The Enhancement of Exercise Training Effects on Respiratory Muscle Function Through Repeated anodal transcranial direct current stimulation Sessions

Background: Transcranial Direct Current Stimulation (a-tDCS) is a non-invasive brain stimulation technique known to modulate cortical excitability, potentially enhancing motor learning and performance. This study aims to investigate whether repeated sessions of a-tDCS can augment the effects of exercise training on respiratory muscle function. Objective: To evaluate the efficacy of repeated a-tDCS sessions in enhancing the outcomes of exercise training on respiratory muscle performance in healthy individuals. Methodology: Participants: Sample Size: 60 healthy adult volunteers. Inclusion Criteria: Age 18-50, non-smokers, no history of respiratory or neurological disorders. Exclusion Criteria: Contraindications to a-tDCS or exercise, current participation in regular respiratory muscle training. Study Design: Randomized Controlled Trial (RCT) Groups: Participants will be randomly assigned to one of three groups: (1) Exercise + a-tDCS, (2) Exercise + Sham a-tDCS, (3) Control (no intervention). Interventions: A-tDCS: 20 minutes of a-tDCS (anodal stimulation over the motor cortex corresponding to the diaphragm), at an intensity of 2 mA, for 10 sessions over two weeks. Exercise Training: Respiratory muscle training exercises, focusing on both inspiratory and expiratory muscles, 30 minutes per session, 5 days a week for two weeks. Sham a-tDCS: Identical setup to the a-tDCS group but with the stimulator turned off after 30 seconds. Outcome Measures: Primary: Improvement in respiratory muscle strength, measured by Maximum Inspiratory Pressure (MIP) and Maximum Expiratory Pressure (MEP). Secondary: Changes in respiratory endurance, measured by the time limit of a breathing task at 75% of MIP. Data Collection: Baseline assessment of respiratory muscle strength and endurance. Post-intervention assessment within 48 hours of the last session. Follow-up assessment 4 weeks post-intervention. Statistical Analysis: Descriptive statistics to summarize demographic and baseline characteristics. ANOVA for between-group comparisons of primary and secondary outcomes. Post-hoc analyses with Bonferroni correction for multiple comparisons. Ethical Considerations: Approval from Monash Human Ethics Committee. Informed consent obtained from all participants. Assurance of confidentiality and the right to withdraw at any time without penalty. Timeline: 12 months. Dissemination: Results will be disseminated through publication in a peer-reviewed journal and presentations at relevant conferences.