Running after ACL surgery can be a daunting task. However, dedicated athletes who have worked hard on their rehab, will eventually meet the criteria to run.
Far too often ACL rehab is centered around timelines and introduced without any testing1, with running being the biggest culprit because of its ease of access. Here's an example of a recommendation to run at the three or four month mark. The desire to keep athletes happy and motivated during their rehab often results in rewarding them with running. Although done with good intent, recommending an athlete run based on time alone is a recipe for long-term issues with the knee joint.
To be clear, an athlete can be cleared to run in four months, but it depends on the criteria cleared. Unfortunately, too many physical therapy clinics let patients run without any testing.
AVA (our ACL Virtual Assistant) recommends the following goals be met before running.
These goals may seem difficult, but they are designed to ensure an athlete can focus on running without harm, which often takes longer than previously thought. Some studies often find that a Quadriceps Strength Limb Symmetry Index (LSI) of 60% is "good enough" to tolerate running2, but a target this low fails to offload the joint well. With a Quadriceps Strength LSI of 80%, this often takes until five or six months to reach.
Athletes who start running after achieving 60% Quadriceps Strength LSI will, to the outside observer, seem normal. But without the strength in the supporting musculature, the knee joint will take a beating with every step, and long term damage beyond the point of observation by the average study is possible. Running in this way may not present any pain or soreness either, which makes it difficult for an athlete to reason why they shouldn’t continue. That's why AVA enforces stricter criteria for clearance to run.
One caveat about the criteria to run is whether Quadriceps Strength LSI versus Quadriceps Rate of Torque Development (RTD) LSI should be considered for running. We are beginning to realize that while strength is a good starting place, rate of torque development for faster, smaller-time efforts, like running, might be more important and should be looked at seriously earlier on in rehab3. We hope to add to AVA a more quantified goal for RTD before running in the future.
Running is an exciting milestone, but this straightforward post is to help reinforce the fact that it should be done when you, the athlete, demonstrate the requisite strength necessary for it. Not a certain amount of time.
If you are an athlete with concerns about your ability to run, do yourself a favor and pick up the ACL Virtual Assistant from the Apple App Store or Google Play Store.
1. Rambaud AJM, Ardern CL, Thoreux P, Regnaux JP, Edouard P. Criteria for return to running after anterior cruciate ligament reconstruction: a scoping review. Br J Sports Med. 2018 Nov;52(22):1437-1444. doi: 10.1136/bjsports-2017-098602. Epub 2018 May 2. PMID: 29720478.
2. Grondin J, Crenn V, Gernigon M, Quinette Y, Louguet B, Menu P, Fouasson-Chailloux A, Dauty M. Relevant Strength Parameters to Allow Return to Running after Primary Anterior Cruciate Ligament Reconstruction with Hamstring Tendon Autograft. Int J Environ Res Public Health. 2022 Jul 6;19(14):8245. doi: 10.3390/ijerph19148245. PMID: 35886096; PMCID: PMC9322324.
3. Knurr KA, Cobian DG, Kliethermes SA, Stiffler-Joachim MR, Heiderscheit BC. The Influence of Quadriceps Strength and Rate of Torque Development on the Recovery of Knee Biomechanics During Running After Anterior Cruciate Ligament Reconstruction. Am J Sports Med. 2023 Oct;51(12):3171-3178. doi: 10.1177/03635465231194617. Epub 2023 Sep 8. PMID: 37681433; PMCID: PMC10985737.
