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Uehara L, Coelho DB, Baptista AF, Santana L, Moreira RJD, Zana Y, Malosá L, Lima T, Valentim G, Cardenas-Rojas A, Fregni F, Corrêa JCF, Corrêa FI. Does Transcranial Direct Current Stimulation reduce central and peripheral muscle fatigue in recreational runners? A triple-blind, sham-controlled, randomized, crossover clinical study. Braz J Phys Ther 2024; 28:101088. [PMID: 38936315 PMCID: PMC11260918 DOI: 10.1016/j.bjpt.2024.101088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 05/01/2024] [Accepted: 06/05/2024] [Indexed: 06/29/2024] Open
Abstract
BACKGROUND Runners seek health benefits and performance improvement. However, fatigue might be considered a limiting factor. Transcranial Direct Current Stimulation (tDCS) has been investigated to improve performance and reduce fatigue in athletes. While some studies showing that tDCS may improve a variety of physical measures, other studies failed to show any benefit. OBJECTIVE To evaluate the acute effects of tDCS on central and peripheral fatigue compared to a sham intervention in recreational runners. METHODS This is a triple-blind, controlled, crossover study of 30 recreational runners who were randomized to receive one of the two interventions, anodal or sham tDCS, after the fatigue protocol. The interventions were applied to the quadriceps muscle hotspot for 20 min. Peak torque, motor-evoked potential, and perceived exertion rate were assessed before and after the interventions, and blood lactate level was assessed before, during, and after the interventions. A generalized estimated equation was used to analyze the peak torque, motor-evoked potential, and blood lactate data, and the Wilcoxon test was used for perceived exertion rate data. RESULTS Our findings showed no difference between anodal tDCS and sham tDCS on peak torque, motor-evoked potential, blood lactate, and perceived exertion rate. CONCLUSION The tDCS protocol was not effective in improving performance and reducing fatigue compared to a sham control intervention. BRAZILIAN CLINICAL TRIALS REGISTRY RBR-8zpnxz.
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Affiliation(s)
- Laura Uehara
- Master's and Doctorate in Rehabilitation Sciences Program, Universidade Nove de Julho, São Paulo, SP, Brazil
| | | | | | - Lucas Santana
- Universidade Federal do ABC (UFABC), São Bernardo do Campo, SP, Brazil
| | | | - Yossi Zana
- Universidade Federal do ABC (UFABC), São Bernardo do Campo, SP, Brazil
| | - Luciana Malosá
- Master's and Doctorate in Rehabilitation Sciences Program, Universidade Nove de Julho, São Paulo, SP, Brazil
| | - Taiane Lima
- Master's and Doctorate in Rehabilitation Sciences Program, Universidade Nove de Julho, São Paulo, SP, Brazil
| | - Gabriela Valentim
- Master's and Doctorate in Rehabilitation Sciences Program, Universidade Nove de Julho, São Paulo, SP, Brazil
| | - Alejandra Cardenas-Rojas
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Felipe Fregni
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - João Carlos Ferrari Corrêa
- Master's and Doctorate in Rehabilitation Sciences Program, Universidade Nove de Julho, São Paulo, SP, Brazil
| | - Fernanda Ishida Corrêa
- Master's and Doctorate in Rehabilitation Sciences Program, Universidade Nove de Julho, São Paulo, SP, Brazil.
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Baharlouei H, Goosheh M, Moore M, Ramezani Ahmadi AH, Yassin M, Jaberzadeh S. The effect of transcranial direct current stimulation on rating of perceived exertion: A systematic review of the literature. Psychophysiology 2024; 61:e14520. [PMID: 38217074 DOI: 10.1111/psyp.14520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 12/07/2023] [Accepted: 12/08/2023] [Indexed: 01/14/2024]
Abstract
The rating of perceived exertion (RPE) is a widely used method for monitoring the load during training, as it provides insight into the subjective intensity of effort experienced during exercises. Considering the role of brain in monitoring and perception of the effort, several studies explored the effect of transcranial direct current stimulation (tDCS) on RPE in different populations. The aim of current study is to review the studies that investigated the effect of tDCS on RPE in three groups including healthy untrained people, physically active persons, and athletes. Nine databases were searched for papers assessing the effect of tDCS on RPE. The data from the included studies were extracted and methodological quality was examined using the risk of bias 2 (ROB2) tool. Thirty-three studies met the inclusion criteria. According to the meta-analysis, active a-tDCS significantly decreased the RPE compared to the sham stimulation. The a-tDCS could decrease the RPE when it was applied over M1 or DLPF. Regarding the measurement tool, Borg's scale 6-20 and OMNI scale could show an improvement in RPE scale. A-tDCS is a promising technique that can decrease the RPE. M1 and DLPFC are suggested as the target area of stimulation. From the tools that measure the RPE, Borg's RPE 6-20 and OMNI scale could better show the effect of a-tDCS.
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Affiliation(s)
- Hamzeh Baharlouei
- Musculoskeletal Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Meysam Goosheh
- Physical Therapy Department, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Maha Moore
- Physical Therapy Department, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Marzieh Yassin
- Iranian Center of Excellence in Physiotherapy, Rehabilitation Research Center, Department of Physiotherapy, School of Rehabilitation Sciences, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Shapour Jaberzadeh
- Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
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Yuan X, Zhong X, Wang C, Yang Y, Jiang C. Evaluation of Transcranial Direct Current Stimulation in Motor Function and Neural Rehabilitation. J ECT 2023; 39:235-241. [PMID: 36988514 DOI: 10.1097/yct.0000000000000918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
ABSTRACT Transcranial direct current stimulation (tDCS) is used in neuromodulation to regulate the excitability of the cerebral cortex and induce neural plasticity. It was initially used to rehabilitate patients with neurological diseases. However, with the increasing number of studies involving healthy individuals, this technology is currently used in the field of sports as well. The administration of tDCS to the cerebral cortex, especially over the primary motor cortex (M1), has been found to improve muscle strength, enhance endurance, and promote motor skills in humans. This study mainly summarizes the effects of tDCS on motor function, mainly involving motor promotion of tDCS in healthy athletes and nonathletes, and in patients diagnosed with neurological diseases. The tDCS is a promising and effective tool used to promote motor function by regulating cortical excitability. However, no consensus is available regarding individually appropriate models of tDCS.
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Affiliation(s)
| | | | | | - Yuan Yang
- College of Physical Education and Sports, Beijing Normal University, Beijing, China
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Zhan J, Yu C, Xiao S, Shen B, Zhang C, Zhou J, Fu W. Effects of high-definition transcranial direct current stimulation on the cortical-muscular functional coupling and muscular activities of ankle dorsi-plantarflexion under running-induced fatigue. Front Physiol 2023; 14:1263309. [PMID: 37841316 PMCID: PMC10570418 DOI: 10.3389/fphys.2023.1263309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 09/22/2023] [Indexed: 10/17/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) can improve motor control performance under fatigue. However, the influences of tDCS on factors contributing to motor control (e.g., cortical-muscular functional coupling, CMFC) are unclear. This double-blinded and randomized study examined the effects of high-definition tDCS (HD-tDCS) on muscular activities of dorsiflexors and plantarflexors and CMFC when performing ankle dorsi-plantarflexion under fatigue. Twenty-four male adults were randomly assigned to receive five sessions of 20-min HD-tDCS targeting primary motor cortex (M1) or sham stimulation. Three days before and 1 day after the intervention, participants completed ankle dorsi-plantarflexion under fatigue induced by prolonged running exercise. During the task, electroencephalography (EEG) of M1 (e.g., C1, Cz) and surface electromyography (sEMG) of several muscles (e.g., tibialis anterior [TA]) were recorded synchronously. The corticomuscular coherence (CMC), root mean square (RMS) of sEMG, blood lactate, and maximal voluntary isometric contraction (MVC) of ankle dorsiflexors and plantarflexors were obtained. Before stimulation, greater beta- and gamma-band CMC between M1 and TA were significantly associated with greater RMS of TA (r = 0.460-0.619, p = 0.001-0.024). The beta- and gamma-band CMC of C1-TA and Cz-TA, and RMS of TA and MVC torque of dorsiflexors were significantly higher after HD-tDCS than those at pre-intervention in the HD-tDCS group and post-intervention in the control group (p = 0.002-0.046). However, the HD-tDCS-induced changes in CMC and muscle activities were not significantly associated (r = 0.050-0.128, p = 0.693-0.878). HD-tDCS applied over M1 can enhance the muscular activities of ankle dorsiflexion under fatigue and related CMFC.
