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Neuromuscular adaptation after ACL reconstruction surgery

Wondering what specific muscle functions to examine when helping people optimize their function after a reconstruction surgery for Anterior Cruciate Ligament (ACL) injury? This recent review can give you useful guidance.

He, X., Leong, H. T., Lau, O. Y., Ong, M. T., & Yung, P. S. (2020). Altered Neuromuscular Activity of the Lower-Extremities During Landing Tasks in Patients With Anterior Cruciate Ligament Reconstruction: A Systematic Review of Electromyographic Studies, Journal of Sport Rehabilitation, 29(8), 1194-1203. Retrieved Jun 29, 2022, from

In a nutshell, people with ACL reconstruction quite consistently showed earlier co-contraction of quadriceps and hamstrings at landing after a jump. This can theoretically delay the stabilization function of gluteus Maximus/medius and gastrocnemius. But the results regarding glute muscles and gastrocnemius were varied due to possible confounding factors such as gender and types of graft.

Even though it was not directly discussed in this review article, it would be also beneficial to look into popliteus as it is an important local stabilizer for the knee on many occasions. In addition, if the glutes become deficient, trunk stabilizers can commonly compensate to support the stance limb when walking. Therefore it will be also helpful to look into the muscles that have a synergistic relationship with gluteal muscles in one leg standing. They are hip abductors, hip adductors, and opposite quadratus lumborum. They are often collectively called Lateral Sling System and is shown in the picture below.

Source: Gibbons, J. (2017). Functional anatomy of the pelvis and the sacroiliac joint: A practical guide. North Atlantic Books.