What This Exercise Does
Heel slides are a fundamental range of motion exercise that helps restore knee flexion (bending) after ACL surgery. After surgery, swelling and scar tissue formation can quickly limit your ability to bend your knee.
- Restores flexion ROM: Gradually increases how far you can bend your knee
- Prevents arthrofibrosis: Reduces risk of excessive scar tissue formation
- Maintains joint mobility: Keeps knee joint lubricated and mobile
- Safe loading: Gentle exercise that doesn't stress the graft
- Patient-controlled: You control the pace and depth
Range of Motion Goals
| Timeframe | Flexion Goal | Notes |
|---|---|---|
| Week 1 | 90° (right angle) | Some protocols allow more; follow yours |
| Week 2 | 110-120° | Should be pain-free at end range |
| Week 4 | 125-130° | Close to full flexion |
| Week 6+ | Full (135-145°) | Match non-surgical leg |
Note: These are general guidelines. Your surgeon's protocol may differ, especially with meniscus repair.
Step-by-Step Instructions
Starting Position
Lie on your back on a firm, smooth surface (bed, floor, or exercise mat). Start with your surgical leg extended straight. If on a bed, you may find it easier to lie on top of the sheets so your heel can slide easily.
Prepare for the Slide
You can use your hands, a towel, or a long strap looped around your foot to help guide and assist the movement. Many people find it helpful to wear a sock for smoother sliding.
💡 Pro Tip
Place a plastic bag under your heel to reduce friction, or use a smooth surface like hardwood floor instead of carpet for easier sliding.
Slide Your Heel Toward Your Buttocks
Slowly slide your heel along the surface toward your buttocks, allowing your knee to bend. Use your hip flexors and/or the strap to assist. Move smoothly—no jerky movements. Go only as far as comfortable.
Hold at End Range
When you reach your current maximum comfortable bend, hold for 2-5 seconds. You should feel a stretch, but NOT sharp pain. Breathe normally during the hold.
Return to Start
Slowly slide your heel back to the starting position, straightening your knee completely. Don't rush—the return phase is equally important.
Repeat
Perform 10-20 repetitions per set. Complete 3-4 sets per day, or as prescribed by your physical therapist.
Common Mistakes to Avoid
- Going too fast: Rushing creates jerky movements that can cause pain and guarding. Slow, controlled motion is key.
- Forcing through sharp pain: Discomfort and stretching sensation is normal; sharp pain is not. Stop if you feel sharp pain.
- Not going far enough: Some people stop too early out of fear. You should feel a stretch at end range.
- Forgetting to straighten fully: Always return to full extension between reps. Extension is equally important as flexion.
- Skipping sessions: Consistency is critical, especially in the first 2 weeks when scar tissue forms fastest.
- High-friction surface: Struggling against friction makes the exercise harder than necessary. Use a smooth surface.
⚠️ Meniscus Repair Patients
If you had meniscus repair along with your ACL reconstruction, your flexion may be limited by your surgeon (often 90° max for the first 4-6 weeks). Follow your specific protocol carefully—meniscus repair changes everything about early ROM.
Variations & Progressions
- Assisted with strap: Loop a yoga strap or towel around your foot to help pull your heel toward you—good for early days
- Active-assisted: Use muscles as much as possible, with strap providing minimal help
- Active (no assistance): Use only leg muscles to perform the slide—more challenging
- Wall slides: Perform with foot on wall, letting gravity assist the bend—good variation
- Seated heel slides: Sitting in a chair, slide foot back under chair—functional variation