Dorsolateral Prefrontal Cortex Transcranial Direct Current and Muscle Fatigue Stimulation on Muscle Fatigue

Overview

The goal of this clinical trial is to learn if transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC) can impact muscle fatigue. The main questions it aims to answer are: 1. Does tDCS of the left DLPFC increase the time that a fatiguing contraction can be maintained? 2. Does tDCS of the left DLPFC decrease the rate of increase of muscle activity, force error, and standard deviation of force during a fatiguing contraction. Researchers will compare tDCS of the left DLPFC to a SHAM stimulation (a type of stimulation that feels like real tDCS but does not elicit physiological effects) to see if tDCS of the left DLPFC works to reduce the progression of muscle fatigue. Participants will: Performing two experimental sessions held 3-10 days apart (usually 7 days) Perform a 9 hole pegboard test, maximum voluntary contractions, and a fatiguing contraction.

Transcranial direct current stimulation (tDCS) delivered to the dorsolateral prefrontal cortex (DLPFC) can increase endurance time in lower body tasks. Therefore, the purpose of this study is to examine the effect of DLPFC-tDCS on the time to task failure (TTF) of a fatiguing contraction performed by hand muscles. The study will use a double-blind, randomized, SHAM-controlled, crossover design with each participant performing two experimental sessions held 3-7 days apart. The only difference between the two sessions will be the type of stimulation (tDCS or SHAM; counterbalanced) applied concurrent with the fatiguing contraction. The fatiguing contraction will involve gripping a manipulandum with the index finger and thumb. This will be accomplished by using a precision grip and matching an isometric target equal to 15% of the maximum voluntary contraction (MVC) for as long as possible until task failure.