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Affiliation(s)
- Jianglong Zhan
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Changxiao Yu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Songlin Xiao
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Bin Shen
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Chuyi Zhang
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Junhong Zhou
- The Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Weijie Fu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Exercise and Health, Shanghai University of Sport, Shanghai, China
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Luo J, Fang C, Huang S, Wu J, Liu B, Yu J, Xiao W, Ren Z. Effects of single session transcranial direct current stimulation on aerobic performance and one arm pull-down explosive force of professional rock climbers. Front Physiol 2023; 14:1153900. [PMID: 37089430 PMCID: PMC10117960 DOI: 10.3389/fphys.2023.1153900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 03/28/2023] [Indexed: 04/25/2023] Open
Abstract
Objective: To explore the effects of single-session transcranial direct current stimulation (tDCS) on aerobic performance and explosive force in the one-arm pull-down of long-term trained rock climbers. Method: Twenty athletes (twelve male and eight female) from the Rock Climbing Team of Hunan province (Hunan, China) were selected for a randomized double-blind crossover study. After baseline tests, All subjects visited laboratories twice to randomly receive either sham or a-tDCS at a current intensity of 2 mA for 20 min. The two visits were more than 72 h apart. Immediately after each stimulation, subjects completed a 9-min 3-level-load aerobic test and a one-arm pull-down test. Results: Differences in the heart rate immediately after 9-min incremental aerobic exercises revealed no statistical significance between each group (p > 0.05). However, the decrease in heart rate per unit time after exercise after real stimulation was significantly better than before stimulation (p < 0.05), and no statistical significance was observed between after sham stimulation and before stimulation (p > 0.05). One-arm pull-down explosive force on both sides after real stimulation was improved by a-tDCS compared with before stimulation, but with no significant difference (p > 0.05). Real stimulation was significantly improved, compared with sham stimulation on the right side (p < 0.05). Conclusion: Single-session tDCS could potentially benefit sports performance in professional athletes.
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Affiliation(s)
- Jia Luo
- Key Laboratory of Kinesiology Evaluation and Recovery of General Administration of Sport of China, Sports Science Institute of Hunan, Changsha, China
| | - Caihua Fang
- Key Laboratory of Kinesiology Evaluation and Recovery of General Administration of Sport of China, Sports Science Institute of Hunan, Changsha, China
| | - Sen Huang
- Key Laboratory of Kinesiology Evaluation and Recovery of General Administration of Sport of China, Sports Science Institute of Hunan, Changsha, China
| | - Jinlong Wu
- College of Physical Education, Southwest University, Chongqing, China
| | - Bowen Liu
- College of Physical Education, Shenzhen University, Shenzhen, China
| | - Jingxuan Yu
- College of Physical Education, Shenzhen University, Shenzhen, China
| | - Wen Xiao
- College of Physical Education, Shenzhen University, Shenzhen, China
| | - Zhanbing Ren
- College of Physical Education, Shenzhen University, Shenzhen, China
- *Correspondence: Zhanbing Ren,
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Savoury RB, Kibele A, Power KE, Herat N, Alizadeh S, Behm DG. Reduced isometric knee extensor force following anodal transcranial direct current stimulation of the ipsilateral motor cortex. PLoS One 2023; 18:e0280129. [PMID: 36608054 PMCID: PMC9821721 DOI: 10.1371/journal.pone.0280129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 12/20/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The goal of this study was to determine if 10-min of anodal transcranial direct current stimulation (a-tDCS) to the motor cortex (M1) is capable of modulating quadriceps isometric maximal voluntary contraction (MVC) force or fatigue endurance contralateral or ipsilateral to the stimulation site. METHODS In a randomized, cross-over design, 16 (8 females) individuals underwent two sessions of a-tDCS and two sham tDCS (s-tDCS) sessions targeting the left M1 (all participants were right limb dominant), with testing of either the left (ipsilateral) or right (contralateral) quadriceps. Knee extensor (KE) MVC force was recorded prior to and following the a-tDCS and s-tDCS protocols. Additionally, a repetitive MVC fatiguing protocol (12 MVCs with work-rest ratio of 5:10-s) was completed following each tDCS protocol. RESULTS There was a significant interaction effect for stimulation condition x leg tested x time [F(1,60) = 7.156, p = 0.010, ηp2 = 0.11], which revealed a significant absolute KE MVC force reduction in the contralateral leg following s-tDCS (p < 0.001, d = 1.2) and in the ipsilateral leg following a-tDCS (p < 0.001, d = 1.09). A significant interaction effect for condition x leg tested [F(1,56) = 8.12, p = 0.006, ηp2 = 0.13], showed a significantly lower ipsilateral quadriceps (to tDCS) relative MVC force with a-tDCS, versus s-tDCS [t(15) = -3.07, p = 0.016, d = -0.77]. There was no significant difference between the relative contralateral quadriceps (to tDCS) MVC force for a-tDCS and s-tDCS. Although there was an overall significant [F(1,56) = 8.36, p < 0.001] 12.1% force decrease between the first and twelfth MVC repetitions, there were no significant main or interaction effects for fatigue index force. CONCLUSION a-tDCS may be ineffective at increasing maximal force or endurance and instead may be detrimental to quadriceps force production.
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Affiliation(s)
- Ryan B. Savoury
- School of Human Kinetic and Recreation, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada
| | - Armin Kibele
- Institute for Sport and Sport Science, University of Kassel, Kassel, Germany
| | - Kevin E. Power
- School of Human Kinetic and Recreation, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada
| | - Nehara Herat
- School of Human Kinetic and Recreation, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada
| | - Shahab Alizadeh
- School of Human Kinetic and Recreation, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada
| | - David G. Behm
- School of Human Kinetic and Recreation, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada
- * E-mail:
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Marinus N, Van Hoornweder S, Aarts M, Vanbilsen J, Hansen D, Meesen R. The influence of a single transcranial direct current stimulation session on physical fitness in healthy subjects: a systematic review. Exp Brain Res 2023; 241:31-47. [PMID: 36357590 PMCID: PMC9648891 DOI: 10.1007/s00221-022-06494-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 10/20/2022] [Indexed: 11/12/2022]
Abstract
Physical fitness is of indisputable importance for both health, and sports. Currently, the brain is being increasingly recognized as a contributor to physical fitness. Hereby, transcranial direct current stimulation (tDCS), as an ergogenic aid, has gained scientific interest. The current PRISMA-adherent review aimed to examine the effect of tDCS on the three core components of physical fitness: muscle strength, -endurance and cardiopulmonary endurance. Randomized controlled- or cross-over trials evaluating the effect of a single tDCS session (vs. sham) in healthy individuals were included. Hereby, a wide array of tDCS-related factors (e.g., tDCS montage and dose) was taken into account. Thirty-five studies (540 participants) were included. Between-study heterogeneity in factors such as age, activity level, tDCS protocol, and outcome measures was large. The capacity of tDCS to improve physical fitness varied substantially across studies. Nevertheless, muscle endurance was most susceptible to improvements following anodal tDCS (AtDCS), with 69% of studies (n = 11) investigating this core component of physical fitness reporting positive effects. The primary motor cortex and dorsolateral prefrontal cortex were targeted the most, with positive results being reported on muscle and cardiopulmonary endurance. Finally, online tDCS seemed most beneficial, and no clear relationship between tDCS and dose-related parameters seemed present. These findings can contribute to optimizing tDCS interventions during the rehabilitation of patients with a variety of (chronic) diseases such as cardiovascular disease. Therefore, future studies should focus on further unraveling the potential of AtDCS on physical fitness and, more specifically, muscle endurance in both healthy subjects and patients suffering from (chronic) diseases. This study was registered in Prospero with the registration number CRD42021258529. "To enable PROSPERO to focus on COVID-19 registrations during the 2020 pandemic, this registration record was automatically published exactly as submitted. The PROSPERO team has not checked eligibility".
