Muscle force contributions to anterior cruciate ligament loading

Review written by Dr Teddy Willsey info

Key Points

  1. The hamstrings appear to be protective against anterior cruciate ligament (ACL) loading, while the quadriceps induce ACL loading and anterior shear force.
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Anterior cruciate ligament (ACL) tears are one of the most common knee injuries sustained during sports, and they are characterized by a costly and lengthy rehabilitation (1). ACL re-injury rates have been reported as high as 30%, with many athletes losing multiple competitive seasons to injury rehabilitation (2). ACL injuries occur most often during non-contact dynamic tasks, shortly after initial contact, where the knee experiences high mechanical loads, compression, rapid loading into flexion, and large degrees of valgus and rotation.

It is thought that effective training of specific muscle groups and movement patterns may mitigate ACL loads during injurious scenarios, thus protecting the ACL from injury. An important prerequisite for clinicians in administering rehabilitation and preventative exercise for the ACL rehabilitation patient is understanding how individual muscles contribute to ACL loading.

The authors sought out to summarize the existing evidence on how specific lower limb muscles contribute to ACL load.

ACL re-injury rates have been reported as high as 30%.
The hamstrings, soleus, and gluteus medius have the greatest ability to oppose ACL loading.


  • The authors included a variety of studies for their narrative review.
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