Running After ACL Reconstruction

Running after ACL Reconstruction 

When an athlete is recovering from an ACL Reconstruction (ACLR) surgery, running is one of the first sport-related activities they return to. Every athlete’s recovery is going to be different, and no two roads are the same so athletes should never compare themselves to others who are recovering. In this article, Coach Lee breaks down a key component of running mechanics that is altered after ACLR and can persist well after an athlete returns to sport.

In a study performed in 2021, they took 13 collegiate athletes who had ACLR (bone-patellar tendon-bone grafts) and they evaluated their running mechanics at the 4 months, 6 months, 8 months, and 12 months post-surgery mark. These athletes had undergone preparticipation performance testing so they could compare the post-surgical data to their preinjury data (so cool!)

What they found:

They found altered running mechanics that was lowest at 4 months but persisted at 12 months post-surgery. Most athletes have returned to sport by 12 months and this study showed they are still running with altered mechanics compared to their preinjury level. Another study found altered mechanics persisting at 2 years. It is unclear if this is a protective mechanism, or a learned movement strategy.

The specifics:

The mechanics most affected involve how the individual is loading the knee. The studies show there is decreased knee flexion (bend) when running on the surgical leg, and the quad function is reduced in both the amount and the rate it is engaging. They run with more stiffness in the surgical knee.

In the graphs below, the surgical limb is the black line, the non-surgical limb is gray.

The top graph shows the decrease in knee bend during running, the middle graph shows the peak activity from the quad, and the bottom graph shows how fast the quad produces that torque. 

You can see the surgical limb is below the non-surgical limb in all 3.

The significance:

Some have hypothesized that this may be one reason individuals have an increased risk for osteoarthritis, as they are not loading the knee at the levels they used to, or compared to their other limb. We know that tissues that experience load get stronger, as long as the loading is gradually applied and progressed. 

At Take It, we work with many former athletes, and they often take up running after sport as a way to exercise and challenge their bodies. If you had any major knee surgery or injury when playing sport, and you have taken up running, I would recommend obtaining a running evaluation to determine if your running mechanics are the same between legs, or if there is still a difference side to side. Identifying this will allow you to train that surgical leg differently in hopes to correct these mechanics and reduce your risk of long-term issues in the future. If you are a local athlete and want to assess your running mechanics in the comfort of your own home, check out our RAD program!

Author: Dr. Annalee Scott, PT, DPT, CSCS