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Affiliation(s)
- Nastasia Marinus
- Rehabilitation Research Center, Faculty of Rehabilitation Sciences, Hasselt University, Agoralaan Building A 3590, Diepenbeek, Belgium. .,Biomedical Research Center, Hasselt University, Diepenbeek, Belgium.
| | - Sybren Van Hoornweder
- Rehabilitation Research Center, Faculty of Rehabilitation Sciences, Hasselt University, Agoralaan Building A 3590, Diepenbeek, Belgium
| | - Marthe Aarts
- Rehabilitation Research Center, Faculty of Rehabilitation Sciences, Hasselt University, Agoralaan Building A 3590, Diepenbeek, Belgium
| | - Jessie Vanbilsen
- Rehabilitation Research Center, Faculty of Rehabilitation Sciences, Hasselt University, Agoralaan Building A 3590, Diepenbeek, Belgium
| | - Dominique Hansen
- Rehabilitation Research Center, Faculty of Rehabilitation Sciences, Hasselt University, Agoralaan Building A 3590, Diepenbeek, Belgium.,Biomedical Research Center, Hasselt University, Diepenbeek, Belgium.,Heart Centre Hasselt, Jessa Hospital, Hasselt, Belgium
| | - Raf Meesen
- Rehabilitation Research Center, Faculty of Rehabilitation Sciences, Hasselt University, Agoralaan Building A 3590, Diepenbeek, Belgium.,Movement Control and Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, Louvain, Belgium
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Transcranial direct current stimulation influences repetitive bimanual force control and interlimb force coordination. Exp Brain Res 2023; 241:313-323. [PMID: 36512062 DOI: 10.1007/s00221-022-06526-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 12/06/2022] [Indexed: 12/15/2022]
Abstract
This study aimed to investigate the potential effect of bilateral transcranial direct current stimulation (tDCS) on repetitive bimanual force control and force coordination in healthy young adults. In this sham-controlled crossover study, 18 right-handed young adults were enrolled. Repetitive bimanual handgrip force control trials were performed by the participants at 40% of maximum voluntary contraction until task failure. We randomly provided bilateral active and sham tDCS to the primary motor cortex (M1) of each participant before conducting the repetitive bimanual force control task. We quantified the number of successful trials to assess the ability to maintain bimanual force control across multiple trials. Moreover, we estimated bimanual force control and force coordination by quantifying force accuracy, variability, regularity, and correlation coefficient in maximal and adjusted successful trials. Force asymmetry was calculated to examine potential changes in motor dependency on each hand during the task. Bilateral tDCS significantly increased the number of successful trials compared with sham tDCS. The adjusted successful trial revealed that participants who received bilateral tDCS maintained better bimanual force control and coordination, as indicated by decreased force variability and regularity as well as more negative correlation coefficient values in comparison with sham condition. Moreover, participants who received bilateral tDCS produced more force from the dominant hand than from the nondominant hand in both maximal and adjusted successful trials. These findings suggest that bilateral tDCS on M1 successfully maintains bimanual force control with better force coordination by modulating motor dependency.
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Garcia-Sillero M, Chulvi-Medrano I, Maroto-Izquierdo S, Bonilla DA, Vargas-Molina S, Benítez-Porres J. Effects of Preceding Transcranial Direct Current Stimulation on Movement Velocity and EMG Signal during the Back Squat Exercise. J Clin Med 2022; 11:jcm11175220. [PMID: 36079150 PMCID: PMC9457333 DOI: 10.3390/jcm11175220] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/26/2022] [Accepted: 08/31/2022] [Indexed: 11/16/2022] Open
Abstract
This study aimed to evaluate the effects of preceding anodal transcranial direct stimulation (a-tDCS) over the dorsolateral prefrontal cortex (DLPFC) during the back squat exercise on movement velocity and surface electromyographic (sEMG) activity. Thirteen healthy, well-trained, male firefighters (34.72 ± 3.33 years; 178 ± 7.61 cm; 76.85 ± 11.21 kg; 26.8 ± 4.2 kg·m−2; back squat 1-repetition maximum 141.5 ± 16.3 kg) completed this randomised double-blinded sham-controlled crossover study. After familiarisation and basal measurements, participants attended the laboratory on two occasions separated by 72 h to receive either Sham or a-tDCS (current intensity of 2 mA for 20 min). Immediately after stimulation, participants completed three sets of 12 repetitions (70% of 1-RM) with three minutes of recovery between sets monitored with a linear position transducer. The sEMG of the rectus femoris (RF) and vastus lateralis (VL) of both legs were recorded. No significant differences were observed between a-tDCS and Sham interventions on mean concentric velocity at any set (p > 0.05). Velocity loss and effort index were significantly higher (p < 0.05) in set 3 compared to set 1 only in the a-tDCS group. The right-leg RM and right-leg VL elicited the greatest muscle activation during set 1 after a-tDCS and Sham, respectively (p < 0.05). Our results revealed that a-tDCS over the DLPFC might impact movement velocity or fatigue tolerance in well-trained individuals. Notwithstanding, significant differences in dominant-leg muscle activity were found both in a-tDCS and Sham.
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Affiliation(s)
- Manuel Garcia-Sillero
- Faculty of Sport Sciences, EADE-University of Wales Trinity Saint David, 29018 Málaga, Spain
- Correspondence:
| | - Iván Chulvi-Medrano
- Sport Performance and Physical Fitness Research Group (UIRFIDE), Department of Physical and Sports Education, University of Valencia, 46010 Valencia, Spain
| | - Sergio Maroto-Izquierdo
- Department of Health Sciences, European University Miguel de Cervantes (UEMC), 47012 Valladolid, Spain
| | - Diego A. Bonilla
- Research Division, Dynamical Business & Science Society—DBSS International SAS, Bogotá 110311, Colombia
- Research Group in Physical Activity, Sports and Health Sciences (GICAFS), Universidad de Córdoba, Montería 230002, Colombia
- Sport Genomics Research Group, Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain
| | - Salvador Vargas-Molina
- Faculty of Sport Sciences, EADE-University of Wales Trinity Saint David, 29018 Málaga, Spain
- Physical Education and Sport, Faculty of Medicine, University of Málaga, 29016 Málaga, Spain
| | - Javier Benítez-Porres
- Physical Education and Sport, Faculty of Medicine, University of Málaga, 29016 Málaga, Spain
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Alix-Fages C, Garcia-Ramos A, Romero-Arenas S, Nadal GC, Jerez-Martínez A, Colomer-Poveda D, Márquez G. Transcranial Direct Current Stimulation Does Not Affect Sprint Performance or the Horizontal Force-Velocity Profile. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2022; 93:650-658. [PMID: 34735312 DOI: 10.1080/02701367.2021.1893260] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 02/10/2021] [Indexed: 06/13/2023]
Abstract
Purpose: The aim of this study was to explore the effects of transcranial direct current stimulation (tDCS) on sprint performance and the horizontal force-velocity (F-v) profile. Method: Thirty-two healthy subjects (25 men and 7 women; age = 21.8 ± 2.4 years) completed three sessions separated by 1 week following a double-blinded crossover design. Each session consisted of two maximal sprints of 30 meters that were performed after applying ANODAL, CATHODAL or SHAM tDCS over the left dorsolateral prefrontal cortex (DLPFC) for 15 minutes at 2 mA. The 30-m time and the horizontal F-v profile variables (theoretical maximal force [F0], theoretical maximal velocity, Fv slope, maximal power [Pmax], decrease in the ratio of horizontal-to-resultant force, and maximal ratio of horizontal-to-resultant force) were compared between the tDCS conditions. Results: No significant differences between the tDCS conditions were observed for any variable (p range = 0.061 to 0.842). The magnitude of the differences was negligible for most of the comparisons (effect size [ES] < 0.20) with the only exception of Pmax and F0 which were greater for the ANODAL compared to the SHAM condition (both ES = 0.20). Conclusions: The application of tDCS over the DLPFC is not effective to increase non-fatigued sprint performance.
