(Anterior cruciate ligament) AND (transcranial magnetic stimulation)

Anterior cruciate ligament (ACL) ruptures result in lasting quadriceps dysfunction that contributes to secondary injury risk and development of osteoarthritis. There is evidence of persistent reduced nervous system drive (corticospinal excitability, CSE) to the quadriceps and sex differences in both quadriceps performance and CSE post-ACL reconstruction (ACLR). The purposes of this study were to investigate the differences in CSE and quadriceps dysfunction after ACLR between sexes and relative to controls. Twenty subjects 4-9 months post ACLR and 20 age, sex, and activity matched controls participated in this study...

PURPOSE: To compare quadriceps corticomuscular coherence (CMC) and force steadiness between individuals with anterior cruciate ligament reconstruction (ACLR) and uninjured controls during a force tracing task. METHODS: Individuals with ACLR (n = 20) and controls (n = 20) performed a knee extension force-control task at 50% of maximal voluntary effort. Electrocortical activity, electromyographic activity, and torque output were recorded concurrently. Corticomuscular coherence in beta (13-30 Hz) and gamma (31-80 Hz) frequency bands was assessed using partial directed coherence between the contralateral motor cortex (e...

This study comprehensively evaluated the test-retest reliability of raw and normalized quadriceps motor evoked responses elicited by transcranial magnetic stimulation (TMS) in individuals with anterior cruciate ligament (ACL) reconstruction. Fifteen participants were tested on three different days that were separated at least by 24 h. Motor evoked responses were collected during a small background contraction on the reconstructed leg across a range of TMS intensities using torque (MEPTORQUE ) and electromyographic (MEPEMG ) responses...

Traumatic musculoskeletal injury (MSI) may involve changes in corticomotor structure and function but direct evidence is needed. To determine the corticomotor basis of MSI, we examined interactions among skeletomotor function, corticospinal excitability, corticomotor structure (cortical thickness and white matter microstructure), and intermittent theta burst stimulation (iTBS)-induced plasticity. Nine women with unilateral anterior cruciate ligament rupture (ACL) 3.2±1.1yr prior to the study and 11 matched controls (CON) completed an MRI session followed by an offline plasticity-probing protocol using a randomized, sham-controlled, double-blind, cross-over study design...

Purpose: This study is aimed at investigating the effect of low-intensity electrical stimulation on the voluntary activation level (VA) and the cortical facilitation/inhibition of quadriceps in people with chronic anterior cruciate ligament lesion. Methods: Twenty former athletes with unilateral ACL deficiencies (ACL group) and 20 healthy subjects (healthy control group) participated in the study. The quadriceps VA level, motor-evoked potential (MEP), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) elicited by transcranial magnetic stimulation were tested before and after 30 minutes of low-intensity electrical stimulation (ES)...

Quadriceps dysfunction persists after anterior cruciate ligament reconstruction (ACLR), yet the etiology remains elusive. Inhibitory and facilitatory intracortical networks (ie, intracortical excitability) may be involved in quadriceps dysfunction, yet the investigation of these networks early after ACLR is sparse. The purposes of this study were to examine (a) changes in intracortical excitability in athletes after ACLR compared to uninjured athletes during the course of postoperative rehabilitation, (b) the association between intracortical excitability and quadriceps strength in athletes after ACLR...

BACKGROUND: Underlying neural factors contribute to poor outcomes following anterior cruciate ligament reconstruction (ACLR). Neurophysiological adaptations have been identified in corticospinal tract excitability, however limited evidence exists on neurostructural changes that may influence motor recovery in ACLR patients. OBJECTIVE: To 1) quantify hemispheric differences in structural properties of the corticospinal tract in patients with a history of ACLR, and 2) assess the relationship between excitability and corticospinal tract structure...

Impaired corticomotor function arising from altered intracortical and corticospinal pathways are theorized to impede muscle recovery following anterior cruciate ligament (ACL) surgery, yet functional implications of centrally driven adaptations remain unclear. We aimed to assess relationships between quadriceps corticomotor and neuromechanical function after ACL surgery, and to compare with contralateral and control limbs. 16 individuals after primary, unilateral ACL surgery and 16 sex- and age-matched controls participated...

