The purpose of this work is to conduct a comparative research-focused study to evaluate the effectiveness of how purposefully induced asymmetric walking protocols restore healthy, symmetric limb loading in individuals following post-anterior cruciate ligament reconstruction (ACLR) surgery. Additionally, computational modeling and machine learning to model knee loading in the clinic to determine the optimal asymmetric walking protocol to restore healthy gait in post-ACLR individuals.

This is an intervention study in which participants will be randomized as to the order in which each of the two sessions are completed. Forty post-ACLR will who present with between-limb gait differences will perform two asymmetric walking sessions where they will walk with between-limb gait speed differences of 0.25 m/s and 0.50 m/s at three 15-minute intervals to evaluate the restoration of healthy gait. Post-ACLR participants will perform an asymmetric walking intervention protocol session on two different days. On one day they will perform the protocol with a 0.25 m/s between-limb difference and on a separate day they will perform the protocol with a 0.50 m/s between limb difference. For the 0.25 m/s condition, one limb will be set to 1.0 m/s and the other 1.25 m/s (i.e., 1.0 m/s - 1.25 m/s). Similarly, for the 0.50 m/s condition, one limb will be set to 1.0 m/s and the other 1.50 m/s (i.e., 1.0 m/s - 1.50 m/s). Each participant will perform both the 0.25 m/s and 0.50 m/s protocols on separate days, and we will randomize who performs which protocol first or second. At least 3 weeks must pass between the two one-day sessions. Patient-specific simulations will be generated in OpenSim for each of the 40 post-ACLR individuals to assess differences in knee joint loading. Together with machine learning, these models will help evaluate the effectiveness of the asymmetric walking protocol in reducing detrimental knee loading. The study team hypothesizes that the 0.50 m/s perturbation will produce a larger reduction in between-limb asymmetry than the 0.25 m/s perturbation and reduce detrimental knee loading.

Inclusion Criteria:

1. Able to read and speak English
2. Age 18 - 30 years old
3. Undergone ACLR surgery at the UConn Musculoskeletal Institute
4. Must not have any concomitant surgeries or injuries
5. Must be cleared to return-to-sport by a physician after they have completed rehabilitation
6. Must be within 1 month of having been cleared for return-to-sport
7. Must present with between-limb gait differences in load rate greater than 10%

Exclusion Criteria:

1. Participants who have any recent inflammation, bleeding disorders, active bleeding, or infection within the lower limbs.
2. History of injuries to their patellar tendon
3. Cannot walk for extended periods of time
4. Cannot have had any back and/or lower extremity injury that affects their ability to move.
5. Cannot have difficulty or pain with walking, raising your arms, jogging, or jumping
6. Must not be allergic to tape.