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Wu Q, Fang G, Zhao J, Liu J. Effect of Transcranial Pulsed Current Stimulation on Fatigue Delay after Medium-Intensity Training. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19127042. [PMID: 35742289 PMCID: PMC9222574 DOI: 10.3390/ijerph19127042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/02/2022] [Accepted: 06/07/2022] [Indexed: 02/04/2023]
Abstract
The purpose of this study was to investigate the effect of transcranial pulsed current stimulation (tPCS) on fatigue delay after medium-intensity training. Materials and Methods: Ninety healthy college athletes were randomly divided into an experimental group (n = 45) and control group (n = 45). The experimental group received medium-intensity training for a week. After each training, the experimental group received true stimulation of tPCS (continuous 15 min 1.5 mA current intensity stimulation). The control group received sham stimulation. The physiological and biochemical indicators of participants were tested before and after the experiment, and finally 30 participants in each group were included for data analysis. Results: In the experimental group, creatine kinase (CK), cortisol (C), time-domain heart rate variability indices root mean square of the successive differences (RMSSD), standard deviation of normal R-R intervals (SDNN), and frequency domain indicator low frequency (LF) all increased slowly after the intervention. Among these, CK, C, and SDNN values were significantly lower than those in the control group (p < 0.05). Testosterone (T), T/C, and heart rate variability frequency domain indicator high frequency (HF) in the experimental group decreased slowly after the intervention, and the HF value was significantly lower than that in the control group (p < 0.05). The changes in all of the indicators in the experimental group were smaller than those in the control group. Conclusion: The application of tPCS after medium-intensity training enhanced the adaptability to training and had a significant effect on the maintenance of physiological state. The application of tPCS can significantly promote the recovery of autonomic nervous system function, enhance the regulation of parasympathetic nerves, and delay the occurrence of fatigue.
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Affiliation(s)
- Qingchang Wu
- College of Sports Science, Nantong University, Nantong 226019, China;
| | - Guoliang Fang
- China Institute of Sport Science, Beijing 100061, China; (G.F.); (J.Z.)
| | - Jiexiu Zhao
- China Institute of Sport Science, Beijing 100061, China; (G.F.); (J.Z.)
| | - Jian Liu
- College of Sports Science, Nantong University, Nantong 226019, China;
- Correspondence:
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12
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Schmaußer M, Hoffmann S, Raab M, Laborde S. The effects of noninvasive brain stimulation on heart rate and heart rate variability: A systematic review and meta-analysis. J Neurosci Res 2022; 100:1664-1694. [PMID: 35582757 DOI: 10.1002/jnr.25062] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/25/2022] [Accepted: 04/30/2022] [Indexed: 12/30/2022]
Abstract
Noninvasive brain stimulation (NIBS) techniques such as transcranial magnetic stimulation and transcranial direct current stimulation are widely used to test the involvement of specific cortical regions in various domains such as cognition and emotion. Despite the capability of stimulation techniques to test causal directions, this approach has been only sparsely used to examine the cortical regulation of autonomic nervous system (ANS) functions such as heart rate (HR) and heart rate variability (HRV) and to test current models in this regard. In this preregistered (PROSPERO) systematic review and meta-analysis, we aimed to investigate, based on meta-regression, whether NIBS represents an effective method for modulating HR and HRV measures, and to evaluate whether the ANS is modulated by cortical mechanisms affected by NIBS. Here we have adhered to the PRISMA guidelines. In a series of four meta-analyses, a total of 131 effect sizes from 35 sham-controlled trials were analyzed using robust variance estimation random-effects meta-regression technique. NIBS was found to effectively modulate HR and HRV with small to medium effect sizes. Moderator analyses yielded significant differences in effects between stimulation of distinct cortical areas. Our results show that NIBS is a promising tool to investigate the cortical regulation of ANS, which may add to the existing brain imaging and animal study literature. Future research is needed to identify further factors modulating the size of effects. As many of the studies reviewed were found to be at high risk of bias, we recommend that methods to reduce potential risk of bias be used in the design and conduct of future studies.
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Affiliation(s)
| | - Sven Hoffmann
- Institute of Psychology, University of Hagen, Hagen, Germany
| | - Markus Raab
- Institute of Psychology, German Sport University, Cologne, Germany.,School of Applied Sciences, London South Bank University, London, UK
| | - Sylvain Laborde
- Institute of Psychology, German Sport University, Cologne, Germany.,UFR STAPS, EA 4260, Université de Caen Normandie, Caen, France
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13
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Liang Z, Zhou J, Jiao F, Gin T, Wang X, Liu Y, Lü J. Effect of Transcranial Direct Current Stimulation on Endurance Performance in Elite Female Rowers: A Pilot, Single-Blinded Study. Brain Sci 2022; 12:brainsci12050541. [PMID: 35624927 PMCID: PMC9139125 DOI: 10.3390/brainsci12050541] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/11/2022] [Accepted: 04/21/2022] [Indexed: 02/04/2023] Open
Abstract
Endurance, which is dependent at least partly upon the activation of the brain cortex, is important for performance in rowing. Transcranial direct current stimulation (tDCS) has shown benefits for endurance, but its effects on the endurance performance of elite rowing athletes are unknown, and are examined in this study. Eight elite female rowers completed 5 km of rowing on an ergometer following stimulation of the tDCS and sham over motor cortices. Each session lasted 20 min and the current was set at 2.2 mA. Time, 500 m/split, power, time corresponding to 500 m (TC500) and power corresponding to 500 m (PC500) were recorded continuously throughout the tests. No significant differences in time, 500 m/split and power were observed between baseline, tDCS and sham. Compared to the sham, tDCS induced a percentage reduction in TC500 from baseline to 2500 m and 4000 m, and a percentage increase in PC500 from baseline to 500 m, 1000 m, 1500 m, 2000 m, 2500 m, 4000 m, 4500 m and 5000 m. One-session tDCS did not have significant benefits for rowing endurance performance in elite professional rowers, and had only marginally greater efficacy compared to sham. These findings offer knowledge helpful to the design of future studies exploring the effects of tDCS on the endurance performance of elite rowers.
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Affiliation(s)
- Zhiqiang Liang
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China; (Z.L.); (F.J.); (X.W.); (J.L.)
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai 200438, China
| | - Junhong Zhou
- Harvard Medical School, Harvard University, Boston, MA 02131, USA;
- The Hinda and Arthur Marcus Institute for Aging Research, Hebrew Senior Life, Roslindale, MA 02131, USA
| | - Fujia Jiao
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China; (Z.L.); (F.J.); (X.W.); (J.L.)
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai 200438, China
| | - Trenton Gin
- College of Art and Science, Cornell University, New York, NY 14850, USA;
| | - Xi Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China; (Z.L.); (F.J.); (X.W.); (J.L.)
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai 200438, China
| | - Yu Liu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai 200438, China
- Correspondence: ; Tel.: +86-021-66507356
| | - Jiaojiao Lü
- School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China; (Z.L.); (F.J.); (X.W.); (J.L.)
