The Voluntary Response Index in Electromyographic Study During Landing Test of the Patients With ACL Deficiency: A New Study Protocol

Abstract

Background:Daily Increased rate of anterior cruciate ligament (ACL) injuries in athletes calls for more investigation in these patients to differentiate copers from noncoper ACL-deficient (ACLD) knees as soon as possible.Objectives:The current study aims to introduce a new electromyographic protocol, named voluntary response index (VRI), that might help to categorize and differentiate patients with ACLD knee from others in the early stage.Materials and Methods:Thirty-four patients with ACLD knee were allocated into two equal groups, namely, coper and noncoper groups, based upon their ability to return to sport during the preceding six months. The patients with ACLD knee were asked to perform a jump on a force platform from a 75-cm distance.Results:The results were compared with 17 matched healthy participants. The electromyographic disposable electrodes were attached to the seven muscles of the lower extremity of the participants before performing the test. The outcome measures were the magnitude and similarity index of the VRI, time to stop, vertical ground reaction force, the displacement of the center of pressure’s (COP) path line length, and the participants’ Tegner, IKDC (International Knee Documentation Committee) as well as KOOS (Knee injury and Osteoarthritis Outcome Score) questionnaires scores. Using the appropriate statistical analysis, the electromyographic and force plate data were compared among the three groups. All efforts went into determining whether an association exists between the findings of each group and the participants’ functional questionnaires scores.Conclusions:The results of this study would be helpful in objectively differentiating the patients with ACLD knee into coper and noncoper groups to receive appropriate treatments before their return to the competitions.

Test-Retest Reliability of Surface Electromyographic Measurements in Athletes With Anterior Cruciate Ligament Reconstruction: A Voluntary Response Index Analysis

“…The VRI of sEMG data had also been used to examine changes in the movement pattern of the cervical muscle groups during head reposition in young adults with chronic neck pain, and it was found that patients with chronic neck pain exhibited altered EMG patterns during voluntary sagittal neck motions [11]. The examples from these studies and several others indicated that VRI analysis could show changes in the CNS motor output that occurred with rehabilitative interventions or disorder progression [9,[11][12][13]17].…”

“…Instead of examining individual muscle activity, it would be more beneficial to examine the activation pattern of all muscles engaged in the entire prototype of a task. In practical application, the magnitude and the similarity activities of all muscles engaged in voluntary movement are studied as a whole rather than studying each muscle individually [12,13].…”

“…The evidence about VRI is still under research. For example, Norouzi et al used VRI to classify and distinguish subjects with ACL deficiency in a primitive stage of injury [13].…”

Motor Control Changes after Innovative Aquatic Proprioceptive Training in Athletes with Anterior Cruciate Ligament Reconstruction: Voluntary Response Index Analysis

“…Due to the scarcity of evidence regarding the effects of proprioception training on VRI components in athletes with ACLR, especially in the aquatic environment, it was difficult to make a direct comparison with previous studies. However, many studies have investigated CNS motor output changes during the progression of certain disorders (13,(21)(22)(23)(24). For example, Cheng et al conducted a study to investigate cervical EMG responses during head tasks in patients with neck pain.…”

Reliability of Voluntary Response Index Analysis Using Surface Electromyography in Professional Football Players

“…Voluntary response index methodologies have been applied in diverse research areas, including incomplete spinal cord injuries (17,18), shoulder dysfunction (19), trunk muscle fatigue (20), anterior cruciate ligament (ACL) injury (21), and trunk muscle activity during variable weight lifting (22). A higher SI value indicates superior motor control in voluntary tasks.…”