Phase 6: Return to Training

Phase 6: Return to Training

You've reached the final stage of your ACL journey. If you've hit your one-year Biodex test with 90–100% limb symmetry, that's a genuine milestone — many patients don't get there, often simply because of life's competing priorities. Take a moment to celebrate this. You've earned it.

What "return to training" actually means

This phase isn't a green light for a full 90-minute soccer match. Return to training is a structured process with a few distinct components:

• Plyometrics — teaching your body to safely absorb shock when landing and jumping.
• Proprioception — single-leg balance work, often combined with reactive drills like catching a ball while balancing, to retrain your knee's positional awareness.

• Acceleration and deceleration — controlled running mechanics. Deceleration force in particular is closely linked to re-injury risk, so this needs specific, deliberate training rather than being left to chance.

The part we cannot measure on a machine: your mind

Everything above is physical, and physical readiness is something we can test objectively. But there's a second dimension to return-to-sport that doesn't show up on a Biodex printout — your psychological readiness. Fear of re-injury, loss of confidence in your knee, and how you appraise your own risk are all real, measurable factors in whether you successfully return to sport, and they don't always move in lockstep with your strength numbers.

This is why I use the ACL-Return to Sport after Injury scale (ACL-RSI) alongside physical testing. It's a validated 12-item questionnaire covering three areas: your emotions about returning, your confidence in your knee's performance, and how you appraise the risk of re-injury.[1]

The research behind this scale is genuinely useful context. In the original validation study, patients were grouped by where they were in their return-to-sport journey, and their average ACL-RSI scores told a clear story: [1]

• Patients who had given up on sport: average score of 39 out of 100
• Patients planning to return but hadn't yet: average score of 55
• Patients who had returned to training only: average score of 63
• Patients who had returned to full competition: average score of 76

Notice that psychological readiness rises step by step as patients progress — and that patients who'd given up on sport altogether scored meaningfully lower than everyone else. That gap is the whole point of measuring this. A patient can be physically cleared and still be carrying enough fear or doubt that they never actually attempt their sport again — the same research found that up to half of ACL-reconstructed athletes don't return to their pre-injury level of sport despite being physically rehabilitated. [1]

How I use this with my patients: once you've built a physical foundation — completed your basic strength and control exercises in this phase — I'll ask you to use the ACL-RSI Calculator. It only takes a few minutes. If your score sits well below where patients at your stage typically land, that's not a failure — it's useful information. It tells us to slow down and address the psychological side directly, whether that means more graduated exposure to sport-specific movements, more time, or a conversation about what exactly you're afraid of. Studies show that return to training and sport after you achieve a ACL-RSI of >70 is associated with a reduced risk of re-injury. [2]

Where the healthcare system's role ends

For most patients, this is achievable through your physiotherapist and strength trainer. But if you're aiming for high-performance or competitive sport, our public healthcare system — including what we offer at NUH — isn't built to carry you all the way there. At that level, you'll need to work with your club's physiotherapists and strength trainers, or, if you're on a national team, with High Performance Sport Singapore (HPSS). Many overseas centres also offer on-field rehabilitation that simply isn't something we provide locally. If competitive return-to-sport is your goal, this is worth planning for early and explicitly with your care team.

Return to training ≠ return to competition

This is a nuance worth sitting with. Your readiness depends heavily on your level of sport and competition — a weekend social game is a very different risk calculus from national-level competition.

Here's where I have to be honest with my patients, even when it's not what they want to hear: I've had patients test at 80% on their Biodex and tell me they're already back playing weekend soccer. Objectively, based on the strength test, they are not fully ready. But ultimately, you know your game, your level, and what you're willing to risk. Some patients choose to wear a brace; others simply play more cautiously. That choice — and that risk — is yours to make with full information.

That choice — and that risk — is yours to make with full information.

It's also worth knowing this: even elite, fully compliant athletes who hit maximum strength benchmarks still sometimes re-tear their ACL. There are simply too many variables at play for anyone — surgeon included — to offer a guarantee. We do everything within our control: the testing, the training, the precautions. Beyond that, in all honesty, we have to trust God with your knee.

So while I can't strictly "clear" you for sport in absolute terms, I can walk this decision through with you — understanding your risk, taking sensible precautions, and making an informed choice together, rather than either of us pretending there's a guarantee where none exists.

Wondering where you stand in your own recovery? Explore the full ACL Recovery Hub →

References

1. Webster KE, Feller JA, Lambros C. Development and preliminary validation of a scale to measure the psychological impact of returning to sport following anterior cruciate ligament reconstruction surgery. Phys Ther Sport. 2008;9(1):9–15.
2. Kumar R, Singh V, Reddy TO. Optimizing return to sports after anterior cruciate ligament reconstruction: A multi-factorial umbrella review on rehabilitation strategies. J Clin Orthop Trauma. 2025;70:103176. Published 2025 Aug 14. doi:10.1016/j.jcot.2025.103176