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai 200438, China
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Wang L, Wang C, Yang H, Shao Q, Niu W, Yang Y, Zheng F. Halo Sport Transcranial Direct Current Stimulation Improved Muscular Endurance Performance and Neuromuscular Efficiency During an Isometric Submaximal Fatiguing Elbow Flexion Task. Front Hum Neurosci 2022; 16:758891. [PMID: 35250511 PMCID: PMC8891483 DOI: 10.3389/fnhum.2022.758891] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 01/20/2022] [Indexed: 12/21/2022] Open
Abstract
The present study examined the effects of transcranial direct current stimulation (tDCS) using Halo Sport on the time to exhaustion (TTE) in relation with muscle activities and corticomuscular coupling of agonist and antagonist muscles during a sustained isometric fatiguing contraction performed with the elbow flexors. Twenty healthy male college students were randomly assigned to tDCS group and control group. The two group participants performed two experimental sessions which consisted of pre-fatigue isometric maximal voluntary contraction (MVC), sustained submaximal voluntary contractions (30% maximal torque) performed to exhaustion, and post-fatigue MVC with the right elbow flexor muscles. Sham stimulation (90 s) and tDCS (20 min) were applied for control and tDCS group participants 20 min prior to the second session test, respectively. MVC strength in pre- and post-fatigue test, TTE, electroencephalogram (EEG), and electromyography (EMG) of biceps brachii (BB) and triceps brachii (TB) were recorded during the tests. It was found that tDCS using the Halo Sport device significantly increased TTE and thus improved muscular endurance performance. The improvement may be partly related to the improvement of neuromuscular efficiency as reflected by decrease of antagonistic muscle coactivation activities, which may be related to cortical originated central processing mechanism of neuromuscular activities.
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Affiliation(s)
- Lejun Wang
- Sport and Health Research Center, Physical Education Department, Tongji University, Shanghai, China
| | - Ce Wang
- Sport and Health Research Center, Physical Education Department, Tongji University, Shanghai, China
| | - Hua Yang
- Sport and Health Research Center, Physical Education Department, Tongji University, Shanghai, China
| | - Qineng Shao
- Sport and Health Research Center, Physical Education Department, Tongji University, Shanghai, China
| | - Wenxin Niu
- Shanghai Yangzhi Rehabilitation Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Ye Yang
- College of Physical Education and Health Science, Yibin University, Sichuan, China
- *Correspondence: Ye Yang,
| | - Fanhui Zheng
- Shanghai Research Institute of Sport Science, Shanghai, China
- Fanhui Zheng,
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15
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Effectiveness of a 12-Week Multi-Component Training Program with and without Transcranial Direct-Current Stimulation (tDCS) on Balance to Prevent Falls in Community-Dwelling Older Adults: A Study Protocol. BIOLOGY 2022; 11:biology11020290. [PMID: 35205156 PMCID: PMC8868777 DOI: 10.3390/biology11020290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 11/26/2022]
Abstract
Simple Summary Falls in community-dwelling individuals aged over 65 produce serious outcomes such as disability, morbidity, and mortality, as well as high healthcare costs. This research aims to assess whether a multicomponent training programme (McTP) combined with a transcranial direct-current stimulation device (tDCS), Halo Sport, produces improvements in balance and other gait-related parameters. Therefore, this study intends to test the efficacy of adding a tCDS device to an McTP in order to prevent falls in older adults by testing the safety, efficacy, and effectiveness of its implementation in care resources for the elderly. Abstract Approximately one-third of elderly people aged over 65 who live in the community experience falls every year, with the proportion increasing with age. Moreover, of those who fall, about half will fall again in the following year. The falls’ consequences include disability, morbidity, and mortality. Although many external and internal factors lead to falls, balance issues play a major role. Multi-component training programs (McTP) usually combine balance, strength, cardiorespiratory fitness, and flexibility, with studies reporting multiple benefits on the health-related quality of life. Halo Sport is a transcranial direct-current stimulation (tDCS) device with promising results for gait performance. This study aims to test the effectiveness of the introduction of a tCDS device to an McTP to prevent falls in older adults. The sample will consist of 46 people aged 65 years or older, randomly assigned to experimental (n = 23) and control (n = 23) groups. The experimental group will perform the McTP while wearing tDCS, and the control group will perform McTP without the device, for three sessions per week over 12 weeks. The main measures will provide information about (1) safety, (2) applicability, (3) balance, (4) number of falls, (5) physical fitness, (6) risk of falling, (7) fear of falling, (8) health-related quality of life, and (9) cognitive function. Among the practical implications of this program, it is intended to provide data on its safety and effectiveness to be implemented in different resources as a tool for the prevention of falls.
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16
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Chinzara T, Buckingham G, Harris D. Transcranial direct current stimulation (tDCS) and sporting performance: A systematic review and meta-analysis of tDCS effects on physical endurance, muscular strength, and visuomotor skills. Eur J Neurosci 2021; 55:468-486. [PMID: 34904303 DOI: 10.1111/ejn.15540] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/01/2021] [Accepted: 11/08/2021] [Indexed: 11/28/2022]
Abstract
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has been linked with a range of physiological and cognitive enhancements relevant to sporting performance. As a number of positive and null findings have been reported in the literature, the present meta-analysis sought to synthesise results across endurance, strength, and visuomotor skill domains to investigate if tDCS improves any aspect of sporting performance. Online database searches in August 2020 identified 43 full-text studies which examined the acute effects of tDCS compared to sham/control conditions on physical endurance, muscular strength, and visuomotor skills in healthy adults. Meta-analysis indicated a small overall effect favouring tDCS stimulation over sham/control (standardized mean difference (SMD)=0.25, CI95%[0.14;0.36]). Effects on strength (SMD=0.31, CI95%[0.10;0.51]) and visuomotor (SMD=0.29, CI95%[0.00;0.57]) tasks were larger than endurance performance (SMD=0.18, CI95%[0.00;0.37]). Meta-regressions indicated effect sizes were not related to stimulation parameters, but other factors such as genetics, gender, and experience may modulate tDCS effects. The results suggest tDCS has the potential to be used as an ergogenic aid in conjunction with a specified training regime.
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Affiliation(s)
- Trish Chinzara
- Department of Sport and Health Science, University of Exeter, UK.,Goldsmiths University of London, London, UK
| | - Gavin Buckingham
- Department of Sport and Health Science, University of Exeter, UK
| | - David Harris
- Department of Sport and Health Science, University of Exeter, UK
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17
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Garner CT, Dykstra RM, Hanson NJ, Miller MG. Transcranial Direct Current Stimulation with the Halo Sport Does Not Improve Performance on a Three-Minute, High Intensity Cycling Test. INTERNATIONAL JOURNAL OF EXERCISE SCIENCE 2021; 14:962-970. [PMID: 34567362 PMCID: PMC8439699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Transcranial direct current stimulation (tDCS) uses a weak electrical current that is sent through the cerebral cortex. The Halo Sport headphones are a user-friendly form of tDCS that is implemented by many athletes purportedly to improve performance. The purpose of this study was to determine the effect of tDCS, using the Halo Sport, on performance variables associated with a high-intensity three-minute cycling test. Eighteen healthy, active individuals (ten men, eight women) volunteered for this study. The Halo Sport headphones were worn during a 20-minute warmup before completing a high-intensity three-minute cycling test. A sham treatment was used in addition to the experimental condition. Ratings of perceived exertion (RPE) were assessed every 30 seconds and electromyography (EMG) of the quadriceps muscle group was measured throughout testing. Two-way repeated measures ANOVAs were used to determine the effect of condition and time on mean RPE, heart rate (HR) and power; paired samples t-tests were also used to compare conditions. Mean HR was higher in the experimental condition (p = 0.038). Otherwise, there were no differences between conditions on any of the variables (mean RPE, cadence and speed, mean and peak HR, power, root mean square EMG). Despite the popularity of this new device, our findings do not support an ergogenic effect. However, further research is warranted.
