GUIDE · 9 MIN READ · ACL RECOVERY

ACL Recovery Timeline, Month by Month

ACL recovery is a 9-to-12-month project for most people, longer for pivot sports. Here's what each phase looks like, what the real milestones are, and the parts most people underestimate.

The four phases, briefly

Most modern ACL rehabilitation protocols break recovery into four overlapping phases: early recovery (range of motion and gait), strength and conditioning, return to running, and return to sport. Progress between phases is criteria-based, not calendar-based — but there's a general time window where most people hit each one. TODO: cite phase model (Delaware-Oslo, Melbourne, Aspetar)

Month 1: Early recovery

The quietest month on the outside — crutches, swelling, limited walking. The busiest month on the inside — the graft is at its weakest, the quad has been shut off by swelling and pain, and the window to protect full extension is closing.

• Week 0-2: swelling management, full passive extension (0°), 90° flexion, consistent quad sets. Crutches as prescribed.
• Week 3-4: extension locked, flexion progressing toward 120°, maybe off one crutch. Stationary bike loops when flexion allows.

Headline metric: can you fully straighten the knee? If yes, you're on track. If no, flag it to your physio.

Month 2-3: Building the base

Walking normalises. Flexion is near-full for most people. The quad starts to look like a quad again, slowly. This is where the gym actually starts.

• Bilateral strength: leg press, step-ups, bodyweight squats to a box.
• Transition to single-leg work by the end of month 3 for most people. TODO: verify single-leg transition timing
• Flexion reaches full by end of month 3 in most protocols.
• Palio tip: start logging per-leg weight for every exercise. LSI only works as a trend if the raw data is there from day one.

Month 4-6: Strength and symmetry

The hard middle. Pain is mostly gone. The surgery feels like last year. The quad still won't match the other side, and the LSI on heavy leg extension sits stubbornly in the 60s or low 70s. This is where motivation collapses for a lot of people — the visible wins slow down and the lonely work begins.

• Progressive heavy lifting on both legs, with structured single-leg work.
• LSI testing on leg extension, leg press, and (as cleared) early hop variants.
• Introduction of jogging on the treadmill, often around month 4-5 if criteria are met.
• Hop testing initiated — single-leg hop for distance, triple hop, timed hop.

Headline metric: quad LSI. Many protocols use around 70% as one of several criteria before running progression, and 90% is a commonly cited guideline later on. Neither number clears you on its own. See the LSI calculator.

Month 6-9: Return to running and cutting

If strength criteria are met, this is where the fun comes back. Running volume builds. Change of direction begins. Plyometrics progress from bilateral to single-leg landings. Sport-specific movements enter the program.

• Running intervals, progressing to continuous running by month 7-8 for most people.
• Deceleration drills, cutting at submaximal speed.
• Depth jumps, bounding, single-leg jumping tests.
• LSI stays the headline. Hop test batteries get formalised.

Month 9-12: Return to sport

Return-to-sport decisions are based on test batteries, not time: strength and hop-test symmetry (90% is a commonly cited guideline, not a pass mark on its own), hop quality (not just distance), psychological readiness, and movement screens under fatigue. Research suggests that for every month return is delayed between 6 and 9 months post-op, re-injury risk drops meaningfully. TODO: cite return-to-sport time/risk research

• Formal return-to-sport test battery.
• Graded return to training sessions.
• Graded return to full match play.

Beyond 12 months

Even once you're back, the ACL isn't done. The re-tear risk and contralateral injury risk stay elevated for the first two years. Most athletes continue a prevention program (Nordic hamstring, single-leg balance, change-of-direction mechanics) for the long haul. TODO: cite 2-year re-tear risk data