Fitness and conditioning is a critical piece of soccer as the entire game is that of continuous running mixed with a lot of short bursts of high tempo, high-intense sprints. For this reason, it is essential to focus on both anaerobic (short duration, high intensity) and aerobic (running long distances) fitness to get your players to match fitness levels.
Fitness and conditioning can be extra exercises before or after training sessions. However, incorporating high-intensity drills will allow coaches to improve your player's fitness levels while teaching the game. As a coach, remove lines from the training sessions, demand high intensity from the players, and take your drills and the player's fitness to the next level.