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Affiliation(s)
- Collin T Garner
- Human Performance and Health Education, Western Michigan University, Kalamazoo, MI, USA
| | - Rachel M Dykstra
- Human Performance and Health Education, Western Michigan University, Kalamazoo, MI, USA
| | - Nicholas J Hanson
- Human Performance and Health Education, Western Michigan University, Kalamazoo, MI, USA
| | - Michael G Miller
- Human Performance and Health Education, Western Michigan University, Kalamazoo, MI, USA
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18
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Effects of Transcranial Direct Current Stimulation on Cycling Time Trial Performance and Prefrontal Cortex Activation. SCI 2021. [DOI: 10.3390/sci3030032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Background: Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low levels of a constant current via scalp electrodes to specifically targeted areas of the brain. The effects of tDCS on whole-body exercise performance has been of interest in recent literature. The purpose of the current investigation was to investigate if tDCS, administered via Halo Sport, influences time trial performance in trained cyclists, and if changes in exercise performance are associated with prefrontal cortex (PFC) activation and/or muscle oxygenation (SmO2). Methods: Twelve recreationally trained cyclists volunteered to participate in a crossover study design involving two 10-kilometer time trials following 20 min of tDCS or a sham condition. Results: t-tests showed there was no significant difference in performance (time to completion) or physiological measures (blood lactate (BL) concentration, heart rate (HR), SmO2, PFC oxygenation) between the Halo and sham conditions. Conclusions: These results indicate that the application of tDCS via Halo Sport does not induce changes in exercise performance or related physiological parameters during a 10-kilometer cycling time trial.
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Acute effect of high-definition and conventional tDCS on exercise performance and psychophysiological responses in endurance athletes: a randomized controlled trial. Sci Rep 2021; 11:13911. [PMID: 34230503 PMCID: PMC8260713 DOI: 10.1038/s41598-021-92670-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 06/03/2021] [Indexed: 02/06/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) has been used aiming to boost exercise performance and inconsistent findings have been reported. One possible explanation is related to the limitations of the so-called "conventional" tDCS, which uses large rectangular electrodes, resulting in a diffuse electric field. A new tDCS technique called high-definition tDCS (HD-tDCS) has been recently developed. HD-tDCS uses small ring electrodes and produces improved focality and greater magnitude of its aftereffects. This study tested whether HD-tDCS would improve exercise performance to a greater extent than conventional tDCS. Twelve endurance athletes (29.4 ± 7.3 years; 60.15 ± 5.09 ml kg-1 min-1) were enrolled in this single-center, randomized, crossover, and sham-controlled trial. To test reliability, participants performed two time to exhaustion (TTE) tests (control conditions) on a cycle simulator with 80% of peak power until volitional exhaustion. Next, they randomly received HD-tDCS (2.4 mA), conventional (2.0 mA), or active sham tDCS (2.0 mA) over the motor cortex for 20-min before performing the TTE test. TTE, heart rate (HR), associative thoughts, peripheral (lower limbs), and whole-body ratings of perceived exertion (RPE) were recorded every minute. Outcome measures were reliable. There was no difference in TTE between HD-tDCS (853.1 ± 288.6 s), simulated conventional (827.8 ± 278.7 s), sham (794.3 ± 271.2 s), or control conditions (TTE1 = 751.1 ± 261.6 s or TTE2 = 770.8 ± 250.6 s) [F(1.95; 21.4) = 1.537; P = 0.24; η2p = 0.123]. There was no effect on peripheral or whole-body RPE and associative thoughts (P > 0.05). No serious adverse effect was reported. A single session of neither HD-tDCS nor conventional tDCS changed exercise performance and psychophysiological responses in athletes, suggesting that a ceiling effect may exist.
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Chen CH, Chen YC, Jiang RS, Lo LY, Wang IL, Chiu CH. Transcranial Direct Current Stimulation Decreases the Decline of Speed during Repeated Sprinting in Basketball Athletes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18136967. [PMID: 34209833 PMCID: PMC8297176 DOI: 10.3390/ijerph18136967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/25/2021] [Accepted: 06/26/2021] [Indexed: 11/16/2022]
Abstract
The purpose of this study was to determine whether transcranial direct current stimulation (tDCS) can improve countermovement jump performance, fatigue index and alleviate the speed decline during repeated shuttle sprints in trained basketball players. Thirteen trained basketball players were divided into the tDCS trial and sham trial by the random crossover design. The tDCS trial was stimulated with 2-mA current in the M1 area in the middle of the top of the head for 20 min. For the sham trial, the current was turned off after 5 s, stopping the electrical stimulation. After warming up, the players underwent countermovement jump test, weighted countermovement jump test and then performed 40 × 15-m sprints with with a 1:4 exercise: rest ratio. The jump height, sprinting time, fatigue index, heart rate and rating of perceived exertion (RPE) were analyzed by paired-sample t-test, when significance was discovered by two-way repeated measures analysis of variance. The study results revealed that the tDCS trial significantly increase the countermovement jump performance (p = 0.04), decrease the sprinting time (p = 0.016), and had improved fatigue index during the sprinting process (p = 0.009). However, the heart rate and RPE during sprinting were nonsignificantly different between the trials. This study has identified that tDCS can decrease the speed decline, fatigue index during sprinting and increase countermovement jump performance without affecting heart rate or the rating of perceived exertion.
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Affiliation(s)
- Che-Hsiu Chen
- Department of Sport Performance, National Taiwan University of Sport, Taichung 404, Taiwan;
| | - Yu-Chun Chen
- Department of Physical Education, National Taiwan University of Sport, Taichung 404, Taiwan; (Y.-C.C.); (R.-S.J.)
| | - Ren-Shiang Jiang
- Department of Physical Education, National Taiwan University of Sport, Taichung 404, Taiwan; (Y.-C.C.); (R.-S.J.)
| | - Lok-Yin Lo
- Graduate Program in Department of Exercise Health Science, National Taiwan University of Sport, Taichung 404, Taiwan;
| | - I-Lin Wang
- College of Physical Education, Hubei Normal University, Huangshi 435002, China;
| | - Chih-Hui Chiu
- Graduate Program in Department of Exercise Health Science, National Taiwan University of Sport, Taichung 404, Taiwan;
- Correspondence: ; Tel.: +886-4-2221-3108 (ext. 3486)
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21
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Alix-Fages C, Romero-Arenas S, Calderón-Nadal G, Jerez-Martínez A, Pareja-Blanco F, Colomer-Poveda D, Márquez G, Garcia-Ramos A. Transcranial direct current stimulation and repeated sprint ability: No effect on sprint performance or ratings of perceived exertion. Eur J Sport Sci 2021; 22:569-578. [DOI: 10.1080/17461391.2021.1883124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Carlos Alix-Fages
- Department of Physical Education, Faculty of Sport Sciences and Physical Education, University of A Coruña, A Coruña, Spain
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain
| | - Salvador Romero-Arenas
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain
| | - Giancarlo Calderón-Nadal
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain
| | - Agustín Jerez-Martínez
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain
| | - Fernando Pareja-Blanco
- Physical Performance & Sports Research Center, Department of Sports and Computers Sciences, Universidad Pablo de Olavide, Seville, Spain
- Faculty of Sport Sciences, Department of Sports and Computers Sciences, Universidad Pablo de Olavide, Seville, Spain
| | - David Colomer-Poveda
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain
| | - Gonzalo Márquez
- Department of Physical Education, Faculty of Sport Sciences and Physical Education, University of A Coruña, A Coruña, Spain
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain
| | - Amador Garcia-Ramos
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
- Department of Sports Sciences and Physical Conditioning, Faculty of Education, Universidad Católica de la Santísima Concepción, Concepción, Chile
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22
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EFFECTS OF TRANSCRANIAL DIRECT CURRENT STIMULATION ON MUSCLE FATIGUE IN RECREATIONAL RUNNERS - RANDOMISED, SHAM-CONTROLLED, TRIPLE-BLIND, CROSS-OVER STUDY - PROTOCOL STUDY. Am J Phys Med Rehabil 2021; 101:279-283. [PMID: 33605575 DOI: 10.1097/phm.0000000000001721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Evaluate the effects of Transcranial Direct Current Stimulation (tDCS) on central and peripheral fatigue in recreational runners. METHODOLOGY A clinical randomized, sham-controlled, triple-blind, cross-over study. There will be 20 adult runners who will be randomized on the first day of the intervention to receive active or sham tDCS before fatigue protocol. After one week, the participants will receive the opposite therapy to the one that they received on the first day. Intervention: The tDCS, 2 mA, will be applied for 20 minutes over the motor cortex. The fatigue protocol will be performed after tDCS, in which the participant should perform concentric knee flexion/ extension contractions until reaching three contractions at only 50% of maximum voluntary contraction. Evaluations: Central fatigue will be evaluated with the motor evoked potential of the quadriceps muscle; peripheral fatigue with the peak torque (N.m) using an isokinetic dynamometer; the electrical activity of the quadriceps muscle using surface electromyography (Hz); blood lactate level (mmol/L); and the subjective perception of effort (Borg scale). All evaluations will be repeated pre and post the interventions. CONCLUSION This study will evaluate the effect of tDCS on fatigue in runners, possibly determining an application protocol for this population.
