Male and female individuals aged 18 to 23 years will be evaluated. The Research Diagnostic Criteria for Temporomandibular Disorders will be applied for the determination of the presence or absence of temporomandibular disorder. Each group (with and without temporomandibular disorder) will then be randomly allocated into a control group and experimental group submitted to pre-fatigue low-level laser therapy. Before and after the induction of fatigue, all volunteers will be evaluated with regard to the range of mandibular movement, bite force, sensitivity to palpation of the muscles evaluated and muscle fatigue. Low-level laser therapy will be administered to the masseter and anterior temporal muscles prior to the induction of fatigue, which will be induced with the use of chewing gum. The data will be submitted to descriptive statistical analysis. The chi-square test and Fisher's exact test will be used to establish the associations of the categorical variables. Pearson correlation coefficients will be calculated for the analysis of the correlation of the continuous variables.