Silva-Batista, C, de Brito, LC, Corcos, DM, Roschel, H, de Mello, MT, Piemonte, MEP, Tricoli, V, and Ugrinowitsch, C. Resistance training improves sleep quality in subjects with moderate Parkinson's disease. J Strength Cond Res 31(8): 2270–2277, 2017—The objectives of this study were to test if 12 weeks of progressive resistance training (RT) improves sleep quality and muscle strength in subjects with moderate Parkinson's disease (PD) and if sleep quality values of subjects with moderate PD are closer to those of age-matched healthy controls (HC) at posttraining. This was a randomized controlled trial conducted between March 2013 and September 2014. Twenty-two subjects with moderate PD were randomly assigned to a nonexercising control group (n = 11) or an RT group (n = 11). Thirty-one HC were not randomized to any group. The RT group performed a RT program twice a week for 12 weeks, whereas the control group made no change to their weekly routine. For subjects with PD, sleep quality (i.e., Pittsburgh Sleep Quality Index [PSQI]) and knee-extensor peak torque were assessed before and after 12 weeks of intervention; for HC, these outcomes were assessed at pretest only. There were differences between RT and control groups in PSQI scores, PSQI subscores(i.e., subjective sleep quality and daytime dysfunction), and knee-extensor peak torque at posttraining (p ≤ 0.05). After RT, the average subjects with PD showed lower (i.e., improved) PSQI scores than the average HC (p ≤ 0.05). A negative association was observed between changes in PSQI scores and changes in knee-extensor peak torque at posttraining (r = −0.58, p = 0.028). No adverse events were reported. The RT is recommended as an adjunct therapeutic method for improving sleep quality of subjects with moderate PD and moving these levels to those observed in HC.