scholarly journals Transcranial Direct Current Stimulation Enhances Muscle Strength of Non-dominant Knee in Healthy Young Males

2021 ◽  
Vol 12 ◽  
Author(s):  
Panpan Lu ◽  
Nicholas J. Hanson ◽  
Lin Wen ◽  
Feng Guo ◽  
Xiaoyu Tian
Keyword(s):  
Muscle Strength ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Knee Extensors ◽  
Mean Power ◽  
Root Mean Square Amplitude ◽  
Mean Power Frequency ◽  
Sham Stimulation ◽  
Direct Current Stimulation

Transcranial direct current stimulation (tDCS) has been applied in training and competition, but its effects on physical performance remain largely unknown. This study aimed to observe the effect of tDCS on muscular strength and knee activation. Nineteen healthy young men were subjected to 20 min of real stimulation (2 mA) and sham stimulation (0 mA) over the primary motor cortex (M1) bilaterally on different days. The maximal voluntary contraction (MVC) of the knee extensors and flexors, and surface electromyography (sEMG) of the rectus femoris (RF) and biceps femoris (BF) were recorded before, immediately after, and 30 min after stimulation. MVC, rate of force development (RFD), and sEMG activity were analyzed before and after each condition. MVC of the non-dominant leg extensor and flexor was significantly higher immediately after real stimulation and 30 min after stimulation than before, and MVC of the non-dominant leg flexor was significantly higher 30 min after real stimulation than that after sham stimulation (P < 0.05). The RFD of the non-dominant leg extensor and flexor immediately after real stimulation was significantly higher than before stimulation, and the RFD of the non-dominant leg extensor immediately after real stimulation and 30 min after stimulation was significantly higher than that of sham stimulation (P < 0.05). EMG analysis showed the root mean square amplitude and mean power frequency (MPF) of the non-dominant BF and RF were significantly higher immediately after real stimulation and 30 min after stimulation than before stimulation, and the MPF of the non-dominant BF EMG was significantly higher 30 min after real stimulation than that after sham stimulation (P < 0.05). Bilateral tDCS of the M1 can significantly improve the muscle strength and explosive force of the non-dominant knee extensor and flexor, which might result from increased recruitment of motor units. This effect can last until 30 min after stimulation, but there is no significant effect on the dominant knee.

scholarly journals Transcranial Direct Current Stimulation Enhances Muscle Strength of Non-dominant Knee in Healthy Young Males

2021 ◽  
Author(s):  
PanPan Lu ◽  
Nicholas J. Hanson ◽  
Lin Wen ◽  
Feng Guo
Keyword(s):  
Muscle Strength ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Knee Extensors ◽  
Mean Power ◽  
Root Mean Square Amplitude ◽  
Young Males ◽  
Sham Stimulation ◽  
Direct Current Stimulation

Abstract Background: Transcranial direct current stimulation (tDCS) has been applied in training and competition, but its effects on physical performance remain largely unknown. The present study aimed to observe the effect of tDCS on muscular strength and activation of the knee in healthy subjects. Methods: Nineteen healthy young males were subjected to 20 min real stimulation (2 mA) and sham stimulation (0 mA) on different days. The maximal voluntary contraction (MVC) of knee extensors and flexors and surface electromyography (sEMG) of the rectus femoris (RF) and biceps femoris (BF) were recorded before, immediately after, and 30 min after stimulation. MVC, rate of force development (RFD), and sEMG activity were analyzed before and after each condition. Results: MVC of left leg extensor and flexor was significantly higher immediately after real stimulation and 30 min after stimulation than before, and MVC of left leg flexor was significantly higher 30 min after real stimulation than that after sham stimulation (P < 0.05). The RFD of left leg extensor and flexor immediately after real stimulation was significantly higher than before stimulation, and the RFD of left leg extensor immediately after real stimulation and 30 min after stimulation was significantly higher than that of sham stimulation (P < 0.05). EMG analysis showed the root mean square amplitude(RMS) and mean power frequency (MPF) of left BF and RF were significantly higher immediately after real stimulation and 30 min after stimulation than before stimulation, and the MPF of left BF EMG was significantly higher 30 min after real stimulation than that after sham stimulation (P < 0.05). Conclusions: Bilateral tDCS of the primary motor cortex can significantly improve the muscle strength and explosive force of the non-dominant knee extensor and flexor, which is manifested by the increase of the amount of motor units recruited during exercise. This effect can last until 30 min after stimulation, but there is no significant effect on the dominant knee.