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Shyamali Kaushalya F, Romero-Arenas S, García-Ramos A, Colomer-Poveda D, Marquez G. Acute effects of transcranial direct current stimulation on cycling and running performance. A systematic review and meta-analysis. Eur J Sport Sci 2021; 22:113-125. [PMID: 33280514 DOI: 10.1080/17461391.2020.1856933] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Transcranial direct current stimulation (tDCS) has been proven to induce positive effects on athletic performance. The present study aimed to analyse the effect of anodal-tDCS on endurance (time to exhaustion [TTE] or endurance time trial [ETT]) and sprint performance during cycling and running tasks. We performed a systematic literature review in the databases Medline (via PubMed), SPORTDiscus and Science Direct. We included only randomised controlled trials conducted with healthy individuals in which an anodal-tDCS protocol was applied prior to cycling or running tests. The effect of anodal-tDCS (experimental condition) was compared against sham stimulation (control condition). A total of 15 interventions from 13 studies were included. The sub-group analysis revealed a positive effect of anodal-tDCS on TTE (standardised mean differences [SMD] = 0.37; 90% confidence interval [CI] = 0.13, 0.61; p = 0.01), but not on ETT (SMD = 0.00; 90% CI = -0.29, 0.30; p = 1.00) or sprint performance (SMD = 0.19; 90% CI = -0.23, 0.60; p = 0.46). The current meta-analysis suggests that the effect of anodal-tDCS on whole-body dynamic exercises (running and cycling) could be task dependent. Specifically, anodal-tDCS enhance running and cycling time to exhaustion performance during TTE tasks but not ETT or sprint tasks. The increase in cortical excitability induced by anodal-tDCS may lead to lower ratings of perceived exertion by reducing the input required to perform the physical task. Task should be taken into account, because it is probably influencing the result obtained by anodal-tDCS.
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Affiliation(s)
- Fernando Shyamali Kaushalya
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain
| | - Salvador Romero-Arenas
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain
| | - Amador García-Ramos
- Department of Sports Sciences and Physical Conditioning, Faculty of Education, Universidad Catolica de la Santisima Concepcion, Concepción, Chile.,Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | | | - Gonzalo Marquez
- Department of Physical Education and Sport, Faculty of Sport Sciences, Catholic University of Murcia (UCAM), Murcia, Spain.,Department of Physical Education, Faculty of Sciences of Sport and Physical Education, University of A Coruña, A Coruña, Spain
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Bilateral Dorsolateral Prefrontal Cortex High-Definition Transcranial Direct-Current Stimulation Improves Time-Trial Performance in Elite Cyclists. Int J Sports Physiol Perform 2020; 16:224-231. [PMID: 33276322 DOI: 10.1123/ijspp.2019-0910] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 03/19/2020] [Accepted: 03/22/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND The effects of anodal transcranial direct-current stimulation (tDCS) on endurance exercise performance are not yet fully understood. Different stimulated areas and low focality of classical tDCS technique may have led to discordant results. PURPOSE This study investigated the effect of a bilateral anodal high-definition tDCS (HD-tDCS) of the dorsolateral prefrontal cortex on the cycling time-trial (TT) performance and physiological and perceptual response at moderate intensity in elite cyclists. METHODS A total of 8 elite cyclists (maximal oxygen consumption: 72.2 [4.3] mL·min-1·kg-1) underwent in a double-blind, counterbalanced, and randomized order the experimental treatment (HD-tDCS) or control treatment (SHAM). After 20 minutes of receiving either HD-tDCS on the dorsolateral prefrontal cortex (F3 and F4) or SHAM stimulation, the participants completed a constant-load trial (CLT) at 75% of the second ventilatory threshold. Thereafter, they performed a simulated 15-km TT. The ratings of perceived exertion, heart rate, cadence, oxygen consumption, and respiratory exchange ratio were recorded during the CLT; the ratings of perceived exertion and heart rate were recorded during the TT. RESULTS The total time to complete the TT was 1.3% faster (HD-tDCS: 1212 [52] s vs SHAM: 1228 [56] s; P = .04) and associated with a higher heart rate (P < .001) and a tendency toward higher mean power output (P = .05). None of the physiological and perceptual variables measured during the CLT highlighted differences between the HD-tDCS and SHAM condition. CONCLUSIONS The findings suggest that bilateral HD-tDCS on the dorsolateral prefrontal cortex improves cycling TT performance without altering the physiological and perceptual response at moderate intensity, indicating that an upregulation of the prefrontal cortex could enhance endurance exercise performance.
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Codella R, Alongi R, Filipas L, Luzi L. Ergogenic Effects of Bihemispheric Transcranial Direct Current Stimulation on Fitness: a Randomized Cross-over Trial. Int J Sports Med 2020; 42:66-73. [PMID: 32781476 DOI: 10.1055/a-1198-8525] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Several types of routines and methods have been experimented to gain neuromuscular advantages, in terms of exercise performance, in athletes and fitness enthusiasts. The aim of the present study was to evaluate the impact of biemispheric transcranial direct current stimulation on physical fitness indicators of healthy, physically active, men. In a randomized, single-blinded, crossover fashion, seventeen subjects (age: 30.9 ± 6.5 years, BMI: 24.8±3.1 kg/m2) underwent either stimulation or sham, prior to: vertical jump, sit & reach, and endurance running tests. Mixed repeated measures anova revealed a large main effect of stimulation for any of the three physical fitness measures. Stimulation determined increases of lower limb power (+ 5%), sit & reach amplitude (+ 9%) and endurance running capacity (+ 12%) with respect to sham condition (0.16<ηp2 < 0.41; p<0.05). Ratings-of-perceived-exertion, recorded at the end of each test session, did not change across all performances. However, in the stimulated-endurance protocol, an average lower rate-of-perceived-exertion at iso-time was inferred. A portable transcranial direct current stimulation headset could be a valuable ergogenic resource for individuals seeking to improve physical fitness in daily life or in athletic training.
