Understanding muscle activation issues after ACL reconstruction

Deficit in Quadriceps Voluntary Activation After Anterior Cruciate Ligament Reconstruction: Roles of the "Learned Non-use" Paradigm and the Interhemispheric Inhibition

Observational Istituto Auxologico Italiano · NCT04837417

This study looks at why some people still have weak thigh muscles after ACL surgery and tries to find ways to improve their recovery.

Quick facts

Study typeObservational
Enrollment10 (estimated)
Ages18 Years to 35 Years
SexMale
SponsorIstituto Auxologico Italiano Academic / other
Locations2 sites (Milan, MI and 1 other locations)
Trial IDNCT04837417 on ClinicalTrials.gov

What this trial studies

This observational study investigates the persistent deficits in voluntary activation of the quadriceps muscle following anterior cruciate ligament (ACL) reconstruction. It aims to understand the role of the 'learned non-use' paradigm and interhemispheric inhibition in these deficits. The study will assess patients who have undergone ACL reconstruction between 6 and 18 months prior to identify factors contributing to ongoing muscle weakness despite rehabilitation efforts. The findings could help refine rehabilitation protocols for better recovery outcomes.

Who should consider this trial

Good fit: Ideal candidates for this study are individuals who have undergone ACL reconstruction within the last 6 to 18 months and meet specific activity and health criteria.

Not a fit: Patients with significant comorbidities or previous knee injuries may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved rehabilitation strategies that enhance muscle activation and reduce the risk of re-injury or osteoarthritis in patients recovering from ACL reconstruction.

How similar studies have performed: While the specific approach of this study may be novel, previous studies have indicated that addressing voluntary activation deficits is crucial for recovery after ACL injuries.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* anterior cruciate ligament tear with arthroscopic reconstruction, between 6 and 18 months before the tests;
* Tegner activity level \> 5;
* Body Mass Index between 18 and 25;
* voluntary knee extension of at least 70°;
* ability to understand the instructions;
* ability to wittingly sign the informed consent form.

Exclusion Criteria:

* other previous knee injuries or surgical interventions;
* major procedures associated with the anterior cruciate ligament reconstruction: osteotomy, other ligaments reconstruction;
* meniscectomy, with surgical removal of more than 30% of the meniscal volume or removal of the meniscal root;
* comorbidities, such as: rheumatic diseases; other congenital or acquired neuromuscular pathologies; diabetes mellitus; osteoporosis; cancer; heart disease; history of epilepsy, endocranial hypertension;
* first degree relatives affected by epilepsy;
* current treatment with oral anticoagulant or antiplatelet therapy;
* drug therapy, which could induce epileptic crisis;
* history of high alcohol consumption;
* implanted electro-sensitive devices;
* implanted intracranial or intraocular metallic devices;
* history of retinal detachment;
* presence of cochlear implant.

Where this trial is running

Milan, MI and 1 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Anterior Cruciate Ligament InjuriesAnterior cruciate ligament reconstructionacquired non-usevoluntary activationquadriceps femorisrehabilitation
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.