Transcranial Stimulation Improves Volume and Perceived Exertion but does not Change Power

Area of Science:

• Neuroscience
• Sports Science
• Exercise Physiology

Background:

• Non-invasive brain stimulation techniques like anodal transcranial direct current stimulation (a-tDCS) are increasingly explored for modulating motor cortex excitability.
• Understanding the effects of a-tDCS on neuromuscular performance and exercise experience is crucial for optimizing training protocols.

Purpose of the Study:

• To investigate the acute effects of a-tDCS applied over the primary motor cortex (M1) on exercise volume, perceived exertion, and neuromuscular performance.
• To compare these effects in trained versus untrained adult males.

Main Methods:

• A single-blind, randomized, sham-controlled study involving 24 male adults (12 trained, 12 untrained).
• Participants underwent a-tDCS or sham stimulation over M1 before performing resistance exercise (back squats to failure).
• Neuromuscular performance (peak power, velocity, force) and total repetitions were assessed.

Main Results:

• a-tDCS significantly increased total repetitions performed and decreased perceived exertion in both trained and untrained groups compared to sham.
• While neuromuscular performance metrics (peak power, velocity, force) decreased post-exercise in both groups, the rate of decline was higher in untrained individuals.
• No significant direct effect of a-tDCS was observed on peak power, peak velocity, or peak force.

Conclusions:

• a-tDCS applied to M1 appears to be an effective strategy for increasing training volume and reducing the subjective feeling of effort during resistance exercise.
• The findings suggest potential benefits of a-tDCS for enhancing exercise capacity in diverse populations, though its direct impact on maximal force production requires further investigation.