To successfully close this research project and in agreement with the stablished objectives and hypothesis, a compendium of three future published articles as part of the thesis. The first article will be a review about the relationships between exercise, sleep quality, physical fitness and dynamic balance. This review article will answer the first hypothesis and objective. The second article, will be an observational research article. The data from the baseline evaluation will allow to run artificial intelligence algorithms, intending to predict the dynamic balance variance based on physical fitness and quality of sleep. This article aims to identify the variables that mostly explain the dynamic balance based on body composition and antropometrics, sleep quality and physical fitness. This article will answer to the second hypothesis and objective. The third article will be a randomized controlled trial article. This part of the research will seek to understand the effects of (8 months) multicomponent exercise training program in antropometric and body composition, sleep quality, physical fitness effects and dynamic balance.

Study design: The present project will adopt a longitudinal approach wherein volunteers will be briefed about the study objectives and protocol and were required to provide informed consent, adhering to the Helsinki Declaration guidelines. Participants were instructed to maintain normal daily life activities to prevent physical inactivity. Inclusion criteria will involve individuals over 65 years old, independent in daily activities, and without chronic diseases requiring pharmacological treatment affecting the experimental protocol, while exclusion criteria included failure to attend more than 25% of training sessions, failure to attend more than four consecutive sessions, or missing evaluation sessions. Participants will be randomly assigned to either the experimental group (EG ≈ 30) or control group (CG ≈ 30). The multicomponent training (MCT) program comprised aerobic, resistance, flexibility, and balance exercises. Sessions lasted 50 to 60 minutes, including warm-up, aerobic exercise, resistance training, balance training, and cool-down. Training intensity gradually increased over time. The experimental group will have three 60-minute sessions weekly for 32 weeks, while the control group will not participate in any exercise program, but they will maintain the daily physical activity. Both groups will be evaluated at two time points: initial assessment (M1) at the start of training and final assessment (M2) after 32 weeks. The Physical fitness will be assessed using the Rikli and Jones Senior Fitness Test. The Sleep quality evaluated by the Pittsburgh Sleep Quality Index (PSQI). Dynamic balance will be assessed using the Timed Up and Go Test (TUG). Additionally, body composition before and after the training program will be evaluated by bioimpedance.

Physical Fitness: The Rikli and Jones Senior Fitness Test will be used to assess the physical fitness. The following tests will be used: limb strength and endurance of lower (30-s chair stand and seat, by the number of repetitions) and upper limbs (arm curl with 2 kg dumbbell); lower flexibility (chair sit-and-reach, in centimeters) and superior flexibility (back scratch, in centimeters); physical mobility, speed, agility and dynamic balance (stand up the chair and run 8-ft up-and-go returning and seat on the chair, measured in seconds); and aerobic endurance (2 min step test, rising and counting the repetitions, when the knee reaches the hip level).

Sleep Quality: The Pittsburgh Sleep Quality Index (PSQI) will be used to assess the sleep quality. This instrument consists in a set of 19 self-reported questions is divided into seven subcategories, covering various aspects of sleep experience such as perceived sleep quality, time taken to fall asleep, duration of sleep, efficiency of sleep, disturbances during sleep, use of sleep aids, and daytime functionality.

Additionally, five extra questions, assessed by the respondent's roommate or bed partner, are included for clinical assessment but do not contribute to the scoring process. The instrument's psychometric properties using a sample of individuals ranging in age from 24 to 83 years. There are some literature that examined the psychometric characteristics of the scale, the developers' initial assessment revealed an internal reliability of α = .83, a test-retest reliability of .85 for the overall scale, with a sensitivity of 89.6% and a specificity of 86.5%.

Dynamic Balance: The Timed Up and Go Test (TUG) will be used to assess the dynamic balance. The individuals will start in a seated position in a chair with armrests. Upon receiving a verbal cue, they stand up, walk approximately 3 meters (10 feet) at their usual pace, turn around, walk back to the chair, and sit down again. This test evaluates dynamic balance by measuring the time taken (in seconds) to complete the task, reflecting the individual's ability to transition between sitting and standing, walk safely, turn, and return to a seated position, which is indicative of their dynamic balance and mobility. Interpretation of the results is based on the completion time, where shorter times suggest better dynamic balance and mobility, while longer times may indicate limitations in balance and mobility. Typically, measured in seconds, cutoff values for the TUG test may vary depending on factors such as age and health status, but shorter completion times generally signify better dynamic balance and mobility, with completion times of approximately 10 seconds or less considered indicative of good functional mobility and balance in older adults.