scholarly journals Cerebellar Transcranial Direct Current Stimulation Improves Maximum Isometric Force Production during Isometric Barbell Squats

2020 ◽  
Vol 10 (4) ◽  
pp. 235 ◽  
Author(s):  
Rouven Kenville ◽  
Tom Maudrich ◽  
Dennis Maudrich ◽  
Arno Villringer ◽  
Patrick Ragert
Keyword(s):  
Muscle Strength ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Voluntary Contraction ◽  
Whole Body ◽  
Anodal Tdcs ◽  
Contraction Force ◽  
Body Movements ◽  
Direct Current Stimulation

Maximum voluntary contraction force (MVC) is an important predictor of athletic performance as well as physical fitness throughout life. Many everyday life activities involve multi-joint or whole-body movements that are determined in part through optimized muscle strength. Transcranial direct current stimulation (tDCS) has been reported to enhance muscle strength parameters in single-joint movements after its application to motor cortical areas, although tDCS effects on maximum isometric voluntary contraction force (MIVC) in compound movements remain to be investigated. Here, we tested whether anodal tDCS and/or sham stimulation over primary motor cortex (M1) and cerebellum (CB) improves MIVC during isometric barbell squats (iBS). Our results provide novel evidence that CB stimulation enhances MIVC during iBS. Although this indicates that parameters relating to muscle strength can be modulated through anodal tDCS of the cerebellum, our results serve as an initial reference point and need to be extended. Therefore, further studies are necessary to expand knowledge in this area of research through the inclusion of different tDCS paradigms, for example investigating dynamic barbell squats, as well as testing other whole-body movements.

scholarly journals Transcranial Direct Current Stimulation at 4 mA Induces Greater Leg Muscle Fatigability in Women Compared to Men

2020 ◽  
Vol 10 (4) ◽  
pp. 244 ◽  
Author(s):  
Craig D. Workman ◽  
Alexandra C. Fietsam ◽  
Thorsten Rudroff
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Fatigue Testing ◽  
Cortical Excitability ◽  
Knee Extensor ◽  
Knee Extensors ◽  
Double Blind ◽  
Direct Current Stimulation ◽  
Leg Muscle

Transcranial direct current stimulation (tDCS) has previously shown different cortical excitability and neuropsychological effects between women and men. However, the sex-specific effects of tDCS on leg muscle fatigability has not been investigated. The purpose of this study was to determine the effects of a single session of 2 mA and 4 mA primary motor cortex tDCS on leg muscle fatigability in healthy young men and women in a crossover design. Twenty participants (women = 10) completed isokinetic fatigue testing (40 maximal reps, 120°/s) of the knee extensors and flexors in conjunction with sham, 2 mA, and 4 mA tDCS in a double-blind, randomized design. The fatigue index from each condition was calculated. Women had significantly greater knee extensor fatigability in the 4 mA condition compared to men (57.8 ± 6.8% versus 44.1 ± 18.4%; p = 0.041, d = 0.99). This study provides additional evidence that responses to tDCS may be sex-specific and highlights the necessity of accounting and powering for sex differences in future investigations.

scholarly journals Transcranial direct current stimulation does not enhance cycling time-trial performance

2019 ◽  
Author(s):  
Justin Andre ◽  
Ann-Maree Vallence ◽  
Hakuei Fujiyama ◽  
Jeremiah Peiffer
Keyword(s):  
Direct Current ◽  
Power Output ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Time Trial ◽  
Cycling Performance ◽  
Time To Exhaustion ◽  
Mean Power ◽  
Mean Values ◽  
Direct Current Stimulation

