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NCT Number: NCT07128602

Determining the Effects of Non-invasive Brain Stimulation to Improve Quadriceps Muscle Function After ACL Reconstruction

After knee surgery for a torn ACL, many women struggle with weak thigh muscles for years, partly due to reduced brain signals to these muscles. Our research tests a new approach to improve recovery by using low-level brain stimulation to boost these signals. The investigators will study 42 women, aged 18-35, who had ACL surgery. They'll be split into two groups: one receiving real brain stimulation and another getting a placebo, both during thigh-strengthening exercises. Over six sessions, the investigators measure thigh muscle strength, speed, and steadiness, plus two brain signal measures, using special equipment. The investigators will also check if stronger brain signals lead to better muscle performance, especially in women. Our goal is to show that this new method strengthens thigh muscles better than standard rehab, helping women recover better after surgery. If successful, this could improve physical therapy for women recovering from ACL surgery, making daily activities and return to sport easier.

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Key information

Conditions

Anterior Cruciate Ligament Reconstruction Rehabilitation Quadriceps Muscle Function

Age range

18 year–35 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Ryan Zarzycki

Glenside, Pennsylvania, 19038, United States

Location status: Recruiting

Location contact

Ryan Zarzycki, PT, PhD

CONTACT

[email protected]

215-572-8527

About this study

Quadricep muscle impairments persist for years after anterior cruciate ligament reconstruction (ACLR). Recent evidence suggests that lower neural drive, (i.e., lower corticospinal excitably (CSE)), is associated with pronounced quadriceps muscle performance deficits, which are more severe in females recovering from ACLR than in males. Current postoperative rehabilitation protocols do not target lower neural drive, which can be achieved through non-invasive brain stimulation. Thus, the long-term goal of this research is to improve the effectiveness of ACLR rehabilitation. The objective of this project is to determine if neural drive is the critical missing link in ACLR rehabilitation. To meet this objective, the investigators will administer anodal transcranial direct current stimulation (tDCS), a type of non-invasive brain stimulation known to increase CSE. The investigators will then assess whether it improves three measures of quadriceps muscle performance (in Aim 1) and two measures of CSE (in Aim 2). In Aim 3, the investigators will determine the relationship between observed changes in quadriceps muscle performance and CSE in female participants recovering from ACLR. These aims will be achieved using a randomized, triple-blinded clinical trial with 42 female individuals after ACLR between the ages of 18 and 35 years. All participants will receive six sessions of active or sham anodal tDCS while they perform isolated quadriceps exercises on an isokinetic dynamometer. The two measures of CSE (i.e. active motor threshold and the slope of transcranial magnetic stimulation (TMS) induced recruitment curves) will be determined using surface electromyography on the vastus medialis and TMS. Three measures of quadriceps performance (i.e. peak torque normalized to body weight, rate of torque development (RTD) from 0-100ms and 100-200ms, and torque steadiness) will be determined following standard isometric muscle testing on an isokinetic dynamometer with the hips flexed to 90° and the knees flexed to 60°.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • females 2-6 months after ACL reconstruction

Exclusion criteria

  • multiple ligament reconstruction
  • osteochondral procedures
  • any previous lower extremity surgery
  • previous ACL injury
  • Metal or implants in the head or neck
  • history of neurological disease
  • seizures
  • severe migraines
  • concussion within the last 6 months

Treatment and study plan

Active Transcranial Direct Current Stimulation (tDCS)

Device

20 minutes of anodal tDCS over the primary motor cortex contralateral to the participants surgical limb during a quadriceps torque matching task

Sham Transcranial Direct Current Stimulation (tDCS)

Device

Participants receive sham tDCS in which the device only delivers current during the first and last 30 seconds while participants perform a quadriceps torque matching task

Primary outcomes

  1. Peak quadriceps muscle torque

    Time frame: Pre and post intervention

    Peak torque during a 5 second maximal voluntary isometric contraction

  2. Corticospinal excitability (Slope)

    Time frame: Pre and post intervention

    Slope of a TMS induced stimulus-response curve

Secondary outcomes

  1. Rate of Torque Development (RTD)

    Time frame: Pre and post intervention

    RTD of a maximal voluntary isometric contraction from onset to 100ms (RTD100) and from 100 to 200ms (RTD200) will be used.

  2. Corticospinal excitability (Active Motor Threshold)

    Time frame: Pre and post intervention

    The lowest stimulator intensity needed to produce consistent MEPs >/= 100 microvolts while the participant maintains an isometric contraction at 5% of their MVIC

Study contacts

Contact information is provided by the study sponsor or research team.

Ryan Zarzycki, PhD

CONTACT

[email protected]

215-572-2852

Sponsors and collaborators

Lead sponsor

Arcadia University

Other

Collaborators

  • Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Registry information

Official study title

Determining the Effects of Non-invasive Brain Stimulation to Improve Quadriceps Muscle Function After ACL Reconstruction.

Important dates

Study start
2025
Primary completion
2028
Study completion
2028
First posted
Aug 19, 2025
Registry last updated
May 7, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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