## 1 Introduction  
The Chilean population has experienced increased longevity in recent decades, leading to an increased incidence of and mortality from neurodegenerative diseases such as Parkinson's disease (PD). PD is a chronic degenerative condition that affects the central nervous system. The main objective of this research is to evaluate the effect of 12-week programs of tonic, isometric, and isometric/vibratory muscular strength training while controlling the manipulation of the intensity variable on motor and non-motor symptomatology in PD patients. The secondary objective is to assess the levels of muscular strength in PD patients and their relationship with motor and non-motor symptomatology. Methods: A parallel-group, randomized trial will randomly assign (\(n=34\)) people of both sexes with Parkinson's disease between stages I-III Hoehn and Yahr (H&Y), aged between 50 and 70 years to one of the experimental groups, in which they will undergo a total of 24 strength training sessions during 12 weeks. During the intervention period, the participants will be advised not to undertake additional exercise programs, to avoid substances that may disrupt metabolism and circadian cycles, and to maintain their medication regimen. The primary or motor evaluation of rest tremor will be performed with an accelerometer (Actigraphy), balance with the Mini-BESTest balance test, gait speed with the Ten Meters Walk Test, and non-motor symptomatology through anxiety, depression (MDS-UPDRS), and quality of life (PDQ-39) questionnaires. The Secondary evaluation of muscle strength will be performed with a functional electromechanical dynamometer. Discussion: Established as a hypothesis is that manipulating intensity variables in 12-week tonic, isometric, and isometric/vibratory muscle strength training programs has an effect on motor and non-motor symptomatology in people with [PERSON]'s disease. The research will establish the extent to which controlled muscular strength training has an effect on relevant factors related to motor and non-motor symptomatology. neurodegenerative disease; Parkinson Disease muscular strength; rehabilitation  
## 1 Introduction  
In recent decades, the Chilean population has experienced an increase in longevity, which has translated into a higher prevalence of neurodegenerative diseases such as Parkinson's disease [1]. Reports indicate that, between 1990 and 2016, deaths attributed to Parkinson's disease (PD) increased by 16.5%, reaching a prevalence rate of 19.9%, making Chile the Latin American country with the highest increase in PD prevalence [2]. PD is a chronic degenerative [3], multisystem pathology that affects the central nervous system and is caused by the loss of dopaminergic neurons in the substantia nigra compacta of the basal ganglia in the midbrain [4], leading to a decrease in dopamine levels, neurovegetative disturbances [5], and motor control impairments [6]. Common symptoms experienced by individuals with PD include resting tremor [7], bradykinesia, joint stiffness, postural instability [8], gait disturbances [9], and reduced functional performance [10]. Non-motor symptoms associated with PD include sleep dysfunction, psychiatric disorders, gastrointestinal disturbances, and autonomic dysfunction [11], which have been defined as non-motor disorders associated with the disease [12]. There is sufficient evidence of the positive effects of physical activity and training programs in people with Parkinson's disease (PD), with reported improvements in overall health and a decrease in motor and non-motor symptomatology associated with the disease [13]. Muscular strength training is one of the strategies used to increase physical activity levels in PD patients [14; 15; 16; 17; 18].