Anterior Cruciate Ligament InjuryNCT03209531
Conditioning Brain Responses to Improve Thigh Muscle Function After Anterior Cruciate Ligament Reconstruction
A study testing Operant Conditioning and Single Pulse Transcranial Magnetic Stimulation in people with Anterior Cruciate Ligament Injury, run by University of Michigan at 1 site in United States.
Trial summary
The purpose of this study is to examine if thigh muscle weakness and the lack of muscle activation that accompanies ACL injury can be improved through a form of mental coaching and encouragement, known as operant conditioning. Read more about this study
- Who is it for?
- Ages 18 to 45 years
- Conditions the study is for
- Anterior Cruciate Ligament Injury
- What is being tested?
- Operant Conditioning and Single Pulse Transcranial Magnetic Stimulation
- Type of treatment
- Medical device, Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 11 participants
- Where
- 1 siteUnited States
- Study dates
- 21 Sep 2017to 24 Nov 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- aged 18-45 years
- suffered an acute, complete ACL rupture
- have undergone ACL reconstructive surgery
- willingness to participate in testing and follow-up as outlined in the protocol
Who cannot join
- have suffered a previous ACL injury;
- have undergone previous major surgery to either knee;
- have a history of recent significant knee injury (other than ACL) or lower-extremity fracture;
- have a history of uncontrolled diabetes or hypertension;
- be pregnant or plan to become pregnant;
- have metal implants in the head;
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- have electronic devices in their ear or heart (e.g., cochlear implants or cardiac pacemakers);
- have unexplained recurrent headaches;
- have a recent history of seizures;
- be taking drugs that reduce seizure threshold;
- have a history of repeated fainting spells;
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Operant Conditioning of Motor Evoked Responses to Improve Quadriceps Function in Individuals With Anterior Cruciate Ligament Reconstruction
The purpose of this study is to examine if thigh muscle weakness and the lack of muscle activation that accompanies ACL injury can be improved through a form of mental coaching and encouragement, known as operant conditioning.
Read the detailed description
Thigh muscle weakness is a common result after anterior cruciate ligament (ACL) injury and reconstruction surgery. Therefore, reducing thigh muscle weakness after ACL injury and reconstructive surgery is important as the quadriceps muscles act as shock absorbers that protect the knee joint. If significant weakness is present in the quadriceps, the knee is exposed to increased forces and often results in degeneration of the structures in the joint leading to osteoarthritis. Thus, it is important to investigate activation and strength rehabilitation methods for the quadriceps muscles. This research study is being done to learn if thigh muscle weakness and the lack of muscle activation that accompanies ACL injury can be improved by conditioning brain responses (elicited by non-invasive transcranial magnetic stimulation) using a form of training called as operant conditioning.
- Conditions
- Anterior Cruciate Ligament Injury
- Being tested
- Operant Conditioning, Control, Single Pulse Transcranial Magnetic Stimulation
- Keywords
- Quadriceps activation deficits, ACL, Surgery, Quadrcieps weakness, Operant conditioning, Cortical excitability
- Medical subject headings
- Anterior Cruciate Ligament Injuries
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Operant ConditioningBehavioural
Active encouragement and feedback to increase motor evoked response when stimulated.
ControlBehavioural
Absence of active encouragement and feedback to increase motor evoked response when stimulated.
Single Pulse Transcranial Magnetic StimulationDevice
Transcranial magnetic stimulation to elicit a motor evoked response from the quadriceps muscles.
| Study group | Role | What they receive |
|---|---|---|
| Operant Conditioning | Experimental | Participants will receive operant conditioning training and single pulse transcranial magnetic stimulation 2-3 times a week for about 8 weeks. Receives: Behavioral: Operant Conditioning; Device: Single Pulse Transcranial Magnetic Stimulation |
| Control | Experimental | Participants will receive single pulse transcranial magnetic stimulation 2-3 times a week for about 8 weeks without operant conditioning training. Receives: Behavioral: Control; Device: Single Pulse Transcranial Magnetic Stimulation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes in Quadriceps muscle strength
Quadriceps strength will be measured using an isokinetic dynamometer. Improvements in quadriceps strength from baseline to the end of intervention will be assessed and compared between groups.
Measured: Approximately 8 weeks after the start of intervention
Secondary outcomes (1)
Changes in voluntary activation
Voluntary activation will be measured using an electrical superimposition technique. Improvements in voluntary activation from baseline to the end of intervention will be assessed and compared between groups.
Measured: Approximately 8 weeks after the start of intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Jul 2017
- Study start21 Sep 2017
- Primary completion24 Nov 2025
- Study completion24 Nov 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Anterior Cruciate Ligament InjuryStudies of the same condition, open and under way.
