Effect of manipulating thevariables that shape thestrength training stimulus onmotor symptoms in peoplewith Parkinson’s disease: asystematic review

Introduction: Parkinson’s disease (PD) is a multisystem neurodegenerative disease that affects the central nervous system. People with Parkinson’s disease (PPD) have both motor and non-motor symptoms. Physical exercise is one of the most promising non-pharmacological interventions to complement medical treatment in PEP. Objective: A systematic review of the literature was to analyze the effect of muscular strength training (ST) on motor symptoms and describe how the variables that shape EF were manipulated in studies conducted with PEP. Methods: A systematic review of the literature was conducted according to the guidelines of the Cochrane Handbook for Systematic Reviews. Studies were identified by searching four electronic databases: Web of Science, Scopus, PubMed, and EBSCOhost. The methodological quality of the selected articles was evaluated using the PEDro scale checklist. The included studies obtained a score ≥ 6. Results: The preliminary search yielded 2830 studies. Twenty articles were considered after reviewing the abstract and full text. Seven studies were rejected for not recording some of the required strength training variables and three were rejected for using supplementary training to strength training. A total of ten studies met the inclusion criteria. ST programs were implemented 2 - 3 times per week with intensities between 30 % - 90 % 1RM, a training volume of 1 - 3 sets and 4 - 20 repetitions, sessions between 35 - 90 minutes with significant improvements in resting tremor, gait measures, bradykinesia and balance. Conclusions:Regardless of how the ST stimulus was configured, there are significant improvements in motor symptoms in PEP. These results promote the implementation of strength training in PEP, but due to the low number of studies (10) and the high variability in the manipulation of the variables that configure the strength training stimulus, they prevent us from knowing which the optimal prescription is to improve the motor symptoms of PEP.