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Knee2026-03-07•7 min read

ACL Tear Recovery: Exercises for Before and After Surgery

Understanding ACL Injuries

The anterior cruciate ligament (ACL) prevents your shin bone from sliding forward under your thigh bone and provides rotational stability. It's most commonly torn during:

  • Sudden stops or direction changes
  • Landing from jumps incorrectly
  • Pivoting with a planted foot
  • Direct contact to the knee

    • You'll often hear or feel a "pop," followed by rapid swelling and instability.

    Do You Need Surgery?

    Not everyone with an ACL tear needs surgery. Consider:

    Surgery is typically recommended if:

  • You're young and active
  • You play pivoting sports (soccer, basketball, skiing)
  • Your knee gives way during daily activities
  • You have multiple ligament injuries
  • You want to return to high-demand activities

    • Conservative treatment may work if:

  • You're less active or older
  • Your activities don't involve pivoting
  • Your knee feels stable with rehab
  • You're willing to modify activities

    • Discuss your lifestyle, goals, and preferences with an orthopedic surgeon.

    Prehab: Before Surgery

    If you're having surgery, "prehab" significantly improves outcomes. Goals:

    1. Reduce swelling

    2. Restore full range of motion

    3. Rebuild quad strength

    4. Improve walking pattern

    Week 1-2 Post-Injury

    RICE Protocol

  • Rest from aggravating activities
  • Ice 20 minutes, multiple times daily
  • Compression with wrap or brace
  • Elevation above heart level

    • Quad Sets

    1. Sit with leg straight

    2. Push the back of your knee into the floor

    3. Tighten your quad muscle

    4. Hold 5 seconds, 20 reps, hourly if possible

    Heel Slides

    1. Sit with leg straight

    2. Slowly slide heel toward buttocks

    3. Use a strap if needed for assistance

    4. Hold 5 seconds at end range

    5. 20 reps, 3x daily

    Straight Leg Raises

    1. Lie on back, uninvolved knee bent

    2. Tighten quad (knee straight)

    3. Lift leg 12 inches, hold 3 seconds

    4. Lower slowly

    5. 3 sets of 10

    Weeks 2-6 (Until Surgery)

    Goals:

  • Full extension (straighten completely—crucial!)
  • Flexion to at least 120°
  • Walk without a limp
  • Good quad function

    • Mini Squats

    1. Stand with feet shoulder-width

    2. Squat to 45-60°

    3. Keep weight on heels

    4. 3 sets of 15

    Step-Ups

    1. Use a 4-6 inch step

    2. Step up, fully straighten knee at top

    3. Control the descent

    4. 3 sets of 10 each leg

    Stationary Bike

    Start with high seat, low resistance. Great for range of motion.

    Post-Surgical Rehabilitation

    ACL reconstruction rehab is a marathon, not a sprint. Most protocols span 9-12 months.

    Phase 1: Protection (Weeks 0-2)

    Goals:

  • Protect the graft
  • Manage swelling
  • Restore extension (CRITICAL)
  • Begin quad activation

    • Extension Focus

    Loss of extension is the #1 complication. Prioritize:

  • Prone hangs (lie face down, knee off edge of bed)
  • Towel under heel, push knee down
  • Multiple times daily

    • Exercises:

  • Quad sets (start day 1)
  • Heel slides
  • Straight leg raises (once quad control returns)
  • Ankle pumps

    • Weight bearing: As tolerated with crutches and brace.

    Phase 2: Early Rehab (Weeks 2-6)

    Goals:

  • Full extension (equal to other side)
  • Flexion to 120°
  • Good quad function
  • Walk without crutches

    • Exercises:

  • Continue extension work
  • Mini squats to 60°
  • Leg press (limited range)
  • Standing hip exercises (all directions)
  • Stationary bike (when flexion allows)
  • Pool walking (when incision heals)

    • Milestone: Walk without a limp before progressing.

    Phase 3: Strengthening (Weeks 6-12)

    Goals:

  • Full range of motion
  • Progressive strengthening
  • Improve balance and proprioception
  • Normal walking and stairs

    • Exercises:

  • Squats to 90°
  • Leg press (increasing range)
  • Romanian deadlifts
  • Step-ups and step-downs
  • Single-leg balance exercises
  • Elliptical, swimming, cycling

    • Balance Work:

  • Single-leg stands (eyes open → closed)
  • Unstable surfaces (pillow, balance board)
  • Perturbation training

    • Phase 4: Running Prep (Months 3-5)

    Goals:

  • Quad strength >80% of other side
  • No swelling with activity
  • Good single-leg control

    • Exercises:

  • Heavier leg press and squats
  • Single-leg press and squats
  • Lunges (forward, lateral, reverse)
  • Deadlifts
  • Sport cord exercises
  • More advanced balance

    • Running Initiation:

  • Usually begins around 12-16 weeks
  • Start with walk-jog intervals
  • Must have >80% quad strength
  • No pain or swelling
  • Good running mechanics

    • Phase 5: Sport-Specific (Months 5-9+)

    Goals:

  • Quad strength >90% of other side
  • Passed hop tests (>90% of other side)
  • Sport-specific movement patterns
  • Psychological readiness

    • Exercises:

  • Plyometrics (jumping, hopping)
  • Agility (cones, ladder)
  • Cutting and pivoting progression
  • Sport-specific drills
  • Scrimmage simulation

    • Return-to-Sport Criteria

    Don't return based on time alone. You should have:

    1. Full range of motion

    2. Strength: Quad and hamstring >90% of other side

    3. Hop tests: >90% of other side

    - Single hop

    - Triple hop

    - Crossover hop

    - Timed hop

    4. Functional movement: Good landing mechanics, no compensations

    5. Psychological readiness: Confidence in your knee

    Most athletes reach these criteria at 9-12 months, though full recovery may take 2 years.

    Common Mistakes

    1. Rushing the timeline — The graft is weakest at 6-12 weeks

    2. Neglecting extension — Must be addressed early and aggressively

    3. Skipping prehab — Better pre-op function = better post-op outcomes

    4. Ignoring the hip — Hip weakness affects knee mechanics

    5. Poor landing mechanics — Address before returning to sport

    6. Psychological factors — Fear of re-injury affects performance

    The Bottom Line

    ACL recovery is long but predictable. Success depends on:

  • Getting full extension early
  • Progressive, consistent strengthening
  • Patience with the timeline
  • Meeting objective return criteria
  • Addressing biomechanics and psychology

    • Follow your protocol, hit your milestones, and give yourself the full time to heal.

    Foundational Rehab offers progressive knee programs aligned with evidence-based ACL rehabilitation protocols.

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