Introduction: Parkinson's disease (PD) is the second most common neurodegenerative disease in the elderly. Chronic and progressive, it includes loss of dopamine, a neurotransmitter involved in the regulation of movement. Thus, functional changes, such as postural disorders, trunk flexor pattern, muscle activation deficits, impairment of gait, balance, and mobility are common findings in this population. Once there is dopaminergic depletion, it is important to identify mechanisms that act in the production and survival of nigral dopaminergic neurons, like the brain-derived neurotrophic factor (BDNF). Studies describe a correlation between serum BDNF levels and PD motor dysfunction. Still, it is presumed that physical therapy can positively regulate substances that act directly on the Central Nervous System, such as BDNF. Physical exercise, in addition to promoting biochemical modulations in PD, can provide benefits in motor symptoms that sometimes do not improve with drugs. Conventional physiotherapy performed on dry land is a therapeutic resource used in PD. The conventional physiotherapy is useful for management of functional changes caused by PD due to muscle strengthening exercises. These exercises can be adapted and performed in water, at different depths, shallow and deep water. Thus, aquatic physiotherapy has been shown to be able to interfere in PD motor disorders, with perspective of maximizing the rehabilitation program effects due to the physical properties of water. These reasons, in addition to the large use of these interventions in the clinical practice and their likely benefits in the PD alterations, suggest the importance of studies in this area. Furthermore, the immediate effects of strengthening interventions with global extensor musculature emphasis on global extensor musculature, and of high-intensity training protocols, which encompass different environments and different depths, on functional and biochemical measures of PD are poorly studied.

Objectives: To verify the acute effects of a global extensor musculature strength training protocol, performed on dry land and shallow water, and of a high-intensity training protocol performed in shallow and deep water on functional and biochemical measurements of individuals with PD.

Methods: This will be a single-blind crossover, cross-sectional study with a 24-hour follow-up. The sample will be composed of subjects between 50 and 70 years old, classified from 1 to 3 in the Hoehn and Yahr scale, with a PD diagnosis rigid-akinetic and/or tremor-dominant type in the "OFF" period of the medication. In this research there will be an intervention group (IG) composed of individuals with Parkinson's disease and a control group (CG) of healthy individuals. Both will be randomly distributed in a randomized way and submitted to two different training sessions, for 60 minutes, at different times, in order to analyze the acute effects and follow-up of the following interventions: a strength training of the global extensor musculature in dry land and shallow water (120 cm deep) and high-intensity training (Borg Scale), at different depths: shallow water (120 cm deep) and deep water. To characterize the sample, anamnesis and Motor Examination of Movement Disorder Society Unified Parkinson Disease Rating Scale (MDS-UPDRS III) will be performed. The individuals will be submitted to pre, post and 24h evaluations after the intervention. Functional measures will be analyzed: postural stability, by stabilometry; strength, by isokinetic dynamometry; spatiotemporal gait variables, with kinematic analysis; balance, with Berg Balance Scale and functional mobility with Timed Up and Go test and biochemical analysis: venous blood collection and ELISA test will be performed measuring serum BDNF levels. In this way, the acute effects of the global extensor musculature strength training protocol and of high-intensity training on the different variables analyzed, environments, depths and moments of evaluation will be analyzed and compared.

Inclusion Criteria:

GI (Individuals with Parkinson Disease):

• Individuals diagnosed with Parkinson's disease for at least 6 months;
• Age between 50 to 70 years;
• Classified on the Hoehn and Yahr scale from 1 to 3;
• Rigid-akinetic and/or tremor-dominant type;
• Individuals who have preserved their cognitive skills, assessed by means of the Mini Mental State Examination (MMSE) and who have a cut-off score of 23/24 (FOLSTEIN et al., 1975).

GC (Healthy individuals):

• Age between 50 to 70 years;
• Individuals who have preserved their cognitive skills (with the same cut-off score as the GI in the MMSE);
• Walk independently.

Exclusion Criteria:

GI (Individuals with Parkinson Disease):

• Individuals who have other associated musculoskeletal and neurological disorders;
• Individuals with dementia installed;
• Individuals with pathologies and injuries associated with the skin that make it impossible to enter the aquatic environment;
• Individuals with hydrophobia.

GC (Healthy individuals):

• Individuals who have musculoskeletal and neurological pathologies;
• Individuals with dementia installed;
• Individuals with pathologies and injuries associated with the skin that make it impossible to enter the aquatic environment;
• Individuals with hydrophobia.