Monitoring and performance assessment in youth and professional soccer playersexploring relationships

Resum

The doctoral thesis will have the following objectives: Study 1: (i) to analyze variations in physical fitness and training load in youth soccer; (ii) to test the relationships between training load and variations in physical fitness in youth soccer; Study 2: (i) to test the relationships between training load and variations in well-being in youth soccer; Study 3: (i) to examine whether variations in physical fitness will be explained by training load, maturation state, and the 2D:4D ratio in youth players; Study 4: (i) to analyze the differences between training: match ratio positions of external load measures in professional soccer; and (vi) to test the relationships between weekly training load and physical demands in professional soccer. Two different samples will be used, one in young and one in adult soccer players. In the juvenile sample, twenty-seven male soccer players (age: 15.0 ± 0.4 years; height: 175 ± 0.6 cm; body mass: 62.1 ± 7.0 kg) from the same sub-15 team will participate in this study. A non-probabilistic convenience sample will be used. The inclusion criteria will be: (i) all players have to participate in at least 90% of the training sessions during the observation period; (ii) for each week, the players have to participate in all training sessions; and (iii) they cannot present injury or illness during observations and evaluations. Goalkeepers will be excluded from the sample. In the professional sample, nineteen adult professional soccer players (age: 27.5 ± 4.6 years; height: 182 ± 6.0 cm; body mass: 73.5 ± 6.3 kg) will participate in this study. The inclusion criteria will be: (i) participation in all training sessions and the match of the same week; (ii) not presenting injury or illness in the weeks prior to the match. Players with more than two weeks of absence will be excluded from the sample. A prospective cohort study design will be used in the juvenile sample. All juvenile players will be monitored daily for 38 weeks. Training load will be quantified through the rate of perceived exertion (RPE). Training load indices will also be calculated: training monotony (TM), weekly training load (wTL), average training load (mTL), and the average of 5 days of training without considering the match (5d-AVG). A four-item questionnaire will be applied daily to quantify the well-being of each player. Fatigue, stress, muscle soreness (DOMS), sleep quality, and the Hooper index will be analyzed. The prediction of maturation state and the 2D:4D ratio of both hands will be recorded at the beginning of the season. At the beginning and end of the season, all players will be assessed for physical fitness. The participants will complete a change of direction test (COD), the Wingate and the 30-15 intermittent fitness test (30-15 IFT), before and after the season. For the sample of adult players, an observational analytical cohort will be used. All adult players will be monitored for 43 weeks, using a 15 Hz GPS system integrating a 100 Hz triaxial accelerometer. Total distance (TD), mean metabolic power (MP), new body load (NBL), accelerations (ACC), and decelerations (DEC) will be recorded during all training sessions and matches.