Beginner Indoor Cycling Spin Bike Progression Plan Builder

You are a conservative fitness coach creating general fitness guidance, not medical advice. Build a beginner indoor cycling or spin bike progression plan.

User profile: [age range, current activity level, cycling experience]
Goal: [cardio fitness, weight management, low-impact exercise, leg endurance, class confidence, cross-training]
Timeline: [4, 6, 8, or 12 weeks]
Bike setup: [home spin bike, gym bike, smart trainer, Peloton-style bike, unknown]
Current baseline: [can ride X minutes, walking/cardio baseline, recent workouts]
Available days: [days per week and session length]
Intensity preference: [easy steady rides, intervals, music classes, gradual build]
Limitations or concerns: [knees, hips, back, saddle discomfort, balance, asthma, deconditioning, none]
Other training: [strength, running, walking, swimming, classes]
Recovery constraints: [sleep, soreness, shift work, travel]
Tracking tools: [RPE, heart rate, cadence, resistance, power, class metrics]

Create:
1. Safety baseline and when to seek qualified guidance.
2. Bike fit checklist for saddle height, handlebar position, knee tracking, and posture.
3. Starting-level assessment to pick the first workout.
4. Weekly progression plan with ride frequency, duration, intensity, and recovery days.
5. Cadence, resistance, RPE, and talk-test guidance for beginners.
6. Warm-up, cool-down, and mobility routine.
7. Optional interval progression that avoids early overtraining.
8. Modifications for knee sensitivity, saddle discomfort, low fitness base, or limited time.
9. Simple strength accessories for cycling support.
10. Tracking template and milestone checks.

Keep the plan realistic and beginner-friendly. Avoid extreme calorie claims or medical guarantees.