tDCS to Increase Aerobic Performance in Runners

Study Overview
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Brief Summary
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Many different factors affect running performance, transcranial direct current stimulation (tDCS) is a widely used and available neuromodulation tool and could hypothetically facilitate the supraspinal drive and thereby act upstream of the motor cortex to prolong the muscles work in time to exhaustion trials. While it appears to decrease the rating of perceived exertion (RPE) during cycling, little is known about the effects of tDCS on physiological performance parameters such as maximal oxygen consumption (VO2max), maximal aerobic speed (MAS) and lactate thresholds in runners. The aim of this prospective randomized sham-controlled clinical trial is to investigate the physiological effects of tDCS applied over the motor cortex on perceived exertion and performance-related parameters measured by an incremental treadmill test to exhaustion. This research thus aims at answering the following questions: Is active tDCS applied bilaterally over the motor cortex significantly more efficient than sham tDCS to improve the TTE? Does active tDCS decreases the RPE, as compared to sham? Is there any significant difference between active and sham tDCS on the physiological parameters measured during an incremental test to exhaustion, namely: VO2max, MAS, respiratory exchange ratio, blood lactate levels, maximal heart rate? Does the baseline level of physical fitness influences response to tDCS? The investigators hypothesize that 1) performance as measured by time to exertion will be increased following active and not sham tDCS due to a decreased perceived rate of exertion without significantly altering the other physiological parameters; and 2) performance as measured by incremental treadmill test to exhaustion will be more improved in recreational as compared to trained runners.

Official Title
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Transcranial Direct Current Stimulation (tDCS) to Improve Maximal Aerobic Performance in Recreational and Trained Runners

Conditions
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Athletic Performance

Intervention / Treatment
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* Device: Transcranial Direct Current Stimulation (tDCS)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy subject Regular running activity above 2 hours/week VO2max above 30 mL/min/kg Exclusion Criteria: Pacemaker Intracerebral metallic implant Smoking Using dietary supplementation or medication potentially affecting the CNS Musculoskeletal injury within the past 6 weeks

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Double-blind randomized sham controlled crossover
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Active tDCS first / Sham tDCS second<br>Receiving active tDCS during the first visit followed by sham tDCS on the next visit | Device: Transcranial Direct Current Stimulation (tDCS)<br>* The active session of tDCS will consist in applying two anodes over M1 bilaterally (C3 and C4 according to the 10-20 international EEG placement) and the cathodes over the occipital areas (O1 and O2), and to inject 2 mA for 20 minutes through sponge electrodes (35 cm²) placed on the scalp using the Startsim 8 (Neuroelectrics, Barcelona). The sham tDCS will use the same montage and device but direct current will only be injected for 30 seconds, with a ramp-up and ramp-down 15 seconds period, to mimic the somatosensory effects of active tDCS.<br>|
| Other: Sham tDCS first / Active tDCS second<br>Receiving sham tDCS during the first visit followed by active tDCS on the next visit | Device: Transcranial Direct Current Stimulation (tDCS)<br>* The active session of tDCS will consist in applying two anodes over M1 bilaterally (C3 and C4 according to the 10-20 international EEG placement) and the cathodes over the occipital areas (O1 and O2), and to inject 2 mA for 20 minutes through sponge electrodes (35 cm²) placed on the scalp using the Startsim 8 (Neuroelectrics, Barcelona). The sham tDCS will use the same montage and device but direct current will only be injected for 30 seconds, with a ramp-up and ramp-down 15 seconds period, to mimic the somatosensory effects of active tDCS.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to exertion (active vs. sham) | Time to achieve exhaustion during a treadmill test where the speed is set at a constant 90% of the individual maximal aerobic speed (determined during the screening visit) | Immediate | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ratings of perceived exertion (RPE) evolution (active vs. sham) | RPE will be assessed continuously (every 3 minutes) during the time to exhaustion trial using the Borg rating of perceived exertion scale (RPE scale). The Borg RPE scale is a quantitative measure of perceived exertion during physical activity. The scale starts with no feeling of exertion, which rates a 6, and ends with very, very hard, which rates a 20. Moderate activities register 11 to 14 on the Borg scale (fairly light to somewhat hard), while vigorous activities usually rate a 15 or higher (hard to very, very hard). | Every 3 minutes during the test to exhaustion until the end of the test (up to 1 hour after the stimulation) | 
| Maximal Oxygen Consumption (VO2max) evolution (active vs. sham) | VO2max will be assessed continuously during the time to exhaustion trial using a gas analyzer | Immediate | 
| Lactate thresholds (active vs. sham) | Levels of blood lactate will be measured continuously (every 3 minutes) during the time to exhaustion trial using capillary blood and a lactate analyzer | Every 3 minutes during the test to exhaustion until the end of the test (up to 1 hour after the stimulation) |