Exercise after ACL surgery — what a biokineticist does

An anterior cruciate ligament (ACL) reconstruction is one of the most common knee surgeries in sport. The surgery itself is a well-rehearsed procedure — but the rehabilitation that follows is where most of the work happens. A typical full recovery takes nine to twelve months, and the quality of your rehab determines whether you return to your sport stronger, weaker, or with a re-tear.

Here's how a biokineticist fits into that journey, and what each phase looks like.

The four phases of ACL rehab

ACL rehabilitation is typically broken into four phases, with significant overlap between professionals.

Phase 1 — Acute (weeks 0–2)

Focus: protect the graft, control swelling, restore full extension, get walking. This phase is led by your physiotherapist and surgeon. Expect crutches, ice, very gentle range-of-motion work, and early quadriceps activation.

Phase 2 — Early strength (weeks 2–6)

Focus: regain range of motion, build single-leg control, address quad inhibition. Still primarily physio territory, with the biokineticist sometimes coming on board towards the end of this phase depending on the surgeon's protocol.

Phase 3 — Strength & control (weeks 6 onwards)

Focus: rebuild full lower-body strength, restore movement quality, start neuromuscular control work. This is where the biokineticist takes the lead. Typical work includes:

• Bilateral and single-leg strength training (squat, hinge, lunge)
• Hamstring strengthening (critical for hamstring-graft ACLs)
• Core stability and trunk control
• Balance and proprioception drills
• Light plyometric introduction towards the end of this phase

Phase 4 — Return to sport (4–9 months)

Focus: build sport-specific power, retrain landing and cutting mechanics, restore confidence. This is the longest phase and where most re-injuries happen if it's rushed. Work includes:

• Plyometric progression (jumping, hopping, bounding)
• Sprint mechanics and acceleration
• Cutting and change-of-direction drills
• Sport-specific scenarios
• Psychological readiness for return

How do we know when you're ready to return to sport?

The single biggest mistake in ACL rehab is returning to sport based on time alone. "It's been nine months, I must be ready." The evidence is clear: return-to-sport criteria, not calendar time, predict re-injury risk.

A biokineticist will use objective testing to decide. Common benchmarks include:

• Quad strength symmetry: the operated leg should be at least 90% as strong as the non-operated leg
• Hop testing: single-leg, triple, crossover and timed hops at ≥90% of the non-operated side
• Landing mechanics: no knee collapse, controlled depth and symmetry on landing
• Psychological readiness: confidence to push the knee at full intensity

Returning to sport before hitting these markers roughly doubles the risk of re-tearing the ACL or tearing the other one.

How long will this take?

Realistic timelines for someone returning to a cutting sport (soccer, rugby, hockey, netball):

• Walking unaided: 2–4 weeks
• Full daily activity: 6–8 weeks
• Gym-based exercise (no jumping): 3 months
• Light running: 4–5 months
• Cutting drills: 6–7 months
• Return to full-contact sport: 9–12 months

For non-cutting sports (cycling, swimming, golf, running), return to sport is faster — sometimes 4–6 months.

The honest truth about ACL rehab

Most patients underestimate how much work is involved in a proper ACL rehab. It's not 10 sessions of physio and a few gym workouts. It's a structured, progressive 9–12 month process with measurable milestones along the way.

The good news: if you do it properly, you can come back stronger and more resilient than you were before the injury. A biokineticist is your partner for the majority of that journey — the months where you go from "knee feels okay" to "I trust this knee on the field again".