Low-Intensity Electrical Stimulation to Improve the Neurological Aspect of Weakness in Individuals with Chronic Anterior Cruciate Ligament Lesion

Abstract

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). Results. Before ES, the quadriceps VA in the ACL lesion legs of the ACL group was lower compared to the legs of the healthy control group (P<0.05). The MEP sizes in the ACL lesion legs and the healthy control were not significantly different. The ACL lesion legs showed lower SICI and higher ICF compared to the healthy control group (P<0.05). After ES, the quadriceps VA level increased and the SICI-ICF was modulated only in the ACL lesion legs (P<0.05) but not in the healthy controls. Conclusions. Low-intensity ES can normalize the modulation of intracortical inhibition and facilitation, thereby ameliorating the activation failure in individuals with ACL lesion.

Mechanism of Fatigue Induced by Different Cycling Paradigms With Equivalent Dosage

“…Before formal testing, subjects usually have several warm-up contractions. The interpolated twitch technique has proved to be valid and used in testing knee extensors of healthy (Huang et al, 2010), Parkinson's disease (Huang et al, 2017), multiple sclerosis (Chang et al, 2011), obstructive sleep apnea (Chien et al, 2010), and ACL injured individuals (Tang et al, 2020). The high ICC of VA also supported that the reliability was high ( Table 3).…”

“…The intensity was then adjusted to 120% of the maximum intensity, which was defined as supramaximal intensity. This intensity was used for testing VA and twitch force which represented central and peripheral components of force (Chang et al, 2011;Huang et al, 2017;Chuang et al, 2019;Tang et al, 2020). To monitor the potential co-contraction, surface electrodes of an electromyographic recorder (B&L Engineering, CA, United States) were positioned on the hamstring muscle with the ground electrode placed on the patella for monitoring by an oscilloscope.…”

Neurocognitive and Neurophysiological Functions Related to ACL Injury: A Framework for Neurocognitive Approaches in Rehabilitation and Return-to-Sports Tests

“…A total of 295 subjects (118 women) with ACL injuries in the age range of 16 to 27 years were included in studies. Thirteen studies 2 , 9 , 25 , 26 , 27 , 28 , 31 , 33 , 36 , 38 , 39 , 45 , 46 examined changes in athletes postinjury, whereas 3 of them 13 , 14 , 22 focused on changes preceding injury with a prospective design. The time course between injury or surgery and examination varied between 2 weeks and 70 months.…”

Effects of Lower Limb Cycling Training on Different Components of Force and Fatigue in Individuals With Parkinson’s Disease

“…During this test, the supramaximal electrical stimulation (200 μs duration with 120% of the maximum intensity) was applied under relax and during knee extensor MVCs to obtain the resting twitch ( T 1 ) and interpolated twitches ( T 2 ). The resting twitch represents the peripheral component of force whereas the interpolated twitch represents the force generated from spared motor units that failed to be activated by the CNS ( Huang et al, 2010 ; Chang et al, 2011 ; Huang et al, 2017 ; Chuang et al, 2019 ; Tang et al, 2020 ). The resting twitch was averaged from the twitch elicited before and after the MVC to avoid the variation caused by force potentiation.…”

“…After the warm-up contractions, participants performed three maximal voluntary contractions (MVCs), each sustained for 5 s. After the MVC test, the VA was evaluated by the interpolated twitch technique (ITT) (Figure 1A). During this test, the to be activated by the CNS (Huang et al, 2010;Chang et al, 2011;Huang et al, 2017;Chuang et al, 2019;Tang et al, 2020). The resting twitch was averaged from the twitch elicited before and after the MVC to avoid the variation caused by force potentiation.…”