BACKGROUND: Persistent quadriceps weakness and activation failure are common in individuals with anterior cruciate ligament (ACL) reconstruction. A growing body of evidence indicates that this chronic quadriceps dysfunction could be partly mediated due to reduced corticospinal excitability. However, current rehabilitation approaches do not directly target corticospinal deficits, which may be critical for restoring optimal clinical outcomes after the surgery. This case study tested the feasibility of operant conditioning of torque responses evoked by transcranial magnetic stimulation (TMS) to improve quadriceps function after ACL reconstruction...

Quadriceps muscle dysfunction is common following anterior cruciate ligament reconstruction (ACLR). Data considering the diversity of neural changes, in-concert with morphological adaptations of the quadriceps muscle, are lacking. We investigated bilateral differences in neural and morphological characteristics of the quadriceps muscle in ACLR participants (n = 11, month post-surgery: 69.4 ± 22.4) compared to controls matched by sex, age, height, weight, limb dominance, and activity level...

Neuromuscular impairments, such as quadriceps weakness and activation deficits, persist after anterior cruciate ligament reconstruction (ACLR). Recent research demonstrating changes in the function of the primary motor cortex after ACLR posits that quadriceps impairments may be influenced by reduced corticospinal excitability. The purpose of this study was to investigate whether the integrity of the neuromotor axis of the vastus medialis is altered in subjects 2 weeks post-ACLR compared to uninjured control subjects...

Decreased voluntary activation contributes to quadriceps weakness following anterior cruciate ligament reconstruction (ACLR). Alterations in neural excitability are likely responsible for reductions in quadriceps voluntary activation, and may be due to specific alterations in intracortical inhibition and facilitation. Therefore, we sought to determine if intracortical inhibition (SICI) and intracortical facilitation (ICF) associate with quadriceps voluntary activation in individuals with ACLR. Twenty-seven participants with a primary, unilateral ACLR were enrolled in this study...

BACKGROUND: Altered quadriceps corticomotor excitability has been demonstrated following anterior cruciate ligament (ACL) injury and reconstruction, however only the single joint vasti muscles have been assessed. There is no current data on rectus femoris corticomotor excitability following ACL injury, the biarticular quadriceps muscle also critical for force attenuation and locomotion. The purpose of this study was to examine rectus femoris corticomotor excitability, intracortical inhibition and cortical motor representation in individuals with and without an ACL injury...

CONTEXT: Neuromuscular dysfunction is common after anterior cruciate ligament reconstruction (ACL-R). However, little is known about quadriceps spinal-reflex and descending corticomotor excitability after ACL-R. Understanding the effects of ACL-R on spinal-reflex and corticomotor excitability will help elucidate the origins of neuromuscular dysfunction. OBJECTIVE: To determine whether spinal-reflex excitability and corticomotor excitability differed between the injured and uninjured limbs of patients with unilateral ACL-R and between these limbs and the matched limbs of healthy participants...

BACKGROUND: Disability is common in a proportion of patients after anterior cruciate ligament reconstruction (ACL-R). Neuromuscular quadriceps deficits are a hallmark impairment after ACL-R, yet the link between muscle function and disability is not understood. PURPOSES: To evaluate the ability of quadriceps strength and cortical excitability to predict self-reported disability in patients with ACL-R. METHODS: Fifteen participants with a history of ACL-R (11 female, 4 male; 172 ± 9...

CONTEXT: Central and peripheral muscle fatigue during exercise may exacerbate neuromuscular factors that increase risk for noncontact anterior cruciate ligament injury. OBJECTIVE: To compare lower extremity motor-evoked potentials (MEPs), muscle strength, and electromyography (EMG) activation after an exercise protocol. DESIGN: Pretest, posttest group comparison. SETTING: University laboratory. PARTICIPANTS: 34 healthy volunteers (17 female, age = 21...

In the present report, we investigated changes in corticomotor excitability associated with unilateral knee dysfunction secondary to anterior cruciate ligament (ACL) injury. Ten participants, each with a previous history of unilateral ACL injury (median time post-injury 22 months) and eight healthy controls underwent transcranial magnetic stimulation (TMS) to assess excitability of the lower limb motor representation. Resting motor thresholds (RMTs) and stimulus response curves were measured at rest, while amplitude of motor evoked potentials and silent period duration were measured during active contraction...