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Affiliation(s)
- Roberto Codella
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milano, Italy.,Department of Endocrinology, Nutrition and Metabolic Diseases, IRCCS MultiMedica, Milan, Italy
| | - Rosario Alongi
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milano, Italy
| | - Luca Filipas
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milano, Italy.,Department of Endocrinology, Nutrition and Metabolic Diseases, IRCCS MultiMedica, Milan, Italy
| | - Livio Luzi
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milano, Italy.,Department of Endocrinology, Nutrition and Metabolic Diseases, IRCCS MultiMedica, Milan, Italy
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Seidel-Marzi O, Ragert P. Neurodiagnostics in Sports: Investigating the Athlete's Brain to Augment Performance and Sport-Specific Skills. Front Hum Neurosci 2020; 14:133. [PMID: 32327988 PMCID: PMC7160821 DOI: 10.3389/fnhum.2020.00133] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/23/2020] [Indexed: 12/22/2022] Open
Abstract
Enhancing performance levels of athletes during training and competition is a desired goal in sports. Quantifying training success is typically accompanied by performance diagnostics including the assessment of sports-relevant behavioral and physiological parameters. Even though optimal brain processing is a key factor for augmented motor performance and skill learning, neurodiagnostics is typically not implemented in performance diagnostics of athletes. We propose, that neurodiagnostics via non-invasive brain imaging techniques such as functional near-infrared spectroscopy (fNIRS) will offer novel perspectives to quantify training-induced neuroplasticity and its relation to motor behavior. A better understanding of such a brain-behavior relationship during the execution of sport-specific movements might help to guide training processes and to optimize training outcomes. Furthermore, targeted non-invasive brain stimulation such as transcranial direct current stimulation (tDCS) might help to further enhance training outcomes by modulating brain areas that show training-induced neuroplasticity. However, we strongly suggest that ethical aspects in the use of non-invasive brain stimulation during training and/or competition need to be addressed before neuromodulation can be considered as a performance enhancer in sports.
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Affiliation(s)
- Oliver Seidel-Marzi
- Institute for General Kinesiology and Exercise Science, Faculty of Sport Science, University of Leipzig, Leipzig, Germany.,Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Patrick Ragert
- Institute for General Kinesiology and Exercise Science, Faculty of Sport Science, University of Leipzig, Leipzig, Germany.,Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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Patel R, Ashcroft J, Patel A, Ashrafian H, Woods AJ, Singh H, Darzi A, Leff DR. The Impact of Transcranial Direct Current Stimulation on Upper-Limb Motor Performance in Healthy Adults: A Systematic Review and Meta-Analysis. Front Neurosci 2019; 13:1213. [PMID: 31803003 PMCID: PMC6873898 DOI: 10.3389/fnins.2019.01213] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/28/2019] [Indexed: 11/25/2022] Open
Abstract
Background: Transcranial direct current stimulation (tDCS) has previously been reported to improve facets of upper limb motor performance such as accuracy and strength. However, the magnitude of motor performance improvement has not been reviewed by contemporaneous systematic review or meta-analysis of sham vs. active tDCS. Objective: To systematically review and meta-analyse the existing evidence regarding the benefits of tDCS on upper limb motor performance in healthy adults. Methods: A systematic search was conducted to obtain relevant articles from three databases (MEDLINE, EMBASE, and PsycINFO) yielding 3,200 abstracts. Following independent assessment by two reviewers, a total of 86 articles were included for review, of which 37 were deemed suitable for meta-analysis. Results: Meta-analyses were performed for four outcome measures, namely: reaction time (RT), execution time (ET), time to task failure (TTF), and force. Further qualitative review was performed for accuracy and error. Statistically significant improvements in RT (effect size −0.01; 95% CI −0.02 to 0.001, p = 0.03) and ET (effect size −0.03; 95% CI −0.05 to −0.01, p = 0.017) were demonstrated compared to sham. In exercise tasks, increased force (effect size 0.10; 95% CI 0.08 to 0.13, p < 0.001) and a trend towards improved TTF was also observed. Conclusions: This meta-analysis provides evidence attesting to the impact of tDCS on upper limb motor performance in healthy adults. Improved performance is demonstrable in reaction time, task completion time, elbow flexion tasks and accuracy. Considerable heterogeneity exists amongst the literature, further confirming the need for a standardised approach to reporting tDCS studies.
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Affiliation(s)
- Ronak Patel
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - James Ashcroft
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Ashish Patel
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Hutan Ashrafian
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Adam J Woods
- Department of Clinical and Health Psychology, Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Harsimrat Singh
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Ara Darzi
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Daniel Richard Leff
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
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Bączyk M, Drzymała-Celichowska H, Mrówczyński W, Krutki P. Long-lasting modifications of motoneuron firing properties by trans-spinal direct current stimulation in rats. Eur J Neurosci 2019; 51:1743-1755. [PMID: 31677210 DOI: 10.1111/ejn.14612] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/07/2019] [Accepted: 10/23/2019] [Indexed: 12/14/2022]
Abstract
Trans-spinal direct current stimulation (tsDCS) is a novel neuromodulatory technique that has been used during neurological rehabilitation and sports to modulate muscle activation. However, the physiological mechanisms that underly the long-lasting functional effects of polarization are not yet fully understood, nor are their relationships with specific neuronal populations. The acute facilitatory and depressive effects of anodal and cathodal polarization on motoneurons have been recently demonstrated, and the aim of this study was to determine whether tsDCS-evoked modulations of motoneuron properties are able to persist over several hours. Intracellular recordings from multiple antidromically identified rat motoneurons were performed both before and after the application of tsDCS (0.1 mA for 15 min), at various time points up to 180 min after the offset of anodal or cathodal tsDCS. The examined effects of anodal polarization included decreased rheobase, voltage threshold, the minimum and maximum currents necessary for rhythmic firing, increased rhythmic firing frequencies and the slope of the f-I relationship. The majority of these facilitatory changes to threshold and firing properties were sustained for 30-60 min after polarization. In contrast, the significant effects of cathodal polarization were absent, except the short-lasting decreased ability for motoneurons to induce rhythmic activity. This study provides direct evidence that a single polarization session can alter the electrophysiological properties of motoneurons for at least one hour and provides a basis for the further use of tsDCS techniques under conditions where the sustained modification of motoneuron firing is desired.
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Affiliation(s)
- Marcin Bączyk
- Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland
| | - Hanna Drzymała-Celichowska
- Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland.,Department of Biochemistry, Poznań University of Physical Education, Poznań, Poland
| | | | - Piotr Krutki
- Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland
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Teunisse W, Youssef S, Schmidt M. Human enhancement through the lens of experimental and speculative neurotechnologies. HUMAN BEHAVIOR AND EMERGING TECHNOLOGIES 2019; 1:361-372. [PMID: 31894206 PMCID: PMC6919332 DOI: 10.1002/hbe2.179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 12/11/2022]
Abstract
Human enhancement deals with improving on and overcoming limitations of the human body and mind. Pharmaceutical compounds that alter consciousness and cognitive performance have been used and discussed for a long time. The prospect of neurotechnological applications such as brain-steered devices or using invasive and noninvasive electromagnetic stimulations of the human brain, however, has received less attention-especially outside of therapeutic practices-and remains relatively unexplored. Reflection and debates about neurotechnology for human enhancement are limited and remain predominantly with neurotech engineers, science-fiction enthusiasts and a small circle of academics in the field of neuroethics. It is well known, and described as the Collingridge dilemma, that at an early stage of development, changes can easily be enacted, but the need for changes can hardly be foreseen. Once the technology is entrenched, opportunities and risks start to materialize, and the need to adapt and change is clearly visible. However, carrying out these changes at such a late stage, in turn, becomes very difficult, tremendously expensive, and sometimes practically impossible. In this manuscript, we compile and categorize an overview of existing experimental and speculative applications of neurotechnologies, with the aim to find out, if these real or diegetic prototypes could be used to better understand the paths these applications are forging. In particular, we will investigate what kind of tools, motivations, and normative goals underpin experimental implementations by neurohackers, speculative designers and artists.
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