Impact of One Additional Substitution on Player Load and Coaching Tactics in Elite Football

Professional football players, coaches, and researchers have discussed additional substitutions in football to reduce player load for a while. However, the effects of additional substitutions on the game have not yet been investigated in detail. The aim of this paper is to determine whether an additional substitution in (1) extra time and (2) regular time would be beneficial and would lead to (a) greater tactical influence of coaches on the match, (b) load reduction during one match, and (c) load reduction during one season. The methodological approach adopted includes two studies, both of which involve data analysis of substitution times (Study 1: n = 3060; Study 2: n = 1153) as well as a survey of football coaches (Study 1: n = 37; Study 2: n = 25). For assessing the effect of an additional substitution in regular time and in extra time, the substitutions made in the Bundesliga, U19-Bundesliga West, DFB-Cup, and 2018 World Cup were evaluated. The findings of this research clearly indicate the potential of an additional substitution by enabling almost 50% of additional load reduction in regular time and 27% in extra time. However, in practice, the findings showed the limits of an additional substitution in extra time on long-term load reduction.