Stationary Bike Protocols
Overview
The stationary bike is often called the "workhorse" of ACL rehabilitation. It's one of the first exercises you'll do and one you'll continue throughout recovery. Early on, it promotes range of motion and reduces stiffness. Later, it provides excellent low-impact cardio conditioning.
Key Benefits
- Promotes knee flexion range of motion
- Reduces swelling through muscle pump action
- Maintains cardiovascular fitness
- Low-impact—minimal stress on graft
- Warms up joints before other exercises
- Psychologically satisfying "exercise" early in recovery
Bike Setup
Seat Height
Early recovery (limited ROM): Raise seat higher than normal. This reduces the knee flexion required to complete a full pedal revolution.
As ROM improves: Gradually lower the seat. Goal is slight knee bend (25-35°) at the bottom of the pedal stroke.
Bike Type Options
Recumbent Bike
Seat with back support, pedals in front. Often easier initially—less balance required, more comfortable positioning.
Upright Bike
Traditional bicycle position. Slightly more quad engagement. Fine once comfortable.
Spin/Indoor Cycle
More aggressive position. Better for advanced cardio work. Avoid standing positions early on.
Progressive Protocol
Phase 1: Rocking (Week 1-2)
Goal: Start moving the knee, even without full revolutions
- Set seat high
- Place feet on pedals
- Rock pedals back and forth (partial rotations)
- Go as far as comfortable in each direction
- 5-10 minutes, multiple times daily
Note: It's okay if you can't complete full revolutions yet. The rocking motion promotes ROM.
Phase 2: Full Revolutions (Week 2-4)
Goal: Complete full pedal circles with minimal resistance
- Keep seat elevated if needed
- Set resistance to zero or very light
- Pedal forward with complete revolutions
- Maintain steady, controlled pace
- 10-15 minutes
Milestone: When you can complete full revolutions without seat elevation, you've achieved roughly 110-115° flexion.
Phase 3: Building Duration (Week 4-8)
Goal: Establish cardio base
- Lower seat to normal height
- Keep resistance light to moderate
- Build to 20-30 minutes continuous
- Maintain RPE 3-4 (light effort)
| Week | Duration | Intensity |
|---|---|---|
| 4 | 15 min | Light |
| 5 | 20 min | Light |
| 6 | 25 min | Light-Moderate |
| 7-8 | 30 min | Moderate |
Phase 4: Adding Resistance (Month 2-3)
Goal: Strengthen quads while building endurance
- Gradually increase resistance
- Maintain cadence of 70-90 RPM
- Include intervals: 2 min hard / 2 min easy
- 30-45 minutes per session
Phase 5: High-Intensity Options (Month 4+)
Goal: Cardiovascular conditioning for return to sport
- Tempo rides: 20-30 min at sustained moderate-hard effort
- Intervals: 30 sec hard / 30 sec easy x 10-20
- Hill simulation: Increasing resistance climbs
- Spin classes: Can participate (stay seated, modify jumps)
Common Mistakes
Seat Too Low
Forces excessive knee flexion at top of stroke. Raise seat if knee feels "crunchy" or painful.
Too Much Resistance Too Soon
Heavy resistance before adequate strength. Start with zero resistance and progress gradually.
Pedaling Backward Only
Some think backward is "safer." Forward pedaling is fine and more functional. Do both.
Ignoring Pain
Pushing through sharp or increasing pain. Bike should be comfortable. Adjust or stop if painful.
Special Considerations
Meniscus Repair
If you had meniscus repair with your ACL surgery, you may have flexion restrictions (e.g., no past 90° for first 4-6 weeks). Keep seat elevated until cleared for full flexion.
BTB Graft
Anterior knee pain is common with BTB grafts. If biking aggravates kneecap pain, try:
- Higher seat position
- Less resistance
- Recumbent bike instead of upright
Sample Weekly Schedule
| Day | Bike Session | Purpose |
|---|---|---|
| Mon | 30 min easy | Warm-up before PT |
| Tue | 20 min intervals | Cardio conditioning |
| Wed | 30 min easy | Active recovery |
| Thu | 30 min easy | Warm-up before PT |
| Fri | 25 min tempo | Sustained effort |
| Sat/Sun | Optional 20-30 min | Active recovery |