A recent study sought to review the literature on the use of open chain exercises post ACL reconstruction.
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STUDY: Who’s afraid of the big bad wolf? Open-chain exercises after anterior cruciate ligament reconstruction – Noehren and Snyder-Mackler 2020
Study reviewed by Christina Le
Key points from the study
- Open-chain exercises are safe to perform after an ACL injury or ACL reconstruction.
- The best way to isolate quadriceps strength is through open-chain exercises.
- Greater quadriceps strength is associated with better self-reported knee function, successful return to sport, and reduced risk of developing knee osteoarthritis.
Background and objective
Increased quadriceps strength post ACL reconstruction is associated with better self-reported outcomes, return to sport, and mitigation or prevention of knee osteoarthritis.
What is an effective way of targeting the quads? Open-chain exercise. This viewpoint paper challenges the two most commonly cited arguments against open-chain exercises and highlights the potential benefit of incorporating them into your ACL rehabilitation programs.
Myth I: Open-Chain Exercises Stretch ACL Grafts
Did you know that walking produces 2-3 times the strain on the ACL compared to an open-chain leg extension exercise? It seems a bit contradictory that clinicians promote early ambulation and weight-bearing following an ACL reconstruction but discourage the use of open-chain exercises.
A systematic review from 2018 which examined 10 randomized controlled trials comparing open and closed-chain exercises concluded there was low to moderate-quality evidence of no difference in anterior tibial laxity, strength, or self-reported function between individuals who completed open and closed-chain exercises.
Myth II: Open-Chain Exercises Are Not Functional
Closed-chain exercises are multi-joint exercises. This means that patients can compensate for weak quadriceps by recruiting other muscle groups (e.g. hip extensors) during them. On the other hand, an open-chain leg extension exercise will, more-or-less, isolate the quadriceps. There is nowhere to hide.
If clinicians are not prescribing open-chain exercises, does that mean they are also failing to truly test quadriceps strength?
Open-chain exercises are safe to perform after ACL reconstruction! In the acute stages of recovery, only low loads are needed to elicit muscle failure. As with your other strength exercises, increase the resistance to 60-70% of a patient’s 1-rep-max and beyond as they progress through their rehabilitation.
The bottom line? Dust off those leg extension machines and put them to use!