Transcranial direct current stimulation (tDCS) to the primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) have separately been shown to increase performance during fixed-work time-to-exhaustion tasks. No studies have examined application of tDCS to these cortical sites in a single study or during self-paced tasks. Objectives: This study examined the influence of anodal-tDCS (A-tDCS) applied to M1 and DLPFC on cycling performance during a self-paced 16.1-km time trial (TT). Design: randomised cross-over design. Methods: Ten cyclists received 20 min of A-tDCS (1.5 mA) applied to M1, DLPFC or the visual cortex (V1; control), followed by a standardised 10-min warmup and a 16.1-km cycling TT. During the TT, heart rate and power output were continuously recorded and mean values for each quartile of the total TT duration were calculated. Ratings of perceive exertion (RPE) were collected at four, eight, 12 and 16.1 km. RESULTS: No differences were observed for the time-to-complete (p=0.07; BF10=1.24) or mean power output (p=0.09; BF10=1.11) during the 16.1-km TT between the M1 (1443.7±81.0 s and 274±44 W), DLPFC (1428.4±80.0 s and 280±39 W) and V1 (1434.8±9.6 s and 279±44 W) conditions. Both HR and RPE progressively increased from the first quartile of the TT with no differences observed between A-tDCS conditions. CONCLUSION: A-tDCS does not represents a viable method to decrease the physiological and perceptual stress during or enhance the performance of a self-paced cycling TT. Nevertheless, these findings should be viewed with respect to the inherent complexities between performance, fatigue and the brain.

scholarly journals Bilateral Transcranial Direct Current Stimulation Modulates Activation-Induced Regional Blood Flow Changes during Voluntary Movement

2011 ◽  
Vol 31 (10) ◽  
pp. 2086-2095 ◽  
Author(s):  
Caroline Paquette ◽  
Michael Sidel ◽  
Basia A Radinska ◽  
Jean-Paul Soucy ◽  
Alexander Thiel
Keyword(s):  
Blood Flow ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Regional Blood Flow ◽  
Active Movement ◽  
Sham Stimulation ◽  
Direct Current Stimulation

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that induces changes in cortical excitability: anodal stimulation increases while cathodal stimulation reduces excitability. Imaging studies performed after unilateral stimulation have shown conflicting results regarding the effects of tDCS on surrogate markers of neuronal activity. The aim of this study was to directly measure these effects on activation-induced changes in regional cerebral blood flow (⊿rBF) using positron emission tomography (PET) during bilateral tDCS. Nine healthy subjects underwent repeated rCBF measurements with 15O-water and PET during a simple motor task while receiving tDCS or sham stimulation over the primary motor cortex (M1). Motor evoked potentials (MEPs) were also assessed before and after real and sham stimulation. During tDCS with active movement, ⊿rBF in M1 was significantly lower on the cathodal than the anodal side when compared with sham stimulation. This decrease in ⊿rBF was accompanied by a decrease in MEP amplitude on the cathodal side. No effect was observed on resting or activated rCBF relative to sham stimulation. We thus conclude that it is the interaction of cathodal tDCS with activation-induced ⊿rBF rather than the effect on resting or activated rCBF itself which constitutes the physiological imaging correlate of tDCS.

scholarly journals Visual Cortex Transcranial Direct Current Stimulation for Proliferative Diabetic Retinopathy Patients: A Double-Blinded Randomized Exploratory Trial

2021 ◽  
Vol 11 (2) ◽  
pp. 270
Author(s):  
Angelito Braulio F. de Venecia ◽  
Shane M. Fresnoza
Keyword(s):  
Diabetic Retinopathy ◽  
Visual Cortex ◽  
Proliferative Diabetic Retinopathy ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Vision Loss ◽  
Sham Stimulation ◽  
Direct Current Stimulation ◽  
Residual Vision ◽  
Cathodal Tdcs

Proliferative diabetic retinopathy (PDR) is a severe complication of diabetes. PDR-related retinal hemorrhages often lead to severe vision loss. The main goals of management are to prevent visual impairment progression and improve residual vision. We explored the potential of transcranial direct current stimulation (tDCS) to enhance residual vision. tDCS applied to the primary visual cortex (V1) may improve visual input processing from PDR patients’ retinas. Eleven PDR patients received cathodal tDCS stimulation of V1 (1 mA for 10 min), and another eleven patients received sham stimulation (1 mA for 30 s). Visual acuity (logarithm of the minimum angle of resolution (LogMAR) scores) and number acuity (reaction times (RTs) and accuracy rates (ARs)) were measured before and immediately after stimulation. The LogMAR scores and the RTs of patients who received cathodal tDCS decreased significantly after stimulation. Cathodal tDCS has no significant effect on ARs. There were no significant changes in the LogMAR scores, RTs, and ARs of PDR patients who received sham stimulation. The results are compatible with our proposal that neuronal noise aggravates impaired visual function in PDR. The therapeutic effect indicates the potential of tDCS as a safe and effective vision rehabilitation tool for PDR patients.

