Effects of transcranial direct current stimulation (tDCS) for delayed-onset muscle soreness after resistance training. Protocol for a randomized clinical trial.
Exercise, Motor Cortex, Muscle Strength, Myalgia, Pain, Transcranial Direct Current Stimulation.
BACKGROUD: Delayed onset muscle soreness (DOMS) is a discomfort described as fatigue, pain and allodynia in the skeletal muscles after exercise. To minimize DOMS it is suggested non-drug therapies such as massage and cryotherapy. A new approach, Transcranial Direct Current Stimulation (tDCS) applied over the primary motor cortex (M1) is the focus of this study. This technique modulates the functional connectivity of sensory networks by modifying the perception of pain. OBJECTIVE: To develop a protocol of a randomized controlled trial to evaluate the effects of tDCS on DOMS in 24, 48 and 72 hours after a protocol of muscle damage induced by resistance exercise. METHODS: The study describes a randomized, controlled, double-blind, two-arm clinical trial protocol following the recommendations of CONSORT/2010. The study will have 6 stages: initial assessment, application of five consecutive sessions of tDCS (second to sixth), a protocol for induction of DOMS and evaluation of pain and functionality after application of the protocol; with 24, 48 and 72 hours. Muscle pain, assessed by Visual Analogue Scale (VAS), will be the primary outcome of the study. The secondary outcomes evaluated will be the elbow joint amplitude for flexion and extension, muscle performance and muscle power, evaluated by the dynamometry. The effects of stimulation shall be calculated using a model of analysis of variance (ANOVA). EXPECTED RESULTS: It is suggested that tDCS could decrease DOMS and improve functionality in active group. This protocol could be applied in further studies with a clinical population, aiming to reduce the negative effects arising from strength exercise, such as fatigue and pain.