Analysis of high-intensity efforts in Brazilian professional soccer players

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.