scholarly journals Can Transcranial Direct Current Stimulation Enhance Functionality in Older Adults? A Systematic Review

2021 ◽  
Vol 10 (13) ◽  
pp. 2981
Author(s):  
Andrés Pino-Esteban ◽  
Álvaro Megía-García ◽  
David Martín-Caro Álvarez ◽  
Hector Beltran-Alacreu ◽  
Juan Avendaño-Coy ◽  
...  
Keyword(s):  
Systematic Review ◽  
Older Adults ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Randomized Clinical Trials ◽  
Scientific Evidence ◽  
Healthy Older Adults ◽  
Sham Stimulation ◽  
Direct Current Stimulation ◽  
Potential Benefits

Transcranial direct current stimulation (tDCS) is a non-invasive, easy to administer, well-tolerated, and safe technique capable of affecting brain excitability, both at the cortical and cerebellum levels. However, its effectiveness has not been sufficiently assessed in all population segments or clinical applications. This systematic review aimed at compiling and summarizing the currently available scientific evidence about the effect of tDCS on functionality in older adults over 60 years of age. A search of databases was conducted to find randomized clinical trials that applied tDCS versus sham stimulation in the above-mentioned population. No limits were established in terms of date of publication. A total of 237 trials were found, of which 24 met the inclusion criteria. Finally, nine studies were analyzed, including 260 healthy subjects with average age between 61.0 and 85.8 years. Seven of the nine included studies reported superior improvements in functionality variables following the application of tDCS compared to sham stimulation. Anodal tDCS applied over the motor cortex may be an effective technique for improving balance and posture control in healthy older adults. However, further high-quality randomized controlled trials are required to determine the most effective protocols and to clarify potential benefits for older adults.

Transcranial direct current stimulation: Adverse effects and the efficacy of a commonly utilised sham protocol

2017 ◽  
Vol 41 (S1) ◽  
pp. S374-S374 ◽  
Author(s):  
A. Kortteenniemi ◽  
T. Ali-Sisto ◽  
J. Wikgren ◽  
S. Lehto
Keyword(s):  
Adverse Effects ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Sham Group ◽  
Control Procedure ◽  
Current Standard ◽  
Sham Stimulation ◽  
Direct Current Stimulation ◽  
Cohen’S D ◽  
Cohen's D

IntroductionTranscranial direct current stimulation (tDCS) is a promising neuromodulation method that has, for example, been used to treat depression. Nevertheless, the adverse effects of tDCS and the validity of the current standard tDCS sham protocols have received limited attention.ObjectivesTo evaluate the extent and types of tDCS adverse effects and to assess the reliability of sham stimulation as a control procedure for tDCS in a double-blind setting.AimsTo compare adverse effects between tDCS and sham stimulation groups, and to determine how well the participants and the experimenter are able to distinguish tDCS from sham stimulation.MethodsA sample of healthy volunteers received a 20-minute session of either tDCS (n = 41; 2 mA) or sham stimulation (n = 41; ramp up 15 s, ramp down 15 s; no current in between). The anode was placed over F3 and cathode over F4. Both the participants and the experimenter reported immediate adverse effects and the perceived likelihood for the participant to receive tDCS. Analyses were conducted using the Mann–Whitney U-test.ResultsThe tDCS group reported more erythema compared with the sham group (P = 0.016, Cohen's D = 0.444). No other significant differences in adverse effects were observed. In the tDCS group, both the participants (P = 0.034, Cohen's D = 0.612) and the experimenter (P = 0.006, Cohen's D = 0.674) reported a higher perceived likelihood of the participant receiving tDCS than in the sham group.ConclusionstDCS has only modest adverse effects. Nevertheless, the current standard sham protocol appears insufficient.Disclosure of interestThe authors have not supplied their declaration of competing interest.

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