Analysis of the effects of photobiomodulation on muscle fatigue of the brachial biceps muscle of healthy individuals

• Grant number: 19/05556-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2019
• End date: January 07, 2021
• Field of knowledge: Engineering - Biomedical Engineering
• Principal Investigator: Mário Oliveira Lima
• Grantee: Alexandre Alves do Nascimento Filho
• Host Institution: Instituto de Pesquisa e Desenvolvimento (IP&D). Universidade do Vale do Paraíba (UNIVAP). São José dos Campos , SP, Brazil

Abstract

Muscle fatigue is caused by biochemical changes that modify the mechanics of muscle contraction, resulting in negative changes in the performance of the contraction. Several resources are studied in order to mitigate this situation, among them can be mentioned the Photobiomodulation (PBMT). The objective was to evaluate the effects of PBMT on fatigue of the biceps brachii muscle in healthy individuals. A comparative, randomized, placebo, double-blind clinical trial with healthy individuals was performed. The study was composed of three groups (Control Group, Placebo Group and PBMT Group) and all individuals passed through all groups, following the randomization criteria. The protocol consisted of applying PBMT to the biceps brachii muscle on the dominant side in the volunteers, previously performing the Maximum Voluntary Isometric Contraction (MVIC) for 50 seconds on the dynamometer. Pain intensity was assessed using the Visual Analog Scale (VAS) of pain, myoelectric activity using surface electromyography associated with the assessment of muscle torque using the dynamometer. The local temperature was evaluated by means of infrared thermography before the application of PBMT (baseline) and one, three, six, nine, twelve and fifteen minutes after MVIC. It was found that the PBMT did not alter the painful intensity, increased the RMS values and the time of onset of muscle fatigue.