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Felipe Arruda Moura, Juliana Exel Santana, Nathália Arnosti Vieira, Paulo Roberto Pereira Santiago and Sergio Augusto Cunha

Abstract

The purpose of this study was to analyse players’ positional variability during the 2012 UEFA European Championship by applying principal component analysis (PCA) to data gathered from heat maps posted on the UEFA website. We analysed the teams that reached the finals and semi-finals of the competition. The players’ 2D coordinates from each match were obtained by applying an image-processing algorithm to the heat maps. With all the players’ 2D coordinates for each match, we applied PCA to identify the directions of greatest variability. Then, two orthogonal segments were centred on each player’s mean position for all matches. The segments’ directions were driven by the eigenvectors of the PCA, and the length of each segment was defined as one standard deviation around the mean. Finally, an ellipse was circumscribed around both segments. To represent player variability, segment lengths and elliptical areas were analysed. The results demonstrate that Portugal exhibited the lowest variability, followed by Germany, Spain and Italy. Additionally, a graphical representation of every player’s ellipse provided insight into the teams’ organisational features throughout the competition. The presented study provides important information regarding soccer teams’ tactical strategy in high-level championships that allows coaches to better control team organisation on the pitch.

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Lucas Adriano Pereira, Victor Freitas, Felipe Arruda Moura, Marcelo Saldanha Aoki, Irineu Loturco and Fábio Yuzo Nakamura

Abstract

The aim of this study was to compare the kinematic characteristics of tennis matches between red clay and hard courts in young tennis players. Eight young tennis players performed two tennis matches on different court surfaces. The match activities were monitored using GPS units. The distance covered in different velocity ranges and the number of accelerations were analyzed. The paired t test and inference based on magnitudes were used to compare the match physical performance between groups. The total distance (24% of difference), high-intensity running distance (15 - 18 km/h) (30% of difference), the number of high-intensity activities (44% of difference), the body load (1% of difference), and accelerations >1.5 g (1.5-2 g and >2 g 7.8 and 8.1 % of difference, respectively) were significantly greater in clay court than hard court matches (p < 0.05). Matches played on the red clay court required players to cover more total and high-intensity running distances and engage in more high-intensity activities than the matches played on the hard court. Finally, on the clay court the body load and the number of accelerations performed (>1.5 g) were possibly higher than on the hard court.

Open access

Felipe Arruda Moura, Ana Lorena Marche, Fabio Giuliano Caetano, Ricardo Da Silva Torres, Luiz Eduardo Barreto Martins and Sergio Augusto Cunha

Abstract

Purpose. The study aim was to characterize high-intensity efforts (HIEs) of soccer players. Methods. The HIE features were quantified according to playing positions, with the consideration of the moment of initial velocity increase, which precedes the velocity threshold. The total of 107 players of Brazilian first division championship were analysed with the automatic tracking method. HIE phase 1 began at the minimum local value and finished when the velocity reached 6.4 m/s. Phase 2 began immediately when the velocity exceeded 6.4 m/s and finished with the velocity lower than 6.4 m/s. Results. External defenders and forwards performed a greater (p < 0.01; d: 1.01-1.17) number of HIEs (40.0 ± 13.5 and 34.9 ± 6.6, respectively) than central defenders (26.6 ± 9.2). With respect to the distance covered and duration of phase 2, external defenders covered a greater (p < 0.01; d: 0.45-0.47) distance (13.5 ± 4.5 m) and spent more (p < 0.01; d: 0.24-0.26) time (1.8 ± 1.3 s) than central defenders (11.5 ± 4.3 m; 1.5 ± 1.2 s), forwards (11.4 ± 4.4 m; 1.5 ± 0.9 s), central midfielders (11.5 ± 4.4 m; 1.5 ± 1.2 s), and external midfielders (11.4 ± 4.6 m; 1.5 ± 1.1 s). Players performed a greater (p = 0.03; d: 2.29-5.17) number of HIEs with more than 120 s of recovery time compared with other time categories. Conclusions. The better characterization of HIE physical demands during soccer matches provides insights for coaches to plan a more specific physical training for professional players.