Strength testing, usually a limb symmetry index score, still decides when most ACL patients return to sport. Calkins (IJSPT 2026) reviewed 53 ACL reconstruction rehabilitation protocols at U.S. academic institutions and found strength requirements in 79.2% of them, with 34 of those 53 setting a specific limb symmetry threshold. Clinicians writing new protocols, or auditing their own, should know how much the field still leans on one number.
What did the scoping review actually find?
Calkins (2026) mapped return-to-sport criteria across 53 U.S. academic ACL reconstruction protocols. Strength testing via limb symmetry index showed up in 42 of them. A specific symmetry threshold, not just a general strength check, was required in 34. That is not one program's preference. It is the dominant pattern across the protocols this review sampled.
Why can strength-only clearance miss what actually predicts reinjury?
A symmetry score answers one question: can the involved limb match the uninvolved limb on a planned, single-direction task. Fältström (2023) followed 117 female football players after ACL reconstruction and found something that should give any strength-first protocol pause. The players who went on to a primary or second ACL injury had jumped farther and hopped more at baseline, not less. Better hop numbers did not protect them. Chmielewski (2024) found a related gap from a different angle: ACL patients gained less on a reaction-time test than on hop testing, which the authors read as a sign that extra mental effort to move may persist after reconstruction even once hop scores look strong. Neither study says strength testing is wrong. Both say it is answering a narrower question than "is this athlete ready."
How does this change Monday morning?
A clearance visit built entirely around a symmetry percentage is testing what the protocols in Calkins' review already test, and nothing past it. Add a reactive measure alongside strength and hop criteria, not instead of them. QuickBoard's Agility Rating captures bilateral reaction time and decision accuracy under full body weight, across five dimensions, and the auto-generated Progress Report gives the clinic a second number to track alongside strength symmetry over the course of rehab. Strength testing and functional progressions still bill under CPT 97530 (Therapeutic Activities) or CPT 97112 (Neuromuscular Re-education). The Agility Rating assessment bills separately under CPT 97750 (Physical Performance Test), in 15-minute increments, on a non-eval day. Run both before the clearance conversation moves forward.
Takeaways
- A scoping review of 53 U.S. academic ACL protocols found strength testing, usually limb symmetry index, as the return-to-sport criterion in 42 of them (Calkins 2026).
- Players who later suffered a primary or second ACL injury had jumped farther and hopped more at baseline, not less (Faltstrom 2023).
- ACL patients gained less on a reaction-time test than on hop testing, a gap hop scores alone do not surface (Chmielewski 2024).
- Add a reactive measure to the clearance conversation. Strength symmetry alone is the dominant protocol pattern, not a complete one.
Strength testing has a real role in ACL clearance. The evidence says it should not be the only role. See Ortho Rehab and ACL Return to Sport for the full clinical use case, Chmielewski 2024 and the rest of the published Research library, and the Agility Rating for how the five-dimension assessment works.
Citations
- Calkins 2026
- Chmielewski 2024
- Faltstrom 2023
See QuickBoard research for full citation details.