- More trials run by University of MichiganThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 11 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Michigan
- Sponsor type
- University, hospital or other
- Collaborators
- Medical University of South Carolina, National Center of Neuromodulation for Rehabilitation, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
- Responsible party
- Principal investigator, Chandramouli Krishnan, University of Michigan
- Investigators
- Chandramouli Krishnan, PhD, Principal investigator, Assistant Professor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03209531
- Sponsor's protocol ID
- HUM00130845
- Other IDs
- P2CHD086844
- Status last verified
- Nov 2025
- First submitted
- 30 Jun 2017
- Last updated
- 26 Nov 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Operant Conditioning of Motor Evoked Responses to Improve Quadriceps Function in Individuals With Anterior Cruciate Ligament Reconstruction
- ClinicalTrials.gov ID
- NCT03209531
- Acronym / sponsor ID
- HUM00130845
- Conditions
- Anterior Cruciate Ligament Injury
- Keywords
- Quadriceps activation deficits, ACL, Surgery, Quadrcieps weakness, Operant conditioning, Cortical excitability
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 11 participants (actual)
- Lead sponsor
- University of MichiganUniversity, hospital or other
- Collaborators
- Medical University of South Carolina, National Center of Neuromodulation for Rehabilitation, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
- Study start
- 21 Sep 2017 (actual)
- Primary completion
- 24 Nov 2025 (actual)
- Study completion
- 24 Nov 2025 (actual)
- First posted
- 6 Jul 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to examine if thigh muscle weakness and the lack of muscle activation that accompanies ACL injury can be improved through a form of mental coaching and encouragement, known as operant conditioning.
Detailed description
Thigh muscle weakness is a common result after anterior cruciate ligament (ACL) injury and reconstruction surgery. Therefore, reducing thigh muscle weakness after ACL injury and reconstructive surgery is important as the quadriceps muscles act as shock absorbers that protect the knee joint. If significant weakness is present in the quadriceps, the knee is exposed to increased forces and often results in degeneration of the structures in the joint leading to osteoarthritis. Thus, it is important to investigate activation and strength rehabilitation methods for the quadriceps muscles. This research study is being done to learn if thigh muscle weakness and the lack of muscle activation that accompanies ACL injury can be improved by conditioning brain responses (elicited by non-invasive transcranial magnetic stimulation) using a form of training called as operant conditioning.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Operant Conditioning | Experimental | Behavioral: Operant Conditioning, Device: Single Pulse Transcranial Magnetic StimulationParticipants will receive operant conditioning training and single pulse transcranial magnetic stimulation 2-3 times a week for about 8 weeks. |
| Control | Experimental | Behavioral: Control, Device: Single Pulse Transcranial Magnetic StimulationParticipants will receive single pulse transcranial magnetic stimulation 2-3 times a week for about 8 weeks without operant conditioning training. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- aged 18-45 years
- suffered an acute, complete ACL rupture
- have undergone ACL reconstructive surgery
- willingness to participate in testing and follow-up as outlined in the protocol
Key exclusion criteria (11 listed)
- have suffered a previous ACL injury;
- have undergone previous major surgery to either knee;
- have a history of recent significant knee injury (other than ACL) or lower-extremity fracture;
- have a history of uncontrolled diabetes or hypertension;
- be pregnant or plan to become pregnant;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Operant ConditioningActive encouragement and feedback to increase motor evoked response when stimulated. | Behavioural | Operant Conditioning |
| ControlAbsence of active encouragement and feedback to increase motor evoked response when stimulated. | Behavioural | Control |
| Single Pulse Transcranial Magnetic StimulationTranscranial magnetic stimulation to elicit a motor evoked response from the quadriceps muscles. | Device | Control, Operant Conditioning |
Primary outcome
Changes in Quadriceps muscle strength
Time frame: Approximately 8 weeks after the start of intervention
Quadriceps strength will be measured using an isokinetic dynamometer. Improvements in quadriceps strength from baseline to the end of intervention will be assessed and compared between groups.
1 secondary outcome
Changes in voluntary activation
Time frame: Approximately 8 weeks after the start of intervention
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Nov 2025.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Chandramouli Krishnan, PhD principal investigator
Assistant Professor
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Operant Conditioning and Single Pulse Transcranial Magnetic Stimulation in people with Anterior Cruciate Ligament Injury, run by University of Michigan at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 26 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Changes in Quadriceps muscle strength (time frame: Approximately 8 weeks after the start of intervention). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Nov 2025.