Procedures

The notational analysis of 918 played matches was carried with the use of the Impire AG match analysis system (Germany) (Tiedemann et al., 2011) with a recording frequency of 25 Hz. Each player’s movement was recorded by two cameras (Link and Weber, 2017). The system utilizes state-of-the-art algorithms and 2-D and 3-D video-recording technology, allowing for detailed motion analysis of entire soccer matches. The major advantages of vision-based systems are their high update rate corresponding to the camera-frame rate and the fact that the players and the ball are tracked simultaneously. The validity and reliability of this system have been described in detail elsewhere (Liu et al., 2013).

Performance-related activities were divided into two groups: (1) physical variables: total distance [km] covered during the match; distance [km] covered at speeds below or above 14.4 km⋅h^–1 (below or above the anaerobic threshold); distance [km] and the percentage of distance covered at intensity ranges <11 km⋅h^–1, 11–14 km⋅h^–1, 14–17 km⋅h^–1, 17–21 km⋅h^–1, 21–24 km⋅h^–1, and >24 km⋅h^–1; numbers of performed sprints during a match (runs with a speed >22.68 km⋅h^–1 and at least 1 s in duration); numbers of efforts at high intensity (above 18 km⋅h^–1); mean running speed [km⋅h^–1]; and peak running speed [km⋅h^–1] (Andrzejewski et al., 2018; Chmura et al., 2018) and (2) technical variables: numbers of shots, i.e., attempts to score a goal made with any (legal) part of the body, either on or off target; numbers of ball touches; numbers of passes, i.e., intentionally played balls from one player to another; pass accuracy [%], i.e., successful passes as a proportion of total passes; numbers of crosses, i.e., any balls sent into the opposition team’s area from a wide position; numbers of one-on-one plays (game actions in which two players from different teams compete for the ball, and the action is always assigned to both participant players); and number and percentage of one-on-one plays won (Konefał et al., 2019a). Additionally, the study also considered the contextual variable of match location, i.e., whether a team was playing at its own ground (1 = Home) or at its opponent’s (0 = Away) (Gonzalez Rodenas et al., 2019). Complete definitions of physical and technical variables are available at the DFL | Definitionskatalog Offizielle Spieldaten – Bundesliga website¹.

For each variable of physical or technical activity performed by a player in a given match, an extra variable was set measuring the change in the coefficient in three consecutive seasons. These additional variables were defined as an interaction term between the original variable and the season’s sequential number, i.e., 0 for the 2014/2015 season, 1 for the 2015/2016 season, and 2 for the 2016/2017 season (Tibshirani, 2011).