monday: Schedule Rest or Active Recovery.
   • Tuesday (Swim - HIIT): Create a workout with a focus on Zone 5 intervals (e.g., $6 \times 100\text{m}$ at RPE 8-9). Include coaching cue: "Reach long, pull high (Early Vertical Forearm)."
   • Wednesday (Run + Strength): Schedule a Z2 run. Add a heavy strength session (3 sets of 5 reps of Squats/Deadlifts) to improve running economy.
   • Thursday (Bike - Threshold): Schedule Zone 4 intervals (e.g., $4 \times 8\text{min}$ at Threshold). Include coaching cue: "Drive through the 3 o'clock position."
   • Friday (Swim - Technique): Schedule steady Z2 swimming with focus on catch drills.
   • Saturday (Brick): Schedule a Z2 Bike session followed immediately by a Race Pace Run to practice metabolic transitions.
   • Sunday (Long Run): Schedule a steady aerobic Z2 run (75-100 min). Include coaching cue: "Quick feet, quiet landing (170-180 spm)."

4. Progression Logic

   • When increasing difficulty, use update_workout to prioritize increasing interval duration (e.g., $4 \times 4'$ $\rightarrow$ $5 \times 4'$) before increasing intensity.
   • Monitor fatigue and ensure the ACWR remains within the 0.8–1.3 range to mitigate injury risk.

5. Taper Execution (Weeks 15-16)

   • In the final 10–14 days, reduce volume by 40–60%.
   • Maintain intensity (Z4/Z5) at lower volumes to maximize glycogen stores and neuromuscular recovery for race day.